Welcome to Week 2 for the 2025 growing season! This week includes: • Weather synopsis • Review monitoring maps to prepare for 2025! • Cutworms • Flea beetles • Cereal leaf beetle • Tick tips • Field heroes • Access PPMN-approved field guides • Crop production guide links • Provincial insect pest report links • Crop report links
Catch Monday’s Insect of the Weekfor Week 2 – This year features lesser-known insect pest species to help producers remain vigilant! Learn more about the Spotted lanternfly!
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.
Dylan Sjolie, Tamara Rounce, Jennifer Otani and Meghan Vankosky
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Week 2
The 2025 growing season continues to be slightly warmer and drier compared to the long-term climate normal for the Canadian prairies (Figure 1). This past week (Apr May 05 – May 11, 2025), average temperatures were 6 °C warmer than normal. Temperatures were warmest in southeast areas of the Canadia prairies, and cooler in the northwest areas surrounding Grande Prairie (Figure 2).
Figure 1. Seven-day average temperature (°C) observed across the Canadian prairies for the period of May 5-11, 2025.Figure 2. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1-May 11, 2025.
Similar to last week, little rain fell across the Canadian prairies (Figure 3). Other than the southwest Alberta and Manitoba corner, growing season cumulative rain totals remain low (Figure 4).
Figure 3. Seven-day average precipitation (mm) observed across the Canadian prairies for the period of May 5-11, 2025.Figure 4. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1-May 11, 2025.
Jennifer Otani, Jonathon Williams and Meghan Vankosky
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Week 2
The Prairie Pest Monitoring Network is a collaborative effort. In-field monitoring data is collected at regional, provincial, and prairie-wide levels. Using Geographic Information Software (GIS), surface area maps are generated from survey data to create prairie-wide maps. Techniques are used to smooth transitions between zones and can affect the values in localized areas and, as such, these maps should be interpreted on a regional level only.
TIP: To prepare for the 2025 field scouting season, review the 2024 Prairie-wide Maps. Take a moment to note which geographic regions for each corresponding insect pest are highlighted in yellow, orange, or red as these are areas and insect pests to prioritize in 2025’s field scouting efforts.
Annual insect distribution maps are posted by the PPMN and can be reviewed on this webpage.
Cutworm scouting spans April to late June across the Canadian prairies! 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 while remaining just below the soil surface, clipping then pulling the plant below the soil surface 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 suggested nominal thresholds for cutworms in several crops (Table 1). The same fact sheet describes important biological information, and provides great cutworm photos to support in-field scouting!
● For Albertans….. If you find cutworms, please consider using the Alberta Insect Pest Monitoring Network’s “2025 Cutworm Reporting Tool” then view the live 2025 cutworm map updated daily. Review the live map to see where cutworms are appearing then prioritize in-field scouting accordingly.
Flea Beetles (Chrysomelidae: Phyllotreta species) – Be on the lookout for flea beetle damage resulting from feeding on canola cotyledons but also on the stem. Two species, Phyllotreta striolata and P. cruciferae, will feed on all cruciferous plants but they can cause economic levels of damage in canola during the seedling stages.
Figure 1. Flea beetle feeding inflicted by overwintered adults including ‘shot-hole’ and stem feeding on seedling canola (B. napus). Photos: AAFC-Beaverlodge-Otani
Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed. Watch for shot-hole feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.
If flea beetle densities are high, seedling damage levels can advance quickly – even within the same day! The cotyledon stage of canola is vulnerable to flea beetle feeding.
Estimating flea beetle feeding damage can be challenging. Using a visual guide to estimate damage can be helpful. Use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon) to help estimate percent of leaf area consumed for canola seedlings – take Figures 2 and 3 scouting!
Figure 2. Canola cotyledons with various percentages of leaf area consume owing to flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).Figure 3. Percent leaf area consumed by flea beetles feeding on canola seedlings (Photo: Soroka & Underwood, AAFC-Saskatoon).
The cereal leaf beetle (Chrysomelidae: Oulema melanopus) has a broad host range. Wheat is the preferred host, but adults and larvae also feed on leaf tissue of oats, barley, corn, rye, triticale, reed canarygrass, ryegrass, fescue, wild oats, millet and other grasses. Yield quality and quantity is decreased, if the flag leaf is stripped. Fun fact: Cereal leaf beetle larvae carry their own fecal waste above their body to help protect themselves from predators.
Fortunately, the parasitoid wasp, Tetrastichus julis Walker (Hymenoptera: Eulophidae), is an important natural enemy of cereal leaf beetle larvae. Learn more about this beneficial insect species featured in Week 9 of 2023’s Insect of the Week!
Cereal Leaf Beetle Lifecycle and Damage:
Adult: Adult cereal leaf beetles (CLB) have shiny bluish-black wing covers (Fig. 1). The thorax and legs are light orange-brown. Females (4.9 to 5.5 mm) are slightly larger than males (4.4 to 5 mm). Adult beetles overwinter in and along the margins of grain fields in protected places such as in straw stubble, under crop and leaf litter, and in the crevices of tree bark. They favour sites adjacent to shelterbelts, deciduous and conifer forests. They emerge in the spring once temperatures reach 10-15 ºC and the adults are active for about 6 weeks. They usually begin feeding on grasses, then move into winter cereals and later into spring cereals.
Figure 1. Adult Oulema melanopus measure 4.4-5.5 mm long (Photo: M. Dolinski).
Egg: Eggs are laid approximately 14 days following the emergence of the adults. Eggs are laid singly or in pairs along the midvein on the upper side of the leaf and are cylindrical, measuring 0.9 mm by 0.4 mm, and yellowish in colour. Eggs darken to black just before hatching.
Larva: The larvae hatch in about 5 days and feed for about 3 weeks, passing through 4 growth stages (instars). The head and legs are brownish-black; the body is yellowish. Larvae are usually covered with a secretion of mucus and fecal material, giving them a shiny black, wet appearance (Fig. 2). When the larva completes its growth, it drops to the ground and pupates in the soil.
Figure 2. Larval stage of Oulema melanopus with characteristic feeding damage visible on leaf (Photo: M. Dolinski).
Pupa: Pupal colour varies from a bright yellow when it is first formed, to the colour of the adult just before emergence. The pupal stage lasts 2 – 3 weeks. Adult beetles emerge and feed for a couple of weeks before seeking overwintering sites. There is one generation per year.
Access scouting tips for cereal leaf beetle or find more detailed information by accessing the Oulema melanopus page from 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.
Reminder – When field scouting, avoid unwanted passengers – remember to watch for ticks at this time of year!
Blacklegged (deer) ticks can carry Lyme Disease, anaplasmosis, babesiosis, or Powassan virus. Access tick information plus how to safely remove and identify a tick provided by Health Canada which also recommends these “before you go” ways to help prevent tick bites: • light coloured, long-sleeved shirts and pants help you spot ticks easier. • tuck shirt bottoms into pants and pant cuffs into socks – seal yourself in and ticks out! • closed-toe shoes keep ticks out! • apply an insect repellent containing DEET or Icaridin to clothing and exposed skin (according to product label directions). • wear permethrin-treated clothing (according to product label direction). …. and review the full set of helpful tips!
Public Health Agency of Canada has a Top 10 Tick Hiding Spots on Your Body available as a poster in multiple languages including Mi’kmaq, Mohawk, Ojibwe (Eastern), French, English, Spanish, Tagalog, Arabic, Punjabi, Chinese (simplified and traditional), and Italien. An example in English is posted below for your quick reference (Fig. 1) so check it, then yourself, and your pets!
Figure 1. Screenshot of Public Health Agency of Canada’s infographic of top 10 tick hiding spots on your body (2020; retrieved 2024May23).
Another good resource is the free eTick APP which is a public platform for image-based identification and population monitoring of ticks in Canada. Both Google Play and iOS versions of the App enab
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.
Every year, these guides are updated with product information and so much more! Hard copies can be purchased via the above websites but also look for the download button to access FREE downloadable PDF copies!
A few other helpful tools to keep at your finger tips:
Jennifer Otani, John Gavloski, James Tansey, Carter Peru, Amanda Jorgensen and Shelley Barkley
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Week 2
Prairie-wide provincial entomologists provide insect pest updates throughout the growing season. Follow the hyperlinks to access their information as the growing season progresses:
ALBERTA’SInsect 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 includes insect-related information: • May 13, 2025 issue includes tick season information, an ‘insects to watch’ section (flea beetle management and cutworm scouting), and links to the Prairie Pest Monitoring Network’s Weekly Update. • April 28, 2025 issue includes recommendation to Scout for cutworms. • April 23, 2025 issue includes “Black caterpillars” feeding in southern Alberta, and Flea beetle risk. • Cutworm live monitoring map for AB – Cumulative counts arising from weekly data are available so refer to the Live Map which already cites 2025 reports! • Diamondback moth pheromone trap live monitoring map for AB – Cumulative counts arising from weekly data are now being generated so refer to the Live Map!
