TEMPERATURE: The 2022 growing season has been cooler than normal. Rainfall has been below normal for Alberta and western Saskatchewan while rainfall amounts have been well above normal for eastern Saskatchewan and Manitoba. This past week (June 6-12, 2022) average daily temperatures were generally warmer than in the previous week. The warmest conditions occurred across southern Manitoba, a region extending from Regina to Saskatoon and southwest to Lethbridge, and in the northern Peace River region (Fig. 1). The average temperature across the prairies was 2 °C warmer than normal.
Though the prairie-wide average 30-day temperature (May 14 – June 12, 2022) was similar to the long-term average value, the average was 1.5 °C warmer than the previous week. Average temperatures have increased across most of the prairies (Fig. 2).
The prairie-wide average growing season (April 1-June 12, 2022) temperature was 1 °C warmer than last week; the average growing season temperature for the prairies has been 1 °C cooler than climate normal values. The growing season continues to be cooler in Manitoba than Saskatchewan and Alberta (Fig. 3).
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.
PRECIPITATION: Seven-day cumulative rainfall ranged between 0 and 42 mm across the prairies, with highest rainfall amounts (20-40 mm) occurring in a region extending from Hanna to Calgary and south to Lethbridge (Fig. 4). Rainfall amounts were generally less than 10 mm for most of Saskatchewan.
30-day accumulation amounts have been well above average across Manitoba but well below normal across southern and western Saskatchewan (Fig. 5). Growing season rainfall for April 1 – June 12, 2022, continues to be greatest across Manitoba and eastern Saskatchewan; rain amounts have been below normal across most of western Saskatchewan and Alberta (Fig. 6).
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 12, 2022. Warmer temperatures over the past 30 days have resulted in increased rates of grasshopper development across Saskatchewan and Alberta; wetter/cooler conditions across eastern Saskatchewan and Manitoba have resulted in delayed development.
Last week, average embryological development was 76 %. This week, average egg development is predicted to be 83 % and is 1 % greater than the long-term development rate. Hatch is progressing across southern and central regions of Alberta and Saskatchewan with hatch rates that range between 15 and 60% (Fig. 1). First to third instar nymphs should be occurring across southern and central regions of Alberta and Saskatchewan. Simulations indicate that 5-10% of the population has hatched across southern and central regions of Manitoba.
Risk estimates, based on meteorological inputs, were used to assess the impact of weather on grasshopper development and population growth potential (Fig. 2). Grasshopper risk is greatest in areas that are warmer and drier than normal. As of June 12, 2022, model output indicates that potential risk is greatest across a region that extends from Lethbridge to Swift Current and Saskatoon. Relative to last week,risk has increased for localized areas across the Peace River region. The simulation indicates that even though temperatures are suitable for grasshopper development, excessive moisture across most of Manitoba has reduced the potential risk from grasshoppers. Overall risk is predicted to be similar to long-term average risk and is currently well below potential risk predictions that were produced for the 2021 growing season.
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 third instar larvae should now be appearing across the prairies. Development is similar to long-term average values. AAW development in central Saskatchewan (Fig. 1) is slower than AAW development in southern Alberta (Fig. 2).
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 western Saskatchewan are predicted to result in more rapid development of cereal leaf beetle (CLB) populations in those regions than in southern Manitoba. CLB model output predicts that hatch should be nearly complete for southern Alberta and western Saskatchewan. First to third instar larvae are predicted to be present in these areas (Fig. 1). As a result of cooler conditions, the model predicts that egg development has been delayed in southern Manitoba; first instar and second instar larvae may be appearing this week (Fig. 2).
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.
Pupal development of bertha armyworm (BAW) is progressing across the prairies with the most rapid development occurring across southern and central regions of Alberta and western Saskatchewan (Fig. 1). Over the next week, adults should be emerging across Alberta, Saskatchewan and localized areas in southern Manitoba.
Use the images below (Fig. 2) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.
Wheat midge (Sitodiplosis mosellana) overwinter as larval cocoons in the soil but soil moisture conditions in May and June largely determine whether or not the larva exits their cocoon to move to the soil surface to continue development (i.e., to pupate then emerge as a midge this season). 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. 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
Compared to last week, the wheat midge model indicates that the development of larval populations has advanced considerably across the eastern prairies and Peace River region. Normal to above-normal rain in Manitoba, eastern Saskatchewan and the Peace River region should be sufficient to promote the movement of wheat midge larvae to the soil surface (Fig. 1). Insufficient rainfall across central Alberta and western Saskatchewan will limit the development of larval populations that are in the soil.
Wheat midge simulations suggest that greater than 60 % of the larval population has moved to the soil surface in some areas of the prairies. Larval populations should begin to transition to the pupal stage over the next seven days. Current development for eastern Saskatchewan and Manitoba is similar to long-term average rates.
Risk estimates, based on meteorological inputs, were used to assess the impact of weather on wheat midge development and potential population growth potential (Fig. 2). Wheat midge risk is greatest in areas that have received normal to above-normal rainfall. As of June 12, 2022, model output indicates that potential risk is greatest across eastern Saskatchewan and Manitoba. Risk in these areas is predicted to be similar to long-term average risk.
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.
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 15, 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! • Flea beetles, cutworms and grasshopper nymphs in MB – Review the above June 15 issue to find greater details but the summary reads as, “Flea beetles levels are at quite high levels in many areas. Some growers have applied up to three insecticide applications for flea beetles, and there has been some reseeding. Some fields of small grains and sunflowers have been sprayed for cutworms. Hatch of the potential pest species of grasshoppers is occurring; some control has occurred in the Central region.” • Diamondback moth pheromone trap monitoring update for MB – “So far, diamondback moth has been found in 29 traps.” Read the report on Page 5 of the June 15, 2022 issue OR review a more detailed summary of cumulative trap counts from 48 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 6of the June 15, 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 continue to come in so refer to the Live Map to review areas where cutworms are being found. So far, black army, pale western, and dingy cutworms have been reported. Use this online form to report cutworms in Alberta.
Review the Sweep-net Video Series including: • How to sweep a field. Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon). Published online 2020. • What’s in my sweep-net? Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon). Published online 2020. • Why use a sweep-net? Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon). Published online 2020.