Released June 7, 2024

Welcome to Week 5 for the 2024 growing season!  This week includes:
• Weather synopsis
• Cutworms
• Grasshoppers
• Diamondback moth
• Bertha armyworm
• Pea leaf weevil
• Detecting and reporting invasive insects
• Field heroes
• Welcome Prairie Weed Monitoring Network
• Provincial insect pest report links
• Crop report links
• Previous posts

Catch Monday’s Insect of the Week for Week 5 – What’s eating my crop? Cereal leaf beetle

Receive free Weekly Updates automatically by subscribing to the website!

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

This week’s weather summary was kindly provided by the Prairie Crop Disease Monitoring Network (PCDMN).

Prairie temperatures and rainfall amounts continue to be above average for the 2024 growing season. This past week (May 27 – June 2, 2024) temperatures were similar to climate normal values. The average temperature across the prairies was 13.1 °C (Figure 1). Warmest temperatures were observed across the Peace River region and a large area that extended west of Winnipeg to Saskatoon and Swift Current. Seven day cumulative rainfalls were highly variable (Figure 2). Average cumulative seven day rainfall was 10.6 mm. Lowest rainfall values were observed across western regions of the prairies, while eastern areas received higher rainfall amounts.

Figure 1. Seven day average temperature (°C) observed across the Canadian prairies for the period of May 27 – June 2, 2024.
Figure 2. Seven day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 27 – June 2, 2024.

The average 30 day temperature (May 4 – June 2, 2024) was 11.1 °C and was 0.5 °C warmer than the long term average temperature. Warmest temperatures were observed south of an area extending from Winnipeg to Saskatoon and southwest to Lethbridge (Figure 3). Most of the prairies have reported 30 day rainfall amounts were normal to above normal. Average cumulative rainfall (mm) over the past 30 days was 70 mm and was 186% of climate normal values. The Peace River region continues to report lowest rainfall totals (Figure 4). Cumulative rainfall continues to be greatest across southern Alberta and most of Manitoba.

Figure 3. 30 day average temperature (°C) observed across the Canadian prairies for the period of May – June 2, 2024.
Figure 4. 30 day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 4 – June 2, 2024.

Since April 1, the 2024 growing season has been 1 °C warmer than average. Compared to climate normals, average growing season temperatures were cooler than normal across most of Alberta and warmer than normal for Manitoba and Saskatchewan (Figure 5). Warmest average temperatures were observed across Saskatchewan and Manitoba (Figure 6).

Figure 5. Growing season average temperature difference from climate normal (°C) observed across the Canadian prairies for the period of April 1 – June 2, 2024.
Figure 6. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1 – June 2, 2024.

Growing season rainfall has been above normal across most of the prairies. Rain amounts have been 197 % of climate normals (Figure 7). Highest cumulative rainfall has been greatest for most of Manitoba and southern Alberta (Figure 8).

Figure 7. Growing season percent of normal rain (%) observed across the Canadian prairies for the period of April 1 – June 2, 2024.
Figure 8. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1 – June 2, 2024.

Growing degree day (GDD) maps for the Canadian prairies for Base 5 ºC and Base 10 ºC (April 1-June 3 2024) can be viewed by clicking the hyperlinks. Over the past 7 days (to June 5, 2024), the lowest temperatures recorded across the Canadian prairies ranged from < -3 to > 9 °C while the highest temperatures observed ranged from < 3 to >25 °C. In terms of precipitation across the Canadian prairies, review the growing season accumulated precipitation (April 1-June 5, 2024), the growing season percent of average precipitation (April 1-June 5, 2024), and the past 7 days (as of June 5, 2024). Access these maps and more using the AAFC Maps of Historic Agroclimate Conditions interface.

Growers can bookmark the AAFC Maps of Current Agroclimate Conditions for the growing season. Historical weather data can be accessed at the AAFC Drought Watch Historical website, Environment and Climate Change Canada’s Historical Data website, or your provincial weather network. The AAFC Canadian Drought Monitor also provides geospatial maps updated monthly.


Reminder – Cutworm scouting spans April to late June across the Canadian prairies!

This past week in Manitoba, Dr. John Gavloski reported sporadic cutworm infestations this spring. At least one canola field was reseeded and sunflower fields were treated with insecticides. Darksided and redbacked cutworms were observed in damaged sunflower fields. Significant cutworm issues have also been reported in Alberta.

Scout fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look.  Plan to follow up by walking these areas either very early or late in the day when some cutworm species (or climbing cutworms) move above-ground to feed.  Start to dig below the soil surface (1-5 cm deep) near the base of symptomatic plants and also any healthy plants immediately adjacent to missing rows or wilting or clipped plants.  Some cutworms feed by remaining just below the soil surface, clipping then pulling the plant below as they munch away! If the plant is well-established (e.g., perennial grass or legume), check within the crown plus in the adjacent soil.  The culprits could be cutworms, wireworms, or more!

Important: Several species of cutworms (Lepidoptera: Noctuidae) can be present in fields.  They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning.  A field guide is available to help growers scout and manage the various species of cutworms that can appear in field crops grown on the Canadian prairies.  Cutworm Pest of Crops is available free in either English or French! Download a searchable PDF copy to access helpful diagnostic photos plus a table showing which larvae are active at different points in the growing season!

Other vital resources to scout and manage cutworms include:
● For anyone on the Canadian prairies, Manitoba Agriculture’s Cutworms in Field Crops fact sheet includes action and economic thresholds for cutworms in several crops, important biological information, and great cutworm photos to support in-field scouting.
● For Albertans….. If you find cutworms, please consider using the Alberta Insect Pest Monitoring Network’s “2024 Cutworm Reporting Tool” then view the live 2024 cutworm map updated daily. Review the live map to see where cutworms are appearing then prioritize in-field scouting accordingly.
● Cutworms were featured as 2024’s first Insect of the Week.


Nymphs of economically important grasshopper species, have been observed at multiple locations in southern Alberta and southern Saskatchewan since mid-May. Last week, there were reports of grasshopper (and flea beetle) damage to emerging canola crops in central Saskatchewan.

Scout for grasshoppers to keep informed of their developmental stage and population density.

Grasshopper Scouting Tips:
Review grasshopper diversity and photos of nymphs, adults, and non-grasshopper species to aid in-field scouting from egg hatch and onwards.
● Carefully check roadside ditches and along field edges but also check the edge of the crop and into the actual field.
● Younger or earlier instar nymphs are easier to manage – visit sites every few days to stay on top of local field conditions.
● A sweep-net can ‘detect’ grasshopper nymphs, however, economic thresholds for grasshoppers are based on the number of grasshoppers per square-metre counts.
● Access the PPMN’s Grasshopper Monitoring Protocol as a guide to help implement in-field monitoring.
● Review grasshopper lifecycle, damage and scouting and economic thresholds to support sound management decisions enabling the preservation of beneficial arthropods and mitigation of economic losses.

Important – A preliminary summary of available thresholds for grasshoppers has been kindly shared by Dr. J. Tansey (Saskatchewan Agriculture) in Table 1. When scouting, compare in-field counts to the available threshold value for the appropriate host crop AND for field or ditch situations. Available thresholds (nominal and economic) help support producers while protecting beneficials (i.e., predators, parasitoids, and pathogens) that regulate natural populations of grasshoppers.

Biological and monitoring information (including tips for scouting and economic thresholds) related to grasshoppers in field crops is posted by Manitoba AgricultureSaskatchewan AgricultureAlberta Agriculture and Irrigation, 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” (2018) accessible as a free downloadable PDF in either English or French on our Field Guides page. Review the historical grasshopper maps based on late-summer in-field counts of adults performed across the Canadian prairies.

Diamondback moth

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Last week, Shelley Barkley (Alberta Agriculture and Irrigation) swept a flixweed patch in a ditch and found very mature diamondback moth larvae in southern Alberta. Thus, in some parts of the prairies, the first local generation of diamondback moth is nearing completion.

Please refer to this week’s Provincial Insect Pest Report Links to find the most up-to-date information summarizing weekly cumulative counts being compiled by provincial pheromone trapping networks across the Canadian prairies in 2024.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba AgricultureSaskatchewan 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” (2018) accessible as a free downloadable PDF in either English or French on our new Field Guides page.

Bertha armyworm

Pheromone traps used to monitor bertha armyworm are typically set up along canola fields when pupal development reaches 75-80%; the 2024 monitoring season will start soon with traps due to be set up the week of June 10, 2024.

Use the images below (Fig. 1) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.

Figure 1. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of ManitobaSaskatchewanAlberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (2018) accessible as a free downloadable PDF in either English or French on our new Field Guides page.

Pea leaf weevil

The annual pea leaf weevil survey is underway! If you have field peas this year, please consider volunteering your fields for this survey. The survey is conducted by counting the characteristic ‘u’ shaped feeding notches made by adult pea leaf weevil at several locations along the field edge.

Adult pea leaf weevil could now be dispersing into emerging field pea and faba bean fields. Watch for ‘u’-shaped notches along the leaf margins of emerging seedlings – for more information about the damage caused to crops by pea leaf weevil, check out the Week 4 Insect of the Week post.

Live adult pea leaf weevil are needed for experiments this spring, so if you are finding weevils in your crops, please contact Dr. Meghan Vankosky (AAFC-Saskatoon; Thank you!

Biological and monitoring information related to pea leaf weevil in field crops is posted by the province of Alberta and in the PPMN monitoring protocol. Also access the Pea leaf weevil page re and Resource DevelopmentSaskatchewan AgricultureAlberta Agriculture and Forestry, the BC Ministry of Agriculture, and the Prairie Pest Monitoring Network.  Also refer to the pea leaf weevil page within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (2018) accessible as a free downloadable PDF in either English or French on our Field Guides page.

Detecting and reporting invasive insects

Early detection is critical for slowing the spread of invasive insects.

A collaborative project developed by the Insect Surveillance Community of Practice and Canadian Plant Health Council has led to a series of posters featuring invasive insects of concern. Each poster includes a QR Code that users can scan to report observations of these priority invasive and migratory insects. Posters are free, printable PDF copies and highlight species of concern across Canada’s regions:
• Prairies (English or French)
• British Columbia (English or French)
• Ontario & Quebec (English or French)
• Atlantic (English or French)

The English version of the Prairies poster is below to view (Front and Back) Use the QR code to report detections or observations of these invasive species.

Field heroes

Reminder – The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops.

Field Heroes resources include:

  1. Real Agriculture went live in 2024 with Season 5 of the Pest and Predators podcast series!
    NEW Episode 30Farmer feedback: Insect pest management practices  Haley Catton and Emma Stephens (Agriculture and Agri-Food Canada-Lethbridge) and Shaun Haney (RealAg). Published online May 29, 2024.
    Episode 29The ecology of fear  Maya Evenden (University of Alberta) and Shaun Haney (RealAg). Published online May 14, 2024.
    Episode 28Research roundup: Lesser clover leaf weevil  Jeremy Irvine (University of Saskatchewan) and Shaun Haney (RealAg). Published online May 1, 2024.
    Episode 27Armoured tanks: Beetles in battle  Tyler Wist (Agriculture and Agri-Food Canada-Saskatoon) and Shaun Haney (RealAg). Published online April 17, 2024.
    Episode 26Invasive species awareness: Knowing what to look for and how to report it  Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon), James Tansey (Saskatchewan Ministry of Agriculture), John Gavloski (Manitoba Agriculture), and Shaun Haney (RealAg). Published online April 2, 2024.
    Episode 25 20 years of canola surveying and counting!  Jennifer Otani (Agriculture and Agri-Food Canada-Beaverlodge) and Shaun Haney (RealAg). Published online March 19, 2024.
    • Review SEASON 4 of the Pest and Predators podcasts (2023)
    • Review SEASON 3 of the Pest and Predators podcasts (2022)
    • Review SEASON 2 of the Pest and Predators podcasts (2021)
    • Review SEASON 1 of the Pest and Predators podcasts (2020)
  2. The Pests and Predators Field Guide (2021) is filled with helpful images for quick insect identification and plenty of tips to manage the pests AND natural enemies in your fields.
  3. Crop Scouting Guides (2021) specific to cereals, oilseeds, or pulses.
  4. Scouting Guides (2022) for aphids, cutworms, diamondback moth larvae, or bertha armyworms.

Follow @FieldHeroes!

Welcome Prairie Weed Monitoring Network

This week, the Prairie Pest Monitoring Network is excited to promote the official launch of the Prairie Weed Monitoring Network’s official website,!

The Western Grains Research Foundation (WGRF) is excited to announce the official launch of, a comprehensive online platform designed to support the Prairie Weed Monitoring Network (PWMN) through the Integrated Crop Agronomy Cluster.

Led by Dr. Charles Geddes and Julia Leeson from Agriculture and Agri-Food Canada (AAFC), the PWMN is a pioneering initiative aimed at implementing an all-inclusive weed biovigilance strategy across the Canadian prairies. The PWMN is a coordinated collaboration among federal, provincial, and academic weed science experts.

 “The launch of marks a significant milestone in the development of the PWMN,” says Dr. Charles Geddes, Weed Scientist, AAFC. “ will serve as the digital home of the PWMN, offering a wealth of resources and up-to-date information on weed abundance, herbicide resistance, and integrated weed management specific to the Canadian prairies.

The PWMN will build on the existing and highly successful models of the Prairie Pest Monitoring Network, and Prairie Crop Disease Monitoring Network, and will formalize and coordinate weed awareness, detection/identification, and assessment activities for the Prairie region.

Laura Reiter, WGRF Board Chair, expressed enthusiasm for the project, stating, “ will be a great resource for farmers, agronomists, and researchers. The website is a great opportunity to provide the agricultural industry with the information required to manage weeds effectively, anticipate new threats, and mitigate herbicide-resistant weeds.”

The Prairie Weed Monitoring Network (PWMN) is supported by funding from Agriculture and Agri-Food Canada through the Sustainable Canadian Agricultural Partnership’s AgriScience Program – Clusters Component, WGRF, Alberta Grains, Alberta Canola, SaskCanola, Saskatchewan Wheat Development Commission, Saskatchewan Pulse Growers, Manitoba Crop Alliance, Manitoba Pulse and Soybean Growers, Manitoba Canola Growers Association, and Prairie Oat Growers Association.

Provincial insect pest report links

Prairie-wide provincial entomologists provide insect pest updates throughout the growing season. Follow the hyperlinks to readily access their information as the growing season progresses:

MANITOBA’S Crop Pest Updates for 2024 have started! Access the online May 30, 2024 report (or review a PDF copy) AND the more recent online June 6, 2024 report (or PDF copy). Bookmark the insect pest homepage to access fact sheets and more! Highlights pulled from the June 6 report include:
Flea beetles in MB – Manitoba Agriculture reported, “some foliar insecticide applications reported from the Northwest and Eastern regions”.
Cutworms in MB – Dr. John Gavloski (Manitoba Agriculture) reported, “sporadic cutworm problems are occurring” and that “reports of a canola field in the Northwest being sprayed for cutworms, and a canola field in the Southwest was reseeded because of cutworms while a sunflower field in the Central region was sprayed for cutworms.”
Diamondback moth pheromone trap monitoring in MB – Reports that, “Diamondback moth have been found in 67 out of 84 traps that counts” and that, “trap counts have generally been low so far in the Northwest and Southwest regions. Some moderate counts have occurred in the Eastern, Interlake and Central regions. The highest cumulative trap count so far is 111 from a trap near Rosenfeld in the Central region.”
True armyworm in MB – Dr. John Gavloski (Manitoba Agriculture) reported that, “Some moderate to high counts have occurred from traps in the Eastern and Interlake regions of Manitoba. The highest cumulative count is 222, from a trap near Dencross in the Eastern region.” Followed with the suggestion that it “would be good to prioritize looking for armyworm larvae while scouting cereals and forage grasses” in “some areas of the Eastern and Interlake regions”.

SASKATCHEWAN’S Crop Production News is back for the 2024 growing season! Access the online Issue #2 report. Bookmark their insect pest homepage to access important information!
As crops emerge in SK – “Be on the lookout for early season pests such as cutworms, wireworms, flea beetles, and root rots”.
Grasshopper hatch in SK – Stay “aware of early season grasshopper damage” as “there are reports of nymphs damaging seedlings” in crops. Access the report to link to information on nymph damage and economic thresholds. The report includes articles on “How to Scout for Grasshoppers” plus “Grasshopper’s Natural Enemies
Diamondback moth in SK – Preliminary cumulative count data from pheromone traps across the province can now be reviewed online.
• Also access the Crops Blog Posts that announced registration for the Crop Diagnostic School 2024 but also posts help for scouting fields for wireworms (May 2024), grasshopper identification: pest or not (Apr 2024), a summary of wheat midge populations and management (Mar 2024), and a description of pea leaf weevil populations (Feb 2024).

ALBERTA’S Insect Pest Monitoring Network webpage links to insect survey maps, live feed maps, insect trap set-up videos, and more. There is also a Major Crops Insect webpage. Remember, AAF’s Agri-News occasionally includes insect-related information, e.g., scout for insect pests (June 3, 2024), scout for grasshoppers (May 27, 2024), flea beetle control (May 6, 2024); cereal insect pests, latest on insects in canola, and post-emergence wireworm scouting (May 13, 2024).
Diamondback moth pheromone trap monitoring update for AB – Cumulative counts arising from weekly data are available so refer to the Live Map. So far, cumulative trap counts from the 29 reporting sites reflect low or “no risk” while two sites in the Peace River region reflect “elevated risk” (as of June 6, 2024).
Cutworm live monitoring map for AB – Cumulative counts arising from weekly data are available so refer to the Live Map. So far, 8 surveyed sites have reported from across the province and all are in southern Alberta.

Crop report links

Access the latest provincial crop reports produced by:
Manitoba Agriculture (subscribe to receive OR access a PDF copy of the May 28, 2024 report or the June 4, 2024 report).
Saskatchewan Agriculture (or access a PDF copy of the May 28-June 3, 2024 report).
Alberta Agriculture and Irrigation (or access a PDF copy of the May 28, 2024 abbreviated report).

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 June 3, 2024 edition).
• The USDA’s Weekly Weather and Crop Bulletin (access a PDF copy of the June 4, 2024 edition).

Previous posts

As the growing season progresses, the Weekly Update topics move on and off the priority list for in-field scouting. It remains useful to keep the list at hand to support season-long monitoring. Click to review these earlier 2024 Posts (organized alphabetically):
2023 Risk maps
Alfalfa weevil (Wk 02)
Crop production guide links (Wk 03)
Flea beetles (Wk 04)
Scouting charts – canola and flax (Wk 03 of 2022)
Tick tips (Wk 04)
Wind trajectory summaries unavailable (Wk 01)