Good luck with harvest!

This is Week 17 and the last Weekly Update for 2020! It’s been an exceptional field season – responding to COVID-19 and a new website for the Prairie Pest Monitoring Network! Watch for special releases during the fall and winter. Your best option is to please subscribe to the new website to stay informed.

We thank the many people who have been monitoring, collecting, compiling and generating data throughout this growing season – your exceptional efforts are appreciated and critical! We also sincerely thank the many researchers, talented technical support staff, and the many students who have contributed to agricultural field crop protection, arthropod biodiversity, and insect pest management this season!

Questions or problems accessing the contents of the Weekly Update? Please email Meghan.Vankosky@canada.ca or Jennifer.Otani@canada.ca .

Weather synopsis

An abbreviated synopsis is provided for the final Weekly Update of the 2020 growing season. It was a warm week for most of the prairies! The highest temperatures the past seven days across the prairies are represented in Figure 1 and ranged from <22 to >35 °C.

Figure 1. Highest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-August 19, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (20Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

All those high temperatures advanced the accumulation of heat units across the prairies. The growing degree day map (GDD) (Base 5 ºC, April 1-August 17, 2020) is below (Fig. 2) while the growing degree day map (GDD) (Base 10 ºC, April 1-August 17, 2020) is shown in Figure 3.

Figure 2. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-August 17, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (20Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 3. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-August 17, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (20Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

So far this growing season, the number of days above 25 °C ranges from 0-10 days in the northwest of the prairies then increases up to 61-70 days in southern Manitoba (Fig. 4). In comparison, the number of days above 30 °C ranges up to 25-27 days in southern Saskatchewan and southern Manitoba (Fig. 5)

Figure 4. Number of days above 25 °C observed across the Canadian prairies this growing season (April 1-August 19, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (20Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 5. Number of days above 30 °C observed across the Canadian prairies this growing season (April 1-August 19, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (20Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

As fields continue to mature in late August and in to September, growers will be watching for cool evenings. The lowest temperatures the past seven days across the prairies are represented in Figure 6 and ranged from <1 to >13 °C.

Figure 6. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-August 19, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (20Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Cumulative rainfall for the past 7 days was lowest across central and southern regions of Alberta and Saskatchewan while western and northern areas of the Peace River region AND eastern Saskatchewan plus much of Manitoba received more moisture (Fig. 7). Cumulative 30-day (Fig. 8) and rainfall for the growing season (April 1-August 19, 2020; Fig. 9) are below.

Figure 7. Observed cumulative precipitation across the Canadian prairies the past seven days (as of August 19, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (20Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 8. Observed cumulative precipitation across the Canadian prairies the past 30 days (as of August 19, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (20Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 9. Observed cumulative precipitation across the Canadian prairies for the growing season (as of August 19, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (20Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The maps above are all produced by Agriculture and Agri-Food Canada. Growers can bookmark the AAFC Current Conditions Drought Watch Maps for the growing season. Historical weather data can be access at the AAFC Drought Watch website, Environment Canada’s Historical Data website, or your provincial weather network.

Predicted diamondback moth development

The Diamondback moth (DBM) model was run with a biofix of May 15, 2020. DBM densities generally increase with increasing numbers of generations. Figure 1 represents the model output for the 2020 growing season (as of August 17, 2020). The number of generations varies from two in western Alberta to four in southeastern Saskatchewan and most of Manitoba (Fig. 1). Next, the model was run with climate normal data to compare the 2020 growing season with an ‘average’ growing season (Fig. 2). The second map (climate normal) indicates that an average growing season results in two to three generations, with a fourth generation predicted to occur near Winnipeg (Fig. 2). These results indicate that there was an elevated DBM risk in 2020.

Figure 1. Using a biofix date of May 15, 2020, the projected number of diamondback moth (Plutella xylostella) generations across the Canadian prairies as of August 17, 2020.
Figure 2. Using a biofix date of May 15, 2020, the projected number of diamondback moth (Plutella xylostella) generations across the Canadian prairies as of August 17, 2020, using climate normal data.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

Monitoring to apply the economic threshold: Remove the plants in an area measuring 0.1 m² (about 12″ square). Beat them on to a clean surface and count the number of larvae (Fig. 3) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

This image has an empty alt attribute; its file name is DBM_Larva_AAFC.jpg
Figure 3. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.
This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 4. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 5. Diamondback moth.

Biological and monitoring information for DBM is posted by Manitoba AgricultureSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  

More information about Diamondback moths can be found by accessing the pages from the  “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide“.  View ONLY the Diamondback moth page but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted grasshopper development

The oviposition index provides a snapshot of how growing season conditions impact grasshopper development and subsequent oviposition. Advanced development of the current generation will result in greater potential egg production by females at the end of this growing season. Figure 1 represents model output for the 2020 growing season (as of August 17, 2020). In Alberta, cooler, wetter conditions in May and June were not conducive for grasshopper development. This has resulted in a prediction for lower oviposition potential for most of Alberta. Warmer, dryer conditions in Manitoba and southeastern Saskatchewan resulted in higher oviposition indices.

This image has an empty alt attribute; its file name is 2020Aug10_Msang_OvipositIndex.png
Figure 1. Predicted oviposition for (Melanoplus sanguinipes) populations across the Canadian prairies (as of August 17, 2020).

The model was run with climate normal data to compare the 2020 growing season with 30 year climate normals. The second map (climate normal) indicates that, in an average growing season, the greatest oviposition index values are observed for southeast Alberta and southwest Saskatchewan (Figure 2). Results suggest that the 2020 growing season was more favourable for grasshopper populations in Manitoba and southeastern Saskatchewan than for western Saskatchewan and most of Alberta.

Figure 2. Predicted oviposition for (Melanoplus sanguinipes) populations across the Canadian prairies (as of August 17, 2020) using climate normal data.

Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba AgricultureSaskatchewan AgricultureAlberta Agriculture and Forestry, the BC Ministry of Agriculture and the Prairie Pest Monitoring Network.  Also refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (Philip et al. 2018) as an English-enhanced or French-enhanced version.

Predicted wheat midge development

Cool, wetter growing seasons generally favour wheat midge development. Wheat midge larvae overwinter in the soil in larval cocoons. Adequate soil moisture (May-June) is required to terminate diapause, resulting in movement of larvae to the soil surface. The wheat midge model was run to determine potential numbers of overwintering wheat midge larvae.

During May and June weather conditions were cooler and wetter than normal across most of Alberta. These model runs indicated that weather conditions that would promote diapause termination and movement of larvae to the soil surface were favourable, and may have resulted in higher than average adult populations in early July. Conversely, warm, dry conditions occurred across most of Manitoba and were not suitable for larval development during May and June. Figure 1 represents the potential number of larval cocoons (as of August 17, 2020). Densities of wheat midge larval cocoons were predicted to be greater across Alberta than Saskatchewan and Manitoba (Fig. 1). Figure 2 provides a comparison of densities for the same time period in 2019. Low densities in 2019 were attributed to well below normal precipitation during the period of April to June (Fig. 2).

Figure 1. Predicted number of larval cocoons of wheat midge (Sitodiplosis mosellana) across the Canadian prairies as of August 17, 2020.
Figure 2. Predicted number of larval cocoons of wheat midge (Sitodiplosis mosellana) across the Canadian prairies as of August 17, 2019.

Review information supporting in-field monitoring for wheat midge (Fig. 3) and its parasitoid, Macroglenes penetrans (Fig. 4), posted back on Week 14 of the 2020 growing season.

This image has an empty alt attribute; its file name is 2016Jul12_IMG_2298_DuftonJorgensen_AAFC%2B%2528revised%2529.jpg
Figure 3. Wheat midge (Sitodiplosis mosellana) laying their eggs on the wheat heads 
(Photo: AAFC-Beaverlodge-S. Dufton & A. Jorgensen).
This image has an empty alt attribute; its file name is 2016Jul12_IMG_2154_DuftonJorgensen_AAFC%2B%2528revised%2529.jpg
Figure 4. Macroglenes penetrans, a parasitoid wasp that attacks wheat midge, measures only ~2 mm long.  (Photo: AAFC-Beaverlodge-S. Dufton).

Information related to wheat midge biology and monitoring can be accessed by linking to your provincial fact sheet (Saskatchewan Agriculture or Alberta Agriculture & Forestry).  A review of wheat midge on the Canadian prairies was published by Elliott, Olfert, and Hartley in 2011.  

More information about Wheat midge can be found by accessing the pages from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide”.  View ONLY the Wheat midge pages but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted pea leaf weevil overwintering

As of August 17, 2020, the Pea leaf weevil (PLW) model indicates that pupation is complete and adults are beginning to emerge from pea fields. The PLW model predicts that warm, dry conditions in June and early July may reduce larval survival. Wetter conditions during June and July were more favourable for PLW population development in Alberta than in eastern Saskatchewan and Manitoba. These factors resulted in lower overwintering adult index values for the eastern prairie region than for western regions (Fig. 1). Figure 2 represents the expected overwintering index values for PLW using climate normal data. Note that, to our knowledge, populations of pea leaf weevil remain low in Manitoba and are confined to the Swan River Valley region at this time.

Figure 1. The predicted overwintering adult index of pea leaf weevil (Sitona lineatus) across the Canadian prairies as of August 17, 2020.
Figure 2. The predicted overwintering adult index of pea leaf weevil (Sitona lineatus) across the Canadian prairies as of August 17, 2020, using climate normal data.

The pea leaf weevil is a slender greyish-brown insect measuring approximately 5 mm in length (Fig. 3, Left image). Pea leaf weevil resembles the sweet clover weevil (Sitona cylindricollis) but the former is distinguished by three light-coloured stripes extending length-wise down thorax and sometimes the abdomen.  All species of Sitona, including the pea leaf weevil, have a short snout.  

Figure 3.  Comparison images and descriptions of four Sitona species adults including pea leaf weevil (Left).

Review a more complete description of this insect posted back on Week 11 of the 2020 growing season. Biological and monitoring information related to pea leaf weevil in field crops is posted by the province of Alberta and in the PPMN monitoring protocol.

Also refer to the pea leaf weevil page within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” – both English-enhanced or French-enhanced versions are available. 

West nile virus risk

Health Canada posts information related to West Nile Virus in Canada and also tracks West Nile Virus through human, mosquito, bird and horse surveillance. Link here to access the most current weekly update (reporting date July 19-25, 2020; retrieved August 20, 2020). The screenshot below (retrieved Aug 20, 2020) serves as reference but access that Health Canada information here.

This image has an empty alt attribute; its file name is 2020Jun28-Jul04_WNV_Weekly_HealthCanada-1024x593.png

The following is offered to predict when Culex tarsalis, the vector for West Nile Virus, will begin to fly across the Canadian prairies (Fig. 1). This week, regions most advanced in degree-day accumulations for Culex tarsalis are shown in Figure 1. As of August 16, 2020 (Fig. 1), areas highlighted yellow and more imminently orange are approaching sufficient heat accumulation for mosquitoes to emerge. Areas highlighted red NOW HAVE Culex tarsalis flying (Fig. 1) – protect yourself by wearing DEET!

This image has an empty alt attribute; its file name is dd20809143-1-1024x727.png
Figure 1. Predicted development of Culex tarsalis across the Canadian prairies (as of August 16, 2020).

Preparing and protecting grains for market

A few helpful tools to keep at your finger tips:

A number of important resources are available at Keep It Clean to help prepare and protect grains for market.  Learn more about preparing canola, cereals and pulses! They also have tools to manage pre-harvest intervals including a spray to swath calculator and describe the importance of avoiding malathion in bins storing canola.

Download searchable PDFs of 2020 Crop Production Guides for Alberta, Saskatchewan and Manitoba.

The Canadian Grain Commission has information to help you manage stored grain.  Read tips to prepare your bins to prevent insect infestations.  If there are insects in your grain, use their online diagnostic tools to help identify the problem species.  If pest species are confirmed, there are control options – read more to make the right choice for your grain storage system and your specific grain.

Harvest Sample Program

Reminder – The Canadian Grain Commission is ready to grade grain samples harvested in 2020.  Samples are accepted up to November 30 but growers normally send samples as soon as harvest is complete.

This is a FREE opportunity for growers to gain unofficial insight into the quality of grain and to obtain valuable dockage information and details associated with damage or quality issues.  The data collected also helps Canada market its grain to the world!

More information on the Harvest Sample Program is available at the Canadian Grain Commission’s website where growers can register online to receive a kit to submit their grain.  

In exchange for your samples, the CGC assesses and provides the following unofficial results FOR FREE:

  • unofficial grade
  • dockage assessment on canola
  • protein content on barley, beans, chick peas, lentils, oats, peas and wheat
  • oil, protein and chlorophyll content for canola
  • oil and protein content and iodine value for flaxseed
  • oil and protein for mustard seed and soybean
  • Falling Number for wheat
  • Vomitoxin (deoxynivalenol or DON) for wheat and corn.

It can be helpful to have grade and quality information on samples before delivering their grain. Read brochures produced by the Canadian Grain Commission describing the Harvest Sample Program and details specific to the Western version of the program.

Stored grain insect survey in Manitoba

Reminder – Entomologists with Agriculture and Agri-Food Canada in Winnipeg are doing a survey in September of insects in farm grain bins. They are looking for 10 farms not far from Winnipeg where they can access grain bins to sample insects. No grain will be removed, just insects. If interested, please contact John Gavloski (John.Gavloski@gov.mb.ca) as soon as possible.

Provincial insect pest report links

Provincial entomologists provide insect pest updates throughout the growing season so link to their information: 

Manitoba‘s Crop Pest Updates for 2020 are available. Access the August 18 2020 report. The summary indicates that, “Grasshoppers continue to be the insect of greatest concern. Some have also commented on the high levels of flea beetles being observed in canola currently.”

Saskatchewan‘s Crop Production News (for Issue 7). Read Issue 7 which includes articles on Pest Scouting 101- Harvest, Promoting and Enhancing Beneficial Insects, and What to Do with Unwanted Pesticides and Obsolete Livestock Medications. Issue 5 included articles on Bertha armyworm, Cabbage seedpod weevil,  FieldWatch – Fostering Communication Between Applicators and Producers, and Look What the Wind Blew in! Diamondback Moths Arrived Early This Spring. Issue #4 included articles on Pest Scouting 101: Mid-Summer, and The Wheat Midge.

•  Alberta Agriculture and Forestry’s Agri-News occasionally includes insect-related information or Twitter users can connect to #ABBugChat Wednesdays at 10:00 am.

Crop report links


Click the provincial name below to link to online crop reports produced by:

• Manitoba Agriculture and Rural Initiatives – Other viewing options include subscribing to receive or access a PDF of August 18, 2020 report.

• Saskatchewan Agriculture  or access a PDF of August 17, 2020 report.

• Alberta Agriculture and Forestry or access a PDF of August 11, 2020 report.

The following crop reports are also available:

• The United States Department of Agriculture (USDA) produces a Crop Progress Report (read the August 17, 2020 edition).

• The USDA’s Weekly Weather and Crop Bulletin (read the August 18, 2020 edition). 

Previous posts

Click to review these earlier 2020 Posts (organized alphabetically):

    • 2019-2020 Risk and forecast maps

    • Alfalfa weevil (Wk08)

    • Aphid mummies (Wk15)

    • Aster leafhopper (Wk05)

    • Beetle data please! (Wk03)

    • Bertha armyworm (Wk16)

    • Bertha armyworm – predicted development (Wk15)

    • Cereal aphid APP (Wk11)

    • Crop protection guides (Wk02)

    • Cutworms (Wk02)

    • Diamondback moth (Wk11)

    • Flea beetles (Wk02)

    • Field heroes (Wk14)

    • John Doane (Wk10)

    • Ladybird beetles (Wk15)

    • Lygus bugs in canola (Wk15)

    • Monarch migration (Wk10)

    • Pea leaf weevil (Wk11)

    • Pea leaf weevil – predicted development (Wk09)

    • Prairie provincial insect webpages (Wk02)

    • Wheat midge (Wk13)

    • Scouting charts – canola and flax (Wk02)

    • Thrips in canola (Wk15)

    • Ticks and Lyme Disease (Wk06)

    • Wind trajectories (Wk09)

    • West nile virus (Wk14)

Weather synopsis

This past week (Aug 4-10, 2020) conditions were generally warm and dry. Weekly prairie temperatures were warmest across Manitoba and Saskatchewan (Fig. 1). Lower temperatures were observed across western and northwestern Alberta (Fig. 1). Though average 30-day (July 12 – August 10, 2020) temperatures continue to be cooler in Alberta than eastern Saskatchewan and Manitoba (Fig. 2), temperature anomalies (mean temperature difference from average; July 14-August 10, 2020) indicate that conditions have generally been warmer than average across most of Alberta as well as Parkland regions of Saskatchewan and Manitoba (Fig. 3).

Figure 1. Observed average temperatures across the Canadian prairies the past seven days (August 4-10, 2020).
Figure 2. Observed average temperatures across the Canadian prairies the past 30 days (July 12-August 10, 2020).
Figure 3. Mean temperature difference from Normal the past 30 days (July 14-August 12, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (12Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Regions in southeastern central and southern Saskatchewan and across southern Manitoba have reported temperatures that have been up to 2 °C cooler than average. Based on growing season temperatures (April 1-August 10, 2020) temperatures were warmest across the southern prairies (Fig. 4). Based on growing season temperature deviations (observed temperatures compared with climate normal temperatures), below average temperatures have been observed across central and western regions of Saskatchewan and central regions of Alberta (Fig. 5). Across southern Alberta and most of Manitoba, temperatures have generally been above average. (Fig. 5)

Figure 4. Observed average temperatures across the Canadian prairies for the growing season (April 1-August 10, 2020).
Figure 5. Observed difference from average temperatures across the Canadian prairies for the growing season (April 1-August 10, 2020).

Most areas reported 7-day cumulative rainfall amounts that were less than 10 mm (Fig. 6). Cumulative 30-day rainfall was lowest across a large area ranging across southern Alberta as well as central and western regions of Saskatchewan (Fig. 7). Growing season rainfall (percent of average) is highly variable across the prairies (Fig. 8). Rainfall has been below normal across most of Saskatchewan as well as southern Alberta, and the Peace River region (Fig. 8).

Figure 6. Observed cumulative precipitation across the Canadian prairies the past seven days (August 4-10, 2020).
Figure 7. Observed cumulative precipitation across the Canadian prairies the past 30 days (July 12-August 10, 2020).
Figure 8. Percent of average precipitation for the growing season (April 1-August 10, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (12Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The growing degree day map (GDD) (Base 5 ºC, April 1-August 9, 2020) is below (Fig. 9) while the growing degree day map (GDD) (Base 10 ºC, April 1-August 9, 2020) is shown in Figure 10.

Figure 9. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-August 9, 2020).
Figure 10. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-August 9, 2020).

The highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <17 to >34 °C (Fig. 11) while the lowest temperatures ranged from <-1 to >13 °C (Fig. 12). So far this growing season (as of August 12, 2020), the number of days above 25 °C ranges from 0-10 days in the west (to west of Calgary, west and north of central Alberta and extending into the south and west of the Peace River region) but extends up to 51-60 days in southern Manitoba (Fig. 13).

Figure 11. Highest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-August 12, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (13Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 12. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-August 12, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (13Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 13. Number of days above 25 °C observed across the Canadian prairies this growing season (April 1-August 12, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (13Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The maps above are all produced by Agriculture and Agri-Food Canada. Growers can bookmark the AAFC Current Conditions Drought Watch Maps for the growing season. Historical weather data can be access at the AAFC Drought Watch website, Environment Canada’s Historical Data website, or your provincial weather network.

Bertha armyworm

Weekly Pheromone-baited Trapping Results – Click each province name to access moth reporting numbers observed in AlbertaSaskatchewan and Manitoba (as they become available). Check these sites to assess cumulative counts and relative risk in your geographic region but remember in-field scouting is required to apply the economic threshold to manage both this pest and its natural enemies. For convenience, screen shots of the above maps or data have been placed below for Alberta, Saskatchewan, and Manitoba.

Monitoring:

  • Larval sampling should commence once the adult moths are noted.
  • Sample at least three locations, a minimum of 50 m apart.
  • At each location, mark an area of 1 m2 and beat the plants growing within that area to dislodge the larvae.
  • Count them and compare the average against the values in the economic threshold table below:

Scouting tips:
● Some bertha armyworm larvae remain green or pale brown throughout their larval life.
● Large larvae may drop off the plants and curl up when disturbed, a defensive behavior typical of cutworms and armyworms.
● Young larvae chew irregular holes in leaves, but normally cause little damage. The fifth and sixth instar stages cause the most damage by defoliation and seed pod consumption. Crop losses due to pod feeding will be most severe if there are few leaves.
● Larvae eat the outer green layer of the stems and pods exposing the white tissue.
● At maturity, in late summer or early fall, larvae burrow into the ground and form pupae.

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting.  Use the images below (Fig. 1) to help identify the economically important larvae.  Review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

This image has an empty alt attribute; its file name is 2019_PPMN-Protocol_BAW_LifeStages_Williams.png
Figure 1. The egg stage (A), larval stage (B), pupal stage (C), and adult stage (D) of bertha armyworm. Photos: Jonathon Williams (AAFC-Saskatoon).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of ManitobaSaskatchewanAlberta and the Prairie Pest Monitoring Network. Also refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted diamondback moth development

This week, the DBM model based on Harcourt (1954) was run with a biofix of May 15, 2020. Most of Alberta has had two generations. It is possible that three generations have been completed across Saskatchewan and southeastern Alberta where it has been warmer. Results indicate that a potential fourth generation may be occurring across southern Manitoba. DBM densities generally increase with increasing numbers of generations. Later maturing canola fields may be susceptible to damage resulting from larval feeding.

Figure 1. Using a biofix date of May 15, 2020, the projected number of diamondback moth (Plutella xylostella) generations across the Canadian prairies as of August 10, 2020.

Monitoring:

Remove the plants in an area measuring 0.1 m² (about 12″ square). Beat them on to a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

This image has an empty alt attribute; its file name is DBM_Larva_AAFC.jpg
Figure 2. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.
This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 3. Diamondback moth pupa within silken cocoon.

Economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 4. Diamondback moth.

Biological and monitoring information for DBM is posted by Manitoba AgricultureSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  

More information about Diamondback moths can be found by accessing the pages from the  “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide“.  View ONLY the Diamondback moth page but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted grasshopper development

As of August 10, 2020, the grasshopper model estimates that prairie grasshopper populations are primarily in the adult stage (Fig. 1). Figure 2 provides an overview of where oviposition is predicted to occur based on weather conditions up to August 10. Oviposition is well underway across southern Manitoba and southeastern Saskatchewan (Fig. 2).

Figure 1. Predicted average development stages of grasshopper (Melanoplus sanguinipes) populations across the Canadian prairies (as of August 10, 2020).
Figure 2. Predicted oviposition for (Melanoplus sanguinipes) populations across the Canadian prairies (as of August 10, 2020).

Recent warm weather in southwestern Alberta has resulted in increased development rates, resulting in predicted occurrence of oviposition. The three graphs compare grasshopper development at Grande Prairie (Fig. 3), Saskatoon (Fig. 4) and Brandon (Fig. 5). Output suggests that adults are beginning to occur near Grande Prairie but oviposition has yet to begin (Fig. 3). Saskatoon (Fig. 4) and Brandon (Fig. 5) populations should be primarily in the adult stage and oviposition should be well underway.

Figure 3. Predicted grasshopper (Melanoplus sanguinipes) phenology at Grande Prairie AB. Values are based on model simulations (April 1-August 10, 2020).
Figure 4. Predicted grasshopper (Melanoplus sanguinipes) phenology at Saskatoon SK. Values are based on model simulations (April 1-August 10, 2020).
Figure 5. Predicted grasshopper (Melanoplus sanguinipes) phenology at Brandon MB. Values are based on model simulations (April 1-August 10, 2020).

Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba AgricultureSaskatchewan AgricultureAlberta Agriculture and Forestry, the BC Ministry of Agriculture and the Prairie Pest Monitoring Network.  Also refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (Philip et al. 2018) as an English-enhanced or French-enhanced version.

Stored grain insect survey in Manitoba

Entomologists with Agriculture and Agri-Food Canada in Winnipeg are doing a survey in September of insects in farm grain bins. They are looking for 10 farms not far from Winnipeg where they can access grain bins to sample insects. No grain will be removed, just insects. If interested, please contact John Gavloski (John.Gavloski@gov.mb.ca) as soon as possible.

Stored product pests

Reminder – The Canadian Grain Commission’s website has an online key to stored product pests.  Growers managing grain storage can find an online identification tool for stored product pests (e.g., Rusty grain beetleRed flour beetleConfused flour beetleSaw-toothed grain beetle, and more).  The online tool features excellent diagnostic photos.  A screen shot of the Canadian Grain Commission’s “Identify an Insect” webpage is included below for reference.

This image has an empty alt attribute; its file name is 2020Aug06_CGC_Snip-1024x746.png

West nile virus risk

Health Canada posts information related to West Nile Virus in Canada and also tracks West Nile Virus through humanmosquitobird and horse surveillance.  Link here to access the most current weekly update (reporting date July 12-18, 2020; retrieved Aug 13, 2020). The screenshot below (retrieved Aug 13, 2020) serves as reference but access that Health Canada information here.

This image has an empty alt attribute; its file name is 2020Jun28-Jul04_WNV_Weekly_HealthCanada-1024x593.png

The following is offered to predict when Culex tarsalis, the vector for West Nile Virus, will begin to fly across the Canadian prairies (Fig. 1). This week, regions most advanced in degree-day accumulations for Culex tarsalis are shown in the map below (yellow, orange then red highlighted areas).  As of August 9, 2020 (Fig. 1), areas highlighted yellow and more imminently orange are approaching sufficient heat accumulation for mosquitoes to emerge.  Areas highlighted red NOW HAVE Culex tarsalis flying (Fig. 1) – protect yourself by wearing DEET!  

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of August 9, 2020).

Harvest Sample Program

The Canadian Grain Commission is ready to grade grain samples harvested in 2020.  Samples are accepted up to November 30 but growers normally send samples as soon as harvest is complete.

This is a FREE opportunity for growers to gain unofficial insight into the quality of grain and to obtain valuable dockage information and details associated with damage or quality issues.  The data collected also helps Canada market its grain to the world!

More information on the Harvest Sample Program is available at the Canadian Grain Commission’s website where growers can register online to receive a kit to submit their grain.  

In exchange for your samples, the CGC assesses and provides the following unofficial results FOR FREE:

  • unofficial grade
  • dockage assessment on canola
  • protein content on barley, beans, chick peas, lentils, oats, peas and wheat
  • oil, protein and chlorophyll content for canola
  • oil and protein content and iodine value for flaxseed
  • oil and protein for mustard seed and soybean
  • Falling Number for wheat
  • Vomitoxin (deoxynivalenol or DON) for wheat and corn.

It can be helpful to have grade and quality information on samples before delivering their grain. Read brochures produced by the Canadian Grain Commission describing the Harvest Sample Program and details specific to the Western version of the program.

Provincial insect pest report links

Provincial entomologists provide insect pest updates throughout the growing season so link to their information: 

Manitoba‘s Crop Pest Updates for 2020 are available. Access the August 11 2020 report. The summary indicates that, “Grasshoppers continue to be the insect of greatest concern. The diamondback moth populations in eastern Manitoba that were of concern in some fields a couple of weeks ago seem to have diminished. Spider mites are being noticed in some soybean fields, but no insecticide applications for them have been reported yet.”

Saskatchewan‘s Crop Production News (for Issue 7). Read Issue 7 which includes articles on Pest Scouting 101- Harvest, Promoting and Enhancing Beneficial Insects, and What to Do with Unwanted Pesticides and Obsolete Livestock Medications. Issue 5 included articles on Bertha armyworm, Cabbage seedpod weevil,  FieldWatch – Fostering Communication Between Applicators and Producers, and Look What the Wind Blew in! Diamondback Moths Arrived Early This Spring. Issue #4 included articles on Pest Scouting 101: Mid-Summer, and The Wheat Midge.

•  Alberta Agriculture and Forestry’s Agri-News occasionally includes insect-related information or Twitter users can connect to #ABBugChat Wednesdays at 10:00 am.

Crop report links

Click the provincial name below to link to online crop reports produced by:

• Manitoba Agriculture and Rural Initiatives – Other viewing options include subscribing to receive or access a PDF of August 11, 2020 report.

• Saskatchewan Agriculture  or access a PDF of August 10, 2020 report.

• Alberta Agriculture and Forestry or access a PDF of July 28, 2020 report.

The following crop reports are also available:

• The United States Department of Agriculture (USDA) produces a Crop Progress Report (read the August 10, 2020 edition).

• The USDA’s Weekly Weather and Crop Bulletin (read the August 11, 2020 edition). 

Previous posts

Click to review these earlier 2020 Posts (organized alphabetically):

    • 2019-2020 Risk and forecast maps

    • Alfalfa weevil (Wk08)

    • Aphid mummies (Wk15)

    • Aster leafhopper (Wk05)

    • Beetle data please! (Wk03)

    • Bertha armyworm – predicted development (Wk15)

    • Cereal aphid APP (Wk11)

    • Crop protection guides (Wk02)

    • Cutworms (Wk02)

    • Diamondback moth (Wk11)

    • Flea beetles (Wk02)

    • Field heroes (Wk14)

    • John Doane (Wk10)

    • Ladybird beetles (Wk15)

    • Lygus bugs in canola (Wk15)

    • Monarch migration (Wk10)

    • Pea leaf weevil (Wk11)

    • Pea leaf weevil – predicted development (Wk09)

    • Prairie provincial insect webpages (Wk02)

    • Wheat midge (Wk13)

    • Scouting charts – canola and flax (Wk02)

    • Thrips in canola (Wk15)

    • Ticks and Lyme Disease (Wk06)

    • Wind trajectories (Wk09)

    • West nile virus (Wk14)

Weather synopsis

This past week (July 28 to August 3, 2020) prairie temperatures were warmest in southeastern Alberta and southwestern Saskatchewan and coolest in southern Manitoba and the Peace River region of Alberta and British Columbia (Fig. 1). Temperatures in the past week represent a switch from previous weeks, where it was warmer in Manitoba than in Alberta. Average 30-day temperatures (July 5 to August 3, 2020) continue to be cooler across most of Alberta than observed in eastern Saskatchewan and Manitoba (Fig. 2). The average 30-day temperature at Winnipeg and Brandon continued to be greater than locations in Alberta and Saskatchewan (Fig. 2).

Figure 1. Observed average temperatures across the Canadian prairies the past seven days (July 28-August 3, 2020).
Figure 2. Observed average temperatures across the Canadian prairies the past 30 days (July 5-August 3, 2020).
Figure 3. Mean temperature difference from Normal the past 30 days (July 1-31, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (13Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Cumulative rainfall for the past 7 days was lowest across southern regions of Alberta, Saskatchewan and Manitoba (Fig. 4). Cumulative 30-day rainfall was lowest across a large area ranging from southwest Saskatchewan to Saskatoon (Fig. 5). Growing season rainfall (percent of average) is below normal across eastern Saskatchewan and localized areas of Manitoba and above normal across most of Alberta (Fig. 6).

Figure 4. Observed cumulative precipitation across the Canadian prairies the past seven days (July 28-August 5, 2020).
Figure 5. Observed cumulative precipitation across the Canadian prairies the past 30 days (July 5-August 3, 2020).
Figure 6. Percent of average precipitation for the growing season (April 1-August 3, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (04Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The growing degree day map (GDD) (Base 5 ºC, April 1-August 3, 2020) is below (Fig. 7) while the growing degree day map (GDD) (Base 10 ºC, April 1-August 3, 2020) is shown in Figure 8.

Figure 7. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-August 3, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (06Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 8. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-August 3, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (06Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <24 to >32 °C (Fig. 9). So far this growing season (as of August 6, 2020), the number of days above 25°C ranges from 0-10 days throughout much of Alberta and into the BC Peace then extends up to 51-60 days in southern Manitoba (Fig. 10).

Figure 9. Highest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-August 3, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (06Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 10. Number of days above 25 °C observed across the Canadian prairies this growing season (April 1-August 5, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (06Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The maps above are all produced by Agriculture and Agri-Food Canada. Growers can bookmark the AAFC Current Conditions Drought Watch Maps for the growing season. Historical weather data can be access at the AAFC Drought Watch website, Environment Canada’s Historical Data website, or your provincial weather network.

Predicted bertha armyworm development

Model simulations for August 3, 2020, indicate that BAW development varies across the prairies. Figures 1 and 2 demonstrate that BAW populations near Winnipeg (Fig. 1) are more advanced than populations near Grande Prairie (Fig. 2). Populations near Winnipeg are predicted to be developing to pupae (Fig. 1). BAW populations near Grande Prairie are expected to be primarily in the larval stage (Fig. 2).

Figure 1. Predicted bertha armyworm (Mamestra configurata) phenology at Winnipeg MB as of August 3, 2020.
Figure 2 Predicted bertha armyworm (Mamestra configurata) phenology at Grande Prairie AB as of August 3, 2020.

Weekly Pheromone-baited Trapping Results – Early season detection of bertha armyworm is improved through the use of pheromone-baited unitraps traps deployed in fields across the Canadian prairies.  Click each province name to access moth reporting numbers observed in AlbertaSaskatchewan and Manitoba (as they become available). Check these sites to assess cumulative counts and relative risk in your geographic region but remember in-field scouting is required to apply the economic threshold to manage both this pest and its natural enemies. For convenience, screen shots of the above maps or data have been placed below for Alberta, Saskatchewan, and Manitoba.

Monitoring:

  • Larval sampling should commence once the adult moths are noted.
  • Sample at least three locations, a minimum of 50 m apart.
  • At each location, mark an area of 1 m2 and beat the plants growing within that area to dislodge the larvae.
  • Count them and compare the average against the values in the economic threshold table below:

Scouting tips:
● Some bertha armyworm larvae remain green or pale brown throughout their larval life.
● Large larvae may drop off the plants and curl up when disturbed, a defensive behavior typical of cutworms and armyworms.
● Young larvae chew irregular holes in leaves, but normally cause little damage. The fifth and sixth instar stages cause the most damage by defoliation and seed pod consumption. Crop losses due to pod feeding will be most severe if there are few leaves.
● Larvae eat the outer green layer of the stems and pods exposing the white tissue.
● At maturity, in late summer or early fall, larvae burrow into the ground and form pupae.

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting.  Use the images below (Fig. 4) to help identify the economically important larvae.  Review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

This image has an empty alt attribute; its file name is 2019_PPMN-Protocol_BAW_LifeStages_Williams.png
Figure 4. The egg stage (A), larval stage (B), pupal stage (C), and adult stage (D) of bertha armyworm. Photos: Jonathon Williams (AAFC-Saskatoon).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of ManitobaSaskatchewanAlberta and the Prairie Pest Monitoring Network. Also refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted diamondback moth development

Based on Harcourt (1954) the DBM model was run with a biofix of May 15, 2020. Model runs (as of August 3, 2020) were conducted with weather data for 2020 (Fig. 1) and climate normals (long term average temperatures). The first map illustrates that potentially three generations have been completed across Manitoba and southeastern Saskatchewan (Fig. 1). Most of the prairies have had two generations (Fig. 1). The second map, showing results for climate normal data, indicates that prairie populations should have completed two generations (Fig. 2).

Figure 1. Using a biofix date of May 15, 2020, the projected number of diamondback moth (Plutella xylostella) generations across the Canadian prairies as of August 3, 2020.
Figure 2. Using a biofix date of May 15, 2020, the projected number of diamondback moth (Plutella xylostella) generations across the Canadian prairies using Climate Normal data.

The charts provide location specific details regarding potential development at Winnipeg (Fig. 3) and Lacombe (Fig. 4). The first chart illustrates DBM development at Winnipeg. Results indicate that there is potential for a fourth generation of DBM to occur in southern Manitoba. Populations near Lacombe are predicted to be completing the second generation.

Figure 3. Predicted diamondback moth (Plutella xylostella) phenology at Saskatoon SK. Values are based on model simulations (April 1-August 3, 2020).
Figure 4. Predicted diamondback moth (Plutella xylostella) phenology at Lacombe AB. Values are based on model simulations (April 1-August 3, 2020).

Monitoring:

Remove the plants in an area measuring 0.1 m² (about 12″ square). Beat them on to a clean surface and count the number of larvae (Fig. 5) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

This image has an empty alt attribute; its file name is DBM_Larva_AAFC.jpg
Figure 5. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.
This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 6. Diamondback moth pupa within silken cocoon.

Economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 7. Diamondback moth.

Biological and monitoring information for DBM is posted by Manitoba AgricultureSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  

More information about Diamondback moths can be found by accessing the pages from the  “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide“.  View ONLY the Diamondback moth page but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted grasshopper development

As of August 3, 2020, the grasshopper model estimates that prairie grasshopper populations are primarily adults (Fig. 1). Based on model simulations, development has been slowest across central and northern regions of Alberta (Fig. 1). The second map provides an overview of where oviposition is predicted to have started (Fig. 2). The yellow and red areas show that oviposition has begun across southern Manitoba and southeastern Saskatchewan (Fig. 2).

Figure 1. Predicted average development stages of grasshopper (Melanoplus sanguinipes) populations across the Canadian prairies (as of August 3, 2020).
Figure 2. Predicted oviposition for (Melanoplus sanguinipes) populations across the Canadian prairies (as of August 3, 2020).

The two graphs compare grasshopper development at Saskatoon (Fig. 3) and Brandon (Fig. 4). Near Saskatoon, grasshopper populations are expected to be mainly in the adult stage with oviposition beginning to occur over the past week (Fig. 3). Around Brandon, adult emergence is complete and oviposition should be well underway (Fig. 4).

Figure 3. Predicted grasshopper (Melanoplus sanguinipes) phenology at Saskatoon SK. Values are based on model simulations (April 1-August 3, 2020).
Figure 4. Predicted grasshopper (Melanoplus sanguinipes) phenology at Brandon MB. Values are based on model simulations (April 1-August 3, 2020).

Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba AgricultureSaskatchewan AgricultureAlberta Agriculture and Forestry, the BC Ministry of Agriculture and the Prairie Pest Monitoring Network.  Also refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (Philip et al. 2018) as an English-enhanced or French-enhanced version.

Lygus bug in canola

On the Canadian prairies, lygus bugs (Heteroptera: Miridae) are normally a complex of several native species usually including Lygus lineolaris, L. keltoni, L. borealis, L. elisus although several more species are distributed throughout Canada. The species of Lygus forming the “complex” can vary by host plant, by region or even seasonally.

Lygus bugs are polyphagous (i.e., feed on plants belonging to several Families of plants) and multivoltine (i.e., capable of producing multiple generations per year). Both the adult (Fig. 1) and five nymphal instar stages (Fig. 2) are a sucking insect. Adults overwinter in northern climates. The economic threshold for Lygus in canola is applied at late flower and early pod stages.  

This image has an empty alt attribute; its file name is 2019_Lygus_lineolaris_AAFC-Sask.png
Figure 1. Adult Lygus lineolaris (5-6 mm long) (photo: AAFC-Saskatoon).
This image has an empty alt attribute; its file name is 2019_Lygus_nymph_AAFC-Sask.png
Figure 2. Fifth instar lygus bug nymph (3-4 mm long) (photo: AAFC-Saskatoon).

Damage: Lygus bugs have piercing-sucking mouthparts and physically damage the plant by puncturing the tissue and sucking plant juices. The plants also react to the toxic saliva that the insects inject when they feed. Lygus bug infestations can cause alfalfa to have short stem internodes, excessive branching, and small, distorted leaves. In canola, lygus bugs feed on buds and blossoms and cause them to drop. They also puncture seed pods and feed on the developing seeds causing them to turn brown and shrivel.

Scouting tips to keep in mind: Begin monitoring canola when it bolts and continue until seeds within the pods are firm. Since adults can move into canola from alfalfa, check lygus bug numbers in canola when nearby alfalfa crops are cut.

Sample the crop for lygus bugs on a sunny day when the temperature is above 20 °C and the crop canopy is dry. With a standard insect net (38 cm diameter), take ten 180 ° sweeps. Count the number of lygus bugs in the net. Sampling becomes more representative IF repeated at multiple spots within a field so sweep in at least 10 locations within a field to estimate the density of lygus bugs. In fact, sampling is most accurate when repeated at a total of 15 spots within the field.  Samples can be taken along or near the field margins. Calculate the cumulative total number of lygus bugs and then consult the sequential sampling chart (Figure 3). 

This image has an empty alt attribute; its file name is 1998_SequentialSampling_WiseAndLamb.png
Figure 3. Sequential sampling for lygus bugs at late flowering stage in canola.

If the total number is below the lower threshold line (Fig. 3), no treatment is needed. If the total is below the upper threshold line, take more samples. If the total is on or above the upper threshold line, calculate the average number of lygus bugs per 10-sweep sample and consult the economic threshold tables (Tables 1 and 2).

The economic threshold for lygus bugs in canola covers the end of the flowering (Table 1) and the early pod ripening stages (Table 2). Once the seeds have ripened to yellow or brown, the cost of controlling lygus bugs may exceed the damage they will cause prior to harvest, so insecticide application is not warranted. Consider the estimated cost of spraying and expected return prior to making a decision to treat a crop. 

This image has an empty alt attribute; its file name is 1998_EconomicThreshold_LateFlower-EarlyPod_Captions-1024x488.png
This image has an empty alt attribute; its file name is 1998_EconomicThreshold_Pod_Captions-1024x461.png

Remember that insecticide applications at bud stage in canola have not been proven to result in an economic benefit in production.  The exception to this is in the Peace River region where early, dry springs and unusually high densities of lygus bug adults can occasionally occur at bud stage.  In this situation, high numbers of lygus bugs feeding on moisture-stressed canola at bud stage is suspected to result in delay of flowering so producers in that region must monitor in fields that fail to flower as expected.

How to tell them apart: The 2019 Insect of the Week’s doppelganger for Wk 15 was lygus bug versus the alfalfa plant bug while Wk 16 featured lygus bug nymphs vs. aphids!  Both posts include tips to to discern the difference between when doing in-field scouting!

Biological and monitoring information related to Lygus in field crops is posted by the provinces of Manitoba or Alberta fact sheets or the Prairie Pest Monitoring Network’s monitoring protocol.  Also refer to the Lygus pages within the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” – both English or French versions are available.

Thrips in canola

Thrips in canola (Thynsanoptera) – While scouting at this time of year, curled canola pods may be encountered.  The culprits are quite possibly thrips.

Figure 1. Thrips damage observed in canola in the northeast of Saskatchewan in July 2016 (Photo: AAFC-Saskatoon, Olfert 2016).

Damage: Flower thrips (Thysanoptera) are pests of a broad range of plants including cereals and broadleaved crops such as canola. Thrips are minute, slender-bodied insects with rasping-sucking mouthparts and feed by rasping the surface of canola buds and sucking up plant fluids. 

Biology: Thrips have six life stages: egg, two larval stages, a prepupal and pupal stage and an adult. Both adults and nymphs cause damage by feeding on the flower and buds. Limited surveys in 1999 in Saskatchewan and Alberta indicated that the predominant species were Frankliniella tritici (flower thrip) followed by Thrips tabaci (onion thrip) and T. vulgatissimus (no common name).

In canola, pods damaged by thrips are often curled and tend to drop prematurely.  Some species, such as T. vulgatissimus have been credited with contributing to pollination.

Read more about thrips in canola by accessing this article by Olfert et al. 1998).

Ladybird beetles and mummies

Ladybird beetle larvae (Fig. 1), pupae (Fig. 2), and adults (Fig. 3) can all be found in fields at this time of year.  Take a look at the various stages and the many patterns of native and introduced species to recognize these as Field Heroes!  Ladybird beetles are categorized as general predators and will feed on several species of arthropods but are partial to aphids.  

Figure 1. Ladybird beetle larva (photo credit: AAFC-Beaverlodge)
Figure 2. Ladybird beetle pupa (photo credit: AAFC-Beaverlodge).
Figure 3. Ladybird beetle (Coccinella septempunctata) (photo credit: AAFC-Beaverlodge)

Another “beneficial” found in fields at this point in the season are mummified aphids (Fig. 4). The “mummy” contains a maturing parasitoid wasp which will emerge from the host and seek other aphids to parasitize. Read more about the amazing Aphidiinae wasps by accessing the pages from the  “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide“.  The guide is available as a free downloadable document in both an English-enhanced or French-enhanced version.

Figure 4. An aphid “mummy” adhered to a wheat awn.  A “mummy” is the aphid host transformed to enclose a soon-to-emerge parasitoid wasp (photo credit: AAFC-Beaverlodge).

West nile virus risk

Health Canada posts information related to West Nile Virus in Canada and also tracks West Nile Virus through humanmosquitobird and horse surveillance.  Link here to access the most current weekly update (reporting date July 12-18, 2020; retrieved Aug 11, 2020). The screenshot below (retrieved Aug 11, 2020) serves as reference but access that Health Canada information here.

This image has an empty alt attribute; its file name is 2020Jun28-Jul04_WNV_Weekly_HealthCanada-1024x593.png

The following is offered to predict when Culex tarsalis, the vector for West Nile Virus, will begin to fly across the Canadian prairies (Fig. 1). This week, regions most advanced in degree-day accumulations for Culex tarsalis are shown in the map below (yellow, orange then red highlighted areas).  As of August 5, 2020 (Fig. 1), areas highlighted yellow and more imminently orange are approaching sufficient heat accumulation for mosquitoes to emerge.  Areas highlighted red NOW HAVE Culex tarsalis flying (Fig. 1) – protect yourself by wearing DEET!  

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of August 5, 2020).

Stored product pests

The Canadian Grain Commission’s website has an online key to stored product pests.  Growers managing grain storage can find an online identification tool for stored product pests (e.g., Rusty grain beetleRed flour beetleConfused flour beetleSaw-toothed grain beetle, and more).  The online tool features excellent diagnostic photos.  A screen shot of the Canadian Grain Commission’s “Identify an Insect” webpage is included below for reference.

Provincial insect pest report links


Provincial entomologists
provide insect pest updates throughout the growing season so link to their information: 

Manitoba‘s Crop Pest Updates for 2020 are available. Access the August 5, 2020 report. The summary indicates that, “Grasshoppers are currently the biggest insect concern. Some sunflower midge has been observed in sunflowers in the Eastern region, mainly around field edges, which is typical for this insect. Lygus bugs have also been noted in sunflower fields. Diamondback moth larvae in canola remains a concern for growers and agronomists in the Eastern region, with lots of scouting and some limited insecticide applications occurring.”

Saskatchewan‘s Crop Production News (for Issue 6). Read Issue 5 which includes articles on Bertha armyworm, Cabbage seedpod weevil,  FieldWatch – Fostering Communication Between Applicators and Producers, and Look What the Wind Blew in! Diamondback Moths Arrived Early This Spring. Issue #4 included articles on Pest Scouting 101: Mid-Summer, and The Wheat Midge.

•  Alberta Agriculture and Forestry’s Agri-News occasionally includes insect-related information or Twitter users can connect to #ABBugChat Wednesdays at 10:00 am.

Crop report links

Click the provincial name below to link to online crop reports produced by:

• Manitoba Agriculture and Rural Initiatives – Other viewing options include subscribing to receive or access a PDF of August 4, 2020 report.

• Saskatchewan Agriculture  or access a PDF of July 28-August 3, 2020 report.

• Alberta Agriculture and Forestry or access a PDF of July 28, 2020 report.

The following crop reports are also available:

• The United States Department of Agriculture (USDA) produces a Crop Progress Report (read the August 3, 2020 edition).

• The USDA’s Weekly Weather and Crop Bulletin (read the August 4, 2020 edition). 

Previous posts

Click to review these earlier 2020 Posts (organized alphabetically):

    • 2019-2020 Risk and forecast maps

    • Alfalfa weevil (Wk08)

    • Aster leafhopper (Wk05)

    • Beetle data please! (Wk03)

    • Cereal aphid APP (Wk11)

    • Crop protection guides (Wk02)

    • Cutworms (Wk02)

    • Diamondback moth (Wk11)

    • Flea beetles (Wk02)

    • Field heroes (Wk14)

    • John Doane (Wk10)

    • Monarch migration (Wk10)

    • Pea leaf weevil (Wk11)

    • Pea leaf weevil – predicted development (Wk09)

    • Prairie provincial insect webpages (Wk02)

    • Wheat midge (Wk13).

    • Scouting charts – canola and flax (Wk02)

    • Ticks and Lyme Disease (Wk06)

    • Wind trajectories (Wk09)

    • West nile virus (Wk14)

Weather synopsis

An abbreviated synopsis of the past week is provided below. Recent warm weather across the Canadian prairies helped crop development this past week

The growing degree day map (GDD) (Base 5 ºC, April 1-July 27, 2020) is below (Fig. 1) while the growing degree day map (GDD) (Base 10 ºC, April 1-July 27, 2020) is shown in Figure 2.

Figure 1. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-July 27, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 2. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-July 27, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <22 to >34 °C (Fig. 3). So far this growing season (up to July 29, 2020), the number of days above 25 ranges from 0-10 days throughout much of Alberta and into the BC Peace then extends up to 41-50 days in southern Manitoba (Fig. 4).

Figure 3. Highest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-July 29, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 4. Number of days above 25 °C observed across the Canadian prairies this growing season (April 1-July 29, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Cumulative rainfall for the past 7 days was lowest across southern regions of Alberta, Saskatchewan, and Manitoba with the exception of around Regina south to the American border, and southwest Manitoba west into the southeast corner of Saskatchewan (Fig. 5). Cumulative 30-day (Fig. 6) and rainfall for the growing season (April 1-July 29, 2020; Fig. 7) are below.

Figure 5. Observed cumulative precipitation across the Canadian prairies the past seven days (as of July 29, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 6. Observed cumulative precipitation across the Canadian prairies the past 30 days (as of July 29, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 7. Observed cumulative precipitation across the Canadian prairies for the growing season (as of July 29, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The maps above are all produced by Agriculture and Agri-Food Canada. Growers can bookmark the AAFC Current Conditions Drought Watch Maps for the growing season. Historical weather data can be access at the AAFC Drought Watch website, Environment Canada’s Historical Data website, or your provincial weather network.

Wheat midge

Click to link to last week’s information posted for Wk 13 (released 23Jul2020) to review the predictive model outputs for this insect pest.

Monitoring: When monitoring wheat fields, pay attention to the synchrony between flying midge and anthesis.  

In-field monitoring for wheat midge should be carried out in the evening (preferably after 8:30 pm or later) when the female midges are most active. On warm (at least 15 ºC), calm evenings, the midge can be observed in the field, laying their eggs on the wheat heads (Fig. 1). Midge populations can be estimated by counting the number of adults present on 4 or 5 wheat heads. Inspect the field daily in at least 3 or 4 locations during the evening.

Figure 1. Wheat midge (Sitodiplosis mosellana) laying their eggs on the wheat heads 
(Photo: AAFC-Beav-S. Dufton & A. Jorgensen).

REMEMBER that in-field counts of wheat midge per head remain the basis of economic threshold decision.  Also remember that the parasitoid, Macroglenes penetrans (Fig. 2), is actively searching for wheat midge at the same time.  Preserve this parasitoid whenever possible and remember your insecticide control options for wheat midge also kill these beneficial insects which help reduce midge populations.

Figure 2. Macroglenes penetrans, a parasitoid wasp that attacks wheat midge, measures only ~2 mm long.  (Photo: AAFC-Beav-S. Dufton).

Economic Thresholds for Wheat Midge:

a) To maintain optimum grade: 1 adult midge per 8 to 10 wheat heads during the susceptible stage.

b) For yield only: 1 adult midge per 4 to 5 heads. At this level of infestation, wheat yields will be reduced by approximately 15% if the midge is not controlled.

Inspect the developing kernels for the presence of larvae and the larval damage. 

Wheat midge and its doppelganger, the lauxanid fly, were featured as the Insect of the Week in 2019 (for Wk11).  Review that post for descriptions and photos to help with in-field scouting for this economic pest of wheat!  Additionally, the differences between midges and parasitoid wasps were featured as the current Insect of the Week in 2019 (for Wk12).  Not all flying insects are mosquitoes nor are they pests – many are important parasitoid wasps that actually regulate insect pest species in our field crops.

Information related to wheat midge biology and monitoring can be accessed by linking to your provincial fact sheet (Saskatchewan Agriculture or Alberta Agriculture & Forestry).  A review of wheat midge on the Canadian prairies was published by Elliott, Olfert, and Hartley in 2011.  

Alberta Agriculture and Forestry has a YouTube video describing in-field monitoring for wheat midge.  

More information about Wheat midge can be found by accessing the pages from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide”.  View ONLY the Wheat midge pages but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

Bertha armyworm

Click to link to last week’s information posted for Wk 13 (released 23Jul2020) to review the predictive model outputs for this insect pest. As larvae now begin to develop and feed in fields, emphasis is now placed on in-field scouting in areas where high moth counts are being intercepted by provincial networks highlighted below.

Weekly Pheromone-baited Trapping Results – Early season detection of bertha armyworm is improved through the use of pheromone-baited unitraps traps deployed in fields across the Canadian prairies.  Click each province name to access moth reporting numbers observed in AlbertaSaskatchewan and Manitoba. Remember in-field scouting is required to apply the economic threshold to manage both this pest and its natural enemies. For convenience, screen shots of available maps or data from Alberta, Saskatchewan, and Manitoba are below.

This image has an empty alt attribute; its file name is 2020Jul15_BAW_SK-791x1024.png
This image has an empty alt attribute; its file name is 2020Jul22_BAW_MB.png

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting.  Use the images above (Fig. 4) to help identify the economically important larvae.  Review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

This image has an empty alt attribute; its file name is 2019_PPMN-Protocol_BAW_LifeStages_Williams.png
Figure 4. The egg stage (A), larval stage (B), pupal stage (C), and adult stage (D) of bertha armyworm. Photos: Jonathon Williams (AAFC-Saskatoon).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of ManitobaSaskatchewanAlberta and the Prairie Pest Monitoring Network. Also refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.

Diamondback moth

Diamondback moth (Plutellidae: Plutella xylostella) – Once the diamondback moth is present in the area, it is important to monitor individual canola fields for larvae.  Warm growing conditions can quickly translate into multiple generations in a very short period!

Monitoring: Remove the plants in an area measuring 0.1 m² (about 12″ square), beat them on to a clean surface and count the number of larvae (Fig. 1) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

This image has an empty alt attribute; its file name is DBM_Larva_AAFC.jpg
Figure 1. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.
This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 2. Diamondback moth pupa within silken cocoon.

Economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 3. Diamondback moth.

Biological and monitoring information for DBM is posted by Manitoba AgricultureSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  

More information about Diamondback moths can be found by accessing the pages from the  “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide“.  View ONLY the Diamondback moth page but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

Lygus bug monitoring

On the Canadian prairies, lygus bugs (Heteroptera: Miridae) are normally a complex of several native species usually including Lygus lineolaris, L. keltoni, L. borealis, L. elisus although several more species are distributed throughout Canada. The species of Lygus forming the “complex” can vary by host plant, by region or even seasonally.

Lygus bugs are polyphagous (i.e., feed on plants belonging to several Families of plants) and multivoltine (i.e., capable of producing multiple generations per year). Both the adult (Fig. 1) and five nymphal instar stages (Fig. 2) are a sucking insect. Adults overwinter in northern climates. The economic threshold for Lygus in canola is applied at late flower and early pod stages.  

This image has an empty alt attribute; its file name is 2019_Lygus_lineolaris_AAFC-Sask.png
Figure 1. Adult Lygus lineolaris (5-6 mm long) (photo: AAFC-Saskatoon).
This image has an empty alt attribute; its file name is 2019_Lygus_nymph_AAFC-Sask.png
Figure 2. Fifth instar lygus bug nymph (3-4 mm long) (photo: AAFC-Saskatoon).

Damage: Lygus bugs have piercing-sucking mouthparts and physically damage the plant by puncturing the tissue and sucking plant juices. The plants also react to the toxic saliva that the insects inject when they feed. Lygus bug infestations can cause alfalfa to have short stem internodes, excessive branching, and small, distorted leaves. In canola, lygus bugs feed on buds and blossoms and cause them to drop. They also puncture seed pods and feed on the developing seeds causing them to turn brown and shrivel.

Scouting tips to keep in mind: Begin monitoring canola when it bolts and continue until seeds within the pods are firm. Since adults can move into canola from alfalfa, check lygus bug numbers in canola when nearby alfalfa crops are cut.

Sample the crop for lygus bugs on a sunny day when the temperature is above 20 °C and the crop canopy is dry. With a standard insect net (38 cm diameter), take ten 180 ° sweeps. Count the number of lygus bugs in the net. Sampling becomes more representative IF repeated at multiple spots within a field so sweep in at least 10 locations within a field to estimate the density of lygus bugs. In fact, sampling is most accurate when repeated at a total of 15 spots within the field.  Samples can be taken along or near the field margins. Calculate the cumulative total number of lygus bugs and then consult the sequential sampling chart (Figure 3). 

This image has an empty alt attribute; its file name is 1998_SequentialSampling_WiseAndLamb.png
Figure 3. Sequential sampling for lygus bugs at late flowering stage in canola.

If the total number is below the lower threshold line (Fig. 3), no treatment is needed. If the total is below the upper threshold line, take more samples. If the total is on or above the upper threshold line, calculate the average number of lygus bugs per 10-sweep sample and consult the economic threshold tables (Tables 1 and 2).

The economic threshold for lygus bugs in canola covers the end of the flowering (Table 1) and the early pod ripening stages (Table 2). Once the seeds have ripened to yellow or brown, the cost of controlling lygus bugs may exceed the damage they will cause prior to harvest, so insecticide application is not warranted. Consider the estimated cost of spraying and expected return prior to making a decision to treat a crop. 

This image has an empty alt attribute; its file name is 1998_EconomicThreshold_LateFlower-EarlyPod_Captions-1024x488.png
This image has an empty alt attribute; its file name is 1998_EconomicThreshold_Pod_Captions-1024x461.png

Remember that insecticide applications at bud stage in canola have not been proven to result in an economic benefit in production.  The exception to this is in the Peace River region where early, dry springs and unusually high densities of lygus bug adults can occasionally occur at bud stage.  In this situation, high numbers of lygus bugs feeding on moisture-stressed canola at bud stage is suspected to result in delay of flowering so producers in that region must monitor in fields that fail to flower as expected.

How to tell them apart: The 2019 Insect of the Week’s doppelganger for Wk 15 was lygus bug versus the alfalfa plant bug while Wk 16 featured lygus bug nymphs vs. aphids!  Both posts include tips to to discern the difference between when doing in-field scouting!

Biological and monitoring information related to Lygus in field crops is posted by the provinces of Manitoba or Alberta fact sheets or the Prairie Pest Monitoring Network’s monitoring protocol.  Also refer to the Lygus pages within the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” – both English or French versions are available.

Field heroes

The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops. Check the recently updated Field Heroes website for scouting guides, downloadable posters, and videos. Learn about these important organisms at work in your fields!  

Real Agriculture went live in 2020 with a Pest and Predators podcast series!

• Access Episode 1 – Do you know your field heroes?

• Access Episode 2 – An inside look at the Prairie Pest Monitoring Network.

• Access Episode 3 – How much can one wasp save you?

• Access Episode 4 – Eat and be eaten — grasshoppers as pests and food

• Access Episode 5 – Killer wasp has only one target — wheat stem sawfly

• Access Episode 6Plentiful parasitoids

Access ALL the Field Heroes links here and be sure to follow @FieldHeroes!

West nile virus risk

Health Canada posts information related to West Nile Virus in Canada and also tracks West Nile Virus through humanmosquitobird and horse surveillance.  Link here to access the most current weekly update (July 5-11, 2020; retrieved July 30, 2020). The screenshot below (retrieved July 30, 2020) serves reference but access that information here.

This image has an empty alt attribute; its file name is 2020Jun28-Jul04_WNV_Weekly_HealthCanada-1024x593.png

The following is offered to predict when Culex tarsalis, the vector for West Nile Virus, will begin to fly across the Canadian prairies (Fig. 1). This week, regions most advanced in degree-day accumulations for Culex tarsalis are shown in the map below (yellow, orange then red highlighted areas).  As of July 30, 2020 (Fig. 1), areas highlighted yellow and more imminently orange are approaching sufficient heat accumulation for mosquitoes to emerge.  Areas highlighted red NOW HAVE Culex tarsalis flying (Fig. 1) – protect yourself by wearing DEET!  

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of July 30, 2020).

Provincial insect pest report links

Provincial entomologists provide insect pest updates throughout the growing season so link to their information: 

Manitoba‘s Crop Pest Updates for 2020 are available. Access the July 29, 2020 report. The summary indicates that, “Grasshoppers are the insect of greatest concern to field crops in Manitoba currently. Some populations of diamondback moth above economic threshold have been found in eastern Manitoba recently.”

Saskatchewan‘s Crop Production News (for Issue 6). Read Issue 5 which includes articles on Bertha armyworm, Cabbage seedpod weevil,  FieldWatch – Fostering Communication Between Applicators and Producers, and Look What the Wind Blew in! Diamondback Moths Arrived Early This Spring. Issue #4 included articles on Pest Scouting 101: Mid-Summer, and The Wheat Midge.

•  Alberta Agriculture and Forestry’s Agri-News occasionally includes insect-related information or Twitter users can connect to #ABBugChat Wednesdays at 10:00 am.

Crop report links

Click the provincial name below to link to online crop reports produced by:

• Manitoba Agriculture and Rural Initiatives – Other viewing options include subscribing to receive or access a PDF of July 28, 2020 report.

• Saskatchewan Agriculture  or access a PDF of July 21-27, 2020 report.

• Alberta Agriculture and Forestry or access a PDF of July 14, 2020 report.

The following crop reports are also available:

• The United States Department of Agriculture (USDA) produces a Crop Progress Report (read the July 27, 2020 edition).

• The USDA’s Weekly Weather and Crop Bulletin (read the July 28, 2020 edition). 

Previous posts


Click to review these earlier 2020 Posts (organized alphabetically):

    • 2019-2020 Risk and forecast maps

    • Alfalfa weevil (Wk08)

    • Aster leafhopper (Wk05)

    • Beetle data please! (Wk03)

    • Cereal aphid APP (Wk11)

    • Crop protection guides (Wk02)

    • Cutworms (Wk02)

    • Diamondback moth (Wk11)

    • Flea beetles (Wk02)

    • John Doane (Wk10)

    • Monarch migration (Wk10)

    • Pea leaf weevil (Wk11)

    • Pea leaf weevil – predicted development (Wk09)

    • Prairie provincial insect webpages (Wk02)

    • Predictive model updates: Bertha armyworm, Grasshoppers, Wheat midge (Wk13).

    • Scouting charts – canola and flax (Wk02)

    • Ticks and Lyme Disease (Wk06)

    • Wind trajectories (Wk09)

Weather synopsis

This past week (July 13-19, 2020) prairie temperatures were warmest in Manitoba and eastern Saskatchewan (Table 1; Fig. 1). Average 7-day temperatures continue to be warmest across Manitoba and eastern Saskatchewan and coolest across most of Alberta(Table 1; Fig. 1).

Figure 1. Observed average temperatures across the Canadian prairies the past seven days (July 13-19, 2020).

Average 30-day (June 20-July 19, 2020) temperatures continued to be cooler in Alberta than eastern Saskatchewan and Manitoba (Table 2; Fig. 2). The average 30-day temperature at Winnipeg and Brandon continued to be greater than locations in Alberta and Saskatchewan(Table 2; Fig. 2). Based on growing season temperatures (April 1 – July 19, 2020), conditions continue to be warmest for southern locations (Table 3).

Figure 2. Observed average temperatures across the Canadian prairies the past 30 days (June 20-July 19, 2020).

Cumulative rainfall for the past 7 days was lowest across southern regions of Alberta and Saskatchewan. Cumulative 30-day rainfall was lowest across a large area ranging from southwest Saskatchewan to Saskatoon. Growing season rainfall (percent of average) is below normal across eastern Saskatchewan and localized areas of Manitoba.

Figure 4. Observed cumulative precipitation across the Canadian prairies the past seven days (July 16-19, 2020).
Figure 5. Observed cumulative precipitation across the Canadian prairies the past 30 days (June 20-July 19, 2020).
Figure 6. Percent of average precipitation for the growing season (April 1-July 19, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (21Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The growing degree day map (GDD) (Base 5 ºC, April 1-July 13, 2020) is below (Fig. 7) while the growing degree day map (GDD) (Base 10 ºC, April 1-July 13, 2020) is shown in Figure 8.

Figure 7. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-July 22, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 8. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-July 22, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <19 to >32 °C (Fig. 9). So far this growing season (up to July 22, 2020), the number of days above 25 ranges from 0-10 days throughout much of Alberta and into the BC Peace then extends up to 41-50 days in southern Manitoba (Fig. 10).

Figure 9. Highest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-July 19, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 10. Number of days above 25 °C observed across the Canadian prairies this growing season (April 1-July 22, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The maps above are all produced by Agriculture and Agri-Food Canada. Growers can bookmark the AAFC Current Conditions Drought Watch Maps for the growing season. Historical weather data can be access at the AAFC Drought Watch website, Environment Canada’s Historical Data website, or your provincial weather network.

Predicted bertha armyworm development

Model simulations for July 19, 2020 (Fig. 1) indicate that 23% of the bertha armyworm (BAW) population is in the egg stage (compared to 35% last week) and 77% are predicted to be larvae (compared to 65% last week). Across the Parkland and Peace River regions, BAW populations are predicted to be primarily in the egg stage (Fig. 1). Other than the Peace River region, populations are primarily in the larval stage (Fig. 1). Fields near Carman, Winnipeg and Morden in Manitoba are expected to have first appearance of pupae, suggesting larval development is advanced (Fig. 1).

Figure 1. Predicted percent of bertha armyworm (Mamestra configurata) population in the larval stage as of July 19, 2020.

The two graphs below demonstrate that BAW populations near Winnipeg (Fig. 2) are more advanced than populations near Grande Prairie (Fig. 3). In Winnipeg populations are primarily in the larval stage with first appearance of pupae (Fig. 2). BAW populations near Grande Prairie are predicted to be in adult, egg and larval stages (Fig. 3).

Figure 2. Predicted bertha armyworm (Mamestra configurata) phenology at Winnipeg MB as of July 19, 2020.
Figure 3. Predicted bertha armyworm (Mamestra configurata) phenology at Grande Prairie AB as of July 19, 2020.

Weekly Pheromone-baited Trapping Results – Early season detection of bertha armyworm is improved through the use of pheromone-baited unitraps traps deployed in fields across the Canadian prairies.  Click each province name to access moth reporting numbers observed in AlbertaSaskatchewan and Manitoba (as they become available). Check these sites to assess cumulative counts and relative risk in your geographic region but remember in-field scouting is required to apply the economic threshold to manage both this pest and its natural enemies. For convenience, screen shots of the above maps or data have been placed below for Alberta, Saskatchewan, and Manitoba.

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting.  Use the images above (Fig. 4) to help identify the economically important larvae.  Review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

This image has an empty alt attribute; its file name is 2019_PPMN-Protocol_BAW_LifeStages_Williams.png
Figure 4. The egg stage (A), larval stage (B), pupal stage (C), and adult stage (D) of bertha armyworm. Photos: Jonathon Williams (AAFC-Saskatoon).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of ManitobaSaskatchewanAlberta and the Prairie Pest Monitoring Network. Also refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted wheat midge development

This week (as of July 19, 2020), regions of the Canadian prairies are either at a sensitive time for wheat midge monitoring OR the opportunity to scout and apply insecticides to prevent adult midge from laying eggs may have passed. Scouting remains essential now, especially in areas where wheat midge development was slightly delayed according to last week’s model output (Table 1). Note that the model predicted populations near Lethbridge, Grande Prairie and Lacombe would be at 90% emergence on July 23, July 25, and July 26, respectively.

This week, wheat midge model runs indicate that, where wheat midge are present and rainfall has been adequate, adult emergence is well underway and oviposition is occurring, and early instar larvae may be present and beginning to feed on developing wheat kernels. Low rainfall amounts across large areas of Manitoba and Saskatchewan has resulted in delayed adult emergence, resulting in lower egg densities, according to our model.

Figure 1. Predicted wheat midge (Sitodiplosis mosellana) phenology at Saskatoon SK.
Values are based on model simulations (April 1-July 19, 2020).
Figure 2. Predicted wheat midge (Sitodiplosis mosellana) phenology at Lacombe AB.
Values are based on model simulations (April 1-July 19, 2020).

Figure 3 compares synchrony between wheat midge and wheat development for fields near Saskatoon. The graph indicates that peak adult emergence and oviposition are likely to occur during anthesis; wheat susceptibility decreases once the crop is flowering (Fig. 3). Figure 4 compares the predicted phenology near Saskatoon of wheat midge adults with Macroglenes penetrans, a parasitoid of wheat midge. The parasitoid wasp seeks out and lays eggs in wheat midge eggs. The graph shows that emergence/oviposition of wheat midge adults and M. penetrans are similar (Fig. 4). Taken together, this information can be used as a guide to determine when fields should be monitored.

Figure 3. Comparison of predicted phenology of wheat midge (Sitodiplosis mosellana) and wheat at Saskatoon SK as of July 19, 2020.
Figure 4. Comparison of predicted phenology of wheat midge (Sitodiplosis mosellana) and its parasitoid, Macroglenes penetrans, at Saskatoon SK as of July 19, 2020.

Information related to wheat midge biology and monitoring can be accessed by linking to your provincial fact sheet (Saskatchewan Agriculture or Alberta Agriculture & Forestry).  A review of wheat midge on the Canadian prairies was published by Elliott, Olfert, and Hartley in 2011.  

Alberta Agriculture and Forestry has a YouTube video describing in-field monitoring for wheat midge.  

More information about Wheat midge can be found by accessing the pages from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide”.  View ONLY the Wheat midge pages but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted grasshopper development

As of July 19, 2020, the grasshopper model estimates that development of first instar nymphs is complete across most of the prairies and that adult grasshoppers may be beginning to emerge in southern Manitoba and Saskatchewan (Fig. 1; Table 1). Based on model simulations, development has been slowest in the Peace River region where average nymph development ranges between the 2nd and 3rd instar stages (Fig. 1; Table 1). Across the southern prairies, the majority of the nymph population is predicted to be in the 4th and 5th instar stages, with adults predicted to occur across southern Manitoba and Saskatchewan, where grasshopper populations are active (Fig. 1; Table 1).

Figure 1. Predicted average development stages of grasshopper (Melanoplus sanguinipes) populations across the Canadian prairies (as of July 19, 2020).

Table 1 indicates that predicted development at Brandon and Winnipeg is well ahead of Lacombe and Grande Prairie. The two graphs below compare grasshopper development at Lacombe (Fig. 2) and Brandon (Fig. 3). Near Lacombe, grasshopper populations are expected to be mainly in the 3rd and 4th instar (Fig. 2). Around Brandon, adult emergence is expected to be well underway, with some lingering 3rd, 4th, and 5th instar individuals remaining in the population (Fig. 3).

Figure 2. Predicted grasshopper (Melanoplus sanguinipes) phenology at Lacombe AB. Values are based on model simulations (April 1-July 19, 2020).
Figure 3. Predicted grasshopper (Melanoplus sanguinipes) phenology at Brandon MB. Values are based on model simulations (April 1-July 19, 2020).

Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba AgricultureSaskatchewan AgricultureAlberta Agriculture and Forestry, the BC Ministry of Agriculture and the Prairie Pest Monitoring Network.  Also refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (Philip et al. 2018) as an English-enhanced or French-enhanced version.

Lygus bug monitoring

On the Canadian prairies, lygus bugs (Heteroptera: Miridae) are normally a complex of several native species usually including Lygus lineolaris, L. keltoni, L. borealis, L. elisus although several more species are distributed throughout Canada. The species of Lygus forming the “complex” can vary by host plant, by region or even seasonally.

Lygus bugs are polyphagous (i.e., feed on plants belonging to several Families of plants) and multivoltine (i.e., capable of producing multiple generations per year). Both the adult (Fig. 1) and five nymphal instar stages (Fig. 2) are a sucking insect. Adults overwinter in northern climates. The economic threshold for Lygus in canola is applied at late flower and early pod stages.  

This image has an empty alt attribute; its file name is 2019_Lygus_lineolaris_AAFC-Sask.png
Figure 1. Adult Lygus lineolaris (5-6 mm long) (photo: AAFC-Saskatoon).
This image has an empty alt attribute; its file name is 2019_Lygus_nymph_AAFC-Sask.png
Figure 2. Fifth instar lygus bug nymph (3-4 mm long) (photo: AAFC-Saskatoon).

Damage: Lygus bugs have piercing-sucking mouthparts and physically damage the plant by puncturing the tissue and sucking plant juices. The plants also react to the toxic saliva that the insects inject when they feed. Lygus bug infestations can cause alfalfa to have short stem internodes, excessive branching, and small, distorted leaves. In canola, lygus bugs feed on buds and blossoms and cause them to drop. They also puncture seed pods and feed on the developing seeds causing them to turn brown and shrivel.

Scouting tips to keep in mind: Begin monitoring canola when it bolts and continue until seeds within the pods are firm. Since adults can move into canola from alfalfa, check lygus bug numbers in canola when nearby alfalfa crops are cut.

Sample the crop for lygus bugs on a sunny day when the temperature is above 20 °C and the crop canopy is dry. With a standard insect net (38 cm diameter), take ten 180 ° sweeps. Count the number of lygus bugs in the net. Sampling becomes more representative IF repeated at multiple spots within a field so sweep in at least 10 locations within a field to estimate the density of lygus bugs. In fact, sampling is most accurate when repeated at a total of 15 spots within the field.  Samples can be taken along or near the field margins. Calculate the cumulative total number of lygus bugs and then consult the sequential sampling chart (Figure 3). 

This image has an empty alt attribute; its file name is 1998_SequentialSampling_WiseAndLamb.png
Figure 3. Sequential sampling for lygus bugs at late flowering stage in canola.

If the total number is below the lower threshold line (Fig. 3), no treatment is needed. If the total is below the upper threshold line, take more samples. If the total is on or above the upper threshold line, calculate the average number of lygus bugs per 10-sweep sample and consult the economic threshold tables (Tables 1 and 2).

The economic threshold for lygus bugs in canola covers the end of the flowering (Table 1) and the early pod ripening stages (Table 2). Once the seeds have ripened to yellow or brown, the cost of controlling lygus bugs may exceed the damage they will cause prior to harvest, so insecticide application is not warranted. Consider the estimated cost of spraying and expected return prior to making a decision to treat a crop. 

This image has an empty alt attribute; its file name is 1998_EconomicThreshold_LateFlower-EarlyPod_Captions-1024x488.png
This image has an empty alt attribute; its file name is 1998_EconomicThreshold_Pod_Captions-1024x461.png

Remember that insecticide applications at bud stage in canola have not been proven to result in an economic benefit in production.  The exception to this is in the Peace River region where early, dry springs and unusually high densities of lygus bug adults can occasionally occur at bud stage.  In this situation, high numbers of lygus bugs feeding on moisture-stressed canola at bud stage is suspected to result in delay of flowering so producers in that region must monitor in fields that fail to flower as expected.

How to tell them apart: The 2019 Insect of the Week’s doppelganger for Wk 15 was lygus bug versus the alfalfa plant bug while Wk 16 featured lygus bug nymphs vs. aphids!  Both posts include tips to to discern the difference between when doing in-field scouting!

Biological and monitoring information related to Lygus in field crops is posted by the provinces of Manitoba or Alberta fact sheets or the Prairie Pest Monitoring Network’s monitoring protocol.  Also refer to the Lygus pages within the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” – both English or French versions are available.

Field heroes

The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops. Check the recently updated Field Heroes website for scouting guides, downloadable posters, and videos. Learn about these important organisms at work in your fields!  

Real Agriculture went live with a Pest and Predators podcast series!

• Access Episode 1 – Do you know your field heroes?

• Access Episode 2 – An inside look at the Prairie Pest Monitoring Network.

• Access Episode 3 – How much can one wasp save you?

• Access Episode 4 – Eat and be eaten — grasshoppers as pests and food

• Access Episode 5 – Killer wasp has only one target — wheat stem sawfly

• NEW – Access Episode 6Plentiful parasitoids

Access ALL the Field Heroes links here and be sure to follow @FieldHeroes!

West nile virus risk

Health Canada posts information related to West Nile Virus in Canada and also tracks West Nile Virus through humanmosquitobird and horse surveillance.  Link here to access the most current weekly update (July 4, 2020; retrieved July 23, 2020). The screenshot below (retrieved July 23, 2020) serves reference but access that information here.

This image has an empty alt attribute; its file name is 2020Jun28-Jul04_WNV_Weekly_HealthCanada-1024x593.png

The following is offered to predict when Culex tarsalis, the vector for West Nile Virus, will begin to fly across the Canadian prairies (Fig. 1). This week, regions most advanced in degree-day accumulations for Culex tarsalis are shown in the map below (yellow, orange then red highlighted areas).  As of July 19, 2020, areas highlighted yellow and more imminently orange are approaching sufficient heat accumulation for mosquitoes to emerge.  Plan to protect yourself by wearing DEET!  

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of July 19, 2020).

Provincial insect pest report links

Provincial entomologists provide insect pest updates throughout the growing season so link to their information: 

Manitoba‘s Crop Pest Updates for 2020 are available. Access the July 22, 2020 report. The summary indicates that, “Grasshoppers and armyworms continue to be the insects of greatest concern. Twostriped grasshopper is mainly into the later nymph stages with some adults present; clearwinged grasshopper adults are present. Lots of reports of Cotesia pupal clusters in some of the cereals, resulting from parasitized armyworm populations. Armyworms seem to be turning to pupae and levels dropping in some areas. Jack pine budworm, a moth whose larvae feed on pines trees, is very abundant this year, and agronomists are noticing the moths around farmyards are enquiring regarding what it is and what it feeds on.”

Saskatchewan‘s Crop Production News and read Issue 5 which includes articles on Bertha armyworm, Cabbage seedpod weevil,  FieldWatch – Fostering Communication Between Applicators and Producers, and Look What the Wind Blew in! Diamondback Moths Arrived Early This Spring. Issue #4 included articles on Pest Scouting 101: Mid-Summer, and The Wheat Midge.

•  Alberta Agriculture and Forestry’s Agri-News occasionally includes insect-related information or Twitter users can connect to #ABBugChat Wednesdays at 10:00 am.

Crop report links

Click the provincial name below to link to online crop reports produced by:

• Manitoba Agriculture and Rural Initiatives – Other viewing options include subscribing to receive or access a PDF of July 21, 2020 report.

• Saskatchewan Agriculture  or access a PDF of July 14-20, 2020 report.

• Alberta Agriculture and Forestry or access a PDF of July 14, 2020 report.

The following crop reports are also available:

• The United States Department of Agriculture (USDA) produces a Crop Progress Report (read the July 20, 2020 edition).

• The USDA’s Weekly Weather and Crop Bulletin (read the July 21, 2020 edition). 

Previous posts

Click to review these earlier 2020 Posts (organized alphabetically):

    • 2019-2020 Risk and forecast maps

    • Alfalfa weevil (Wk08)

    • Aster leafhopper (Wk05)

    • Beetle data please! (Wk03)

    • Cereal aphid APP (Wk11)

    • Crop protection guides (Wk02)

    • Cutworms (Wk02)

    • Diamondback moth (Wk11)

    • Flea beetles (Wk02)

    • John Doane (Wk10)

    • Monarch migration (Wk10)

    • Pea leaf weevil (Wk11)

    • Pea leaf weevil – predicted development (Wk09)

    • Prairie provincial insect webpages (Wk02)

    • Scouting charts – canola and flax (Wk02)

    • Ticks and Lyme Disease (Wk06)

    • Wind trajectories (Wk09)

Weather synopsis

The 2020 growing season, April 1 – July 12, 2020, has been cooler and wetter than normal across many locations in Alberta and Saskatchewan. Conditions in Manitoba have been warmer and dryer than normal. This past week (July 6-12, 2020) prairie temperatures were warmest in Manitoba and eastern Saskatchewan (Table 1; Fig. 1). Average 7-day temperatures continue to be warmest across Manitoba and eastern Saskatchewan and coolest across most of Alberta (Table 1; Fig. 1).

Figure 1. Observed average temperatures across the Canadian prairies the past seven days (July 6-12, 2020).

Average 30-day (June 13-July 12, 2020) temperatures continue to be cooler in Alberta than in southern Saskatchewan and Manitoba (Table 2; Fig. 2). The average 30-day temperature at Winnipeg and Brandon continued to be greater than locations in Alberta and Saskatchewan (Fig. 2). Temperature anomalies indicate that temperatures have been below normal across most of Alberta and Saskatchewan and were 0 to 2 °C warmer than average across eastern Saskatchewan and southern Manitoba (Table 2; Fig. 3). Based on growing season temperatures (April 1 – July 12, 2020), conditions have been warmest for southern locations (Table 3).

Figure 2. Observed average temperatures across the Canadian prairies the past 30 days (June 13-July 12, 2020).
Figure 3. Mean temperature difference from Normal the past 30 days (June 16-July 13, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (13Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Cumulative rainfall for the past 7 days was lowest across southern regions of Alberta and across most of Manitoba (Table 1 Fig. 4). Lethbridge reported 4.2 mm and Winnipeg reported 1.4 mm (Table 1). Cumulative 30 day rainfall continued to be greatest across central regions of Alberta (Table 2; Fig. 5). Rainfall amounts were lowest across southern regions of the prairies (Table 2; Fig. 5).

Figure 4. Observed cumulative precipitation across the Canadian prairies the past seven days (July 6-12, 2020).

Total 30-day rainfall at Brandon, Winnipeg and Swift Current was less than 100 mm (Table 2; Fig. 5). Lethbridge has reported 122.3 mm (261% of normal) in the past 30 days (Table 2). Growing season rainfall (percent of average) is below normal across eastern Saskatchewan and localized areas of Manitoba.

Figure 5. Observed cumulative precipitation across the Canadian prairies the past 30 days (June 13-July 12, 2020).
Figure 6. Percent of average precipitation for the growing season (April 1-July 13, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (14Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The growing degree day map (GDD) (Base 5 ºC, April 1-July 13, 2020) is below (Fig. 7):

Figure 7. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-July 13, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (16Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The growing degree day map (GDD) (Base 10 ºC, April 1-July 13, 2020) is below (Fig. 8):

Figure 8. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-July 13, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (16Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The highest temperatures (°C) observed the past seven days ranged from <15 to >33 °C in the map below (Fig. 9).

Figure 9. Highest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-July 13, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (16Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The maps above are all produced by Agriculture and Agri-Food Canada. Growers can bookmark the AAFC Current Conditions Drought Watch Maps for the growing season. Historical weather data can be access at the AAFC Drought Watch website, Environment Canada’s Historical Data website, or your provincial weather network.

Predicted bertha armyworm development

Model simulations for July 12, 2020 indicate that 35% of the population is in the egg stage (37% last week) and 65% of the population is in the larval stages (14% last week). Across the Parkland and Peace River regions, BAW populations are predicted to be primarily in the egg stage (Fig. 1). Populations across southern regions are primarily in the larval stage (Fig. 1).

Figure 1. Predicted percent of bertha armyworm (Mamestra configurata) population in the larval stage as of July 12, 2020.

The two graphs below demonstrate that larval development near Brandon is predicted to be ahead of fields near Grande Prairie. In Brandon, populations are primarily in the larval stage (Fig. 2) while BAW populations near Grande Prairie are predicted to be predominantly in adult and egg stages (Fig. 3).

Figure 3. Predicted bertha armyworm (Mamestra configurata) phenology at Brandon MB as of July 12, 2020.
Figure 3. Predicted bertha armyworm (Mamestra configurata) phenology at Grande Prairie AB as of July 12, 2020.
Figure 5. The egg stage (A), larval stage (B), pupal stage (C), and adult stage (D) of bertha armyworm. Photos: Jonathon Williams (AAFC-Saskatoon).

Weekly Pheromone-baited Trapping Results – Early season detection of bertha armyworm is improved through the use of pheromone-baited unitraps traps deployed in fields across the Canadian prairies.  Click each province name to access moth reporting numbers observed in AlbertaSaskatchewan and Manitoba (as they become available). Check these sites to assess cumulative counts and relative risk in your geographic region but remember in-field scouting is how the economic threshold is applied to manage this pest.

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting.  Use the images above (Fig. 5) to help identify the economically important larvae.  Review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of ManitobaSaskatchewanAlberta and the Prairie Pest Monitoring Network. Also refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted wheat midge development

Wheat midge model runs indicate that, where wheat midge are present, adult emergence is well underway and oviposition is occurring across most prairie locations. The map suggests that, as of July 12, 2020, populations are primarily in the egg stage (Fig. 1). Low rainfall amounts across large areas of Manitoba and Saskatchewan has resulted in delayed adult emergence, resulting in lower egg densities.

Figure 1. Predicted percent of population of wheat midge (Sitodiplosis mosellana) at adult stage across the Canadian prairies (as of July 12, 2020).

The next 10-14 days are very important for monitoring wheat midge populations for the purpose of making management decisions. Simulations were run to July 26 to assess population development over the next 10 days (Table 1). The following table indicates that 50% emergence of adults should occur this week at Saskatoon and next week at Lacombe (Table 1). This week populations in Manitoba are predicted to be at 90% adult emergence (Table 1).

The two graphs below illustrate the development of wheat midge populations near Saskatoon (Fig. 2) and Lacombe (Fig. 3). Adult numbers are currently peaking near Saskatoon while adult emergence near Lacombe is not expected to peak until next week.

Figure 2. Predicted wheat midge (Sitodiplosis mosellana) phenology at Saskatoon SK projected to July 21, 2020.
Figure 3. Predicted wheat midge (Sitodiplosis mosellana) phenology at Lacombe AB projected to July 21, 2020.

The next two graphs compare the synchrony between wheat midge and wheat for fields near Lacombe (Fig. 4). The graph indicates that peak adult emergence and oviposition may occur during anthesis; wheat susceptibility decreases once the crop is flowering (Fig. 4).

Figure 4. Comparison of predicted phenology of wheat midge (Sitodiplosis mosellana) and wheat at Lacombe AB projected to July 21, 2020.

The last graph compares phenology (Saskatoon) of wheat midge adults with Macroglenes penetrans, a parasitoid of wheat midge (Fig. 5). The parasitoid wasp lays eggs in wheat midge eggs. The graph shows that emergence/oviposition of wheat midge adults and M. penetrans are similar (Fig. 5). This information can be used as a guide to determine when fields should be monitored.

Figure 5. Comparison of predicted phenology of wheat midge (Sitodiplosis mosellana) and its parasitoid, Macroglenes penetrans, at Saskatoon SK projected to July 21, 2020.

Information related to wheat midge biology and monitoring can be accessed by linking to your provincial fact sheet (Saskatchewan Agriculture or Alberta Agriculture & Forestry).  A review of wheat midge on the Canadian prairies was published by Elliott, Olfert, and Hartley in 2011.  

Alberta Agriculture and Forestry has a YouTube video describing in-field monitoring for wheat midge.  

More information about Wheat midge can be found by accessing the pages from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide”.  View ONLY the Wheat midge pages but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted grasshopper development

As of July 12, 2020, the grasshopper model estimates that development across the prairies ranges from 1st instar stage to adults. Based on the model simulations, development has been slowest in the Peace River region where average nymph development ranges between the 2nd and 3rd instars (Fig. 1; Table 1). Across the southern prairies, the majority of the nymph population is predicted to be in the 3rd to 5th instar stages, with adults predicted to occur across southern Manitoba where populations are active (Fig. 1; Table 1). Across the prairies, populations are predicted to be 6, 6, 11, 27, 24, 21 and 5% in egg, first, second, third, fourth, fifth and adult stages, respectively.

Figure 1. Predicted average instar stages of grasshopper (Melanoplus sanguinipes) populations across the Canadian prairies (as of July 12, 2020).

Table 1 indicates that predicted development at Brandon and Winnipeg is well ahead of Lacombe and Grande Prairie. The two graphs compare grasshopper development in Saskatoon (Fig. 2) and Winnipeg (Fig. 3). Grasshopper populations near Saskatoon are predominantly in the 4th and 5th instars with first appearance of adults beginning to occur (Fig. 2). Populations near Winnipeg are expected to be primarily adults (Fig. 3).

Figure 2. Predicted grasshopper (Melanoplus sanguinipes) phenology at Saskatoon SK. Values are based on model simulations (April 1-July 12, 2020).
Figure 3. Predicted grasshopper (Melanoplus sanguinipes) phenology at Winnipeg MB. Values are based on model simulations (April 1-July 12, 2020).

Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba AgricultureSaskatchewan AgricultureAlberta Agriculture and Forestry, the BC Ministry of Agriculture and the Prairie Pest Monitoring Network.  Also refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (Philip et al. 2018) as an English-enhanced or French-enhanced version. 

Lygus bug monitoring

On the Canadian prairies, lygus bugs (Heteroptera: Miridae) are normally a complex of several native species usually including Lygus lineolaris, L. keltoni, L. borealis, L. elisus although several more species are distributed throughout Canada. The species of Lygus forming the “complex” can vary by host plant, by region or even seasonally.

Lygus bugs are polyphagous (i.e., feed on plants belonging to several Families of plants) and multivoltine (i.e., capable of producing multiple generations per year). Both the adult (Fig. 1) and five nymphal instar stages (Fig. 2) are a sucking insect. Adults overwinter in northern climates. The economic threshold for Lygus in canola is applied at late flower and early pod stages.  

Figure 1. Adult Lygus lineolaris (5-6 mm long) (photo: AAFC-Saskatoon).
Figure 2. Fifth instar lygus bug nymph (3-4 mm long) (photo: AAFC-Saskatoon).

Damage: Lygus bugs have piercing-sucking mouthparts and physically damage the plant by puncturing the tissue and sucking plant juices. The plants also react to the toxic saliva that the insects inject when they feed. Lygus bug infestations can cause alfalfa to have short stem internodes, excessive branching, and small, distorted leaves. In canola, lygus bugs feed on buds and blossoms and cause them to drop. They also puncture seed pods and feed on the developing seeds causing them to turn brown and shrivel.

Scouting tips to keep in mind: Begin monitoring canola when it bolts and continue until seeds within the pods are firm. Since adults can move into canola from alfalfa, check lygus bug numbers in canola when nearby alfalfa crops are cut.

Sample the crop for lygus bugs on a sunny day when the temperature is above 20 °C and the crop canopy is dry. With a standard insect net (38 cm diameter), take ten 180 ° sweeps. Count the number of lygus bugs in the net. Sampling becomes more representative IF repeated at multiple spots within a field so sweep in at least 10 locations within a field to estimate the density of lygus bugs. In fact, sampling is most accurate when repeated at a total of 15 spots within the field.  Samples can be taken along or near the field margins. Calculate the cumulative total number of lygus bugs and then consult the sequential sampling chart (Figure 3). 

Figure 3. Sequential sampling for lygus bugs at late flowering stage in canola.

If the total number is below the lower threshold line (Fig. 3), no treatment is needed. If the total is below the upper threshold line, take more samples. If the total is on or above the upper threshold line, calculate the average number of lygus bugs per 10-sweep sample and consult the economic threshold tables (Tables 1 and 2).

The economic threshold for lygus bugs in canola covers the end of the flowering (Table 1) and the early pod ripening stages (Table 2). Once the seeds have ripened to yellow or brown, the cost of controlling lygus bugs may exceed the damage they will cause prior to harvest, so insecticide application is not warranted. Consider the estimated cost of spraying and expected return prior to making a decision to treat a crop. 

Remember that insecticide applications at bud stage in canola have not been proven to result in an economic benefit in production.  The exception to this is in the Peace River region where early, dry springs and unusually high densities of lygus bug adults can occasionally occur at bud stage.  In this situation, high numbers of lygus bugs feeding on moisture-stressed canola at bud stage is suspected to result in delay of flowering so producers in that region must monitor in fields that fail to flower as expected.

How to tell them apart: The 2019 Insect of the Week’s doppelganger for Wk 15 was lygus bug versus the alfalfa plant bug while Wk 16 featured lygus bug nymphs vs. aphids!  Both posts include tips to to discern the difference between when doing in-field scouting!

Biological and monitoring information related to Lygus in field crops is posted by the provinces of Manitoba or Alberta fact sheets or the Prairie Pest Monitoring Network’s monitoring protocol.  Also refer to the Lygus pages within the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” – both English or French versions are available.

Field heroes


The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops. Check the recently updated Field Heroes website for scouting guides, downloadable posters, and videos. Learn about these important organisms at work in your fields!  

Real Agriculture went live with a Pest and Predators podcast series!

• Access Episode 1 – Do you know your field heroes?

• Access Episode 2 – An inside look at the Prairie Pest Monitoring Network.

• Access Episode 3 – How much can one wasp save you?

• Access Episode 4 – Eat and be eaten — grasshoppers as pests and food

• Access Episode 5 – Killer wasp has only one target — wheat stem sawfly

Access ALL the Field Heroes links here and be sure to follow @FieldHeroes!

West nile virus risk

Health Canada posts information related to West Nile Virus in Canada and also tracks West Nile Virus through humanmosquitobird and horse surveillance.  Link here to access the most current weekly update (July 4, 2020). The screenshot below was retrieved 16Jul2020 as reference but access that information here.

This image has an empty alt attribute; its file name is 2020Jun28-Jul04_WNV_Weekly_HealthCanada-1024x593.png

The following is offered to predict when Culex tarsalis, the vector for West Nile Virus, will begin to fly across the Canadian prairies (Fig. 1). This week, regions most advanced in degree-day accumulations for Culex tarsalis are shown in the map below (yellow, orange then red highlighted areas).  As of July 13, 2020, areas highlighted yellow and more imminently orange are approaching sufficient heat accumulation for mosquitoes to emerge.  Plan to protect yourself by wearing DEET!  

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of July 13, 2020).

Provincial insect pest report links

Provincial entomologists provide insect pest updates throughout the growing season so link to their information: 

Manitoba‘s Crop Pest Updates for 2020 are available. Access the July 15, 2020 report. The summary indicates that, “Armyworms and grasshoppers continue to be the biggest insects concern on crops in Manitoba. Scouting for diamondback moth continues, with just one report of spraying for diamondback moth. Spraying for goosefoot groundling moth and a stem borer maggot has been reported from quinoa. Green cloverworm has been found on soybeans in eastern Manitoba, but not at levels that would be economical. Pupal clusters of Cotesia, a parasitoid of armyworms and other caterpillars, have been reported to be quite abundant in some of the fields that had armyworms.”

Saskatchewan‘s Crop Production News and read Issue 5 which includes articles on Bertha armyworm, Cabbage seedpod weevil,  FieldWatch – Fostering Communication Between Applicators and Producers, and Look What the Wind Blew in! Diamondback Moths Arrived Early This Spring. Issue #4 included articles on Pest Scouting 101: Mid-Summer, and The Wheat Midge.

•  Alberta Agriculture and Forestry’s Agri-News occasionally includes insect-related information or Twitter users can connect to #ABBugChat Wednesdays at 10:00 am.

Crop report links

Click the provincial name below to link to online crop reports produced by:

• Manitoba Agriculture and Rural Initiatives – Other viewing options include subscribing to receive or access a PDF of July 14, 2020 report.

• Saskatchewan Agriculture  or access a PDF of July 7-13, 2020 report.

• Alberta Agriculture and Forestry or access a PDF of June 29, 2020 report.

The following crop reports are also available:

• The United States Department of Agriculture (USDA) produces a Crop Progress Report (read the July 13, 2020 edition).

• The USDA’s Weekly Weather and Crop Bulletin (read the July 14, 2020 edition). 

Previous posts

Click to review these earlier 2020 Posts (organized alphabetically):

    • 2019-2020 Risk and forecast maps

    • Alfalfa weevil (Wk08)

    • Aster leafhopper (Wk05)

    • Beetle data please! (Wk03)

    • Cereal aphid APP (Wk11)

    • Crop protection guides (Wk02)

    • Cutworms (Wk02)

    • Diamondback moth (Wk11)

    • Flea beetles (Wk02)

    • John Doane (Wk10)

    • Monarch migration (Wk10)

    • Pea leaf weevil (Wk11)

    • Pea leaf weevil – predicted development (Wk09)

    • Prairie provincial insect webpages (Wk02)

    • Scouting charts – canola and flax (Wk02)

    • Ticks and Lyme Disease (Wk06)

    • Wind trajectories (Wk09)

Welcome to our NEW Website!

This image has an empty alt attribute; its file name is 2020Jun30_PPMN_Logo_Wide-1024x85.png

We’ve got a new logo AND A NEW HOME!

The Prairie Pest Monitoring Network is excited to share our new website as we continue to update and expand! We have a few VERY IMPORTANT DETAILS below – please read on and Subscribe!

Re-Subscribe to receive our Weekly Updates – Due to Canada’s Anti-Spam Legislation and just plain good manners, we cannot copy your subscription from the old Blog to this new website. Please go to our homepage, click the red “subscribe today” button, type your email address in the white box, confirm you’re NOT a robot, then watch your Inbox or Spam folder to confirm your subscription. Subscribers receive the Weekly Update, Insect of the Week, and any new updates delivered to their Inbox in our new newsletter format.

Same great information – The new website is organized like the Blog. Risk maps, insect monitoring protocols, Weekly Updates, and Insect of the Week features are all easy to find. We’re still working in the background on the new website so don’t be surprised if you link back to the PPMN Blog – we’re keeping it but all new content will move to the new website as of July 10, 2020.

You made us a success – Thank you for using the Blog since it was launched in 2015! We are able to transition to a website now because the Blog is so popular. The new website overcomes some of the Blog shortcomings (e.g., data storage limits). In the future, we hope to introduce new tools to improve insect pest monitoring and insect pest management. Over the coming months, we will work to add information, pictures and links.

And, as usual…… Questions or problems accessing the contents of this Weekly Update? Please email Meghan.Vankosky@canada.ca or Jennifer.Otani@canada.ca . Past “Weekly Updates” can be accessed on our Weekly Update Blog Page.

Weather synopsis

This week, June 29-July 5, 2020, prairie temperatures were warmest in Manitoba and eastern Saskatchewan and seven day cumulative rainfall varied across the prairies (Table 1). Average 7-day temperatures continue to be warmest across Manitoba and eastern Saskatchewan and coolest across most of Alberta (Fig. 1). The weekly average temperature at Winnipeg (24.5 °C) was 6.6 °C warmer than the long term average value and was 10.9 °C warmer than the 7-day observed temperature at Grande Prairie (Table 1; Fig. 1). The average weekly temperature for Lethbridge was 13.8 °C and 2.3 °C cooler than normal (Table 1).

Figure 1. Observed average temperatures across the Canadian prairies the past seven days (June 29-July 5, 2020).

Average 30-day (June 6-July 5, 2020) temperatures continue to be cooler in Alberta than southern Saskatchewan and Manitoba (Table 2). The average 30-day temperature at Winnipeg and Brandon continued to be greater than locations in Alberta and Saskatchewan (Table 2; Fig. 2). June temperature anomalies indicate that temperatures have been below normal across most of Alberta and Saskatchewan and were 0 to 2 °C warmer than average across southeastern Saskatchewan and southern Manitoba (Table 2; Fig. 3). Based on growing season temperatures (April 1 – July 5, 2020), conditions were warmest for southern locations (Table 3).

Figure 2. Observed average temperatures across the Canadian prairies the past 30 days (June 6-July 5, 2020).
Figure 3. Mean temperature difference from Normal for the month of June 2020.
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (05Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Cumulative rainfall for the past 7 days was lowest across western regions of Saskatchewan (Table 1; Fig. 4). Lethbridge reported 69.4 mm. Cumulative 30-day rainfall continued to be greatest across central regions of Alberta (Table 2; Fig. 5). Rainfall amounts were lowest across the most of Saskatchewan.

Figure 4. Observed cumulative precipitation across the Canadian prairies the past seven days (June 29-July 5, 2020).

Total 30-day rainfall at Saskatoon, Lethbridge, Lacombe and Grande Prairie exceeded 100 mm (Table 2; Fig. 5). Saskatoon has reported 156.6 mm (277% of normal) in the past 30 days (Table 2). Growing season rainfall (percent of average) is below normal southern Saskatchewan and most of Manitoba. Rainfall amounts are above average across central regions of Saskatchewan and across Alberta.

Figure 5. Observed cumulative precipitation across the Canadian prairies the past 30 days (June 6-July 5, 2020).
Figure 6. Percent of average precipitation for the growing season (April 1-July 5, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (05Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The growing degree day map (GDD) (Base 5 ºC, April 1-July 6, 2020) is below (Fig. 7):

Figure 7. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-July 6, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (09Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The highest temperatures (°C) observed the past seven days ranged from <15 to >33 °C in the map below (Fig. 8).

Figure 8. Highest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-July 8, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (09Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The maps above are all produced by Agriculture and Agri-Food Canada. Growers can bookmark the AAFC Current Conditions Drought Watch Maps for the growing season. Historical weather data can be access at the AAFC Drought Watch website, Environment Canada’s Historical Data website, or your provincial weather network.

Predicted wheat midge development

Wheat midge overwinter as larval cocoons in the soil.  Soil moisture conditions in May and June can have significant impact on wheat midge emergence.  Adequate rainfall promotes termination of diapause and movement of larval to the sol surface where pupation occurs.  Insufficient rainfall in May and June can result in delayed movement of larvae to the soil surface. Elliott et al. (2009) reported that wheat midge emergence was delayed or erratic  if rainfall did not exceed 20-30 mm during May.  Olfert et al. (2016) ran model simulations to demonstrate how rainfall impacts wheat midge population density. Our wheat midge model (Olfert et al. 2020) indicates that dry conditions may result in: (a) Delayed adult emergence and oviposition, (b) Reduced numbers of adults and eggs.

Wheat midge model runs indicate that, where wheat midge are present, pupation is occurring across Alberta, northwest Saskatchewan and southern Manitoba (Fig. 1). Simulations suggest that, though still less than 15%, adult emergence has begun, most notably across Alberta (Fig. 1). Females lay eggs on developing wheat heads. This typically occurs in evenings when winds are calm. Wheat midge monitoring protocol suggests that wheat fields should be inspected for adults in late June and early July as wheat heads are emerging. The next three weeks are very important for monitoring wheat midge populations for the purpose of making management decisions.

Figure 1. Predicted percent of population of wheat midge (Sitodiplosis mosellana) at adult stage across the Canadian prairies (as of July 5, 2020).

Simulations were run to July 21 to assess population development over the next two weeks (Figs. 2-4). The first graph illustrates development of wheat midge populations near Saskatoon (Fig. 2). Adult emergence has begun and should peak next week, suggesting that monitoring fields for adults should begin in the next few days. Oviposition has just started and larvae will occur soon after.

Figure 2. Predicted wheat midge (Sitodiplosis mosellana) phenology at Saskatoon SK projected to July 21, 2020.

The second graph compares synchrony between wheat midge and wheat for fields near Lacombe (Fig. 3). The graph indicates that adult emergence and oviposition may occur this year when the crop is most susceptible.

Figure 3. Comparison of predicted phenology of wheat midge (Sitodiplosis mosellana) and wheat at Lacombe AB projected to July 21, 2020.

The last graph compares phenology of wheat midge adults near Saskatoon with the phenology of Macroglenes penetrans, a parasitoid of wheat midge (Fig. 4). The parasitioid wasp lays is eggs inside wheat midge eggs. The graph shows that the timing of emergence and oviposition of wheat midge adults is similar to the emergence and oviposition timing of M. penetrans. All of this information can be used as a guide to determine when fields should be monitored.

Figure 4. Comparison of predicted phenology of wheat midge (Sitodiplosis mosellana) and its parasitoid, Macroglenes penetrans, at Saskatoon SK projected to July 21, 2020.

Information related to wheat midge biology and monitoring can be accessed by linking to your provincial fact sheet (Saskatchewan Agriculture or Alberta Agriculture & Forestry).  A review of wheat midge on the Canadian prairies was published by Elliott, Olfert, and Hartley in 2011.  

Alberta Agriculture and Forestry has a YouTube video describing in-field monitoring for wheat midge.  

More information about Wheat midge can be found by accessing the pages from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide”.  View ONLY the Wheat midge pages but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted grasshopper development

As of July 5, 2020, the grasshopper model estimates that hatch is essentially complete. Development is slowest in the Peace River region where the simulation indicates that approximately 30% of the population is still in the egg stage (Fig. 1). Across the prairies, the majority of the nymphal population is predicted to be in the second to fourth instar stages (Table 1; Fig. 1). Development in Manitoba is predicted to be well ahead of most locations across Alberta (Table 1; Fig. 1). Recent warm temperatures in eastern Saskatchewan and Manitoba have resulted in higher rates of grasshopper development. This week, adults are predicted to occur at locations across southern Manitoba and southeastern Saskatchewan (Table 1; Fig. 1). Across the prairies, populations are predicted to be 11, 9, 25, 25, 22, 8 and less than 1% in egg, first, second, third, fourth, fifth and adult stages, respectively (Table 1).

Figure 1. Predicted average instar stages of grasshopper (Melanoplus sanguinipes) populations across the Canadian prairies (as of July 5, 2020).

The two graphs compare predicted development for Saskatoon (Fig. 2) and Winnipeg (Fig. 3). Grasshopper populations near Saskatoon are expected to be predominantly in the third and fourth instars (Fig. 2) while populations near Winnipeg are expected to be primarily in the fifth instar with some adults beginning to appear (Fig. 3).

Figure 2. Predicted grasshopper (Melanoplus sanguinipes) phenology at Saskatoon SK. Values are based on model simulations (April 1-July 5, 2020).
Figure 3. Predicted grasshopper (Melanoplus sanguinipes) phenology at Winnipeg MB. Values are based on model simulations (April 1-July 5, 2020).

Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba AgricultureSaskatchewan AgricultureAlberta Agriculture and Forestry, the BC Ministry of Agriculture and the Prairie Pest Monitoring Network.  Also refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (Philip et al. 2018) as an English-enhanced or French-enhanced version. 

Predicted bertha armyworm development

Model simulations for July 5, 2020, indicate that 5 % of the population is in the pupal stage (26 % last week), 43 % is in the adult stage (52 % last week), and 37 % of the population is in the egg stage (20 % last week). In southern Manitoba and southeastern Saskatchewan, larval stages are predicted to increase this week (14 % compared to 2 % last week). Across the Parkland and Peace River regions, BAW populations are predicted to be mostly adults with oviposition occurring in these areas (Fig. 1). Operation of BAW traps in these areas should continue until adult emergence is complete. Populations across southern regions are primarily in the larval stage (Fig. 2).

Figure 1. Predicted percent of bertha armyworm (Mamestra configurata) population in the adult stage as of July 5, 2020.
Figure 2. Predicted percent of bertha armyworm (Mamestra configurata) population in the larval stage as of July 5, 2020.

The two graphs demonstrate that larval development near Brandon (Fig. 3) is predicted to be ahead of fields near Lethbridge (Fig. 4).

Figure 3. Predicted bertha armyworm (Mamestra configurata) phenology at Brandon MB as of July 5, 2020.
Figure 4. Predicted bertha armyworm (Mamestra configurata) phenology at Lethbridge AB as of July 5, 2020.
Figure 5. The egg stage (A), larval stage (B), pupal stage (C), and adult stage (D) of bertha armyworm. Photos: Jonathon Williams (AAFC-Saskatoon).

Weekly Pheromone-baited Trapping Results – Early season detection of bertha armyworm is improved through the use of pheromone-baited unitraps traps deployed in fields across the Canadian prairies.  Click each province name to access moth reporting numbers observed in AlbertaSaskatchewan and Manitoba (as they become available). Check these sites to assess cumulative counts and relative risk in your geographic region but remember in-field scouting is how the economic threshold is applied to manage this pest.

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting.  Use the images above (Fig. 5) to help identify the economically important larvae.  Review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of ManitobaSaskatchewanAlberta and the Prairie Pest Monitoring Network. Also refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.

Diamondback moth

Once diamondback moth is present in the area, it is important to monitor individual canola fields for larvae.  Warm growing conditions can quickly translate into multiple generations in a very short period!

Wind Trajectory Updates – Completed for 2020 growing season as of Week 09 (released June 22, 2020).

Weekly Pheromone-baited Trapping Results – Early season detection of diamondback moth is improved through the use of pheromone-baited delta traps deployed in fields across the Canadian prairies.  Click each province to access moth reporting numbers observed in AlbertaSaskatchewan and Manitoba as they become available. Check these sites to assess cumulative counts and relative risk in your geographic region.

Monitoring: Remove the plants in an area measuring 0.1 m² (about 12″ square), beat them on to a clean surface and count the number of larvae (Fig. 1) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 1. Diamondback larva measuring ~8 mm long.Note brown head capsule and forked appearance of prolegs on posterior.
Figure 2. Diamondback moth pupa within silken cocoon.

Economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

Figure 3. Diamondback moth.

Biological and monitoring information for DBM is posted by Manitoba AgricultureSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  

More information about Diamondback moths can be found by accessing the pages from the  “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide“.  View ONLY the Diamondback moth page but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

Pea leaf weevil

Models runs predicting spring adult activity, oviposition and larval development for this pest are completed as of Week 9 (June 21, 2020).  Use the following information to aid in-field scouting for larvae.

The pea leaf weevil is a slender greyish-brown insect measuring approximately 5 mm in length (Fig. 1, Left image). Pea leaf weevil resembles the sweet clover weevil (Sitona cylindricollis) but the former is distinguished by three light-coloured stripes extending length-wise down thorax and sometimes the abdomen.  All species of Sitona, including the pea leaf weevil, have a short snout.  

Figure 1.  Comparison images and descriptions of four Sitona species adults including pea leaf weevil (Left).

Adults will feed upon the leaf margins and growing points of legume seedlings (alfalfa, clover, dry beans, faba beans, peas) and produce a characteristic, scalloped (notched) edge.  Females lay 1000 to 1500 eggs in the soil either near or on developing pea or faba bean plants from May to June.

Larvae develop under the soil and are “C” shaped and milky-white with a dark-brown head capsule ranging in length from 3.5-5.5 mm (Figure 2).  Larvae develop through five instar stages.  After hatching, larvae seek and enter the roots of a pea plant.  Larvae will enter and consume the contents of the nodules of the legume host plant. It is the nodules that are responsible for nitrogen-fixation which affect yield plus the plant’s ability to input nitrogen into the soil. Consumption of or damage to the nodules (Figure 3) results in partial or complete inhibition of nitrogen fixation by the plant and results in poor plant growth and low seed yields.

Figure 2. Larva of pea leaf weevil in soil (Photo: L. Dosdall).
Figure 3. Damaged pea nodules (Photo: L. Dosdall).

Biological and monitoring information related to pea leaf weevil in field crops is posted by the province of Alberta and in the PPMN monitoring protocol.

Also refer to the pea leaf weevil page within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” – both English-enhanced or French-enhanced versions are available. 

Cereal Aphid Manager

Aphids can cause significant damage to fields and increase crop losses but low densities in a grain field sometimes have little economic impact on production. This is especially true if the aphid’s natural enemies (beneficial insects) are present in the field because they can keep the aphids under control.

The Cereal Aphid Manager is an easy-to-use mobile app that helps farmers and crop advisors control aphid populations in wheat, barley, oat or rye. It is based on Dr. Tyler Wist’s (AAFC-Saskatoon) Dynamic Action Threshold model. The model treats the grain field as an ecosystem and takes into account many complex biological interactions including:

  • the number of aphids observed and how quickly they reproduce
  • the number of different natural enemies of aphids in the field and how many aphids they eat or parasitize per day
  • the lifecycles of aphids and their enemies taking into account developmental stages, egg laying behaviour, population growth rate, lifespan, etc.

Frequent in-field scouting, supported by the app’s dynamic threshold, allows growers to weigh the above factors and the app predicts what the aphid population will be in seven days and the best time to apply insecticide based on economic thresholds.

To learn more and to download, go to AAFC’s CAM webpage

West nile virus risk

Health Canada posts information related to West Nile Virus in Canada and also tracks West Nile Virus through humanmosquitobird and horse surveillance.  Link here to access the most current weekly update (July 4, 2020). The screenshot below was retrieved 09Jul2020 as reference but access that information here.

The following is offered to predict when Culex tarsalis, the vector for West Nile Virus, will begin to fly across the Canadian prairies (Fig. 1). This week, regions most advanced in degree-day accumulations for Culex tarsalis are shown in the map below.  As of July 8, 2020, areas highlighted yellow are approaching sufficient heat accumulation for mosquitoes to emerge.  Plan to protect yourself by wearing DEET!  

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of July 8, 2020).

Scouting charts for canola and flax

Reminder – Field scouting is critical – it enables the identification of potential risks to crops. Accurate identification of insect pests PLUS the application of established monitoring methods will enable growers to make informed pest management decisions.

We offer TWO generalized insect pest scouting charts to aid in-field scouting on the Canadian prairies:

1. CANOLA INSECT SCOUTING CHART

2018_ScoutingChart_Canola

 
2. FLAX INSECT SCOUTING CHART

2018_ScoutingChart_Flax

These charts feature hyperlinks directing growers to downloadable PDF pages with photos within the “Field crop and forage pests and their natural enemies in western Canada: Identification and management field guide“.

Whenever possible, monitor and compare pest densities to established economic or action thresholds to protect and preserve pollinators and beneficial arthropods. Economic thresholds, by definition, help growers avoid crop losses related to outbreaking insect pest species.

Field heroes

The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops. Check the recently updated Field Heroes website for scouting guides, downloadable posters, and videos. Learn about these important organisms at work in your fields!  

Real Agriculture went live with a Pest and Predators podcast series!

• Access Episode 1 – Do you know your field heroes?

• Access Episode 2 – An inside look at the Prairie Pest Monitoring Network.

• Access Episode 3 – How much can one wasp save you?

• Access Episode 4 – Eat and be eaten — grasshoppers as pests and food

• NEW – Access Episode 5 – Killer wasp has only one target — wheat stem sawfly

Access ALL the Field Heroes links here and be sure to follow @FieldHeroes!

Provincial insect pest report links

Provincial entomologists provide insect pest updates throughout the growing season so link to their information: 

Manitoba‘s Crop Pest Updates for 2020 are available. Access the July 8, 2020 report. The summary indicates that, “Armyworms are being found at high levels in many cereal and forage grass fields in the Eastern, Interlake, Central, and Southwest regions. High levels of grasshoppers continue to be found and controlled in some areas.”

Saskatchewan‘s Crop Production News and read Issue 4 which includes articles on Pest Scouting 101: Mid-Summer, and The Wheat Midge.

•  Alberta Agriculture and Forestry’s Agri-News occasionally includes insect-related information or Twitter users can connect to #ABBugChat Wednesdays at 10:00 am.

Crop reports

Click the provincial name below to link to online crop reports produced by:

• Manitoba Agriculture and Rural Initiatives – Other viewing options include subscribing to receive or access a PDF of July 7, 2020 report.

• Saskatchewan Agriculture  or access a PDF of June 30-July 6, 2020 report.

• Alberta Agriculture and Forestry or access a PDF of June 29, 2020 report.


The following crop reports are also available:

• The United States Department of Agriculture (USDA) produces a Crop Progress Report (read the July 6, 2020 edition).

• The USDA’s Weekly Weather and Crop Bulletin (read the July 7, 2020 edition). 

Previous posts

Click to review these earlier 2020 Posts (organized alphabetically):

    • 2019-2020 Risk and forecast maps

    • Alfalfa weevil (Wk08)

    • Aster leafhopper (Wk05)

    • Beetle data please! (Wk03)

    • Crop protection guides (Wk02)

    • Cutworms (Wk02)

    • Flea beetles (Wk02)

    • John Doane (Wk10)

    • Monarch migration (Wk10)

    • Pea leaf weevil – predicted development (Wk09)

    • Prairie provincial insect webpages (Wk02)

    • Scouting charts – canola and flax (Wk02)

    • Ticks and Lyme Disease (Wk06)

    • Wind trajectories (Wk09)

Weekly Update

This image has an empty alt attribute; its file name is 2020Jun30_PPMN_Logo_Wide-1024x85.png

Happy Birthday Canada!

Warmer temperatures last week continue to move our growing season forward and there are more insects to prioritize on scouting lists again this week. Bertha armyworm pheromone monitoring numbers are coming in as cooperators work with their provincial networks to help assess risk levels in the form of cumulative moth counts.  We are also poised for wheat midge emergence across the prairies and we dedicate this Weekly Update and remember Dr. John Doane, an entomologist whose research on this pest and many other species contributed significantly to insect pest management on the Canadian prairies.

Access information to support your in-field insect monitoring efforts in the complete Weekly Update either as a series of Posts for Week 10 OR a downloadable PDF.

Questions or problems accessing the contents of this Weekly Update? Please email Meghan.Vankosky@canada.ca or Jennifer.Otani@canada.ca. Past “Weekly Updates” can be accessed on our Weekly Update Blog Page.

Weekly Update

Time to transition to more insects in field crops – add a few more to your scouting list!

Access information to support your in-field insect monitoring efforts in the complete Weekly Update either as a series of Posts for Week 9 OR a downloadable PDF.

Stay Safe!

Questions or problems accessing the contents of this Weekly Update? Please email Meghan.Vankosky@canada.ca or Jennifer.Otani@canada.ca. Past “Weekly Updates” can be accessed on our Weekly Update Blog Page.

Weekly Update

Another BIG Weekly Update – several predictive model updates have been generated this week! Find updated information for bertha armyworm, grasshoppers, cereal leaf beetle, alfalfa weevil, wheat midge and pea leaf weevil.  Keep scrolling down and it’s time to get in fields to scout!

Access information to support your in-field insect monitoring efforts in the complete Weekly Update either as a series of Posts for Week 8 OR a downloadable PDF.

Questions or problems accessing the contents of this Weekly Update? Please email Meghan.Vankosky@canada.ca or Jennifer.Otani@canada.ca. Past “Weekly Updates” can be accessed on our Weekly Update Blog Page.

Weekly Update

This time it’s a BIG Weekly Update – several predictive model updates have been generated this week! Find updated information for bertha armyworm, grasshoppers, cereal leaf beetle, alfalfa weevil, wheat midge and pea leaf weevil.  A new Pests & Predators podcast is available and much more.  Keep scrolling down and it’s time to get in fields to scout!

Access information to support your in-field insect monitoring efforts in the complete Weekly Update either as a series of Posts for Week 7 OR a downloadable PDF.

Stay Safe!

Questions or problems accessing the contents of this Weekly Update?  Please e-mail Meghan.Vankosky@canada.ca or Jennifer.Otani@canada.ca.  Past “Weekly Updates” can be accessed on our Weekly Update page.

Weekly Update

This week cutworms, flea beetles, diamondback moths, grasshopper nymphs, alfalfa weevil larvae and bertha armyworm pheromone-baited traps will be going out – a busy week! Several economic pests Canadian growers contend with are now developing into the more damaging stages so get in to those fields!

Access information to support your in-field insect monitoring efforts in the complete Weekly Update either as a series of Posts for Week 6 OR a downloadable PDF.

Stay Safe!

Questions or problems accessing the contents of this Weekly Update?  Please e-mail Dr. Meghan Vankosky or Jennifer Otani.  Past “Weekly Updates” can be accessed on our Weekly Update page.

Weekly Update

Scouting for insect pests in field crops needs to step up a notch now across the prairies. Several of the economic pests Canadian growers contend with are now developing into the more damaging stages of their lifecycles.

Access information to support your in-field insect monitoring efforts in the complete Weekly Update either as a series of Posts for Week 5 OR a downloadable PDF.

Stay Safe!

Questions or problems accessing the contents of this Weekly Update?  Please e-mail Dr. Meghan Vankosky or Jennifer Otani.  Past “Weekly Updates” can be accessed on our Weekly Update page.

Weekly Update

The phenology models used to predict insect staging and associated risk to field crops on the Prairies is a complex system with multiple moving parts.  Last week, phenology model output and map development was not available owing to the detection of an error in one of the underlying datasets required to run the models.  We are pleased to report that the error has been resolved for this week.

At this moment, segments of earlier 2020 Weekly Updates have been pulled back.  The phenology models for Wk01 and Wk02 will be reposted once we have had opportunity to re-run the models with the correct datasets and re-map the model outputs.  Stay tuned and thank you for your patience!

Access information to support your in-field insect monitoring efforts in the complete Weekly Update either as a series of Posts for Week 4 OR  a downloadable PDF.

Stay Safe!

Questions or problems accessing the contents of this Weekly Update?  Please e-mail Dr. Meghan Vankosky or Jennifer Otani.  Past “Weekly Updates” can be accessed on our Weekly Update page.

Weekly Update

A bit of sun, some snow, some rain, a bit too hot and still too cold in other areas – typical spring weather for our prairie producers!

This week the incredible team working to provide weather-related data for PPMN forecasting is coping with technical difficulties so several of the normal updates are not available but stay tuned!

Access information to support your in-field insect monitoring efforts in the complete Weekly Update either as a series of Posts for Week 3 OR  a downloadable PDF.

Stay Safe!

Questions or problems accessing the contents of this Weekly Update?  Please e-mail Dr. Meghan Vankosky or Jennifer Otani.  Past “Weekly Updates” can be accessed on our Weekly Update page.