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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.
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.
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 Agriculture, Saskatchewan 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.
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).
Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta 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.
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; meghan.vankosky@agr.gc.ca). Thank you!
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.
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.
This week, the Prairie Pest Monitoring Network is excited to promote the official launch of the Prairie Weed Monitoring Network’s official website, PrairieWeeds.com!
The Western Grains Research Foundation (WGRF) is excited to announce the official launch of Prairieweeds.com, 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 Prairieweeds.com marks a significant milestone in the development of the PWMN,” says Dr. Charles Geddes, Weed Scientist, AAFC. “Prairieweeds.com 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, “Prairieweeds.com 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.
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’SCrop 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”.
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 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.
Insect scouting and monitoring season is getting into full swing!
Weather patterns in May and so far in June have been perfect for the development of some insect pests, but suboptimal for others. However, it is hard to generalize, as some parts of the prairies have been wet and others dry. Similarly, some areas have been very warm, while others have been cooler. This year it will be very important to scout and to monitor insect populations at the field-scale.
Grasshoppers thrive in warm, dry conditions. This week, some 4th instar nymphs were spotted in ditches in southwestern Saskatchewan, although there are many first, second and some third instar nymphs as well. Signs of damage are starting to appear. Overall grasshopper development continues to be ahead of schedule and two-striped grasshoppers continue to be prevalent.
Diamondback moths that arrived in early May have likely reproduced and adult moths found now could be from the first generation produced on the prairies. Diamondback moths develop rapidly when it is warm and their population densities can build up quickly with each generation. Be ready to scout if pheromone traps in your area have detected diamondback moths this spring.
Bertha armyworm development is also well ahead of schedule – pupal development could be 90% complete in some areas and adult moths could already be flying around. Watch the provincial websites in Alberta, Saskatchewan, and Manitoba for reports on bertha armyworm pheromone trap captures for your area over the next few weeks.
This week, the Insect of the Week featured ground beetles and rove beetles! Both can prey on different life stages of the pea leaf weevil and on other insect pests (and slugs!).
Please read this week’s posts in the Weekly Update for more information about the insects listed above and for a sneak peak of wheat midge development!
Remember, insect Monitoring Protocols containing helpful insect pest biology, how and when to plan for in-field scouting, and economic thresholds to help support in-field management decisions. All are available to read or download for free!
Questions or problems accessing the contents of this Weekly Update? Please contact Dr. Meghan Vankosky (meghan.vankosky@agr.gc.ca) to get connected to our information. Past Weekly Updates, full of information and helpful links, can be accessed on our Weekly Update page.
Average prairie temperatures continued to be well above average from May 29 to June 4. The prairie average daily temperature was 5°C warmer than normal (Fig. 1). The warmest temperatures were observed across southern Manitoba and southeastern Saskatchewan. The coolest temperatures occurred in the Peace River region where temperatures in northwestern Alberta and northeastern British Columbia were similar to climate normal temperatures.
Figure 1. Seven-day average temperature (°C) observed across the Canadian prairies for the period of May 29 to June 4, 2023.
Average temperatures over the past 30 days (May 6 to June 4, 2023) have been 4°C above normal with the warmest values being reported across Manitoba and Saskatchewan (Fig. 2). Average temperatures (30-day) ranged from 13.9°C at Grande Prairie, Alberta to 18.4°C at Morden, Manitoba.
Figure 2. 30-day average temperature (°C) across the Canadian prairies for the period of May 6 to June 4, 2023.
Since April 1, the 2023 growing season has been coolest across eastern Saskatchewan and western Manitoba (Fig. 3). Alberta temperatures continue to be above average. Relative to climate normals, temperatures continue to be above average in the Peace River region.
Figure 3. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1 to June 4, 2023.
Seven-day cumulative rainfall was nominal for most of Alberta and Manitoba from May 29 to June 4. Eastern Saskatchewan reported greater than 40 mm of rain in the last 7 days (Fig. 4). Coronach, Saskatchewan reported 74 mm and Canora, Saskatchewan had 51 mm in the last 7 days.
Figure 4. Seven-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 29 to June 4, 2023.
Saskatchewan has generally had more rainfall over the past 30 days than Alberta and Manitoba (Fig. 5). Saskatchewan has had 85-150% of normal rainfall. Central and southern Alberta and most of Manitoba have had 40-60% of normal rainfall in the last 30 days.
Figure 5. 30-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 6 to June 4, 2023.
Growing season rainfall has been lowest in southern Alberta and highest in Saskatchewan and the Peace River region (Fig. 6). Hanna, Alberta has reported only 21 mm of rain since April 1 and Brooks, Alberta has had only 25 mm. In contrast, Assiniboia, Saskatchewan has had 114 mm of rain since April 1, 2023 and Valley View, Alberta has recorded 110 mm.
Figure 7. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1 to June 4, 2023.
Over the past 30 days, different parts of the prairies have been characterized by warm/dry, warm/wet, cool/dry, and cool/wet conditions (Fig. 7). Thus far, locations in southern Manitoba have experienced the warmest and driest growing conditions. The Peace River region has been the coolest and the wettest. Southern Alberta has been the driest and coolest. Many locations in Saskatchewan have had average temperatures and rainfall, although Coronarch is an interesting outlier that has been about average in terms of temperature but also quite wet.
Figure 7. A scatterplot of prairie locations based on 30-day total rain (y-axis) and temperature (x-axis) for site-specific comparison of weather conditions experienced during the last 30 days of the 2023 growing season (May 6 to June 4, 2023). Graph by Ross Weiss.
‘Reverse trajectories’ refer to air currents that are tracked back in time from specified Canadian locations over a five-day period prior to their arrival date. Of particular interest are those trajectories that, prior to their arrival in Canada, originated over northwestern and southern USA and Mexico, anywhere diamondback moth populations overwinter and adults are actively migrating. If diamondback adults are present in the air currents that originate from these southern locations, the moths may be deposited on the Prairies at sites along the trajectory, depending on the local weather conditions at the time that the trajectories pass over our area (e.g., rain showers, etc.). Reverse trajectories are the best available estimate of the ”true” 3D wind fields at a specific point. They are based on observations, satellite and radiosonde data.
Relative to the previous two weeks, there was a significant increase in the number of reverse trajectories that entered the Canadian prairies between May 31 and June 6, 2023 (Fig. 1). This week, most of the reverse trajectories that crossed the prairies originated from the Great Plains (Nebraska, Kansas, Texas, Oklahoma). In earlier weeks of this growing season, most of the reverse trajectories originated from the Pacific Northwest. The number of reverse trajectories originating from California and Mexico also significantly increased in the last week. These results may indicate potential introductions of diamondback moth and leafhoppers to the prairies.
Figure 1. The average number (based on a 5-day running average) of reverse trajectories (RT) that have crossed the prairies for the period of May 8 to June 6, 2023.
Mexico, California and Texas: This week, 63 reverse trajectories crossed into the prairies from Mexico and the US southwest. These trajectories were predicted to cross into southeastern Saskatchewan and Manitoba (Fig. 2)
Figure 2. Total number of dates with reverse trajectories originating over Mexico, California and Texas that have crossed the prairies between April 1 and June 6, 2023.
Pacific Northwest (Idaho, Oregon, Washington): This week 104 reverse trajectories were predicted to cross the prairies, with the majority of Pacific Northwest reverse trajectories reported to pass over Alberta and western Saskatchewan (Fig. 3).
Figure 3. Total number of dates with reverse trajectories originating over the Idaho, Oregon, and Washington that have crossed the prairies between April 1 and June 6, 2023.
Oklahoma and Texas: In the last week, 98 reverse trajectories that originated over Texas and Oklahoma passed through the prairies, particularly through Manitoba and southeastern Saskatchewan and (Fig. 4).
Figure 4. The total number of dates with reverse trajectories originating over Oklahoma and Texas that have crossed the prairies between May 1 and June 6, 2023.
Kansas and Nebraska: Between May 31 and June 6, 2023 there were 119 reverse trajectories have been reported that originated in Kansas and Nebraska and passed over southeastern Saskatchewan and southern Manitoba (Fig. 5).
Figure 5. The total number of dates with reverse trajectories originating over Kansas and Nebraska that have crossed the prairies between May 1 and June 6, 2023.
Model simulations were used to estimate development of grasshoppers as of June 4, 2023. Compared with average spring temperatures, well above normal temperatures across the prairies continue to result in rapid grasshopper development. Model runs suggest that this spring’s hatch is still proceeding with 68% of the hatch now complete (Fig. 1). In an average year, only 6% of the grasshopper hatch would be completed by this time in June. Hatch is predicted to be well underway across Alberta, western regions of Saskatchewan and southern Manitoba (Fig. 1).
Figure 1. Predicted grasshopper (Melanoplus sanguinipes) hatch (%) across the Canadian prairies as of June 4, 2023.
As of June 4, 32% of the grasshopper population is predicted to be in the egg stage, 34% first instar, 21% second instar, 12% third instar and 0.5% in the fourth instar. Based on average instar, development is most advanced across Alberta and a large area of Saskatchewan (Fig. 2). Field observations from June 7, 2023 agree with the model predictions.
Figure 2. Predicted grasshopper (Melanoplus sanguinipes) development, presented as average instar, across the Canadian prairies as of June 4, 2023.
In contrast to 2023, in an average year, most of the grasshopper population would still be in the egg stage or in the first instar stage at this time in early June.
Geospatial maps and model predictions are tools to help time in-field scouting on a regional scale but grasshopper development can vary and is only accurately assessed through scouting. Monitor roadsides and field margins to assess the development and densities of local grasshopper populations. Due to their small size, it may be difficult to visually observe first and second instar grasshoppers in roadside vegetation and field margins. If possible, use a sweep net to sample grasshoppers in ditches and along the edges of crops. Sweep net sampling allows for easier assessments of grasshopper densities at this time of year. Using the grasshoppers collected in sweep nets, we can also determine which life stages are present (which nymphal instars) and the species that are present. Information about grasshoppers and monitoring is available from the Prairie Pest Monitoring Network, in the Field Crop and Forage Pests guide, Alberta Agriculture and Irrigation, Saskatchewan Ministry of Agriculture, and Manitoba Agriculture.
Diamondback moths (Plutella xylostella) are a migratory invasive species; after initial migration into the prairies, diamondback moths can have multiple non-migratory generations during the growing season. Diamondback moth development can be rapid during periods of warm weather. Model simulationsto June 4, 2023, indicate that the first generation of non-migrant adults (based on early-May arrival dates) is currently occurring across the Canadian prairies. If above-normal temperatures persist, then we may start to see some second-generation diamondback moths next week.
The life cycle of diamondback moth can rapidly progress from egg (A) to larvae (B and C), to pupae (D) to adults (E). Photo credit: Jonathon Williams, AAFC-Saskatoon.
On the prairies, we use a network of pheromone traps to detect the first spring appearance of diamondback moths. Now, local scouting is needed to determine if diamondback moth pose a threat to crops. To scout, estimate the number of diamondback moth larvae per m2 at several locations in a field. The economic threshold for diamondback moth is NOT based on pheromone traps or sweep net samples, but on the density of larvae per plant. For immature and flowering canola, the economic threshold is 100-150 larvae/m2. In podded canola, the economic threshold is 200-300 larvae/m2. See the Field Crop and Forage Pests guide and monitoring protocol for more information about scouting for diamondback moth.
Based on model simulations, development of overwintered bertha armyworm (Mamestra configurata) pupae continues to be significantly ahead of normal for most of the prairies. Bertha armyworm pupae across the prairie region are expected to be at least 90% finished their larval development (Fig. 1); as a result, adults might already be emerging in some areas.
Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development (%) across the Canadian prairies as of June 4, 2023.
The bertha armyworm model predicts that adults could already be present in a region between Lethbridge, Alberta and Swift Current, Saskatchewan (Fig. 2). Adult moths may also be flying near Edmonton, Alberta and in the northern limits of the Peace River region (Fig. 2).
Figure 2. The proportion of the bertha armyworm (Mamestra configurata) population that is predicted to be in the adult stage (% of total population) across the Canadian prairies as of June 4, 2023.
Wheat midge (Sitodiplosis mosellana) overwinter as larval cocoons in the soil. Adequate rainfall in May and June is a signal to larval cocoons to end their diapause and move to the soil surface to pupate. where pupation occurs. Insufficient rainfall in May and June can result in delayed movement of larvae to the soil surface. Wheat midge emergence may be delayed or erratic if rainfall does not exceed 20-30 mm during May. The Olfert et al. (2020) model indicated that dry conditions may result in: a. Delayed adult emergence and oviposition b. Reduced numbers of adults and eggs
Figure 1. Areas in western Canada where cumulative rainfall (mm) from May 1 to June 4, 2023 is sufficient (greater than 30 mm) to promote movement of wheat midge (Sitodiplosis mosellana) larvae to the soil surface.
In the last few weeks, rainfall events over parts of the prairies may have provided the cue to end wheat midge larval diapause. From May 1 to June 4, cumulative rainfall was normal or above normal in the Peace River region and parts of Saskatchewan (Fig. 1). Larvae, if present, are likely moving towards the soil surface in the Peace River region and in wet areas of Saskatchewan (Fig. 2).
Figure 2. The proportion of the wheat midge (Sitodiplosis mosellana) larval population that has moved to the soil surface across western Canada, as of June 4, 2023.
In contrast to the wet areas on the prairies, wheat midge adult emergence might be delayed in dry areas 2023. It is also possible that the wheat midge larval cocoons will remain in a diapause state until a future year when spring moisture is more suitable for wheat midge development.
Scouting for adult wheat midge usually starts in late June or early July. Over the next few weeks, the Prairie Pest Monitoring Network will continue to use phenology models to predict that status of wheat midge development and provide additional updates.
The 2023 growing season is in full swing and researchers working with insects, weeds, plant pathogens, and crops are very busy across the prairie region! For something new this year, the Prairie Pest Monitoring Network will occasionally include Prairie Research Updates in the Weekly Update. This post will highlight the hard work of our colleagues at Agriculture and Agri-Food Canada (AAFC) research centers, at universities, and by other research organizations across western Canada. If you have ideas for a Prairie Research Update, please contact Dr. Meghan Vankosky (meghan.vankosky@agr.gc.ca).
Science News from the Prairies is an AAFC newsletter that highlights work by scientists at AAFC research centres in Alberta, Saskatchewan, and Manitoba. The June 3, 2023 edition highlights the Plant Gene Resources of Canada, a plant gene bank at the AAFC Saskatoon Research and Development Centre. Plant gene banks serve to maintain the genetic diversity of plants by collecting, preserving, and rejuvenating plant reproductive material and sharing their resources to support plant breeding programs, education, and research. Read more about the Plant Gene Resources of Canada and other AAFC research projects in Science News from the Prairies.
To learn more about entomology research at the AAFC Saskatoon Research and Development Centre, please read “Pest Detective: How AAFC is using pest monitoring data to model climate change impacts” available in English and in French.
Visit the Alberta Insect Pest Monitoring Network and Crop Insects pages for information about insects and monitoring in Alberta, including links for live maps from the 2023 monitoring season for diamondback moth, bertha armyworm, cutworms and others.
Watch for new issues of the Saskatchewan Crop Production News coming soon in 2023 and browse the articles from 2022 for information from the past.
The latest Manitoba Crop Pest Update for 2023 was posted on June 7. Watch their website for new Crop Pest Updates as the season continues and check out the archives to read past Updates.
Pea leaf weevils may be prowling legume crops, but ground beetles and rove beetles are on the hunt as well. This Insect of the Week features two large groups of insects: ground beetles (Carabid beetles) and rove beetles (Staphylinid beetles). Many of species of ground beetles and some rove beetles are generalist predators, like ants, centipedes and spiders. These arthropods are not picky when it comes to choosing a meal and they often target pests in crop fields.
From left to right, a Carabid beetle (about 2 cm long), a Carrion beetle (about 2 cm long) and a Staphylinid beetle (less than 1 cm long). Photo credit: Jonathon Williams, AAFC-Saskatoon.
Based on research conducted in western Canada, at least two species of ground beetle have pea leaf weevil on the menu. First, a small beetle called Bembidion quadrimaculatum can feast on pea leaf weevil eggs.
Small bodied (2-3 mm long) Bembidion quadrimaculatum ground beetles can eat pea leaf weevil eggs. Photo credit: Shelby Dufton, AAFC-Beaverlodge Research Farm
A larger beetle called Pterostichus melanariuswill catch and eat adult pea leaf weevils. Other pests that different ground beetle species may eat include cutworms, aphids, wheat midge, cabbage root maggots, slugs, and many others!
A pinned Pterostichus melanarius specimen. These ground beetles eat larger prey, including adult pea leaf weevils. Photo credit: Shelby Dufton, AAFC-Beaverlodge Research FarmA ground beetle (likely from the genus Pterostichus) next to a finger for scale. Photo credit: A. Harpe, AAFC-Beaverlodge Research Farm
Ground beetles are characterized by long threadlike antennae, have a body that is flattened top-to-bottom, and have strong legs designed for running, large eyes, and obvious jaws (mandibles).
Rove beetles, like ground beetles, can be important predators of a number of insect pests! Some species will feed on pea leaf weevil eggs. One species of the rove beetle, Aleochara bilineata, is an important natural enemy of cabbage, seedcorn, onion and turnip maggots. Rove beetles are small, thin and have shortened fore-wings that leave most of their abdomen exposed.
A pinned Staphylinid (rove) beetle (<1cm long). Photo credit: Shelby Dufton, AAFC-Beaverlodge Research Farm
For more information on these field heroes and the other pests they help to manage, see the Field Crop and Forage Pests and their Natural Enemies in Western Canada guide. The guide has helpful information about the life cycle of these and other predators. The guide also has tips for conserving predators and parasitoids and pictures to help with identification. Please visit the PPMN Field Guide page to download a copy of the guide in French.
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.
TEMPERATURE: The 2022 growing season has been cooler than normal, particularly in Manitoba. This past week (May 30 – June 5, 2022) average daily temperatures were similar to the previous week. The average temperature across the prairies was 1 °C cooler than normal (Fig. 1). Temperatures were warmest in Alberta and coolest in Manitoba.
Figure 1. Seven-day average temperature (°C) across the Canadian prairies for the period of May 30-June 5, 2022.
Average 30-day temperatures (May 7 – June 5, 2022) were warmest in southern Manitoba and southeastern Saskatchewan (Fig. 2). The average temperature across the prairies was similar to long-term average values. Temperature anomalies (difference between observed and climate normals) over the past 30 days indicate that temperatures across southern Saskatchewan and southern Alberta were cooler than average (Fig. 3).
Figure 2. 30-day average temperature (°C) across the Canadian prairies for the period of May 7-June 5, 2022.Figure 3. 30-day average temperature anomaly (°C difference from climate normals) observed across the Canadian prairies for the period of May 7-June 5, 2022.
The growing season (April 1 – June 5, 2022) has been cooler in Manitoba than in Saskatchewan and Alberta (Fig. 4; Table 1). The average growing season temperature for the prairies has been 1.5 °C cooler than climate normal values.
Figure 4. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1 to June 5, 2022.
PRECIPITATION: Rainfall has been well below normal for Alberta and western Saskatchewan while rainfall amounts have been well above normal for eastern Saskatchewan and Manitoba in 2022. Seven-day cumulative rainfall ranged between 0 and 62 mm with the highest rainfall amounts occurring across Manitoba (Fig. 5). This week southwestern Saskatchewan and southern Alberta received 10-20 mm of rain.
Figure 5. Seven-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 30-June 5, 2022.
Rain (30-day accumulation) amounts have been well above average across the eastern prairies, particularly southeastern Manitoba; rain amounts have been well below normal in Alberta and western Saskatchewan (Figs. 6 and 7).
Figure 6. 30-day cumulative rainfall (mm) observed across the Canadian prairies the past 30 days (May 29-June 5, 2022).Figure 7. Growing season cumulative rain anomaly (% if climate normals) observed across the Canadian prairies for the period of May 7-June 5, 2022.
Growing season rainfall for April 1 – June 5, 2022, continues to be greatest across Manitoba and eastern Saskatchewan; conditions have been well below normal across most of Saskatchewan and Alberta (Fig. 8; Table 1).
Figure 8. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1 to June 5, 2022.
Growing degree day (GDD) maps for Base 5 ºC and Base 10 ºC (April 1-June 6, 2022) can be viewed by clicking the hyperlinks. Over the past 7 days (May 31-June 6, 2022), the lowest temperatures recorded across the Canadian prairies ranged from < -4 to >8 °C while the highest temperatures observed ranged from <6 to >24 °C. Some areas of the prairies hit warmer temperatures with a slight bump in the number of sites experiencing days at or above 25 °C across the prairies – a maximum of 4 days. Access these maps and more using the AAFC Maps of Historic Agroclimate Conditions interface.
The grasshopper (Acrididae: Melanoplus sanguinipes) model predicts development using biological parameters known for the pest species and environmental data observed across the Canadian prairies on a daily basis. Review lifecycle and damage information for this pest. Review the historical grasshopper maps based on late-summer adult in-field counts performed across the prairies.
Model simulations were used to estimate percent grasshopper egg development and hatch as of June 5, 2022. Recent warmer temperatures in Saskatchewan and Alberta have resulted in increased rates of grasshopper development. In contrast, cooler/wetter conditions across eastern Saskatchewan and Manitoba have resulted in delayed development. Last week, average embryological development was 73%.
This week, average egg development is predicted to be 76% and is similar to the long-term development rate (Fig. 1). Hatch is progressing across southern and central regions of Alberta and Saskatchewan (Fig. 2). This week grasshoppers (1-3rd instars) were abundant at specific locations across west-central Saskatchewan. Some fields were showing signs of grasshopper feeding.
Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development (%) across the Canadian prairies as of June 5, 2022.Figure 2. Predicted grasshopper (Melanoplus sanguinipes) hatch (%) across the Canadian prairies as of June 5, 2022.
Risk estimates, based on meteorological inputs, were used to assess the impact of weather on potential grasshopper development and population growth potential (Fig. 3). A bioclimate simulation model was developed to assess how climatic factors influence occurrence and relative abundance. Potential risk is based on weekly growth index values. Grasshopper risk is greatest in areas that are warmer and drier than normal. As of June 5, 2022, model output indicates that potential risk is greatest across eastern Alberta and western Saskatchewan. Cooler/wetter conditions in eastern Saskatchewan and Manitoba are predicted to reduce potential risk.
Hatch is progressing across southern Alberta and western Saskatchewan (Fig. 3). Last week, grasshopper hatchlings were collected in an area between Saskatoon and Kindersley. Southern Alberta and western Saskatchewan have received the least amount of rain during the growing season. Grasshopper risk can be greater when conditions are warm and dry.
Figure 3. Predicted risk for the migratory grasshopper (Melanoplus sanguinipes) across the Canadian prairies as of June 5, 2022.
The alfalfa weevil (AAW) (Curculionidae: Hypera postica) model predicts development using biological parameters known for the pest species and environmental data observed across the Canadian prairies on a daily basis. Review lifecycle and damage information for this pest.
Model simulations for alfalfa weevil (AAW) indicate the appearance of first and second instar larvae should be occurring across the prairies. Development in southern Manitoba (Fig. 1) is slower than development in southern Alberta (Fig. 2). Development is similar to long-term average values.
Figure 1. Predicted status of alfalfa weevil (Hypera postica) populations near Winnipeg MB as of June 5, 2022.Figure 2. Predicted status of alfalfa weevil (Hypera postica) populations near Medicine Hat AB as of June 5, 2022.
Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted 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.
The cereal leaf beetle (CLB) (Chysomelidae: Oulema melanopus) model predicts larval development using biological parameters known for the pest species and environmental data observed across the Canadian prairies on a daily basis. Review lifecycle and damage information for this pest.
Warmer conditions in southern Alberta and southwestern Saskatchewan are predicted to result in more rapid development of cereal leaf beetle (CLB) populations compared to southern Manitoba. CLB model output suggests that the hatch should be nearly complete for southern Alberta and Saskatchewan. First and second instar are predicted to be present in these areas (Fig. 1). As a result of cooler conditions, egg development is predicted to be delayed in southern Manitoba (Fig. 2). First instar larvae should begin to occur by the end of this week in Manitoba.
Figure 1. Predicted status of cereal leaf beetle (Oulema melanopus) populations near Lethbridge AB as of June 5, 2022.Figure 2. Predicted status of cereal leaf beetle (Oulema melanopus) populations near Brandon MB as of June 5, 2022.
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.
Compared to average development, bertha armyworm (BAW) pupal development in 2022 continues to be delayed for the Peace River region, Manitoba and southern and eastern regions of Saskatchewan (Fig. 1). Pupal development across southern and central Alberta and Saskatchewan is similar to long-term average values. Development in this region is 60-75% complete.
We suggest that BAW pheromone traps be placed in fields when pupal development is 75-80% to ensure that traps are in place prior to emergence of adults. Based on current runs, it is advisable that traps for Alberta and Saskatchewan be placed in fields by the end of this week (June 6-10). Traps should be put out in Manitoba and the Peace River region next week.
Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development (%) across the Canadian prairies as of June 5, 2022.
Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta 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.
Wheat midge (Sitodiplosis mosellana) overwinter as larval cocoons in the soil. Soil moisture conditions in May and June can have significant impacts on wheat midge emergence. Adequate rainfall promotes termination of diapause and movement of larvae to the soil surface where pupation occurs. Insufficient rainfall in May and June can result in delayed movement of larvae to the soil surface. Elliott et al. (2009) reported that wheat midge emergence was delayed or erratic if rainfall did not exceed 20-30 mm during May. Olfert et al. (2016) ran model simulations to demonstrate how rainfall impacts wheat midge population density. The Olfert et al. (2020) model indicated that dry conditions may result in: a. Delayed adult emergence and oviposition b. Reduced numbers of adults and eggs
As of June 5, 2022, normal to above normal rainfall in Manitoba, eastern Saskatchewan and the British Columbia Peace River region should be sufficient to promote the movement of wheat midge larvae to the soil surface this year (Fig. 1). Warmer temperatures in central Manitoba are expected to advance larval development over the next seven days. Current development for eastern Saskatchewan and Manitoba is similar to long-term average rates.
Figure 1. Percent of wheat midge larval population (Sitodiplosis mosellana) that has moved to the soil surface across western Canada,as of June 5, 2022.
Additional information can be accessed by reviewing the Wheat midge pages extracted from the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide” (2018) accessible as a free downloadable PDF in either English or French on our new Field Guides page.
1. REVERSE TRAJECTORIES (RT) Since May 1, 2022 the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Relative to previous weeks, there was a significant decrease in the number of trajectories that were predicted to cross over the prairies from May 31 – June 6, 2022. This week reverse trajectories generally originated over the arctic before entering the prairies.
Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of May 1-June 6, 2022.
a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories have been reported to pass over southern and central Alberta and western Saskatchewan (Fig. 2). This past week (May 31-June 6, 2022) the ECCC model predicted that 26 reverse trajectories passed over the prairies. This is a significant decrease compared to the previous week (n=124).
Figure 2. Total number of dates with reverse trajectories originating over the Idaho, Oregon, and Washington that have crossed the prairies between April 1 and June 6, 2022.
b. Mexico and southwest USA (Texas, California) – This past week (May 31 to June 6, 2022) reverse trajectories that originated from Mexico, California or Texas crossed over Carman and Selkirk (May 31, 2022). Since April 1, reverse trajectories were reported for Manitoba (Portage, Selkirk, Brandon, Carman, Russell) and eastern Saskatchewan (Gainsborough, Grenfell) (Fig. 3).
Figure 3. The total number of dates with reverse trajectories originating over Mexico, California and Texas that have crossed the prairies between April 1 and June 6, 2022.
c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan (Fig. 4). This past week (May 31 to June 6, 2022) there has been an increase in the number of reverse trajectories that have crossed over southeastern Saskatchewan (Weyburn and Gainsborough) and Manitoba (Portage and Brandon).
Figure 4. The total number of dates with reverse trajectories originating over Texas and Oklahoma that have crossed the prairies between May 1 and June 6, 2022.
d. Nebraska and Kansas – Reverse trajectories, originating from Kansas and Nebraska, have crossed southeastern Saskatchewan and southern Manitoba (Fig. 5). This past week (May 31 to June 6, 2022) the ECCC model predicted that 6 reverse trajectories passed over the prairies. This is a significant decrease compared to the previous week (n=27).
Figure 5. The total number of dates with reverse trajectories originating over Kansas and Nebraska that have crossed the prairies between April 1 and June 6, 2022.
2. FORWARD TRAJECTORIES (FT) The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) that were predicted to cross the Canadian prairies (Fig. 6). This week (May 31 to June 6, 2022) there were fewer (n=12) forward trajectories predicted to cross the prairies than the previous week (n=45). Results indicate that the greatest number of forward trajectories entering the prairies have originated from the Pacific Northwest (Idaho, Oregon, Washington), Montana and Wyoming.
Figure 6. Total number of dates with forward trajectories, originating from various regions of the United States and Mexico, crossing the prairies between April 1 and June 6, 2022.
View historical PPMN wind trajectory reports by following this link which sorts the reports from most recent to oldest.
Provincial entomologists provide insect pest updates throughout the growing season so link to their information:
MANITOBA’SCrop Pest Updates for 2022 are up and running! Access a PDF copy of the June 8, 2022 issue here. Bookmark their Crop Pest Update Index to readily access these reports and also bookmark their insect pest homepage to access fact sheets and more! • Diamondback moth pheromone trap monitoring update for MB – “So far, diamondback moth has been found in 25 traps. Levels are generally very low, with the exception that some moderate counts have occurred in the Eastern and Central region, particularly over the past few weeks.” Read the report on Page 7 of the June 8, 2022 issue OR review a more detailed summary of cumulative trap counts from 38 sites deployed across the province. • Armyworm pheromone trap monitoring is underway in MB – “So far, counts have generally been quite low, with armyworm moths only being caught in 6 traps.” Read the report on Page 7-8 of the June 8, 2022 issue.
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. The new webpage does not replace the Insect Pest Monitoring Network page. Remember, AAF’s Agri-News occasionally includes insect-related information. Twitter users can connect to #ABBugChat Wednesdays at 10:00 am. • Diamondback moth pheromone trap monitoring update for AB – Cumulative counts arising from weekly data are available so refer to the Live Map. So far, low numbers of diamondback moth have been intercepted across the province. • Cutworm live monitoring map for AB – Reports are starting to come in so refer to the Live Map to review areas where cutworms are being found. So far, black army and pale western cutworms have been reported. Use this online form to report cutworms in Alberta.
Continuing our series on Prairie wireworms, this week we highlight the sugarbeet wireworm, Limonius californicus.
This species is less abundant than Hypnoidus bicolor or the Prairie grain wireworm (Selatosomus aeripennisdestructor), but some fields have a major problem with this species. Limonius californicus wireworms are 17-22 mm long at maturity and can be aggressive feeders. The literature reports it is more likely to be found in irrigated fields.
The life cycle of L. californicus on the Prairies is not well known. Our current information is based on lab studies in California in the 1940s, where larvae lived for 2-5 years before undergoing metamorphosis into adult click beetles.
Wireworm size varies within a species depending on age. Photo: W. van Herk, AAFC-Agassiz
AAFC has recently released a new field guide on Prairie pest wireworms. It has information on biology, monitoring and management, and research on wireworms on the Prairies. Preview pages extracted from the guide highlighting Limonius californicus by clicking here.
Free digital copies in both official languages can be downloaded at these links:
Free hard copies are also available while supplies last. Email Haley Catton at haley.catton@agr.gc.ca to request your copy.
Did you know?
– A new pheromone has recently been discovered by researchers at Simon Fraser University AAFC that attracts male beetles. This pheromone will help monitoring efforts.
References:
Gries R, Alamsetti SK, van Herk WG, Catton HA, Meers S, Lemke E, Gries G (2021) Limoniic acid – major sex pheromone component of the click beetles Limonius canus and L. californicus. Journal of Chemical Ecology 41:123-133. https://doi.org/10.1007/s10886-020-01241-y
Van Herk, W. G., Labun, T. J., & Vernon, R. S. (2019). Efficacy of diamide, neonicotinoid, pyrethroid, and phenyl pyrazole insecticide seed treatments for controlling the sugar beet wireworm, Limonius californicus (Coleoptera: Elateridae), in spring wheat. Journal of the Entomological Society of British Columbia, 115, 86-100.
Week 5 and things are starting to heat up! Be sure to catch the Insect of the Week – it’s cereal leaf beetle! This week there’s more updated information coming your way and be sure to review the Previous Posts to keep all of the PPMN’s nsect monitoring resources at hand!
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.
TEMPERATURE: This past week (May 24-30, 2021) the average temperature across the prairies was 1 °C cooler than normal (Fig. 1). Temperatures were warmest across most of Alberta and coolest across Saskatchewan and central regions of Manitoba. Across the prairies, the average 30-day (May 1-30) temperature was almost 2 °C warmer than last week and similar to climate normal values. Warmest temperatures were observed across southern Manitoba (Table 1; Fig. 2).
Figure 1. 7-day average temperature (°C) observed across the Canadian prairies for the period of May 24-30, 2021.Figure 2. 30-day average temperature (°C) observed across the Canadian prairies for the period of May 1-30, 2021.
The 2021 growing season (April 1 – May 31) has been characterized by near-normal temperatures. Temperatures have been warmest for southern Manitoba, western Saskatchewan and southern Alberta (Table 2; Fig. 3).
Figure 3. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1-May 30, 2021.
The growing degree day map (GDD) (Base 5 ºC, April 1-May 31, 2021) is provided below (Fig. 4) while the growing degree day map (GDD) (Base 10 ºC, April 1-May 31, 2021) is shown in Figure 5.
Figure 4. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-May 31, 2021). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (03Jun2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=trueFigure 5. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-May 31, 2021). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (03Jun2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
Several areas were on the receiving end of frost and many folks are still watching to see how their crops recover. The lowest temperatures recorded ranged from <-14 to >0 °C (Fig. 6) while the highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <11 to >25 °C (Fig. 7).
Figure 6. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (May 27-Jun 2, 2021). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (03Jun2021) although PDF file format was not available. Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=trueFigure 7. Highest temperatures (°C) observed across the Canadian prairies the past seven days (May 27-Jun 2, 2021). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (03Jun2021) although PDF file format was not available. Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
PRECIPITATION: This week, significant precipitation was reported across central regions of Saskatchewan and Alberta while minimal rain was reported across Manitoba and western Alberta (Fig. 8). Rainfall amounts for the period of May 1-30 (30-day accumulation) were 123 % of long-term average values. Rainfall amounts have been near normal to above normal for large areas of Alberta and southern Saskatchewan. Well above normal rain was reported for Edmonton and Regina. Below normal rainfall amounts were reported for central and northern areas of the Peace River region and across Manitoba (Table 1; Fig. 9).
Figure 8. 7-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 24-30, 2021.Figure 9. 30-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 1-30, 2021.
Average growing season (April 1 – May 30) precipitation was 105 % of normal with the greatest precipitation occurring near Edmonton and across eastern Saskatchewan. Most of Manitoba and the Peace River region have had 60 % or less of normal precipitation during the 2021 growing season so far (Table 2; Fig. 10).
Figure x. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1-May 30, 2021.
Access Environment and Climate Change Canada’s weather radar mapping interface. Options to access preceeding precipitation events include clicking off either an 1 or 3 hours time interval, using an 8-colour or 14-colour index. or changing the base map.
Access background information for how and why wind trajectories are monitored in this post.
1. REVERSE TRAJECTORIES (RT) This past week there were an increasing number of reverse trajectories moving north from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Though this US region can be a source of diamondback moths, the ECCC models predict air movement, not actual occurrence of diamondback moths.
Figure 1. The average number (based on a 5 day running average) of reverse trajectories that have crossed the prairies for the period of May 15 – June 3 2021.
a. Pacific Northwest (Idaho, Oregon, Washington) – This week there were 53 trajectories (compared to 36 last week) that crossed Alberta, Manitoba and Saskatchewan. In previous years, the majority of Pacific Northwest reverse trajectories usually have been reported to pass over southern Alberta. However, tis growing season, PNW trajectories have crossed all parts of the prairies (Figs. 2 and 3).
Figure 2. Total number of reverse trajectories originating across Idaho, Oregon, and Washington and have crossed specific prairie locations between March 18 and June 3, 2021.Figure 3. Total number of dates with reverse trajectories originating over the Pacific Northwest (Idaho, Oregon, and Washington) and have crossed the prairies between March 24 and June 3, 2021.
b. Mexico and southwest USA (Texas, California) – Compared to previous years, there has been a noticeable increase in the number of trajectories from the southern US. The majority of these trajectories have crossed Manitoba and eastern Saskatchewan (Fig. 4). This week there were no trajectories (compared to 54 last week) that originated in Mexico or the southwest USA that crossed the prairies (Fig. 5).
Figure 4. Total number of reverse trajectories originating across Mexico, California and Texas and have crossed specific prairie locations between March 18 and June 3, 2021.Figure 5. The total number of dates with reverse trajectories originating over Mexico, California and Texas and have crossed the prairies between March 24 and June 3, 2021.
c. Oklahoma and Texas – The majority of these trajectories have passed over Manitoba and eastern Saskatchewan (Fig. 6). This week there were no trajectories (compared to 51 last week) originating in Oklahoma or Texas that passed over the prairies (Fig. 7).
Figure 6. Total number of reverse trajectories originating across Oklahoma and Texas and have crossed specific prairie locations between March 18 and June 3, 2021.Figure 7. The total number of dates with reverse trajectories originating over Oklahoma and Texas and have crossed the prairies between March 24 and June 3, 2021.
d. Kansas and Nebraska – Similar to results for Oklahoma and Texas, the majority of these trajectories crossed Manitoba and eastern Saskatchewan (Fig. 8). This week there was one trajectory that originated in Kansas or Nebraska that passed over Carman, Manitoba (Fig. 9). Relative to the reverse trajectories associated with Oklahoma and Texas, the trajectories from Kansas and Nebraska have crossed further into Alberta (Fig. 9).
Figure 8. Total number of reverse trajectories originating across Kansas and Nebraska and have crossed specific prairie locations between March 18 and June 3, 2021.Figure 9. The total number of dates with reverse trajectories originating over Kansas and Nebraska and have crossed the prairies between March 24 and June 3, 2021.
2. FORWARD TRAJECTORIES (FT) a. Continuing a trend that began last week, this week there was a decrease in the number of forward trajectories that were predicted to cross the prairies (Fig. 10). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line). The data suggests that, compared to this week, there will be decreased potential for the introduction of DBM to the prairies.
Figure 10. The average number (based on a 5-day running average) of forward trajectories that were predicted to cross the prairies for the period of May 15-June 3, 2021.
Model simulations to May 30, 2021, indicate that BAW pupal development is 45-60 % complete across the prairies (Fig. 1). Recent warm conditions in Alberta and southern Manitoba have resulted in the rapid development of BAW pupae (Fig. 2 C). The weather forecast for this week suggests that above-normal temperatures will occur. This could result in faster development of BAW pupae. BAW traps should be placed in fields when pupal development is approximately 80 %.
Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development across the Canadian prairies as of May 30, 2021.
IMPORTANT: Table 1 provides estimates for when the pheromone-baited green unitrap should be deployed. Based on weather conditions up to May 30, 2021, and model output, BAW adults (Fig. 2 D) may begin to emerge by mid to late June. Typically, moths emerge over an ~6 week period so cumulative counts of moths intercepted in these green unitraps provides insight into anticipated risk and prioritization for in-field scouting of the damaging larval stages later this summer.
Figure 2. The egg stage (A), larval stage (B), pupal stage (C), and adult stage (D) of bertha armyworm. Photos: Jonathon Williams (AAFC-Saskatoon).
Model projections to June 30 predict that development near Regina (Fig. 3) will be more advanced than at Grande Prairie (Fig. 4). The model predicts that egg hatch will begin in late June near Regina.
Figure 3. Predicted development of bertha armyworm (Mamestra configurata) populations near Regina, Saskatchewan, as of May 30, 2021 (projected to June 30, 2021).Figure 4. Predicted development of bertha armyworm (Mamestra configurata) populations near Grande Prairie, Alberta as of May 30, 2021 (projected to June 30, 2021).
Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta 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.
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).
Model simulations were used to estimate grasshopper egg development as of May 30, 2021. Average development of eggs is 78 % and is well ahead of the long-term average of 67 %. Warm conditions across southeastern Saskatchewan and southern Manitoba (May 1-30) have been responsible for the advanced development of eggs near Regina, Saskatoon, Brandon and Winnipeg (Fig. 1). Egg development is predicted to exceed 80 % across most of the southern prairies (Fig. 2).
Figure 1. Predicted percent embryonic development of grasshopper eggs across the Canadian prairies as of May 30, 2021.Figure 2. Predicted grasshopper (Melanoplus sanguinipes) embryological development (%) across the Canadian prairies as of May 30, 2021.
First hatchlings usually are observed once eggs reach 80 % development. As of May 30, hatch was predicted to be occurring across most of the prairies with hatch rates approaching 15-20 % across southern Manitoba and Saskatchewan (Fig. 3).
Figure 3. Predicted grasshopper (Melanoplus sanguinipes) hatch (%) across the Canadian prairies as of May 30, 2021.
The model was projected to June 15 to determine potential development at Saskatoon and Brandon over the next two weeks (Figs. 4 and 5). Results suggest that by June 15 hatch could be greater than 65 % at both locations and nymph populations will consist of first, second, and third instars. Drought conditions tend to favour the development of grasshopper populations while delaying crop development. If dry conditions persist, crop development may be delayed across Manitoba. This may result in conditions conducive to crop damage from grasshoppers as hatch progresses in June. Monitor roadsides and field margins to assess the development and densities of local grasshopper populations.
Figure 4. Predicted development of M. sanguinipes populations near Saskatoon, Saskatchewan as of May 30, 2021 (projected to June 15, 2021).Figure 5. Predicted development of M. sanguinipes populations near Brandon, Manitoba as of May 30, 2021 (projected to June 15, 2021).
The cereal leaf beetle (CLB) model predicts that egg hatch is progressing across the prairies. The graphs provide a comparison of development at Lacombe (Fig. 1) and at Lethbridge (Fig. 2). The simulation indicates that second instar larvae will be observed over the next few days.
Figure 1. Predicted status of cereal leaf beetle (Oulema melanopus) populations near Lacombe, Alberta as of May 30, 2021 (projected to June 15, 2021).Figure 2. Predicted status of cereal leaf beetle (Oulema melanopus) populations near Lethbridge, Alberta as of May 30, 2021 (projected to June 15, 2021).
Lifecycle and Damage:
Adult: Adult cereal leaf beetles (CLB) have shiny bluish-black wing covers (Fig. 3). 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 3. 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. 4). When the larva completes its growth, it drops to the ground and pupates in the soil.
Figure 4. 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.
Model simulations for alfalfa weevil (AAW) predict, as of May 30, that egg hatch should be nearly complete across Manitoba and Saskatchewan. First instar larvae should be appearing across most of Manitoba (Fig. 1). The following graphs indicate that development is more advanced near Winnipeg (Fig. 2) than near Lethbridge (Fig. 3). This week, larval populations in southern Manitoba should be primarily in the second instar while populations in southern Alberta may consist of first instar larvae. Results suggest that by June 15, populations will be in the second and third larval instars across southern Alberta and that Manitoba populations will be in third and fourth instar stages.
Figure 1. Predicted development of Hypera postica (alfalfa weevil) populations across the prairies as of May 30, 2021.Figure 2. Predicted status of alfalfa weevil (Hypera postica) development for populations near Winnipeg, Manitoba as of May 30, 2021 (projected to June 15, 2021).Figure 3. Predicted status of alfalfa weevil (Hypera postica) development for populations near Lethbridge, Alberta as of May 30, 2021 (projected to June 15, 2021).
The larval stage of this weevil feeds on alfalfa leaves in a manner that characterizes the pest as a “skeletonizer” (Fig. 4). The green larva features a dorsal white line down the length of its body, has a dark brown head capsule, and will grow to 9 mm long.
Figure 4. Developmental stages of the alfalfa weevil (Hypera postica). Composite image: J. Soroka (AAFC-Saskatoon).
Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon). Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (2018; accessible in either English-enhanced or French-enhanced versions).
The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops.
Two NEW Field Heroes resources for 2021 include:
The NEW Pests and Predators Field Guideis filled with helpful images for quick insect identification and plenty of tips to manage the pests AND natural enemies in your fields. Claim your free copy at http://fieldheroes.ca/fieldguide/ or download for free to arm your in-field scouting efforts!
Bertha armyworm pheromone trap monitoring update for MB – Cooperators will soon deploy pheromone traps according to details provided on page 7 of the June 2, 2021, report.
Bertha armyworm pheromone trap monitoring update for SK – Cooperators will soon deploy pheromone traps at sites across the province.
Diamondback moth pheromone trap monitoring update for SK – follow this link to find current DBM counts. At this point, extremely low numbers have been intercepted but monitoring continues. Seven moths were reported across the entire province so far (2021May19 Carter, pers. comm.).
Bertha armyworm pheromone trap monitoring update for AB – Cooperators will soon deploy pheromone traps so refer to the Live Map starting next week.
Diamondback moth pheromone trap monitoring update for AB – Refer to the Live Map which still reports extremely low numbers of moths intercepted so far (as of 03Jun2021).
Cutworm reporting tool for AB – Refer to the Live Map which reports three sites with cutworms (as of 03Jun2021).
This week’s Insect of the Week is the cereal leaf beetle (Oulema melanopus). Wheat is their preferred host, but they also feed on oat, barley, corn, rye, triticale, reed canary grass, ryegrass, fescue, wild oat, millet and other grasses. Adults and larvae feed on the leaf tissue of host plants. Yield quality and quantity is decreased if the flag leaf is stripped. It is also interesting to note that larvae carry all their own fecal waste with them as protection from predators and parasitoids.
Cereal leaf beetle damage (Bugwood, Bob Hammon)
Adults are 6-8 millimeters (0.25-0.31 inches) long with reddish legs and thorax (middle section between head and abdomen) and metallic bluish-black head and elytra (wing coverings). Mature larvae are 4-5 mm long (0.16-0.20 inches) with a hump-back body.
Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990s.
Scouting for insect pests in field crops needs to step up a notch now across the prairies. Several of the economic pests Canadian growers contend with are now developing into the more damaging stages of their lifecycles.
This week’s Insect of the Week feature crops are peas and faba beans, two important Prairie pulse crops. Our feature entomologist this week is Shelley Barkley (Alberta Agriculture and Forestry).
Pea Field cc by 2.0 Gilles San Martin
Peas and faba beans are relative newcomers to Prairie large-scale agriculture. Up until the 70s, a typical crop rotation may have been some combination of cereal and summer fallow. Dr. Al Slinkard was hired by the University of Saskatchewan-Crop Development Centre (CDC) in 1972 as a pulse breeder, starting a major transformation of Prairie agriculture. First came dry peas and lentils followed by many other pulse crops. Now there is a team of four pulse breeders at the CDC to carry on Dr. Slinkard’s legacy. And of course, let’s not forgot about the many federal, provincial, university and private industry Prairie pulse breeders that have come along since the 70s.
In 2019, dry peas were grown on 1.7 million hectares (4.3 million acres) on the Prairies, yielding 4.2 million tonnes (4.6 million US tons). Faba beans were grown (37,300 hectares / 92,100 acres) and yielded 107,000 tonnes (118,000 US tons).
Name: Shelley Barkley Affiliation: Alberta Agriculture and Forestry Contact Information: shelley.barkley@gov.ab.ca, @Megarhyssa
How do you contribute in insect monitoring or surveillance on the Prairies?
I am managing the insect monitoring and surveillance program for Alberta Agriculture and Forestry in 2020.
In your opinion, what is the most interesting field crop pest on the Prairies?
It is not a field crop pest, but lily leaf beetle tops my list. So stunningly beautiful, but so devastating to lilies. I am in a war to bring these animals to a tolerable level in my lily bed without having to resort to removing the lilies.
Of the field crop pests, I think bertha armyworm is very interesting, especially how it has capitalized on the introduction of canola. Bertha armyworm have taught me population dynamics, and shown me biocontrol at work in the field. You can read that stuff in a text book, but once you see it in real life you have a new appreciation for nature…and science fiction movies.
What is your favourite beneficial insect?
Ambush bugs are my favourite. I think this species was a model for dragons on Game of Thrones and other works of dragon fiction. All the bumps and lumps on its head and thorax. And those front legs…if only I could have guns like that!
Tell us about an important project you are working on right now.
Delivering insect survey results to the agriculture industry in AB in a timely fashion is my most important current project. I am supporting the industry to the best of my ability.
What tools, platforms, etc. do you use to communicate with your stakeholders?
Twitter, and email are my go to. I also enjoy sharing my photography.
A busy week – seeding is underway across the prairies! Our many field crop entomologists and their integral cooperators are busy deploying various insect monitoring equipment in fields too.
This week marks the return of the Insect of the Week for the 2019 growing season! The initial four weeks will feature invasive species of insects then we will transition to arthropod doppelgangers in an effort to support in-field scouting efforts with identification tips.
The Prairie Pest Monitoring Network is also excited to support the new Prairie Crop Disease Monitoring Network (PCDMN) by promoting their 2019 Cereal Rust Risk Report. This is a new initiative and reports will be available to support in-field scouting.
Weather synopsis – Daily average temperatures continue to be cooler than normal for the early growing season. This past week (April 30-May 7, 2019), the average temperature (0.5 °C) was approximately 6 °C cooler than normal (Fig. 1). The warmest temperatures were observed in southern AB and southeastern SK (Fig. 1). Average 30-day temperatures were well below normal (Fig. 3). Across the prairies, average temperatures (April 9-May 6) was 0 to -3 °C below normal (Fig. 2).
Figure 1. Average Temperature (°C) across the Canadian prairies the past seven days (April 30-May 7, 2019). Figure 2. Average Temperature (°C) across the Canadian prairies the past 30 days (April 7-May 7, 2019). Figure 3. Mean temperature differences from Normal across the Canadian prairies from April 9-May 6, 2019. Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (09May2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
Seven day cumulative rainfall shows that minimal rain was observed across large areas in MB and SK (Fig. 4). Rainfall (30 day accumulation) amounts (Fig. 5) have been well below average for most of the prairies (66% of average) (Fig. 6). Rainfall amounts across southern SK are normal to above normal (Fig. 6).
Figure 4. Cumulative precipitation observed the past seven days across the Canadian prairies (April 30-May 7, 2019). Figure 5. Cumulative precipitation observed the past 30 days across the Canadian prairies (April 7-May 7, 2019). Figure 6. Percent of average precipitation across the Canadian prairies the past 30 days (as of May 8, 2019). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (09May2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
Soil moisture values are low across large generally low.
Figure 7. Modelled soil moisture (%) across the Canadian prairies as of May 7, 2019.
The growing degree day map (GDD) (Base 5 ºC, March 1 – June 18, 2017) is below:
Figure 8. Growing degree day (Base 5 ºC) across the Canadian prairies for the growing season (April 1-May 6, 2019). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (09May2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
The growing degree day map (GDD) (Base 10 ºC, March 1 – June 18, 2017) is below:
Figure 9. Growing degree day (Base 10 ºC) across the Canadian prairies for the growing season (April 1-May 6, 2019). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (09May2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990s.
In a continuing effort to produce timely information, the wind trajectory reports are available in two forms:
DAILY REPORTS, as they can be generated, are accessible as a downloadable PDF file on this page.
Cutworms (Noctuidae) – A field guide is available to help growers scout and manage Cutworms. Cutworm Pest of Crops is available for free in either English or French and is posted on the Cutworm Field Guide page!
Several species of cutworms can be present in fields (Refer to downloadable PDF below). They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning. Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol. Also refer to Manitoba Agriculture cutworm fact sheet which includes action and economic thresholds for cutworms in several crops.
In 2018, the Insect of the Week featured two economically important species of cutworms and some of the important natural enemies that help regulate these pests:
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 later in the day when some cutworm species move above-ground to feed. Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant. If the plant is well-established, check within the crown in addition to the adjacent soil. The culprits could be wireworms or cutworms.
Flea Beetles (Chrysomelidae: Phyllotreta species)– Reminder – 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.
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.
Estimating flea beetle feeding damage can be challenging. Using a visual guide to estimate damage can be helpful. Canola Watch circulated this article but also use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon) – take it scouting!
Figure 1. Canola cotyledons with various percentages of leaf area consume owing to flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).
Figure 2. Percent leaf area consumed by flea beetles feeding on canola seedlings (Photo: Soroka & Underwood, AAFC-Saskatoon).
Refer to the flea beetle page from the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” as an English-enhanced or French-enhanced version.
Alfalfa Weevil (Hypera postica) – Degree-day maps of base 9°C are produced using the Harcourt/North Dakota models (Soroka et al. 2015). Models predicting the development of Alfalfa weevil (AAW) across the prairies are updated weekly to help growers time their in-field scouting for second-instar larvae.
AAW model runs indicate that oviposition should have begun in the Brooks (Rosemary) AB (Fig. 1) and Regina SK regions (Fig. 2). Note that this week’s cool temperatures have reduced oviposition rates (based on model predictions).
Figure 1. Predicted status of alfalfa weevil populations near Swift Current SK as of May 7, 2019.
Figure 2. Predicted status of alfalfa weevil populations near Swift Current SK as of May 7, 2019.
The larval stage of this weevil feeds on alfalfa leaves in a manner that characterizes the pest as a “skeletonizer”. The green larva featuring a dorsal, white line down the length of its body has a dark brown head capsule and will grow to 9mm long.
Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon). Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (Philip et al. 2015). The guide is available in both a free English-enhancedor French-enhanced version.
Pea Leaf Weevil (Sitona lineatus) – The PLW model was run for Red Deer AB (Fig. 1) and Saskatoon SK (Fig. 2). The predictive model outputs suggest that PLW adults are active but oviposition has not begun.
Figure 1. Predicted status of pea leaf weevil populations near Red Deer as of May 7, 2019. Figure 2. Predicted status of pea leaf weevil populations near Saskatoon SK as of May 7, 2019.
Pea leaf weevils emerge in the spring primarily by flying (at temperatures above 17ºC) or they may walk short distances. Pea leaf weevil movement into peas and faba beans is achieved primarily through flight. Adults are slender, greyish-brown measuring approximately 5 mm in length (Fig. 3, Left).
The pea leaf weevil resembles the sweet clover weevil (Sitona cylindricollis) but the former is distinguished by three light-coloured stripes extending length-wise down thorax and sometimes the abdomen. All species of Sitona, including the pea leaf weevil, have a short snout.
Figure 3. Comparison images and descriptions of four Sitona species adults including pea leaf weevil (Left).
Adults will feed upon the leaf margins and growing points of legume seedlings (alfalfa, clover, dry beans, faba beans, peas) and produce a characteristic, scalloped (notched) edge. Females lay 1000 to 1500 eggs in the soil either near or on developing pea or faba bean plants from May to June.
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.
Cereal leaf beetle (Oulema melanopus) – The cereal leaf beetle model indicates that oviposition is well underway in Lethbridge AB as of May 7, 2019 (Fig. 1).
Figure 1. Predicted status of cereal leaf beetle populations near Lethbridge AB as of April 30, 2019
Lifecycle and Damage:
Adult: Adult cereal leaf beetles (CLB) have shiny bluish-black wing-covers (Fig. 2). The thorax and legs are light orange-brown. Females (4.9 to 5.5 mm) are slightly larger than the 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 shelter belts, deciduous and conifer forests. They emerge in the spring once temperature reaches 10-15 ºC and are active for about 6 weeks. They usually begin feeding on grasses, then move into winter cereals and later into spring cereals.
Figure 2. 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 mid vein 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. 3). When the larva completes its growth, it drops to the ground and pupates in the soil.
Figure 3. 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.
Fact sheets for CLB are published by the province of Alberta and available from the Prairie Pest Monitoring Network. Also access the Oulema melanopus page from the new “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide”.
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).
This week, cool temperatures this week were predicted to result in minimal embryological development. As of May 7, 2019, predicted development was 60% and is similar to long term average values (Fig. 1). As embryological development approaches 100%, scouting for nymphs of pest species of grasshoppers should begin.
Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 7, 2019.
Reminder – The Prairie Pest Monitoring Network’s 2019 Grasshopper Forecast Map was released in March. Review all the current risk and forecast maps by linking here. While spring temperatures, soil moisture conditions, and precipitation can all have an impact on overwintered grasshopper eggs, areas highlighted orange or red in the 2019 forecast map should be vigilant this spring by performing in-field scouting to assess nymph densities.
Provincial entomologists provide insect pest updates throughout the growing season so we link to their most recent information:
• Manitoba‘s Insect and Disease Updates for 2019 will be posted here and includes updates from Dr. John Gavloski.
• Saskatchewan‘s Crop Production News for 2019 will be posted here and frequently includes updates from Dr. James Tansey and Mr. Carter Peru.
• Alberta Agriculture and Forestry’s Call of the Land regularly includes insect pest updates from Mr. Scott Meers. The most recent Call of the Land was posted March 18-22, 2019 but did not include an insect update.
This week’s Insect of the Week is the brown marmorated stink bug (Halyomorpha halys). Stink bugs get their name from the foul odour they release when threatened. Brown marmorated stink bug is not known to be established in the Prairies, but the species has been found in the Southern Interior of BC, in Ontario and Quebec. Feeding causes damage to seeds and seed pods, reducing yield. Nymphs and adults prefer field corn and soybean, but infestations have been reported on rape, pea, sunflower and cereals in the USA. They have also been known to attack tree fruits, berries, vegetables and many ornamental trees and shrubs.
Brown marmorated stink bug – adult (CC-BY 2.0 Katja Schulz)
This insect is featured in our Field Crop and Forage Pests and their Natural Enemies Field Guide which is available for download from the Insect Field Guide page.
New for 2019 – The Prairie Crop Disease Monitoring Network (PCDMN) represents the combined effort of our prairie pathologists who work together to support in-field disease management in field crops.
In 2019, the PCDMN will release a series of weekly Cereal Rust Risk Reports throughout May and June. Information related to trajectory events based on forecast and diagnostic wind fields and cereal rust risk is experimental, and is OFFERED TO THE PUBLIC FOR INFORMATIONAL PURPOSES ONLY.
Background: Agriculture and AgriFood Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990s. Trajectory models are used to deliver an early-warning system for the origin and destination of migratory invasive species, such as diamondback moth. In addition, plant pathologists have shown that trajectories can assist with the prediction of plant disease infestations and are also beginning to utilize these same data. An introduction will be presented of efforts to identify wind trajectory events that may bring rust urediniospores into Western Canada from epidemic areas in the central and Pacific northwest (PNW) regions of the USA. Identification of potential events as well as an assessment of epidemic severity from source locations, and prairie weather conditions, will be used to assess the need for prompt targeted crop scouting for at-risk regions of the Canadian Prairies.
This week, two documents are available from the PCDMN:
Synopsis of May 7, 2019, Weekly Cereal Rust Risk Report:
1. Pacific Northwest – Given limited stripe rust development in the PNW, a relatively low number of recent wind trajectories from the PNW, cool Prairie weather conditions, and early stages of Prairie crop development, as of early May the risk of stripe rust appearance from the PNW is limited and scouting for this disease is not urgent.
2. Texas-Nebraska corridor – Given limited leaf and stripe rust development in this corridor, a relatively low number of recent wind trajectories from this area, cool Prairie weather conditions, and early stages of Prairie crop development, as of early May the risk of leaf and stripe rust appearance from the Texas-Nebraska corridor is limited and scouting for these diseases is not urgent.
3. Where farmers or consultants noticed stripe rust development on winter wheat in the fall of 2018, it is recommended to scout winter wheat fields that have resumed growth this spring. Scouting is especially critical where the variety being grown is susceptible to stripe rust. Currently, there are no early spring reports of stripe rust on winter wheat.
This week’s Insect of the Week is a frustrating pest of many crops: wireworm. Wireworms are the soil-dwelling larval stage of the click beetles (Elateridae). There are hundreds of click beetle species in the prairies, but the term wireworm refers to those that are pests, which in Canada is approximately 20 species. With the loss of effective insecticides (e.g. lindane), wireworms have re-emerged in recent years as primary pests of potato, cereals, and vegetables. On the prairies, we have 3 predominant pest species (Selatosomus destructor, Limonius californicus, and Hypnoidus bicolor; see photo), and their larvae vary (among other things) in life history (2-7 years), color (white to orange), cuticle thickness, distribution, behaviour, and susceptibility to insecticides.
Wireworms are patchy in distribution, difficult to monitor, and difficult to kill. We have a lot to learn about these resilient pests. Since the mid-1990’s AAFC has had a national research team (Bob Vernon et al.) screening for effective insecticides and developing trapping and monitoring methods, cultural controls (e.g., crop rotation), and biocontrols to manage the adult and larval forms of these pests.
For more information about wireworms, check out our Insect of the Week page!
The three most troublesome wireworm species on the prairies in their adult and larval stages. Note the different sizes and colours. From left to right, S. destructor, L. californicus, H. bicolor. Photo by David Shack, AAFC-Lethbridge.
Weather synopsis – This past week (May 28-June 4, 2018), the average temperature was very similar to the long term normal (Fig. 1). The warmest weekly temperatures occurred across Manitoba. The 30-day average temperature (April 29 – May 29) was approximately 2 °C warmer than long term average (Fig. 2). Across the prairies, the average temperature for May was up to 5 °C warmer than average.
Figure 1. Weekly (May 28–June 4, 2018) average temperature (°C) . Figure 2. The 30 day (April 29 – May 29, 2018) average temperature (°C).
Weekly precipitation was above average and 30-day total rainfall is approximately 20% less than average (Figs. 3 and 4).
Figure 3. Weekly (May 28 – June 4, 2018) cumulative precipitation (mm).Figure 4. The 30-day (May 28 – June 4, 2018) cumulative precipitation (mm).
Accumulated precipitation for the growing season (April 01-June 4, 2018) is shown below.
The map below reflects the Highest Temperatures occurring over the past 7 days (May 29-June 4, 2018) across the prairies.
The map below reflects the Lowest Temperatures occurring over the past 7 days (May 29-June 4, 2018) across the prairies.
The growing degree day map (GDD) (Base 10ºC, March 1 – June 3, 2018) is below:
The growing degree day map (GDD) (Base 5ºC, March 1 – June 3, 2018) 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.
Background: Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories to deliver an early-warning system for the origin and destination of migratory invasive agricultural pests.
We receive two types of model output from ECCC: reverse trajectories (RT) and forward trajectories (FT):
(i) ‘Reverse trajectories’ (RT) refer to air currents that are tracked back in time from specified Canadian locations over a five-day period prior to their arrival date.
(ii) ‘Forward trajectories’ (FT) have a similar purpose; however, the modelling process begins at sites in USA and Mexico. The model output predicts the pathway of a trajectory. Again, of interest are the winds that eventually end up passing over the Prairies.
Current Data The number of Reverse Trajectories (RTs), crossing the prairies in May 2018, was lower than the long term average (2007 – 2017). The total number of incoming trajectories (sum of Pacific Northwest and southwest USA/Mexico) for 2018 was less than similar values for 2017 and 2007 – 2017. Based on RTs by region, the number of RTs from the Pacific Northwest (PNW) was less than 2007 – 2017 and 2017. To date, the RTs originating in the southwest USA/Mexico in 2018, have been greater in number than in 2017 and less than the long term average (Fig. 1).
Figure 1. Total number of reverse trajectories by geographic region (Pacific Northwest and Mexico and the southwest USA) for May 2018.
The following maps summarize the main results of a survey of pest species of wireworms of the Canadian Prairie Provinces. Samples (both larvae and beetles) were submitted to Dr. Bob Vernon’s lab in Agassiz, BC, from 2004 to 2017, and identified by Dr. Wim van Herk (Fig. 1). Species identifications were confirmed with barcoding.
Figure 1. Sampling locations for click beetles and wireworm larvae (Coleoptera: Elateridae) submitted for wireworm surveying from 2004-2017.
Approximately 600 samples were submitted, with the number of larvae per sample typically less than five (Fig. 1). More samples are welcome, particularly from areas currently not well represented on the maps.Please provide either the legal land description or latitude and longitude coordinates with a sample. Any information on the cropping history or whether fields were irrigated is helpful.
The main findings of this survey are that: 1. Wireworms are re-emerging as primary pests of cereals and other crops, particularly in southern Alberta and Saskatchewan. This can be attributed to several factors, including changes in seeding and cultivation resulting in higher soil moisture and increased food availability, and therefore greater wireworm survival; the elimination of effective insecticides such as lindane and the decline of organochlorine residues in the soil; and the present lack of insecticides that actually kill wireworms.
2. Limonius californicus is generally the predominant pest species in fields reporting heavy wireworm damage, occasionally building up to very high populations and resulting in complete crop wrecks (Fig. 2). This was not the case when Glen et al. (1943) or Doane (1977) conducted their surveys; L. californicus was considered a minor species at those times. Selatosomus destructor (Fig. 3) and Hypnoidus bicolor (Fig. 4) are still the most common species. The pest status of another commonly found species, the predaceous Aeolus mellillus (Fig. 5), is unclear. The following species listed by Glen et al. (1943) as pests of agriculture in the Prairie Provinces were found also, but infrequently: Agriotes mancus, A. criddlei, A. stabilis, Hemicrepidius memnonius, L. pectoralis, and various Dalopius sp.
Figure 2. Distribution of Limonius californicus (Coleoptera: Elateridae) submitted for wireworm surveying from 2004-2017.Figure 3. Distribution of Selatosomus destructor (Coleoptera: Elateridae) submitted for wireworm surveying from 2004-2017.Figure 4. Distribution of Hypniodes bicolor (Coleoptera: Elateridae) submitted for wireworm surveying from 2004-2017.Figure 5. Distribution of Aeolus mellillus (Coleoptera: Elateridae) submitted for wireworm surveying from 2004-2017.
3. Multiple pest species are frequently found in the same fields where damage is reported (i.e. about 25% of the time, despite the small number of larvae per sample). This is particularly important as pest species can vary considerably in the type of damage they cause (e.g. it remains unclear if H. bicolor is damaging to potato), their life history (e.g. duration of the larval stage), and susceptibility to insecticides.
Acknowledgements: These maps are only possible thanks to the collections done by a large team of local entomologists and agrologists. We are extremely grateful to them; thank you to everyone who participated! A special thank you to Ted Labun and colleagues at Syngenta Crop Protection (Canada), and to Bayer CropScience, for providing the bulk of the samples.
Disclaimer: Please do not distribute or use the contents of this post, including any maps, without obtaining prior permission.
Obtain further information or arrange shipment of wireworm or click beetle samples by contacting: Dr. Wim van Herk Agriculture and Agri-Food Canada Agassiz Research and Development Centre 6947 Highway 7, Agassiz, BC, V0M 1A0 wim.vanherk@agr.gc.ca
Further wireworm reading: Burrage RH (1964) Trends in damage by wireworms (Coleoptera: Elateridae) in grain crops in Saskatchewan, 1954–1961. Canadian Journal of Plant Science, 44: 515–519. https://doi.org/10.4141/cjps64-102
Doane JF (1977) Spatial pattern and density of Ctenicera destructor and Hypolithus bicolor (Coleoptera: Elateridae) in soil in spring wheat. The Canadian Entomologist 109: 807–822. https://doi.org/10.4039/Ent109807-6
Doane JF (1977) The flat wireworm, Aeolus mellillus: studies on seasonal occurrence of adults and incidence of the larvae in the wireworm complex attacking wheat in Saskatchewan. Environmental Entomology 6: 818–822. https://doi.org/10.1093/ee/6.6.818
Glen R, King KM, Arnason AP (1943) The identification of wireworms of economic importance in Canada. Canadian Journal of Research 21: 358-387. https://doi.org/10.1139/cjr43d-030
van Herk WG, Vernon RS (2014) Click beetles and wireworms (Coleoptera: Elateridae) of Alberta, Saskatchewan, and Manitoba. In: Arthropods of Canadian Grasslands (Volume 4): Biodiversity and Systematics Part 2. (Edited by D.J. Giberson and H.A. Carcamo). Biological Survey of Canada, pp. 87-117. https://biologicalsurvey.ca/monographs/read/17
Zacharuk RY (1962) Distribution, habits, and development of Ctenicera destructor (Brown) in western Canada, with notes on the related species C. aeripennis (Kby.) (Coleoptera: Elateridae). Canadian Journal of Zoology 40: 539–552. https://doi.org/10.1139/z62-046
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).
As of June 4, 2018, predicted hatch was 51% (31% last week; long term average was 11%). Hatch is predicted to be nearly complete in southeast AB and southern MB (Fig. 1). Grasshopper populations are primarily in the first instar (Fig. 2).
Figure 1. Grasshopper hatch (%) based on model simulations, for April 1-June 4, 2018.Figure 2. Percent of grasshopper population that is in the first instar, based on model simulations, for April 1-June 4, 2018.
Cereal leaf beetle (Oulema melanopus) – Model output indicates that CLB are primarily in the larval stage (Fig. 1).
Figure 1. Percent of cereal leaf beetle population that is in the larval stage, based on model simulations, for April 1-June 4, 2018.
Lifecycle and Damage:
Adult: Adult cereal leaf beetles (CLB) have shiny bluish-black wing-covers (Fig. 2). The thorax and legs are light orange-brown. Females (4.9 to 5.5 mm) are slightly larger than the 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 shelter belts, deciduous and conifer forests. They emerge in the spring once temperature reaches 10-15 ºC and are active for about 6 weeks. They usually begin feeding on grasses, then move into winter cereals and later into spring cereals.
Figure 2. 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 mid vein 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. 3). When the larva completes its growth, it drops to the ground and pupates in the soil.
Figure 3. 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.
Fact sheets for CLB are published by the province of Alberta and available from the Prairie Pest Monitoring Network. Also access the Oulema melanopus page from the new “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide”.
Bertha armyworm (Lepidoptera: Mamestra configurata) – The BAW model is predicting that pupae are developing rapidly in the soil and that development is well ahead of average (Fig. 1). Development is expected to be 5 – 6 days faster than average.
Though cooler temperatures have slowed BAW development, moths are predicted to emerge 10 days ahead of average (Table 1). Pupal development is approximately 82% (Fig. 1). Model output predicts that emergence may begin as early as June 9th.
Table 1. Projected dates for BAW adult emergence for June 4, 2018 (projected to June 30, 2018).
Figure 1. Predicted bertha armyworm pupal development (as of June 3, 2018).
Pea Leaf Weevil (Sitona lineatus) – The PLW model predicts that oviposition is occurring across southern and central regions of the prairies (example Red Deer (Fig. 9).
Figure 1. Predicted pea leaf weevil phenology at Red Deer AB. Values are based on model simulations, for April 1-May 28, 2018 (projected to July 15, 2018).
Pea leaf weevils emerge in the spring primarily by flying (at temperatures above 17ºC) or they may walk short distances. Pea leaf weevil movement into peas and faba beans is achieved primarily through flight. Adults are slender, greyish-brown measuring approximately 5 mm in length (Fig. 2, Left).
The pea leaf weevil resembles the sweet clover weevil (Sitona cylindricollis) but the former is distinguished by three light-coloured stripes extending length-wise down thorax and sometimes the abdomen. All species of Sitona, including the pea leaf weevil, have a short snout.
Figure 2. Comparison images and descriptions of four Sitona species adults including pea leaf weevil (Left).
Adults will feed upon the leaf margins and growing points of legume seedlings (alfalfa, clover, dry beans, faba beans, peas) and produce a characteristic, scalloped (notched) edge. Females lay 1000 to 1500 eggs in the soil either near or on developing pea or faba bean plants from May to June.
Reminder – The 2017 risk map for pea leaf weevils was released in March 2018. The map is based on the number of feeding notches observed in peas (Fig. 3).
Figure 3. Estimates of pea leaf weevil (S. lineatus) densities based on feeding notches observed in peas grown in Alberta and Saskatchewan in 2017.
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.
Alfalfa Weevil (Hypera postica) – The AAW model runs for Swift Current SK indicate that oviposition is well underway in southern Saskatchewan (Fig. 1). Larvae should be primarily second and third instars. Fourth instar larvae may be occurring as well.
Figure 1. Average developmental alfalfa weevil stage. Values are based on model simulations, for April 1-June 4, 2018.
The larval stage of this weevil feeds on alfalfa leaves in a manner that characterizes the pest as a “skeletonizer”. The green larva featuring a dorsal, white line down the length of its body has a dark brown head capsule and will grow to 9mm long.
Use the photo below as a visual reference to identify alfalfa weevil larvae. Note the white dorsal line, the tapered shape of the abdomen and the dark head capsule.
Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon). Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (Philip et al. 2015). The guide is available in both a free English-enhancedor French-enhanced version.
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.
Provincial entomologists provide insect pest updates throughout the growing season so we link to their most recent information:
Manitoba‘s Insect and Disease Update for 2018 will be posted soon. Review the most recent update (June 4, 2018) prepared by John Gavloski and Holly Derksen. The insect update notes flea beetles in canola and cutworms with monitoring for alfalfa weevil larvae underway. Diamondback moth trap numbers remain low and bertha armyworm pheromone traps will go up this week. Saskatchewan‘s Crop Production News for 2018 is now posted. Access Report #1 posted May 31, 2018, and be sure to review the articles posted for flea beetles and pea leaf weevils to prepare for field scouting. Also know that Saskatchewan growers can review diamondback moth pheromone trap counts in the upper right of the diamondback moth page. Access Alberta Agriculture and Forestry’s Call of the Land for insect pest updates from Scott Meers. The most recent Call of the Land (posted on May 31, 2018) and highlights scouting for flea beetles with the warmer weather, glassy cutworms in perennial forages crops and more recently in the irrigated acres to the south of the province (please report using online cutworm reporting tool), relatively low numbers of diamondback moth on pheromone traps in the 4th week of monitoring and relatively low pea leaf weevil numbers so far based on field assessments completed in southern Alberta to date.
We continue to track the migration of the Monarch butterflies as they move north by checking the 2018 Monarch Migration Map! A screen shot of the map has been placed below as an example (retrieved 29May2018) but follow the hyperlink to check the interactive map!
Visit the Journey North website to learn more about migration events in North America and visit their monarch butterfly website for more information related to this fascinating insect.
This week’s “Insect of the Week” is the Pea Leaf Weevil. Larval hosts are field peas and faba beans. Adults can spread to other cultivated and wild legumes, such as alfalfa, beans and lentils. Each adult female lays up to 300 eggs in one summer! The eggs hatch in the soil near developing plants and larvae move to feed on nitrogen-fixing nodules. This results in partial or complete inhibition of nitrogen fixation by the plant, causing poor plant growth. Adults feed on leaves and growing points of seedlings, causing notches in leaf margins.
Adult, larval and egg stages overlap and all three can be present over most of the growing season. For more information about Pea Leaf Weevil risk in your area, see the 2017 Insect Risk Maps page. Also, we have posted a NEW Pea Leaf Weevil monitoring protocol.
For more information on the pea leaf weevil, see the Insect of the Week page.
Pea leaf weevil – adult, eggs (Mike Dolinski, MikeDolinsky@hotmail.com)
Weather synopsis – Across the prairies, this week’s average temperatures were slightly cooler than normal.
After a wetter week in central and northern Alberta, the most current 7-day rainfall was greater in the east of central Alberta into central Saskatchewan down into Manitoba.
The 30-day rainfall amounts were average to below average across the southern prairies.
The map below reflects the Accumulated Precipitation for the Growing Season so far for the prairie provinces (i.e., April 1-May 31, 2017):
The map below shows the Lowest Temperatures the Past 7 Days (May 25-31, 2017) across the prairies:
Whereas the map below shows the Highest Temperatures the Past 7 Days (May 25-31, 2017):
The updated growing degree day map (GDD) (Base 5ºC, March 1 – May 28, 2017) is below:
While the growing degree day map (GDD) (Base 10ºC, March 1 – May 28, 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.
THE WEEK OF MAY 29, 2017: Wind trajectory data processing by AAFC-Saskatoon Staff began in April. Reverse Trajectories track arriving air masses back to their point of origin while Forward Trajectories predict favourable winds expected to arrive across the Canadian Prairies for the week of May 23, 2017: Reverse trajectories (RT) Overall, the number of RTs entering the prairies from the Pacific
Northwest has been lower than average. The map (Fig. 1) shows that the greatest number
of RTs from the Pacific Northwest continued to be across southern Alberta.
Figure 1. Number of Reverse Trajectories (RT) originating in the Pacific Northwest that
arrived at sites across the Canadian prairies from April 1-May 29, 2017.
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.
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. Estimating flea beetle feeding damage can be challenging. Using a visual guide to estimate damage can be helpful. Canola Watch circulated this article but also use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon) – take it scouting!
Figure 1. Canola cotyledons with various percentages of leaf area consume owing to flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).
Figure 2. Percent leaf area consumed by flea beetles feeding on canola seedlings (Photo: Soroka & Underwood, AAFC-Saskatoon).
Refer to the flea beetle page from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” as an English-enhanced or French-enhanced version.
Cutworms (Noctuidae) – NEW – Just in time for spring scouting! A new field guide is now available to help growers scout and manage Cutworms! Cutworm Pest of Crops is now available for free in either English or French and is featured at our newCutworm Field Guide!
Keep an eye on 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 later in the day when some cutworm species move above-ground to feed. Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant. If the plant is well-established, check within the crown in addition to the adjacent soil. The culprits could be wireworms or cutworms.
Several species of cutworms can be present in fields. They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning. Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol. Also refer to the Manitoba Agriculture cutworm fact sheet which includes action and economic thresholds for cutworms in several crops.
For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2017 Cutworm Reporting Tool”. The map now has reports of pale western and redbacked cutworms in central and southern Alberta so view the live 2017 cutworm map.
Cereal leaf beetle (Oulema melanopus) – As of May 29, 2017, the CLB model indicates that larvae should be present across the southern prairies (Fig. 1). Compared to Lethbridge AB, populations near Brandon MB are predicted to be delayed by approximately five days. At Lethbridge, the hatch should be almost complete, while hatch should be approximately 50% complete near Brandon.
Figure 1. Predicted percent of Cereal leaf beetle (Oulema melanopus) in larval stage
across the Canadian prairies as of May 29, 2017.
Lifecycle and Damage: Adult: Adult cereal leaf beetles (CLB) have shiny bluish-black wing-covers (Fig. 2). The thorax and legs are light orange-brown. Females (4.9 to 5.5 mm) are slightly larger than the 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 shelter belts, deciduous and conifer forests. They emerge in the spring once temperature reaches 10-15 ºC and are active for about 6 weeks. They usually begin feeding on grasses, then move into winter cereals and later into spring cereals.
Figure 2. Adult Oulema melanopus (~4.4-5.5 mm long).
Egg: Eggs are laid approximately 14 days following the emergence of the adults. Eggs are laid singly or in pairs along the mid vein 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. 3). When the larva completes its growth, it drops to the ground and pupates in the soil.
Figure 3. Larval stage of Oulema melanopus with characteristic feeding damage visible on leaf.
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.
Fact sheets for CLB are published by the province of Alberta and available from the Prairie Pest Monitoring Network. Also access the Oulema melanopus page from the new “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide”.
Alfalfa Weevil (Hypera postica) – Reminder – Biological information and photos of all life stages of this insect can reviewed on the Week 4 post. The larval stage of this weevil feeds on alfalfa leaves in a manner that characterizes the pest as a “skeletonizer”.
Degree-day maps of base 9°C are now being produced by Soroka, Olfert, and Giffen (2016) using the Harcourt/North Dakota models. Models predicting the development of Alfalfa weevil across the prairies are updated weekly to help growers time their in-field scouting for second-instar larvae. Compare the following predicted development stages and degree-day values from Soroka (2015) to the map below.
As of May 29, 2017, embryological development (hatch) is predicted to be greatest across south and central regions of the prairies (Fig. 2).
Figure 1. Heat units accumulated necessary for the development of Alfalfa weevil (Hypera postica)
across the Canadian prairies (April 1-May 29, 2017).
The map below reflects the predicted stage of development of alfalfa weevil (as of May 29th) and suggests the percent of the population at first instar stage across the Canadian prairies (as of May 29th).
Figure 2. Predicted percent of H. postica population at first instar stage
across the Canadian prairies (as of May 29, 2017).
Use the photo below as a visual reference to identify alfalfa weevil larvae. Note the white dorsal line, the tapered shape of the abdomen and the dark head capsule.
Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon) and additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (Philip et al. 2015). That guide is available in both a free English-enhancedor French-enhanced version.
