Weekly Update

Week 16 and this marks the final Weekly Update of the 2021 growing season! Watch the website in late February when 2022 forecast maps will begin to be released and the Weekly Update will return in May 2022. An even easier option is to subscribe to the website to receive updates automatically!

This week, please pay special attention to the Provincial Insect Pest Report section – provincially-led surveys continue for grasshoppers and wheat midge but also find links to permit land access and to help monitor in 2022! Once again, we thank the many folks who participated in insect monitoring in field crops grown across the prairies! We also thank the key individuals who worked to create the data and information presented within the Weekly Updates!

As swathers and combines continue to move across the prairies, we wish everyone good weather and a safe harvest! Be sure to catch the Insect of the Weekit’s the Japanese beetle!

Stay safe and good scouting to you!

Questions or problems accessing the contents of this Weekly Update?  Please contact us so we can connect you to our information. Past “Weekly Updates” can be accessed on our Weekly Update page.

Weather synopsis

TEMPERATURE: This past week (August 9 – 15, 2021) the prairies continued to experience above-average temperatures and extremely dry conditions. Across the prairies, the average 30-day (July 17 – August 15, 2021) temperature was 1.5 °C warmer than climate normal values. The warmest temperatures were observed across the southern prairies (Fig. 1). A comparison of temperature anomalies (difference between average and observed temperatures) for this period indicated that southern Alberta and northeast Saskatchewan were approximately 3 °C warmer than normal (Fig. 2). Average temperatures around Peace River, Edmonton, and southern Manitoba were most similar to climate normal values.

Figure 1. 30-day average temperature (°C) observed across the Canadian prairies for the period of July 17– August 15, 2021.
Figure 2. Temperature anomalies (difference from climate normal values) for average temperature (°C) observed across the Canadian prairies for the period of July 17 – August 15, 2021.

The 2021 growing season (April 1 – August 15, 2021) has been 1.5 °C warmer than average (Fig. 3). Growing season temperature anomalies indicate that Parkland and Peace River regions have been 1.5-2.5 °C warmer than normal (Fig. 4).

Figure 3. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1 – August 15, 2021.
Figure 4. Temperature anomalies (difference from climate normal values) for average temperature (°C) observed across the Canadian prairies for the period of April 1 – August 15, 2021.

Growing degree day (GDD) maps for Base 5 ºC and Base 10 ºC (April 1-August 9, 2021) can be viewed by clicking the hyperlinks. Over the past 7 days (August 12-18, 2021), the lowest temperatures recorded across the Canadian prairies ranged from < -1 to >11 °C while the highest temperatures observed ranged from <20 to >37 °C. Check the number of days of >25 °C or >30 °C across the Canadian prairies (April 1-August 11, 2021). Access these maps and more using the AAFC Drought Watch webpage interface.

PRECIPITATION: Weekly (August 9-15, 2021) rainfall amounts were generally less than 5 mm. Rainfall amounts for the period of July 17 – August 15 (30-day accumulation) have been well below average with most of the prairies reporting rain amounts that were less than 40 mm (Fig. 5). Growing season precipitation has been below average across most of the prairies with cumulative rain amounts that have been less than 100 mm. A region extending from Lethbridge to northeastern Saskatchewan has had less than 100 mm of rain (Fig. 6).

Figure 5. 30-day cumulative rainfall (mm) observed across the Canadian prairies for the period of July 17 – August 15, 2021
Figure 6. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1 – August 15, 2021.

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

Predicted diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Model runs based on climate normals data indicate that most DBM populations should be in the third generation with second-generation DBM predicted for areas within the Peace River region and localized areas of fourth-generation DBM occurring across southern Alberta, Saskatchewan and Manitoba (Fig. 1). Model simulations based on current growing season weather indicate that, compared to climate normal results, there has been an additional generation (fourth) of non-migrant adults that are currently occurring across the Canadian prairies (Fig. 2).

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) that are expected to have occurred across the Canadian prairies as of August 15 (based on climate normals data).
Figure 2. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to occur across the Canadian prairies as of August 15, 2021.

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

Figure 3. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

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

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Figure 4. Diamondback moth pupa within silken cocoon.
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Figure 5. Diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (accessible in either English-enhanced or French-enhanced versions).

Predicted grasshopper development

Model simulations were used to estimate grasshopper (Melanoplus sanguinipes) development and oviposition as of August 15, 2021. Above-average temperatures during June, July, and early August continue to result in a noticeable increase in the rates of oviposition.

Grasshoppers generally begin to lay eggs in early August. Model simulations for 2021 predicted that oviposition was expected to begin in mid-July. Earlier oviposition can result in above-average production of eggs and increased overwintering survival of eggs. This may result in potential increased grasshopper risk for the 2022 growing season. Model runs for the 2021 growing season (April 1 – August 15) indicated that oviposition should now be occurring across most of the prairies and is predicted to be greatest in southeastern Alberta (Fig. 1).

Figure 1. Grasshopper (Melanoplus sanguinipes) oviposition index across the Canadian prairies as of August 8, 2021. Higher values indicate greater potential for oviposition.

Grasshopper Scouting Steps:
Review grasshopper diversity and scouting information including photos of nymphs, adults, and non-grasshopper species to aid in-field scouting and accurately apply thresholds for grasshoppers.
● Measure off a distance of 50 m on the level road surface and mark both starting and finishing points using markers or specific posts on the field margin.
● Start at one end in either the field or the roadside and walk toward the other end of the 50 m, making some disturbance with your feet to encourage any grasshoppers to jump.
● Grasshoppers that jump/fly through the field of view within a one-meter width in front of the observer are counted.
● A meter stick can be carried as a visual tool to give perspective for a one-meter width. However, after a few stops, one can often visualize the necessary width and a meter stick may not be required. Also, a hand-held counter can be useful in counting while the observer counts off the required distance.
● At the endpoint, the total number of grasshoppers is divided by 50 to give an average per meter. For 100 m, repeat this procedure.
Compare counts to the following damage levels associated with pest species of grasshoppers:
0-2 per m² – None to very light damage
2-4 per m² – Very light damage
4-8 per m² – Light damage
8-12 per m² – Action threshold in cereals and canola
12-24 per m² – Severe damage
24 per m² – Very severe damage
For lentils at flowering and pod stages, >2 per m² will cause yield loss.
For flax at boll stages, >2 per m² will cause yield loss.
● More practically, the following thresholds are offered but, in the event of additional crop stress (e.g., drought), the use of “may be required” versus “control usually required” requires careful consideration:

Biological and monitoring information (including tips for scouting and economic thresholds) related to grasshoppers in field crops is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan 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” (accessible in either English-enhanced or French-enhanced versions).

West nile virus risk

The following is offered to help predict when Culex tarsalis, the vector for West Nile Virus, will begin to fly across the Canadian prairies. By this week, all regions across the prairies have now accumulated sufficient degree-day heat units for Culex tarsalis to develop to adult stages, if present in the region (Fig. 1).

As of August 15, 2021 (Fig. 1), C. tarsalis development has now reached the point that adults are predicted to be flying across all areas of the Canadian prairies. Outdoor enthusiasts falling within areas highlighted red OR in areas that have accumulated >400 degree-days for C. tarsalis to emerge should wear DEET to protect against WNV!

Figure 1. Predicted development of Culex tarsalis across the Canadian prairies (as of August 15, 2021).

The Public Health Agency of Canada posts information related to West Nile Virus in Canada and also tracks West Nile Virus through human, mosquito, bird and horse surveillance. Link here to access their most current weekly update (reporting date August 13, 2021; retrieved August 19, 2021). The screenshot below (retrieved 19Aug2021) serves as a reference and reports one human case of WNV, two positive wild birds, and positive mosquito pools in Ontario.

Bird surveillance continues to be an important way to detect and monitor West Nile Virus. The Canadian Wildlife Health Cooperative (CWHC) works with governmental agencies (i.e., provincial laboratories and the National Microbiology Laboratory) and other organizations to report the occurrence of WNV. Dead birds retrieved from areas of higher risk of West Nile Virus are tested for the virus. A screenshot of the latest reporting results posted by Canadian Wildlife Health Cooperative is below (reporting date August 18, 2021; retrieved 19Aug2021) which reports 3 positive birds collected in both Ontario and Quebec.

Anyone keen to identify mosquitoes will enjoy this pictorial key for both larvae and adults which is posted on the Centre for Disease Control (CDC) website but sadly lacks a formal citation other than “MOSQUITOES: CHARACTERISTICS OF ANOPHELINES AND CULICINES prepared by Kent S. Littig and Chester J. Stojanovich” and includes Pages 134-150. The proper citation may be Stojanovich, Chester J. & Louisiana Mosquito Control Association. (1982). Mosquito control training manual. pp 152.

Early detection of invasive insect species

Many of Canada’s economically important species of insect pests originated as invasive species that managed to relocate and establish self-sustaining populations. Over time, they became increasingly widespread and so frequently abundant that they became part of the annual list of species we monitor and attempt to manage.

Examples of invasive species that now exist as part of our field crop landscape include wheat midge, cereal leaf beetle, cabbage seedpod weevil, pea leaf weevil, swede midge – in fact, the list of invasive species is far longer! It’s important to consider the impact of invasive species AND recognize that a growing list of species will likely affect field crops in Canada. Globalization, adaptation, and the development of new cultivars suited to Canada’s growing regions, climate change, plus many other factors will contribute to the reality: we can expect more invasive species to continue to arrive.

Where can you play a role??? Early detection and accurate identification are key steps involved in mitigating the risks associated with new invasive species. Many levels of government are active in the ongoing battle against invasive species. Even so, initial detections often arise from keen in-field scouting by producers or agrologists so access these resources to help identify the “that’s weird” or “I haven’t seen that before”. And be sure to thank the many entomologists – regional, provincial, federal, and some amazing amateurs PLUS the folks at Canadian Food Inspection Agency (CFIA) who ALL work to stand on guard for thee!

Canadian Food Inspection Agency’s (CFIA) main Plant Health section can be accessed here.

• More specifically, CFIA’s Plant Pests and Invasive Species information is accessible here.

• Did you know…. CFIA’s top field crop invasive species include anything falling under the List of Pests Regulated by Canada which is accessible here. Caveats are that (i) some species may be on the list (e.g., codling moth) that are not necessarily a high priority but remain to maintain regulatory policy or (ii) list may include species yet to be removed.

• Anyone can access diagnostic information for invasive species at CFIA’s Plant Pest Surveillance section accessible here.

HERE’S WHERE YOU CAN HELP – Experienced producers and agrologists make important discoveries every day! Keep Canadian agriculture strong and support the detection of invasive species using this important information and the three options when encountering unusual damage symptoms or unknown insect species:

Important details to be ready to report: Be ready to include details to make a “report” – Sightings need to be validated so providing as much detail as possible will help the expert confirm identifications and relocate the site, if the issue demands urgent attention.
◦ Date of observation
◦ Nearest town and province
◦ Latitude x longitude values
◦ Host plant(s)
◦ Good photo(s) – lateral, dorsal, damage symptoms, host plant, etc., with some sort of size reference is ideal
◦ Chronological photos (i.e., that tell the story of detection and how and when symptoms or specimen came to your attention)
◦ A specimen may be needed by your provincial entomologist or CFIA

Option 1: Contact your provincial entomologist to confirm identifications and details – they are able to help and historically have acted to triage reports then direct relevant information to CFIA counterparts:
◦ Manitoba (John.Gavloski@gov.mb.ca )
◦ Saskatchewan (james.tansey@gov.sk.ca)
◦ Alberta (shelley.barkley@gov.ab.ca)

Option 2: Alternatively, reports can be sent directly using one of the following paths:
◦ Using CFIA’s Report A Pest website form
◦ Contact a local CFIA office
◦ Or contact CFIA’S general surveillance account email at cfia.surveillance-surveillance.acia@canada.ca
◦ Or contact CFIA’s Survey Biologist for the Western Area (david.holden@canada.ca)

Option 3: Another alternative is to consider documenting your query using iNaturalist.ca (read more here). The basic steps involved are:
◦ Create an account at iNaturalist.ca (https://inaturalist.ca/signup)
◦ Watch your Inbox for a basic how-to guide.
◦ Upload photos or videos (e.g., bird calls) to create an “Observation”
◦ iNaturalist subscribers considered to be experts will help identify your observation.

An APP with a difference – iNaturalist.ca

Smartphones and their evolving photographic capacity continue to enhance our ability to learn about the environment around us. Millions of APPs have been developed to harness information and agriculture continues to benefit.

iNaturalist.ca is beneficial to download. It helps users identify terrestrial organisms by connecting to “experts” who help identify and provide information to users but there’s an underlying secondary benefit: Researchers, institutions, and active research projects can set up Lists and access observations within iNaturalist. As the homepage says, “Every observation can contribute to biodiversity science, from the rarest butterfly to the most common backyard weed.” We reached out to the Canadian Food Inspection Agency (CFIA) who are already using and accessing valuable data from this resource.

What’s best – iNaturalist.ca OR iNaturalist.com? Canadian Food Inspection Agency (CFIA) and the team that focuses on the detection of invasive species generally recommends iNaturalist.ca because it allows Canadians better access to Canadian experts and Canadian data.

Is iNaturalist.ca worth using to identify unknown insects encountered in field crops? iNaturalist.ca is going to be the leader in early detections and is a fairly intuitive and usable tool for everyone. It’s not perfect for all organisms but works well for many. CFIA staff are actively monitoring it and, in the near future, CFIA hopes to set up an account that might allow users to flag observations for their team to see more rapidly.

How does CFIA mine iNaturalist and what is the value? CFIA uses a script through the Intauralist API to query for any mentions of our targeted list under the project here: Important Pest Species List for Canada – Lookout · iNaturalist. CFIA staff members receive a daily email of all the target list mentions (i.e., includes insects, plants, and mollusks). In order to increase early detections, CFIA’s also trying to retrieve data from comments such as when someone mentions a new record or new detection. At this point, only a few pathogens are listed in our pest lookout because many of CFIA’s regulated pests would need more than a picture (so we didn’t add them). CFIA staff believe iNaturalist.ca is a great tool for early detection because the number of observations is very large and growing like crazy AND they are geographically widespread.

The basic steps involved are:
◦ Create an account at iNaturalist.ca (https://inaturalist.ca/signup).
◦ Watch your Inbox for a basic how-to guide.
◦ Upload photos or videos (e.g., bird calls) to create an “Observation”.
◦ iNaturalist subscribers considered to be experts will help identify your observation.

Crop Metrics Application

Reminder – Agriculture and Agri-Food Canada has released the Canadian Crop Metrics application. This product contains useful and interesting information about the current status of crops grown across Canada. The application also presents data for a number of pest insects including bertha armyworm, diamondback moth, grasshoppers and wheat midge.

Read over the synopsis of the Canadian Crop Metrics application to gain a sense of what the resource has to offer and how to optimize access. It allows users to look at specific regions and generate reports, graphs, and tables to compare current conditions to historical conditions for 11 different crop types. Weather data is updated regularly and yield estimates are updated monthly from July to October. Forecasts are made at the beginning of the months of July, August and September for all crops, and an additional forecast is made for corn and soybeans (late season crops) at the beginning of October. Forecasts are jointly produced by Agriculture and Agri-Food Canada and Statistics Canada using historical yield, climate and satellite data as inputs.

Screenshots of the application are below for reference. Get started here!

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 2021 are now available – access the August 11, 2021 report here. Be sure to bookmark their Crop Pest Update Index to readily access these reports! Bookmark their insect pest homepage to access fact sheets and more!
The late-season grasshopper survey is underway in Manitoba – Anyone interested can access the survey protocol posted here.

SASKATCHEWAN’S Crop Production News is available. Access Issue #5 online which includes information describing supporting pollinators in an agriculture habitat. Be sure to bookmark their insect pest homepage to access important information!
PLEASE participate in the fall wheat midge soil core survey by registering fields at the pest survey sign-up webpage! – Producers need to sign up to allow access to their land to help build the 2022 forecast map!
PLEASE volunteer to monitor bertha armyworm in 2022 by emailing pestsurveys@gov.sk.ca – Please state that you would “like to participate in the BAW survey”.

ALBERTA’S Insect Pest Monitoring Network webpage links to insect survey maps, live feed maps, and insect trap set-up videos and more. There is also a Major Crops Insect webpage. The new webpage does not replace the Insect Pest Monitoring Network page. Remember, AAF’s Agri-News occasionally includes insect-related information or Twitter users can connect to #ABBugChat Wednesdays at 10:00 am (through the growing season).
Consider getting involved with annual insect surveying by signing up to allow access to your land– Producers who participate help build population maps of pest insects. Email shelley.barkley@gov.ab.ca to sign up for 2022!

Crop report links

Click the provincial name below to link to online crop reports produced by:
Manitoba Agriculture and Resource Development (subscribe to receive OR access a PDF copy of the August 17, 2021 report; retrieved 19Aug2021).
Saskatchewan Agriculture (or access a PDF copy of the August 10-16, 2021 report; retrieved 19Aug2021).
Alberta Agriculture and Forestry (or access a PDF copy of the August 10, 2021 report; retrieved 19Aug2021).

The following crop reports are also available:
• The United States Department of Agriculture (USDA) produces a Crop Progress Report (access a PDF copy of the August 16, 2021 edition; retrieved 19Aug2021).
• The USDA’s Weekly Weather and Crop Bulletin (access a PDF copy of the August 17, 2021 edition; retrieved 19Aug2021).

Previous posts

As the growing season progresses, the various Weekly Update topics move on and off the priority list for in-field scouting but they should be kept at hand to support season-long monitoring. Click to review these earlier 2021 Posts (organized alphabetically):
2020-2021 Risk and forecast maps
Alfalfa weevil – predicted development (Wk07)
Aphids in field crops (Wk09)
Bertha armyworm (Wk12)
Bertha armyworm – predicted development (Wk09)
Cabbage seedpod weevil monitoring (Wk09)
Calls for survey help (Wk14)
Cereal aphid manager APP (Wk07)
Cereal leaf beetle – predicted development (Wk07)
Crop protection guides (Wk03)
Cutworms (Wk02)
European corn borer – nation-wide monitoring project (Wk07)
Field heroes (Wk15)
Flea beetles (Wk02)
Flea beetles – predicted geographic distribution and abundance (Wk04)
Fuzzy white “eggs” on barley or wheat (Wk13)
Grasshopper diversity and scouting photos (Wk08)
Ladybird beetles (Wk03)
Lygus bug monitoring (Wk15)
Midges in canola (Wk11)
Monarch migration (Wk09)
Pea leaf weevil (Wk03)
Praire-wide survey of stored grain pests (Wk13)
Pre-Harvest Intervals (Wk15)
Scouting charts – canola and flax (Wk03)
Slugs and their parasites (Wk04)
Thrips in canola (Wk12)
Weather radar mapping interface (Wk06)
Wheat midge – predicted development (Wk08)
Wheat midge – predicted development (Wk15)
Wind trajectories for monitoring insect movement (Wk02)
Wind trajectories – weekly reports (Wk09)
Wireworms (Wk02)


Japanese beetle (Bruce Marlin CC-BY 3.0)

As the name suggest, the Japanese beetle is native to Japan but has been present in North American since 1916. While an annual trapping program in Canada has been in place since 1939, complete elimination has not been achieved. Fortunately, it has not reached the Prairies yet, but it is found in southern Ontario, Quebec, New Brunswick, Prince Edward Island and Nova Scotia. It has been detected in Vancouver, British Columbia and the CFIA is leading a coordinated eradication program and has implemented efforts to prevent the pest’s spread outside Vancouver. The rest of British Columbia is still considered free of Japanese Beetle. In the USA, eastern states are considered generally infested (from Minnesota south to Arkansas and across to the Atlantic Coast, excluding Mississippi [partial infestation], and Florida and Louisiana [no infestation]); central states are partially infested (from North Dakota south to Texas); and western states (including Alaska and Hawaii) have no infestations (USDA Japanese Beetle FAQ). Quarantine and phytosanitary regulations are in force to limit movement of infested materials from infested states into or through non-infested states to protect the agriculture sector.

Potential host plants on the Prairies include corn and soybean, but the Japanese beetle also targets fruit crops like peach, apple, apricot, cherry and plum, as well as berries like blueberry, raspberry. Damage from adult Japanese beetles includes leaves that have been chewed down to the vein. Damaged leaves turn brown and drop, leaving plants vulnerable to disease and limiting overall growth. Larvae feed on roots, causing additional stunting in addition to potential wilting and sometimes death.

Adults are almost 10 millimetres long and oval. Their abdomen, thorax and head are metallic green with metallic copper-brown wing coverings and white hair along the abdomen. Larvae grow to 25 millimetres and are C-shaped white grubs with a yellowish-brown head. A V-shaped spine arrangement can be seen on the last body segment. 

Japanese beetle larval development (David Cappaert — Michigan State University CC-BY 3.0)

Biological and monitoring information related to Japanese beetles in field crops can be found on our Monitoring page. For more information, visit the Japanese beetle page on the Canadian Food Inspection Agency website.