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! 

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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.

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Figure 2. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.
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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).

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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.

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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.

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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)