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.

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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! 

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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.

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Figure 1. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.
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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).

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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.  

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Figure 1. Adult Lygus lineolaris (5-6 mm long) (photo: AAFC-Saskatoon).
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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). 

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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. 

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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.

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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 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)

Sweet Clover Pests / Feature Entomologist: Sean Prager

This week’s Insect of the Week featured crop is sweet clover: a soil-building, weed suppressing legume. Our feature entomologist this week is Sean Prager.

Sweet clover
cc by 2.0 Phil Gayton

Native to Turkey, Canadian sweet clover includes plants developed from Spanish and Siberian sources. Tolerant to cold, drought and various soil textures, sweet clover is a robust crop that is grown across the Prairies. Sweet clover has a taproot that can grow as deep as 1. 5 metres (5 feet) by the end of spring, adding nitrogen and organic matter to soil. As a forage grazed by livestock, it achieves maximum palatability and feed quality between 25 and 35 centimetres (10-14 inches) in height, as it reaches the bud stage. As sweet clover matures, it loses its palatability. Sweet clover contains a unique chemical called coumarin. When sweet clover is exposed to mold growth, coumarin is converted into the anticoagulant dicoumarol, which poses a risk to livestock consuming contaminated hay or silage. For this reason, proper harvesting of sweet clover for hay or silage is essential.

Sweet clover is vulnerable to several pests. Monitoring and scouting protocols as well as economic thresholds (when available) are found in Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Management and the Cutworm Pests of Crops on the Canadian Prairies: Identification and Management Field Guide. Additional monitoring protocols exist to control certain pests.

Sweet clover plant
cc by 2.0 Des Blenkinsopp
Sweet clover pests
  • Alfalfa caterpillar
  • Army cutworm
  • Beet webworm
  • Blister beetle
  • Clover root weevil
  • Grasshoppers
  • Mormon crickets
  • Sweet clover weevil
  • Variegated cutworm
Sweetclover weevil – AAFC

Entomologist of the Week: Sean Prager

Name: Sean Michael Prager
Affiliation: Department of Plant Sciences, University of Saskatchewan
Contact Information:
sean.prager@usask.ca
306-361-8525
Agriculture Building, 51 Campus Drive, Saskatoon, SK S7N 5A8

How do you contribute in insect monitoring or surveillance on the Prairies?

I coordinate the Lygus surveys in faba bean as part of the provincial monitoring and survey efforts in Saskatchewan. Our lab also occasionally conducts other studies that result in pest information for crops in the prairies.

In your opinion, what is the most interesting field crop pest on the Prairies?

The first insects I worked on were mosquitoes. Because of that experience, I have always been really interested in disease vectors. On the Prairies, Aster Leafhoppers are a vector and pest that have some pretty neat aspects to their biology. They can be a major problem in canola; although the events are rare. Finally, they are also really useful for many of the ecological questions our lab asks.

What is your favourite beneficial insect?

As a postdoc, I studied a small parasitoid wasp called Aphelinus rhamni. It is a species that parasitizes aphids, especially soybean aphid. It was collected in Asia and has potential as a classical biological control agent.

Tell us about an interesting project you are working on right now.

I think the work we are doing to develop thresholds for aphids in pulse crops will be very useful on the Prairies and is quite interesting. Similarly, the work we have been doing on Lesser clover leaf weevils in red clover has been interesting as well and will hopefully be important to industry.

What tools, platforms, etc. do you use to communicate with your stakeholders?

We use many of the standard tools. My lab has a website (www.pragerlab.ca), a twitter account (@USaskENt), and Instagram. We are more active in some places than others. In addition to that, members of my lab often attend field days and grower meetings.

Weekly Update

Greetings!

Week 14 and it’s again filled with in-field monitoring, data collection, and field tour events for all our Staff!  Please bookmark the Blog or subscribe to receive the latest growing season information!

Please access the complete Weekly Update either as a series of Posts for Week 14 (July 11, 2019) OR a downloadable PDF. Be sure to check out the Insect of the Week – the rest of the growing season features doppelgangers to aid in-field scouting!

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

Subscribe to the Blog by following these easy steps!

Weather synopsis

Prairie temperatures continue to be cooler than average. Temperatures this week were approximately 1 °C cooler than last week (Fig. 1).  The warmest temperatures were observed across MB while temperatures were cooler in western SK and across AB. 

Figure 1. Average temperature (°C) across the Canadian prairies the past seven days (July 2-July 8, 2019).

Across the prairies, 30-day average temperatures have been approximately 1.5 °C cooler than normal (Fig. 2). Average 30-day temperatures were warmest across southern MB and SK. Cooler temperatures were reported across eastern and northern AB. 

Figure 2. Average temperature (°C) across the Canadian prairies the past 30 days (June  8- July 8, 2019).

Growing season temperatures (April 1-July 1, 2019) have been 1 °C cooler than average; the warmest temperatures were observed across the southern prairies (Fig. 3). 

Figure 3. Average temperature (°C) across the Canadian prairies for the growing season (April 1-July 8, 2019).

This past week, significant rainfall amounts were reported central AB (Fig. 4). Minimal rainfall was reported across MB and southern AB. Across the prairies, rainfall amounts for the past 30 days have been highly variable (Fig. 5). Dry conditions persisted across much of MB and southern AB. Rainfall was well above average in SK.  Growing season rainfall amounts have been below average for most of the prairies, particularly across southern regions of AB and eastern MB (Fig. 6). 

Figure 4. Cumulative precipitation observed the past seven days across the Canadian prairies (July 2-8, 2019).
Figure 5. Cumulative precipitation observed the past 30 days across the Canadian prairies (June 8-July 8, 2019).
Figure 6. Cumulative precipitation observed over the growing season across the Canadian prairies (April 1-July 8, 2019).

Based on modeled soil moisture (Fig. 7), recent rains have improved soil moisture values across a large area of SK. Predicted soil moisture continues to be low across large regions of eastern MB and southern AB. 

Figure 7. Modeled soil moisture (%) across the Canadian prairies as of July 8, 2019.

The growing degree day map (GDD) (Base 5 ºC, April 1-July 7, 2019) is below (Fig. 8):

Figure 8. Growing degree day (Base 5 ºC) across the Canadian prairies for the growing season (April 1-July 7, 2019).

The growing degree day map (GDD) (Base 10 ºC, April 1-July 7, 2019) is below (Fig. 9):

Figure 9. Growing degree day (Base 10 ºC) across the Canadian prairies for the growing season (April 1-July 7, 2019).

The lowest temperatures (°C) observed the past seven days ranged from at least 13 to at least 1 °C in the map below (Fig. 10).

Figure 10. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (to July 11, 2019).  
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (011Jul2019).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

The highest temperatures (°C) observed the past seven days ranged from less than 15 to at least 30 °C in the map below (Fig. 11).

Figure 11. Highest temperatures (°C) observed across the Canadian prairies the past seven days (to July 11, 2019).  
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (011Jul2019).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

The maps above are all produced by Agriculture and Agri-Food Canada.  Growers can bookmark the AAFC Drought Watch Maps for the growing season.

Bertha armyworm monitoring

Bertha armyworm (Lepidoptera: Mamestra configurata– Early instar bertha armyworm are predicted to begin appearing across the prairies.  A model run for Saskatoon SK indicates that the hatch should be complete (Fig.1) and that BAW should be in the early instar (Fig. 2).

Figure 1.  Predicted status of bertha armyworm (Mamestra configurata) populations as of July 8, 2019.
Figure 2. Predicted percent of bertha armyworm (Mamestra configurata)  populations at LARVAL STAGE across the Canadian prairies as of July 8 2019. 

Important – Watch your provincial monitoring networks who are weekly recording cumulative pheromone-baited traps in AlbertaSaskatchewan, and Manitoba (pg 8).

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.

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting.  Use the images below (Fig. 3) to help identify egg masses and the economically important larvae in canola.

Figure 3. Stages of bertha armyworm from egg (A), larva (B), pupa (C) to adult (D).
Photos: J. Williams (Agriculture and Agri-Food Canada)

Now is the time to do in-field scouting for this insect pest.  Review the Insect of the Week which features bertha armyworm and its doppelganger, the clover cutworm!

Predicted grasshopper development

Grasshopper Simulation Model Output – The grasshopper simulation model will be used to monitor grasshopper development across the prairies. Weekly temperature data collected across the prairies is incorporated into the simulation model which calculates estimates of grasshopper development stages based on biological parameters for Melanoplus sanguinipes (Migratory grasshopper).

Cool temperatures continue to result in reduced grasshopper development rates. Populations are developing into third and fourth instars. Based on model runs, approximately 13% of the population is in the first instar, 23%  is predicted to be in the second instar, and 32% is in the third instar, 21%  are predicted to be in the fourth instar and l4% may be in the fifth instar. Grasshopper development this season has been similar to long term average development. The following map (Fig. 1) indicates that grasshopper populations across the southern prairie are mostly in the third instar. Compared to last week development has increased across southern regions of the prairies. Grasshopper development has been greatest near Winnipeg MB.

Figure 1. Predicted development stages of grasshopper (Melanoplus sanguinipes) populations across the Canadian prairies (as of July 8, 2019). 

This week, the Insect of the Week’s Doppelganger features GRASSHOPPERS!!!  Check out the excellent nymph photos to help your in-field scouting!

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” which is available as a free downloadable document in either an English-enhanced or French-enhanced version.

Wheat midge

Wheat Midge (Sitodiplosis mosellana) – Where wheat midge are present, cool, dry conditions have resulted in delayed emergence of adults. Wheat midge larvae have moved to the soil surface and pupae are appearing.  In some locations adults should be beginning to emerge. The wheat midge model predicts that 45% (54% last week) of the population are in the larval  cocoon stage and 47% (42% last week) of the population is predicted to have moved to the soil surface. This week 7% (3.4% last week) is predicted to be in the pupal stage. Adults have begun to emerge in localized areas in southern AB and MB. 

The first map indicates the percent of the population that is in the larval stage, at the soil surface.  Midge development in SK was reduced due to dry soil moisture conditions. The second map indicates that pupae may be present in some fields in southern AB and MB. It should be noted that, based on fall surveys in 2018, wheat midge populations were expected to be low across most of AB and SK.

Figure 1.  Percent of larval population at the soil surface (as of July 8, 2019) across the Canadian prairies.
Figure 2. Percent of  population AT PUPAL STAGE (as of July 8, 2019) across the Canadian prairies.
Figure 3. Percent of  population AT ADULT STAGE (as of July 8, 2019) across the Canadian prairies.

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 15ºC), calm evenings, the midge can be observed in the field, laying their eggs on the wheat heads (photographed by AAFC-Beav-S. Dufton & A. Jorgensen below). 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.

REMEMBER that in-field counts of wheat midge per head remain the basis of economic threshold decision.  Also remember that the parasitoid, Macroglenes penetrans (photographed by AAFC-Beav-S. Dufton below), 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.

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 (for Wk10).  Check that post for help with in-field scouting for this economic pest of wheat!  The differences between midges and parasitoid wasps are featured as the current Insect of the Week (for Wk11).  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.  

NEW – Alberta Agriculture and Forestry has also released a YouTube video describing in-field monitoring for wheat midge this week.  

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.

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.

Figure 1. Diamondback larva measuring ~8mm 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.

Provincial Insect Pest Report Links

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

Manitoba‘s Crop Pest Updates for 2019 are posted here. Access Issue #8 posted July 10, 2019 which includes more thistle caterpillar information, updated bertha armyworm pheromone trap information, the presence of low numbers of green cloverworm in some pulse crop fields, grasshopper presence, andsome higher numbers of diamondback moth larvae in some canola.

Saskatchewan‘s Crops Blog Posts includes a segment on “Economic thresholds” by Kaeley Kindrachuk posted in May 2019. Also access the Crop Production News with Issues:

•  Alberta Agriculture and Forestry’s Agri-News includes an insect-related item in the July 8, 2019 edition with an important reminder that field scouting in July can lead to a more successful crop.

Crop report links

Crop reports are produced by:

The following crop reports are also available:

West Nile Virus and Culex tarsalis

West Nile Virus Risk –  In 2018, there were 426 human clinical cases of West Nile virus (WNV) in Canada (Fig. 1). 

Figure 1. Geographic distribution of WNV human clinical cases and asymptomatic infections in Canada, 2018.
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (11Jul2019).  Access the full map at https://www.canada.ca/en/public-health/services/publications/diseases-conditions/west-nile-virus-surveillance/2018/november-11-december-15-week-46-50.html

Health Canada posts information related to West Nile Virus in Canada.  Health Canada also tracks WNV through humanmosquitobird and horse surveillance.  Link here to access the most current weekly update (June 29, 2019). The screenshot below was retrieved 11Jul2019 as reference but access that information here.

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  Take note of the provincial distribution of positive WNV birds in 2018 (table posted below as reference).

The following is offered to predict when Culex tarsalis will begin to fly (Fig. 2) across the Canadian prairies. Protect yourself by wearing DEET!  The regions most advanced in degree-day accumulations for Culex tarsalis, the vector for West Nile Virus, are shown in the map below.  Areas highlighted lime green in the map below (Fig. 2) are on the verge of approaching sufficient heat accumulation for mosquitoes to emerge soon.  

Figure 2. Predicted development of Culex tarsalis, across the Canadian prairies (as of July 7, 2019).

Once the adults emerge, the following map demonstrates how quickly a Culex tarsalis mosquito carrying WNV can become fully infective (i.e., when it has accumulated 109 base 14.3° degree days) – as quickly as 20-22 days, given the current environmental conditions in the highlighted areas of the map below (Figure 3).

Field Events – Speak to an entomologist

Public summer field events – Coming to a field near you –  Prairie field crop entomologists are already scheduled to be at these 2019 field tour events from May-August (be sure to re-confirm dates and details as events are finalized):

•  July 22, 2019: Pulse grower gathering held near Three Hills AB.  Check Alberta Pulse Growers Event Page for more information.  Entomologists presenting: Graduate students from Dr. Maya Evenden’s (U of A) working on pea leaf weevil.

•  July 23-24, 2019: Crop Diagnostic School, Scott Saskatchewan. Read more about this event.  Entomologists presenting: Meghan Vankosky, Tyler Wist.

•  July 24, 2019: Crops-a-Palooza. Held at Canada-Manitoba Crop Diversification Centre (CMCDC), Carberry, Manitoba. Read more about this event. Entomologist participating: John Gavloski, Vincent Hervet, Tharshi Nagalingam, Bryan Cassone.

•  August 8, 2019:  2019 Wheatstalk to be held at Teepee Creek AB.  View event info/registration details.   Entomologists tentatively participating: Jennifer Otani, Shelby Dufton, Amanda Jorgensen, Boyd Mori.

  August 8, 2019. Horticulture School. Agriculture and Agri-Food Canada Research Farm, Portage la Prairie, Manitoba. View event info/registration details.  Entomologist presenting: John Gavloski, Kyle Bobiwash.

Preparing and protecting grains for market

A few helpful tools to keep at your finger tips:

Since May we have posted our prairie provinces’ searchable PDFs of Crop Production Guides.

Keeping It Clean has information to help prepare and protect your grains for market.  Check out their site to find important information.  Learn more about avoiding malathion in bins storing canola, access their spray to swath calculator, and access a pre-harvest glyphosate staging guide

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.

Interested in signing up for Canadian Grain Commission’s Harvest Sample Program?

Previous Posts

Click to review these earlier 2019 Posts:

2019 Risk and forecast maps – Week 2

Alfalfa weevil – Week 11

Bertha armyworm (predicted development) – Week 12

Cabbage seedpod weevil – Week 11
Cereal aphid manager APP – Week 12
Cereal leaf beetle – Week 9
Crop protection guides – Week 6
Cutworms – Week 5

Field heroes – Week 6
Flea beetles – Week 5

Grasshoppers – Week 10

Insect scouting chart for Canola – Week 5
Insect scouting chart for Flax – Week 5

Monarch migration – Week 13

Painted lady butterfly – Week 8
Pea leaf weevil – Week 10
Prairie Crop Disease Monitoring Network – Week 11

Ticks and Lyme disease – Week 4
Timely IOTW to review – Week 13

Weather Radar – Week 6
Wildfires – Week 8

Wind trajectories – Review Page for list of PDFs for Weeks 1-12

Insect of the Week – Doppelgangers: Grasshoppers

Bruner grasshopper (Melanoplus bruneri) adult. 
Photo credit: S. Barkley, Alberta Agriculture and Forestry.

The case of the prairie grasshoppers: There are 80 grasshopper species on the prairies but only a few that are considered pests. These include Packard (Melanopus packardii), clearwinged (Camnula pellucida), migatory (Melanopus sanguinipes), two-striped (Melanopus bivittatus) and Bruner Melanoplus bruneri) grasshoppers. They are recognizable as grasshoppers (similar body shape and distinctive large rear legs) and, depending on the species, range in size from 21 to 40 centimetres (8.25 to 15.75 inches). Most of these pest species can be distinguished by colouring and size. However, the Bruner and migratory grasshoppers are difficult to tell apart, needing to rely on examining the male genitalia (see Insect of the Week post from July , 2018).

For more information about grasshopper pests, see our Insect of the Week page!

Packard grasshopper – egg, nymph, adult
AAFC
Clearwinged grasshopper – egg, nymph, adult
AAFC
Migratory grasshopper – adult
Joseph Berger, Bugwood.org
Two-striped grasshopper – adult
John Gavloski, Manitoba Agriculture,
Food and Rural Development

More information related to the Bruner grasshopper:

See also:

Predicted grasshopper development (July 5, 2019)

Specific information about these grasshoppers, other pests and natural enemies can be found in the updated Field Crop and Forage Pests and their Natural enemies in Western Canada field guide.

The case of the innocuous versus the evil twin: When making pest management decisions, be sure that the suspect is actually a pest. This can be challenge since insects often mimic each other or look very similar. An insect that looks, moves and acts like a pest may in fact be a look-alike or doppelganger.

Doppelgangers may be related (e.g. same genus) or may not be related, as in the case of monarch butterflies (Danaus plexippus) and viceroys (Limenitis achrippus). Doppelgangers are  usually relatively harmless but sometimes the doppelganger is a pest yet their behaviour, lifecycle or hosts may be different.

Correctly identifying a pest enables selection of the most accurate scouting or monitoring protocol. Identification and monitoring enables the application of economic thresholds. It also enables a producer to select and apply the most effective control option(s) including method and timing of application.  For the rest of the growing season, the Insect of the Week will feature insect crop pests and their doppelgangers.

Review previously featured insects by visiting the Insect of the Week page.

Weekly Update

Hello!

We’re doing a bit of catch-up with the Weekly Update….

Please view the Weekly Update FOR WEEK 14 (August 9, 2018) which is available only as a PDF.  Also review the Insect of Week for Week 14 featuring both the Natural enemies of wheat stem sawfly plus the English grain aphid.

The Weekly Update FOR WEEK 15 (August 16, 2018) is available as either as a series of Posts  OR a downloadable PDF version.  Also review the “Insect of the Week” for Week 15!

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

Subscribe to the Blog by following these three steps!

Insect of the Week – Natural Enemies of the wheat stem sawfly

This week’s Insects of the Week are the natural enemies (@FieldHeroes) of the wheat stem sawfly, namely Bracon cephi (Gahan) and B. lissogaster (Hymenoptera: Braconidae).

Nine species of parasitic wasps are known to attack wheat stem sawfly but Bracon cephi and B. lissogaster are the main species that help regulate this pest in North America.  These closely related wasp species are described as idiobiont ectoparasitoids meaning the parasitoid larva, after hatching from an egg laid on the surface of the sawfly larva, feeds on the exterior of the host. Normally, both Bracon species will complete their development (i.e., pupates) inside the wheat stem within the integument of the sawfly larva or just beside the consumed host.  There are two generations of B. cephi and B. lissogaster per year.  The first generation normally completes its lifecycle then escapes from the wheat stem to locate a new sawfly larva to parasitize.  The second generation of these wasps will overwinter within the wheat stem.

These wasps are 2-15 mm long and are usually brown in colour. They have a narrow waist connecting the abdomen to the thorax and the combined length of head plus thorax is equal to the length of the abdomen.  These parastiod wasps have long antennae and two pairs of transparent wings. Females have a noticeable ovipositor protruding from the end of the abdomen.

For more information about the natural enemies of the wheat stem sawfly, check out our Insect of the Week page!

Bracon cephi (Gahan) (H. Goulet)

Extra Insect of the Week – English grain aphid (Hemiptera: Aphididae)

The English grain aphid (Sitobion avenae) has started to appear across the Prairies in various cereal crops this past week so the time to scout is now. Look for this aphid infesting wheat heads (favourite host) as well as barley, oat, rye, Timothy and canaryseed.

This aphid can also be a vector for barley yellow dwarf virus. You might see the green, red colour morph or both morphs in fields this year (Fig. 1). You will probably also see ladybeetle (@FieldHeroes) adults and larvae hunting the aphids (Fig. 2). The economic threshold for aphids in spring wheat in Western Canada is 12-15 aphids per head prior to the soft dough stage. 

Agriculture and Agri-Food Canada, with funding from the Pest Management Centre, has developed a smartphone app called Cereal Aphid Manager (CAM) to facilitate scouting for aphids in cereals that also allows you to record the beneficial insects in the field that can keep aphid populations below the economic threshold – available at Apple iTunes and Google Play app stores. CAM information and download links.

For more information on the English grain aphid, check out our Insect of the Week page!

Submitted by Dr. Tyler Wist (Tyler.Wist@agr.gc.ca).

Fig. 1 Green and red morph English grain aphid
(Tyler Wist, AAFC)
Fig. 2 Seven-spotted lady bird larva hunting aphids
(Tyler Wist, AAFC)

Cabbage seedpod weevil

Cabbage seedpod weevil (Ceutorhynchus obstrictus) –  There is one generation of CSPW per year and the overwintering stage is the adult which is an ash-grey weevil measuring 3-4mm long (Refer to lower left photo).  Adults typically overwinter in soil beneath leaf litter within shelter belts and roadside ditches.




Monitoring:  
 ● Begin sampling when the crop first enters the bud stage and continue through the flowering. 
 ● Sweep-net samples should be taken at ten locations within the field with ten 180° sweeps per location.  
 ● Count the number of weevils at each location. Samples should be taken in the field perimeter as well as throughout the field.  
 ● Adults will invade fields from the margins and if infestations are high in the borders, application of an insecticide to the field margins may be effective in reducing the population to levels below which economic injury will occur.  
 ● An insecticide application is recommended when three to four weevils per sweep are collected and has been shown to be the most effective when canola is in the 10 to 20% bloom stage (2-4 days after flowering starts). 
 ● Consider making insecticide applications late in the day to reduce the impact on pollinators.  Whenever possible, provide advanced warning of intended insecticide applications to commercial beekeepers operating in the vicinity to help protect foraging pollinators.  
 ● High numbers of adults in the fall may indicate the potential for economic infestations the following spring.


Damage: Adult feeding damage to buds is more evident in dry years when canola is unable to compensate for bud loss.  Adults mate following a pollen meal then the female will deposit a single egg through the wall of a developing pod or adjacent to a developing seed within the pod (refer to lower right photo).  Eggs are oval and an opaque white, each measuring ~1mm long.  Typically a single egg is laid per pod although, when CSPW densities are high, two or more eggs may be laid per pod.

There are four larval instar stages of the CSPW and each stage is white and grub-like in appearance ranging up to 5-6mm in length (refer to lower left photo).  The first instar larva feeds on the cuticle on the outside of the pod while the second instar larva bores into the pod, feeding on the developing seeds.  A single larva consumes about 5 canola seeds.  The mature larva chews a small, circular exit hole from which it drops to the soil surface and pupation takes place in the soil within an earthen cell.  Approximately 10 days later, the new adult emerges to feed on maturing canola pods.  Later in the season these new adults migrate to overwintering sites beyond the field.


Please find additional detailed information for CSPW in fact sheets posted by Alberta Agriculture and ForestrySaskatchewan Agriculture, or the Prairie Pest Monitoring Network.

Also watch provincial reports for updates on surveying underway now.  Alberta Agriculture & Forestry has posted a live CSPW map and online reporting tool for growers.  A screenshot (retrieved 03Aug2017) is included below.

Provincial Insect Pest Reports

Provincial entomologists provide insect pest updates throughout the growing season so we have attempted to link to their most recent information: 


● Manitoba’s Insect and Disease Update for 2017 is prepared by John Gavloski and Pratisara Bajracharya and read Issue #11 (posted August 2, 2017) noting diamondback moth exceeding economic thresholds in some fields, higher numbers of soybean aphids but the appearance of natural enemies in response to their prey (so growers may refer to the Soybean Aphid App to help monitor and manage that pest), and high levels of bertha armyworm larvae have been scouted in Holland and Austin areas.

● Saskatchewan’s Crop Production News – 2017 – Issue #4 includes information related to soybean pests prepared by Joel Peru. That report includes an update on scouting and management tips for painted lady butterflies (also described in Week 6) and Aphanomyces root rot.  A reminder to watch for the final bertha armyworm pheromone trap counts update on the 2017 map.

● Watch for Alberta Agriculture and Forestry’s Call of the Land and access the most recent Insect Update (August 3, 2017) provided by Scott Meers. This week diamondback moth numbers have exploded in southern Alberta so canola growers need to be scouting right up to swathing but be aware of Pre-harvest intervals! The annual grasshopper survey begins the first week of August for that province’s Agricultural Fieldmen. In central Alberta,
Red turnip beetle are now starting to feed, mate and lay eggs that overwinter. Painted lady butterfly – the 2nd generation is starting to fly and lay eggs now so sunflower, soybean and borage growers need to continue to monitor.

Crop reports

Crop reports are produced by:
• Manitoba Agriculture, Rural Development (July 31, 2017)
• Saskatchewan Agriculture Crop Report (July 24-31, 2017)

• Alberta Agriculture and Forestry Crop Report (July 25, 2017)


West Nile Virus and Culex tarsalis

West Nile Virus Risk –  The regions most advanced in degree-day accumulations for Culex tarsalis, the vector for West Nile Virus, are shown in the map below.  As of July 30, 2017areas highlighted in red on the map below have accumulated sufficient heat for C. tarsalis to fly.  Areas highlighted in red, orange and even yellow will have C. tarsalis flying so wear your DEET to stay protected!




The Public Health Agency of Canada posts information related to West Nile Virus in Canada.  In 2016, 104 human clinical cases of West Nile Virus were reported.  The map of clinical cases of West Nile Virus in Canada in 2017 is updated through the summer and two cases of viral West Nile have been reported so far (as of July 22, 2017).  Both cases were reported from Ontario (in Timiskaming and Windsor-Essex).

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  As of August 3, 2017, 964 birds were examined and 23 have tested positive for West Nile virus; two from Manitoba, eight from Ontario, and 13 from Quebec.


The Public Health Agency of Canada also monitors and posts updates on the status of WNV in Mosquitoes.  As of July 22, 2017, Quebec, Ontario, Manitoba and Saskatchewan have reports of positive mosquito pools of West Nile Virus.  A total of 47 positive mosquito pools have been found: 

  • 33 from Ontario [Peel Regional (5), Toronto (6), Halton(5), Haliburton-Kwartha-Pine Ridge District(1), Simcoe Muskoka District (1), Windsor-Essex County (6), Eastern Ontario (1), Durham Reginal (1), Hamilton (1), Haliburton-Kawarta-Pine Ridge district (1), Hastings and Prince Edward Countries (2), and York Regional (3)];  
  • 11 from Manitoba [(Winnipeg (3), Southern (2), Interlake eastern (1), and Prairie Mountain(5)]; 
  • 2 from Quebec [Montérégie (1), Laval (1)], and 
  • 1 from Saskatchewan. 

Insect of the Week – Red clover casebearer moth

This week’s Insect of the Week is the red clover casebearer moth. As it’s name suggests, its primary host is red clover, but larvae also reportedly feed on alsike, stone, white and zig-zag clover. The mature larvae are contained within portable cases made of withered flower petals and silk and they feed from the front end of the case on developing seed in the floret. They can consume up to three seeds per day. In areas with high numbers of these moths, such as the Peace River region in BC and AB, red clover stands should only be grown for one year in rotation.

For more information on the red clover casebearer moth, visit our Insect of the Week page.

Red clover case bearer moth – adult (Tim Haye)
Red clover casebearer moth – sealed overwintering larval cases (Boyd Mori)



Remember the NEW Cutworm Field Guide is free and downloadable in 2017!

Weekly Update – Greetings!

Greetings!

Please access the Weekly Update for August 3, 2017 (Week 14), as either a series of Posts  or a downloadable PDF.   


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

Subscribe to the Blog by following these three steps!

Weekly Update – Weather Synopsis

Weather synopsis – This past week’s temperatures were above normal in many locations on the prairies, especially south and central Alberta and Saskatchewan (Fig. 1).  

Figure 1. Highest temperatures across the Canadian prairies the 
past seven days (July 25-31, 2017).



Seven-day rainfall accumulations were low across the prairies. Total 30-day rainfall accumulations indicate that conditions are normal to dryer-than-normal for most of the prairies (Fig. 2). 

Figure 2.  Percent of average precipitation across the Canadian prairies the 
past 30 days (July 2-31, 2017). 



Growing season (April 1 – July 31, 2017) percent of average precipitation continues to be average for some areas of Alberta, but below average for most of Saskatchewan and Manitoba.

Figure 3.  Percent of average precipitation across the Canadian prairies over 
the growing season (April 1-July 31, 2017).




The growing degree day map (GDD) (Base 10ºC, March 1 – July 30, 2017) is below:








The growing degree day map (GDD) (Base 5ºC, March 1 – July 30, 2017) is below:







The maps above are all produced by Agriculture and Agri-Food Canada.  Growers may wish to bookmark the AAFC Drought Watch Maps for the growing season.

Weekly Update – Pre-Harvest Intervals (PHI)

Pre-Harvest Interval (PHI) – Growers with late-season insect pest problems will need to remember to factor in the PHI which is the minimum number of days between a pesticide application and swathing or straight combining of a crop.  

The PHI recommends sufficient time for a pesticide to break down and a PHI-value is both crop- and pesticide-specific.  Adhering to the PHI is important for a number of health-related reasons but also because Canada’s export customers strictly regulate and test for the presence of trace residues of pesticides.

An excellent summary of PHI for various pesticides in their various crops was posted by Saskatchewan Agriculture’s Danielle Stephens in 2016 within their Crop Production News.


In 2013, the Canola Council of Canada created and circulated their “Spray to Swath Interval Calculator” which was intended to help canola growers accurately estimate their PHI.  Other PHI are described in your provincial crop protection guides and remember that specific crop x pesticide combinations will mean different PHIs.  More information about PHI and Maximum Residue Limits (MRL) is available on the Canola Council of Canada’s website.

Weekly Update – Crop protection guides

Crop Protection Guides – If you don’t have a copy of your province’s Crop Protection Guide, please make use of these links to access:
• Saskatchewan’s Crop Protection Guide
• Manitoba’s Guide to Crop Protection Guide 
• Alberta’s Crop Protection or Blue Book 
• Western Committee on Crop Pests Guidelines for the Control of Crop Pests




Recall earlier this spring that Health Canada’s Pest Management Regulatory Agency launched a new mobile app to access pesticide labels registered for use in Canada. The App helps homeowners, farmers, industry, provincial and federal organizations access details for pest control products from a smartphone or tablet.  Download it as either:

Weekly Update – Diamondback moth

Diamondback moth (Plutellidae: Plutella xylostella) – Last week, biofix dates were used to predict the number of generations of DBM as of July 24, 2017.  That data predicted the completion of two generations of DBM across the Canadian prairies.  The number of generations, combined with the recent heat, has resulted in densities of DBM above threshold in some fields this week!  In-field scouting is critical and necessary to protect developing pods since DBM larvae will feed on the exterior which can render pods prone to shattering even in high temperatures and high winds or during swathing and direct-harvesting.  

REMINDER – Once diamondback moth is present in the area, it is important to monitor individual canola fields for larvae.  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. 4) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.  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  (approximately 1-2 larvae per plant).


Figure 4. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.


Figure 5. Diamondback moth pupa within silken cocoon.


Biological and monitoring information for DBM is posted by Manitoba Agriculture, Food and Rural DevelopmentSaskatchewan AgricultureAlberta Agriculture and Forestry, and the Prairie Pest Monitoring Network.  

More information about Diamondback moths 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 Diamondback moth page but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.


Figure 6. Diamondback moth.


Across the prairies, provincial staff coordinate diamondback pheromone trapping during the growing season:

● Low numbers of moths have been reported across Saskatchewan for the 2017 pheromone monitoring.  
● Manitoba Agriculture and Rural Initiatives posted low DBM counts which can be reviewed here.  
● Alberta Agriculture and Forestry has a live 2017 map reporting Diamondback moth pheromone trap interceptions.  A copy of the map (retrieved July 20, 2017) is below for reference.

Weekly Update – Bertha Armyworm

Bertha armyworm (Lepidoptera: Mamestra configurata– REMINDER – Reporting sites across the prairies have generally reported lower cumulative interceptions and cumulative counts are summarized by provincial staff in ManitobaSaskatchewan and Alberta.

Manitoba counts as of July 26, 2017



Saskatchewan map as of July 19, 2017



Alberta map as of July 26, 2017


In-field monitoring for egg masses and newly emerged larvae (photo below) should initially focus on the undersides of leaves plus watch the margins of leaves for feeding.  Bertha armyworm larvae will also feed on newly developing pods so the whole plant should be examined.  Watch for the following life stages:





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.

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:  


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 new “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.

Weekly Update – Lygus in canola

Lygus bugs (Lygus spp.) – Reminder – The economic threshold for Lygus in canola is applied at late flower and early pod stages.  

Adult L. lineolaris (5-6 mm long) (photo: AAFC-Saskatoon).

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. They 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.

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.

Repeat the sampling in another 14 locations. 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 C). If the total number is below the lower threshold line, 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 table.

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


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.


Table 1.  Economic thresholds for lygus bugs in canola at late flowering and early pod stages (Wise and Lamb 1998).

1 Canola crop stage estimated using Harper and Berkenkamp 1975).
2 Economic thresholds are based on an assumed loss of 0.1235 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).


Table 2.  Economic thresholds for lygus bugs in canola at pod stage (Wise and Lamb 1998).

 3 Economic thresholds are based on an assumed loss of 0.0882 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).


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-enhanced or French-enhanced versions are available.

Update from the field….

Many prairie growers have a cutworm or armyworm story of woe but this time around growers on Vancouver Island near Port Alberni contended with an unusual pest – True armyworm (Mythimna unipuncta) in high densities were eating up hay fields and pasture!  Thanks to Tracy Hueppelsheuser with the BC Ministry of Agriculture who shared this CTV news clip.


Remember the NEW Cutworm Field Guide is free and downloadable in 2017!

Weekly Update – Time of Swathing for Canola

The Canola Council of Canada created a guide to help growers estimate swathing time in canola.  A screen shot of the downloadable Canola Swathing Guide has been included below for reference.





Weekly Update – Insects as food

Earlier this summer a link was posted taking readers to an article about unique popcorn toppings.  While novel, the cricket topping for popcorn will surely be followed by other insect-based food items in the future. In 2013, a FAO report entitled, “Edible insects: future prospects for food and feed security” was published.  The document noted a predicted global population of 9 billion by 2050, the increasing need for more sustainable means to produce food and the feasibility of insects as means to do 


Last week, the Financial Post printed a follow-up article describing Canadian entrepreneurs and their efforts to mainstream insects as food for humans, livestock and pets.

Weekly Update – Previous Posts

The following is a list of 2017 Posts – click to review:

Alfalfa Weevil (Week 11)


Brood X Cicadas


Cabbage seedpod weevil (Week 12)

Canola scouting chart
Cereal leaf beetle
Crickets with your popcorn
Cutworms

Diamondback moth


Flax scouting chart

Flea beetles


Grasshoppers (Week 13)

Iceberg reports


Lily leaf beetle


Monarch migration (Week 10)


Painted lady butterflies (Week 9)

Pea leaf weevil
PMRA Pesticide Label Mobile App

Nysius niger (Week 8)


Ticks and Lyme disease


Weather radar

Wheat midge
White grubs in fields (Week 9)
Wildfires (Week 13)

Wind trajectories

Insect of the Week – Natural Predators

The importance of non-crop areas as habitat for beneficial insects



Last year, the focus of the
Beneficial 
Insect of the Week was crop pests. This year,
we’re changing things up and highlighting the many natural enemies that
help you out, silently and efficiently killing off crop pests. [note: featured
Insects of the Week in 2015 are available on the
 Insect of the Week page] 
Natural enemies don’t just appear from nowhere – they rely on nearby
non-crop and (semi-)natural sites for shelter, food, overwintering sites and
alternate hosts for when crop pests are either not present or in low numbers.
How you manage these sites can have a huge impact on natural enemies’ capacity
to supress pests when you need them to. These same sites are also essential
habitats for pollinators, important for maximizing yield of non-cereal seed
crops (e.g. oil seed crop). A recent publication, ‘Agricultural practices that
promote crop pest suppression by natural predators’, describes the role of
non-crop areas and management practices to nurture natural enemy populations.
Go to the Insect of the Week page for download links for
this publication. There you will also find more information about natural
enemies, the pests they control and details about important crop and forage
pest insects by downloading the new Field Crop and Forage Pests and their
Natural Enemies in Western Canada – Identification and Management Field Guide.



Weekly Update

Greetings!

A downloadable PDF version of the complete Weekly Update for Week 14 (August 3, 2016) can be accessed here.  

This edition includes the “Insect of the Week” featuring beneficial arthropods in 2016!

Subscribe to the Blog by following the instructions posted here!  You can receive automatic updates in your inbox through the growing season.



Questions or problems accessing the contents of this Weekly Update?  Please e-mail either Dr. Owen Olfert or Jennifer Otani.  Past “Weekly Updates” are very kindly archived to the Western Forum website by webmaster, Dr. Kelly Turkington.  

Weekly Update – Weather Synopsis

The map below reflects the 7 Day cumulative precipitation map (July 26-August 1, 2016)


While the map below summarizes the cumulative precipitation for the growing season (April 1-August 1, 2016).



The accumulated precipitation for the growing season (April 1-August 1, 2016) is mapped below.



The updated growing degree day map (GDD) (Base 5ºC, March 1 – July 31, 2016) is below:



While the growing degree day map (GDD) (Base 10ºC, March 1 – July 31, 2016) is below:




The map below shows the Lowest Temperatures the Past 7 Days (July 26-August 1, 2016) across the prairies:



The map below shows the Highest Temperatures the Past 7 Days (July 26-August 1, 2016):



While the map below reflects the number of consecutive days above 25°C across the prairies for the growing season as of July 29, 2016.

The maps above are all produced by Agriculture and Agri-Food Canada.  Growers may wish to bookmark the AAFC Drought Watch Maps for the growing season.


Additional precipitation and temperature data or maps are provided by the following:

Manitoba Agriculture’s Crop Weather Report
Alberta Agriculture and Food’s Weather Stations
Saskatchewan’s Cumulative Precipitation Map
Environment Canada’s Historical Data Interface

Weekly Update – Pre-Harvest Intervals (PHI)

Pre-Harvest Interval (PHI) – Growers with late-season insect pest problems will need to remember to factor in the PHI which is the minimum number of days between a pesticide application and swathing or straight combining of a crop.  


The PHI recommends sufficient time for a pesticide to break down and a PHI-value is both crop- and pesticide-specific.  Adhering to the PHI is important for a number of health-related reasons but also because Canada’s export customers strictly regulate and test for the presence of trace residues of pesticides.


An excellent summary of PHI for various pesticides in their various crops was posted by Saskatchewan Agriculture this week within their Crop Production News.


In 2013, the Canola Council of Canada created and circulated their “Spray to Swath Interval Calculator” which was intended to help canola growers accurately estimate their PHI.  Other PHI are described in your provincial crop protection guides and remember that specific crop x pesticide combinations will mean different PHIs.  More information about PHI and Maximum Residue Limits (MRL) is available on the Canola Council of Canada’s website.

Weekly Update – Lygus in canola

Lygus bugs (Lygus spp.) – Reminder – The economic threshold for Lygus in canola is applied at late flower and early pod stages.  

Adult L. lineolaris (5-6 mm long) (photo: AAFC-Saskatoon).

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. They 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.

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.

Repeat the sampling in another 14 locations. 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 C). If the total number is below the lower threshold line, 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 table.

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


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.


Table 1.  Economic thresholds for lygus bugs in canola at late flowering and early pod stages (Wise and Lamb 1998).

1 Canola crop stage estimated using Harper and Berkenkamp 1975).
2 Economic thresholds are based on an assumed loss of 0.1235 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).


Table 2.  Economic thresholds for lygus bugs in canola at pod stage (Wise and Lamb 1998).

 3 Economic thresholds are based on an assumed loss of 0.0882 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).


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-enhanced or French-enhanced versions are available.

Bertha Armyworm

Bertha armyworm (Lepidoptera: Mamestra configurata– Reminder – Reporting sites across the prairies have generally reported lower cumulative interceptions but moderate numbers have been intercepted a few sites within Manitoba and Saskatchewan.  


Cumulative counts from pheromone traps are summarized and mapped by provincial staff in ManitobaSaskatchewan and Alberta.  Screen shots of the three maps are provided below:

Manitoba map (screenshot retrieved August 3, 2016):



Saskatchewan map (screenshot retrieved August 3, 2016):



Alberta map (screenshot retrieved August 3, 2016):



Reminder – In-field monitoring for egg masses and newly emerged larvae (photo below) should initially focus on the undersides of leaves plus watch the margins of leaves for feeding.  Bertha armyworm larvae will also feed on newly developing pods so the whole plant should be examined.  Watch for the following life stages:





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.

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:  


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 new “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.

Cabbage seedpod weevil

Cabbage seedpod weevil (Ceutorhynchus obstrictus) –  Reminder – There is one generation of CSPW per year and the overwintering stage is the adult which is an ash-grey weevil measuring 3-4mm long (Refer to lower left photo).  Adults typically overwinter in soil beneath leaf litter within shelter belts and roadside ditches.

Monitoring:  
 ● Begin sampling when the crop first enters the bud stage and continue through the flowering. 
 ● Sweep-net samples should be taken at ten locations within the field with ten 180° sweeps per location.  
 ● Count the number of weevils at each location. Samples should be taken in the field perimeter as well as throughout the field.  
 ● Adults will invade fields from the margins and if infestations are high in the borders, application of an insecticide to the field margins may be effective in reducing the population to levels below which economic injury will occur.  
 ● An insecticide application is recommended when three to four weevils per sweep are collected and has been shown to be the most effective when canola is in the 10 to 20% bloom stage (2-4 days after flowering starts). 
 ● Consider making insecticide applications late in the day to reduce the impact on pollinators.  Whenever possible, provide advanced warning of intended insecticide applications to commercial beekeepers operating in the vicinity to help protect foraging pollinators.  
 ● High numbers of adults in the fall may indicate the potential for economic infestations the following spring.

Damage: Adult feeding damage to buds is more evident in dry years when canola is unable to compensate for bud loss.  Adults mate following a pollen meal then the female will deposit a single egg through the wall of a developing pod or adjacent to a developing seed within the pod (refer to lower right photo).  Eggs are oval and an opaque white, each measuring ~1mm long.  Typically a single egg is laid per pod although, when CSPW densities are high, two or more eggs may be laid per pod.


There are four larval instar stages of the CSPW and each stage is white and grub-like in appearance ranging up to 5-6mm in length (refer to lower left photo).  The first instar larva feeds on the cuticle on the outside of the pod while the second instar larva bores into the pod, feeding on the developing seeds.  A single larva consumes about 5 canola seeds.  The mature larva chews a small, circular exit hole from which it drops to the soil surface and pupation takes place in the soil within an earthen cell.  Approximately 10 days later, the new adult emerges to feed on maturing canola pods.  Later in the season these new adults migrate to overwintering sites beyond the field.


Please find additional detailed information for CSPW in fact sheets posted by Alberta Agriculture and ForestrySaskatchewan Agriculture, or the Prairie Pest Monitoring Network.

Also watch provincial reports for updates on surveying underway now.  Alberta Agriculture & Forestry has released a new live CSPW map and online reporting tool for growers.  A screenshot (retrieved August 3, 2016) is included below.


Weekly Update – West Nile Virus and Culex tarsalis

West Nile Virus Risk –  The regions most advanced in degree-day accumulations for Culex tarsalis, the vector for West Nile Virus, are shown in the map below.  As of July 31, 2016areas highlighted in yellow, orange, or red on the map below have accumulated sufficient heat for C. tarsalis to fly so wear your DEET to stay protected!



The Public Health Agency of Canada posts information related to West Nile Virus in Canada.  The map of clinical cases of West Nile Virus in Canada in 2016 is posted (as of July 23, 2016) while a screen shot is provided below (retrieved August 3, 2016).



The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus.  As of August 3, 2016, 27 birds were submitted for testing yet none have tested positive for West Nile virus. 

Provincial Insect Pest Reports

Provincial entomologists provide insect pest updates throughout the growing season so we have attempted to link to their most recent information: 

– Manitoba’s Insect and Disease Update which includes lygus in canola, wheat midge, and a few sites showing moderate risk levels for bertha armyworm based on phermone trap interceptions (July 27, 2016, prepared by John Gavloski and Pratisara Bajracharya).


– Saskatchewan’s Crop Production News includes pre-harvest intervals (PHI) for a long list of field crop pesticides in Issue 6prepared by Danielle Stephens.  As the report notes, “all pesticides have a PHI” specific for product and crop type.  The PHI prevents crops exceeding Maximum Residue Levels (MRL) that will affect the quality of seed in terms of export.

– Watch for Alberta Agriculture and Forestry’s Call of the Land for updates from Scott Meers  who recently provided an update (posted on July 28, 2016) noting completion of Bertha armyworm pheromone trap monitoring and lower numbers throughout Alberta, low numbers of the orange-morph of English grain aphids, and swede midge in the northeast of Alberta.

Weekly Update – Crop reports

Crop reports are produced by:

– Manitoba Agriculture, Rural Development (August 2, 2016).
– Saskatchewan Agriculture Crop Report (July 25, 2016) which is also posted in a printer-friendly version.

– Alberta Agriculture and Forestry (for July 26, 2016).

This week, the USDA’s Crop Progress Report (posted August 1, 2016) which includes harvest and condition ratings for winter wheat, spring wheat, oat, barley, plus range and pasture conditions is available. 

The USDA also produces a World Agricultural Production Report (July 2016) which estimates production across the globe for corn, cotton, rapeseed, and wheat but also includes tabular data for other grains.

Weekly Update – Time of Swathing for Canola

The Canola Council of Canada created a guide to help growers estimate swathing time in canola.  A screen shot of the downloadable Canola Swathing Guide has been included below for reference.

Weekly Update – Harvest Sample Program

The Canadian Grain Commission is ready and willing to grade grain samples harvested in 2016.  Samples are accepted up to November but send samples as soon a harvest is complete.


This is a FREE opportunity for growers to gain unofficial insight into the quality of their 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:
  • dockage assessment on canola
  • unofficial grade
  • 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 soybeans
Many producers find having both grade and quality information on their samples before delivering their grain to be helpful.

Weekly Update – Previous Posts

The following is a list of previous 2016 Posts – click to review:

Alfalfa weevil

Aphids in canola 


Bertha armyworm development and flight

Cabbage root maggot
Canola scouting chart
Cereal leaf beetle
Crop protection guides
Cutworms


Diamondback moth

Environment Canada’s radar maps to follow precipitation events


Flea beetles in canola


Grasshoppers

Iceburg reports

Insects in our diet

Monarch migration

Multitude of mayflies


Pea leaf weevil monitoring

Predicted cereal leaf beetle development

Predicted lygus bug development
Predicted wheat midge development

Swede midge



Thrips in canola

Weather Synopsis (Week 12)

Wind trajectories

Weekly Update – Wheat midge

Wheat Midge (Sitodiplosis mosellana– Predictive modelling will be used again to help  forecast wheat midge emergence across the Canadian prairies.  The map below predicts the geographic distribution and corresponding accumulation of heat units necessary for wheat midge to emerge from puparia developing in the soil.  


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 15ºC), calm evenings, the midge can be observed in the field, laying their eggs on the wheat heads (photographed by AAFC-Beav-S. Dufton & A. Jorgensen below). 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.


REMEMBER that in-field counts of wheat midge per head remain the basis of economic threshold decision.  Also remember that the parasitoid, Macroglenes penetrans (photographed by AAFC-Beav-S. Dufton below), 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.




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 growers in Alberta can access mapped cumulative counts from wheat midge pheromone traps.  A screen shot of the map is provided below (retrieved August 3, 2016).


Additional 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.

Insect of the Week – Ladybird beetle larva

Last year, the focus of the Beneficial Insect of the Week was crop pests. This year, we’re changing things up and highlighting the many natural enemies that help you out, silently and efficiently killing off crop pests. [note: featured Insects of the Week in 2015 are available on the Insect of the Week page] 

You can’t tell by looks whether an insect is a good bug (beneficial) or a bad bug (pest). And while you might recognize the adult, the immature form might appear quite alien. This is definitely the case with the ladybird beetle (aka lady beetle). This cute, orange, nearly round beetle with varying number of spots depending on species appears harmless but is a voracious eater, consuming up to 100 aphids a day (and other soft bodied insects). The larvae (slate blue, elongated body with varying black and yellow patterns) can be just as hungry.

One of the exciting projects at Agriculture Canada is looking at how natural enemies like ladybird beetles control cereal aphids in wheat, oat, barley and rye, preventing them from causing economic damage without you having to lift a finger (or hook up a sprayer). Of course, there are times when there aren’t enough free helpers/natural enemies and we’re developing an app that will help growers figure out if and when they need to control cereal aphids. (Refining and making accessible to growers a validated dynamic action threshold for cereal aphid control in cereal crops).

For more information about these natural enemies, other pests they control and other important crop and forage insects, see the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide for identification, life cycle and conservation options (download links for field guide available on the Insect of the Week page).


Ladybird beetle larva eating aphids
Mike Dolinski, MikeDolinski@hotmail.com

Insect of the Week – Red turnip beetle

This week’s Insect of the Week is the red turnip beetle (Entomoscelis americana Brown) (from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide – download links available on the Insect of the Week page).