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Ross Weiss, Tamara Rounce, Owen Olfert, Jennifer Otani and Meghan Vankosky
Categories
Week 7
TEMPERATURE: This past week (June 13-19, 2022) the average daily temperature (prairies) was 1 °C warmer than the previous week and 1.5 °C warmer than normal (Fig. 1). Though the prairie-wide average 30-day temperature (May 21 – June 19, 2022) was similar to long-term average values, the average 30-day temperature for May 21 to June 19 was 1.5 °C warmer than the average 30-day temperature for May 14 to June 12 (Fig. 2).
Figure 1. Seven-day average temperature (°C) across the Canadian prairies for the period of June 13-19, 2022.Figure 2. 30-day average temperature (°C) across the Canadian prairies for the period of May 21-June 19, 2022.
The growing season (April 1 – June 19, 2022) temperature for the prairies has been 1 °C cooler than climate normal values. The growing season has been warmest across western Saskatchewan and the southern and central regions of Alberta (Fig. 3; Table 1).
Figure 3. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1 to June 19, 2022.
Table 1. Growing season (April 1 – June 19, 2022) temperature and rainfall summary for specific locations across the Canadian prairies.
PRECIPITATION: Weekly (June 13-19) rainfall varied across the prairies. Significant rainfall was reported across Alberta (Fig. 4). Rainfall amounts were generally less than 10 mm for most of Saskatchewan. 30-day accumulation amounts have been well above average across large areas of Manitoba and Alberta while rainfall accumulation has been well below normal across Saskatchewan (Fig. 5).
Figure 4 Seven-day cumulative rainfall (mm) observed across the Canadian prairies for the period of June 13-19, 2022.Figure 5. 30-day cumulative rainfall (mm) observed across the Canadian prairies the past 30 days (May 21-June 19, 2022).
Growing season rainfall for April 1 to June 19, 2022, continues to be greatest across Manitoba and southeastern Saskatchewan; rain amounts have been below normal across central Saskatchewan and near normal for Alberta (Fig. 6; Table 1).
Figure 6. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1 to June 19, 2022.
Ross Weiss, Tamara Rounce, David Giffen, Owen Olfert, Jennifer Otani and Meghan Vankosky
Categories
Week 7
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. Model outputs provided below as geospatial maps are a tool to help time in-field scouting on a regional scale but local development can vary and is only accurately assessed through in-field scouting.
Review lifecycle and damage information for this pest to support in-field scouting.
Model simulations were used to estimate percent grasshopper egg development and hatch as of June 19, 2022. Warmer temperatures across the southern prairies have resulted in increased rates of grasshopper egg development and hatch is now well underway. Egg hatch may be nearly complete for some regions.
Last week, the average embryological development was 83 %. This week, average egg development is predicted to be 90 % and is 2 % greater than the long-term development rate for this time in the growing season. Hatch is progressing across the prairies, with southern and central regions of Alberta and Saskatchewan having hatch rates greater than 75% (Fig. 1). Compared to last week, recent warm conditions across southern Manitoba have resulted in higher hatch rates.
Figure 1. Predicted migratory grasshopper (Melanoplus sanguinipes) hatch (%) across the Canadian prairies as of June 19, 2022.
Based on estimates of average nymphal development, first to third instar nymphs should be occurring across southern and central regions of Alberta and Saskatchewan (Fig. 2). Warm, dry conditions across central and southern regions of Saskatchewan have resulted in rapid grasshopper development.
Figure 2. Predicted migratory grasshopper (Melanoplus sanguinipes) development, presented as average instar, across the Canadian prairies as of June 19, 2022.
Ross Weiss, Tamara Rounce, David Giffen, Owen Olfert, Jennifer Otani and Meghan Vankosky
Categories
Week 7
Compared to long-term averages, bertha armyworm (BAW) development has been delayed thus far in the 2022 growing season. Pupal BAW development is progressing across the prairies. This week, pupal development is predicted to complete and adult emergence is expected to occur across most of the prairies (Fig. 1). Adult emergence should have already begun across a region extending from Lethbridge to Regina and north to Saskatoon. Adult emergence near Regina, Saskatchewan (Fig. 2) is predicted to be one week ahead of central Alberta (Fig. 3). Oviposition should begin over the next 7-10 days.
Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development (%) across the Canadian prairies as of June 19, 2022.Figure 2. Predicted bertha armyworm (Mamestra configurata) populations near Regina, Saskatchewan as of June 19, 2022(projected to June 30, 2022, based on long-term average conditions). Figure 3. Predicted bertha armyworm (Mamestra configurata) populations near Lacombe, Alberta as of June 19, 2022(projected to June 30, 2022, based on long-term average conditions).
Use the images below (Fig. 4) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.
Figure 4. 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.
Ross Weiss, Tamara Rounce, David Giffen, Owen Olfert, Jennifer Otani and Meghan Vankosky
Categories
Week 7
Soil moisture conditions in May and June can have significant impacts on wheat midge emergence. Where wheat midge cocoons are present in soil, the 2022 growing season’s rainfall during May and June should be sufficient to terminate diapause and induce the larvae to move to the soil surface. The map in Figure 1 provides a visual representation of regional estimates of wheat midge movement to the soil surface, where pupal development will occur, then adults will begin to emerge. Remember – the rate of development and timing of adult midge emergence varies at the field level and can only be verified through in-field scouting. Fields within regions receiving sufficient rainfall should soon scout! Midge flight coinciding with the beginning of anthesis is a crucial point when in-field counts of wheat midge on plants are carefully compared to the economic thresholds.
As of June 19, 2022, wheat midge development is predicted to be most advanced in eastern Saskatchewan and the western Peace River region (British Columbia) (Fig. 1). The model was projected to July 10 (based on long-term average conditions) to predict potential wheat midge stages in early July. Simulations indicate that midge development will be more advanced at Estevan, Saskatchewan (Fig. 2) and Melfort, Saskatchewan (Fig. 3), than at Grande Prairie, Alberta (Fig. 4). Adults should begin to emerge in late June or early July.
Figure 1. Percent of wheat midge larval population (Sitodiplosis mosellana) that have moved to the soil surface across western Canada,as of June 19, 2022.Figure 2. Predicted development of wheat midge (Sitodiplosis mosellana) populations near Estevan, Saskatchewan, as of June 19, 2022(projected to July 10, 2022, based on long-term average conditions) Figure 3. Predicted development of wheat midge (Sitodiplosis mosellana) populations near Melfort, Saskatchewan, as of June 19, 2022(projected to July 10, 2022, based on long-term average conditions) Figure 3. Predicted development of wheat midge (Sitodiplosis mosellana) populations near Grande Prairie, as of June 19, 2022(projected to July 10, 2022, based on long-term average conditions)
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 have originated from the Pacific Northwest (Idaho, Oregon and Washington). The number of incoming trajectories during the first two weeks of June was much lower than this past week (June 14-20, 2022) (Fig. 1). The number of reverse trajectories, originating from Mexico, California, Texas, Oklahoma, Nebraska and Kansas have significantly increased since June 18th.
Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of June 1-20, 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 (June 14-20, 2022) the ECCC model predicted that 124 reverse trajectories would cross the prairies. This is similar to the number of reverse trajectories expected in the previous week (n=134).
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 20, 2022.
b. Mexico and southwest USA (Texas, California) – Prior to this past week, the most recent reverse trajectories that originated from Mexico, California or Texas crossed over the Canadian prairies on May 31st. This week a total of 44 reverse trajectories were predicted to cross the prairies. Most reverse trajectories have entered Manitoba during the 2022 growing season. This week trajectories crossed Medicine Hat, Kindersley, and Swift Current.
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 20, 2022.
c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan. This week, a number of these reverse trajectories passed over central Saskatchewan, including Saskatoon, Moose Jaw and Regina (Fig. 4). This week there were significantly more (n=44) reverse trajectories than last week (n=1) that originated from Texas and Oklahoma.
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 20, 2022.
d. Nebraska and Kansas – Similar to last week, a number of reverse trajectories originating from Kansas and Nebraska have crossed central and western prairie locations (Fig. 5). This past week (June 14-20, 2022) the ECCC model predicted that 51 reverse trajectories passed over the prairies. This is a significant increase from the previous week (n=8).
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 20, 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 (June 14-20, 2022) there was an increase in the number (n=50) of forward trajectories predicted to cross the prairies (n=34 last week). 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 20, 2022.
View historical PPMN wind trajectory reports by following this link which sorts the reports from most recent to oldest.
Jennifer Otani, John Gavloski, James Tansey, Carter Peru and Shelley Barkley
Categories
Week 7
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 22, 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! • Grasshopper nymphs, lygus bugs, pea leaf weevils in MB were new additions to the June 22 issue. • Diamondback moth pheromone trap monitoring update for MB – “So far, diamondback moth has been found in 33 traps.” Read the report on Page 5 of the June 22, 2022 issue OR review a more detailed summary of cumulative trap counts from 51 sites deployed across the province. • Armyworm pheromone trap monitoring is underway in MB – Review the current cumulative counts in the June 22, 2022 issue and find a link to review a map of counts compiled from Manitoba, Eastern Canada and several northeast states of the United States.
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. • Bertha armyworm 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 bertha armyworm moths have been intercepted across the province. • 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. Use this online form to report cutworms in Alberta.
This week we look at a small sap-feeding insect with a high economic threshold, and how counting a few beneficial insects helps make informed economical management decisions.
Soybean aphid (Aphis glycines) was first found in North America in 2000. They are specific, feeding and functioning as a potential pest of ONLY soybeans (Fig. 1). Like some other aphids, soybean aphids overwinter on an alternate plant host completely different from their main summer soybean host; they overwinter as eggs only on buckthorn (Rhamnus sp.). It is not known if soybean aphids overwinter well in the Canadian prairies. Every spring, populations of soybean aphid may be highly dependent on what moves in, and when. There have been years when this newly established insect was at economic levels, but high populations are erratic and do not occur every year.
Figure. 1 Soybean aphids on underside of soybean leaf. Photo: J. Gavloski
Appearance and monitoring tips for soybean aphids (Fig. 2): • Small, light yellow, with black cornicles (tailpipes). • Winged adults have black heads and thorax. • A hand-lens may be helpful for verification.
Figure 2. Dorsal view of mature soybean aphid. Photo: J. Gavloski
Sample weekly, even daily, after bloom. Check the undersides of leaves to look for aphids. Ants on plants may hint that aphids are present (some ant species like feeding on aphid honeydew). To avoid bias and inaccurate estimates of pest populations, RANDOMLY select soybean plants to assess then count and note soybean aphid densities.
If aphid levels are high, numbering in the hundreds, exact counts are not possible and likely impractical. Instead, practice visually estimating densities (Fig. 3). Photo keys are available to help. Don’t count the white shed cuticles you may see on plants with many aphids.
Figure 3. Examples of different soybean aphid densities. Photo: J. Gavloski
An app called Aphid Advisor, factors several natural enemies into the management decision and recommends looking for several natural enemies, such as lady beetles (Fig. 4), lacewings, hover fly larvae (Fig. 5), minute pirate bugs, parasitized aphids, etc. Information on Aphid Advisor is available at: http://www.aphidapp.com
The action threshold (density where action is recommended to mitigate damaging densities associated with economic loss) is an average of 250 aphids per plant applied from onset of bloom to early stages of seed development and typically involves rapidly increasing aphid populations. If using Aphid Advisor, a dynamic action threshold, which includes the impact of natural enemies, will be calculated.
If control of soybean aphids is necessary, selective insecticides that kill aphids but are harmless to their natural enemies are now available. See your provincial Guide to Crop Protection or contact your local provincial entomologist for more details.
Figure 4. Lady beetle larva foraging amongst soybean aphids. Photo: J. Gavloski
Figure 5. Larvae of two different species of hover fly (Syrphidae) foraging amongst soybean aphids. Photo: J. Gavloski
Additional information on soybean aphids can be found in the Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Management: AAFC-Field-Guide (2018) as both ENGLISH and FRENCH resources that are freely downloadable and searchable.
Did you know? Pinkish, white, or tan and fuzzy soybean aphids are infected with a fungus! Fungal pathogens can reduce aphid numbers in warm and humid conditions.
References: Ragsdale, D.W., B. P. McCornack, R. C. Venette, B. D. Potter, I. V. MacRae, E. W. Hodgson, M. E. O’Neal, K. D. Johnson, R. J. O’Neil, C. D. DiFonzo, T. E. Hunt, P. A. Glogoza, and E. M. Cullen. 2007. Economic Threshold for Soybean Aphid (Hemiptera: Aphididae). Journal of Economic Entomology. Vol. 100: 1258-1267. https://doi.org/10.1093/jee/100.4.1258
Hallett, R.H., C.A. Bahlai, Y. Xue and A.W. Schaafsma. 2014. Incorporating Natural Enemy Units into a Dynamic Action Threshold for the Soybean Aphid, Aphis glycines (Homoptera: Aphididae). Pest Management Science. Vol. 70: 879-888. https://doi.org/10.1002/ps.3674
