Grasshoppers thrive in warm, dry conditions. The first adult two-striped grasshoppers of 2023 were reported in southern Alberta and Saskatchewan in the last 5 days, although the majority the grasshopper population are still nymphs. Signs of damage in the roadsides and field edges are being reported. Now is the time to scout for grasshoppers in your fields.
Diamondback moths develop rapidly when it is warm and their population densities can build up quickly with each generation. Like other insects, bertha armyworm development is also well ahead of schedule. Other green caterpillars, like clover cutworm and alfalfa looper, might also be found in canola crops at this time of year. Correctly identifying green caterpillars is important to ensure the correct economic thresholds (where available) and management tactics are used.
This year could be an interesting year for wheat midge. Some areas have had sufficient rain to trigger the end of diapause and the completion of larval and pupal development, but crop staging is also widely variable. Scouting for wheat midge will be important in the next few weeks.
This week, the Insect of the Week featured the cereal leaf beetle, a pest of cereal crops. Next week, we will feature a very important natural enemy of cereal leaf beetle, the parasitoid Tetrastichus julis.
Remember, insect Monitoring Protocols containing information about in-field scouting as well as information about insect pest biology and identification.
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.
This past week (June 12-18, 2023), the prairie average daily temperature was 1.8°C warmer than normal (Fig. 1). The warmest temperatures were observed across southern Manitoba and Saskatchewan and the coolest temperatures occurred across the Peace River region of British Columbia and Alberta.
Figure 1. Seven-day average temperature (°C) observed across the Canadian prairies for the period of June 12-18, 2023.
Average temperatures over the past 30 days (May 20 to June 18, 2023) have been 4°C above normal with the warmest temperatures being reported across Manitoba and Saskatchewan (Fig. 2).
Figure 2. 30-day average temperature (°C) across the Canadian prairies for the period of May 20 to June 18, 2023.
Rainfall events were observed across the prairie region in the last week. The 7-day cumulative rainfall was 80-95mm in a region around Edmonton, Alberta (Fig. 3). Areas west of Edmonton that were evacuated due to forest fires are now flooded.
Figure 3. Seven-day cumulative rainfall (mm) observed across the Canadian prairies for the period of June 12 – 18, 2023.
The greatest 30-day rainfall totals (90-140mm) were reported from Red Deer to Grande Prairie, Alberta for the period from May 20 to June 18, 2023 (Fig. 4). Rainfall totals continue to be lowest across the southern prairies.
Figure 4. 30-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 20 to June 18, 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, as represented in the scatter plot (Fig. 5). Grande Prairie and Lacombe, Alberta have generally been cooler and wetter than most other locations across the prairies, while locations in Manitoba have experienced mostly warm and dry weather so far in 2023.
Figure 5. Site-specific comparison of 30-day average temperature (°C) and cumulative rainfall (mm) observed across the Canadian prairies for the period of May 20 to June 18, 2023. The red line indicates the average temperature and the blue line represents the average rainfall for the period of May 20 to June 18, 2023.
‘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.
Mexico, California and Texas: This week (June 14 – 20, 2023), no reverse trajectories originating over Mexico, California, or Texas, were predicted to pass over the prairies.
Pacific Northwest (Idaho, Oregon, Washington): This week, 90 reverse trajectories were predicted to cross the prairies. The majority of Pacific Northwest reverse trajectories were reported to pass over Alberta and western Saskatchewan (Fig. 1).
Figure 1. 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, 2023.
Oklahoma and Texas: This week only one (1) reverse trajectory that originated over Texas and Oklahoma was predicted to pass through the prairies, near Selkirk, Manitoba (Fig. 2).
Figure 2. The total number of dates with reverse trajectories originating over Oklahoma and Texas that have crossed the prairies between April 1 and June 20, 2023.
Kansas and Nebraska: This week there were 9 reverse trajectories, originating over Kansas and Nebraska, that were predicted to pass over Saskatchewan and Manitoba (Fig. 3).
Figure 3. The total number of dates with reverse trajectories originating over Kansas and Nebraska that have crossed the prairies between April 1 and June 20, 2023.
Model simulations were used to estimate development of grasshoppers as of June 18, 2023. Warm temperatures continue to promote rapid grasshopper development. Model runs suggest that this spring’s hatch is 99% complete. As of June 18, grasshoppers should range from first to fourth instars. Based on average instar, development is most advanced across the southern prairies where 70% of the population is predicted to be third and fourth instars (Fig. 1). The model indicates that grasshopper development should be most advanced near Morden, Manitoba and Kindersley, Saskatchewan.
Figure 1. Predicted grasshopper (Melanoplus sanguinipes) development, presented as average instar, across the Canadian prairies as of June 18, 2023.
Entomologists across western Canada are closely watching the grasshopper situation. The first adult two-striped grasshopper was found in southern Alberta on June 15 (first reported on Twitter by Dr. Dan Johnson, University of Lethbridge) and in southern Saskatchewan on June 20 (reported by Taylor Dzikowski and Ross Weiss, both from AAFC-Saskatoon).
Geospatial maps, like that in Fig. 1, are tools to help time in-field scouting on a regional scale. However, grasshopper development can vary from region to region and from field to field. To best assess local grasshopper development, scouting is required. In Saskatchewan, grasshoppers have already been observed in field crops in some regions and there have been reports of spraying for grasshoppers in some areas. Scout or monitor grasshopper populations in roadsides and field margins to assess the development and densities of local grasshopper populations.
Diamondback moths (Plutella xylostella) were first found on pheromone traps across western Canada in early May in 2023. After the first migrant adults arrive, there can be multiple non-migrant populations of diamondback moth, with the population density potentially increasing with each generation. Average development, based on climate normals, suggests that diamondback moths should be in the first non-migrant generation. However, diamondback moth development can be rapid during periods of warm weather, such as we have experienced across most of western Canada so far this spring. As a result, model simulationsto June 18, 2023, indicate that prairie diamondback moth populations are now in the second non-migrant generation (Fig. 1).
Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of June 18, 2023.
Local scouting is needed to determine if diamondback moths 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.
The life stages of diamondback moth: A) eggs, B) early instar larva, C) later instar larva, D) pupa, and E) adult. Picture credit: Jonathon Williams, AAFC-Saskatoon.
Based on model simulations, bertha armyworm development continues to be 7-10 days ahead of normal. Where present, females should have already begun to lay eggs (Fig. 1).
Figure 1. Proportion (% of total population) of the bertha armyworm (Mamestra configurata) population that is expected to be in the egg stage across the Canadian prairies as of June 18, 2023.
In some areas, first instar larvae (caterpillars) may be present (Fig. 2).
Figure 2. Proportion (% of total population) of the bertha armyworm (Mamestra configurata) population that is expected to be in the larval stage across the Canadian prairies as of June 18, 2023.
This week there have been some reports of large green caterpillars on canola crops in Alberta and Saskatchewan. The green caterpillars are too advanced in their development to be bertha armyworm. These are more likely to be alfalfa looper or clover cutworm. This week, a Canola Watch quiz challenges us to identify ‘green worms‘ in oilseed crops and provides excellent information about how to tell the difference between bertha armyworm, alfalfa looper, diamondback moth, clover cutworm, and cabbageworm.
Wheat midge (Sitodiplosis mosellana) overwinter as larval cocoons in the soil. Soil moisture conditions in May and June largely determine whether or not larvae exit cocoons to move to the soil surface to continue development (i.e., to pupate then emerge as adults 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 and June.
Cumulative rainfall from May 1-June 18, 2023 across western Manitoba, most of Saskatchewan, and northwestern Alberta now exceeds the threshold (30 mm) required to terminate larval diapause. Though late, the rainfall event last week in the Edmonton region of Alberta may promote movement of larvae to the soil surface.
The wheat midge model indicates that, where wheat midge populations are present, larvae have begun to move to the soil surface (Fig. 1).
Figure 1. Proportion (%) of the larval population of wheat midge (Sitodiplosis mosellana) that is expected to have moved to the soil surface across western Canada, as of June 18, 2023.
Pupae are expected to be in the soil in the Peace River region, localized areas of Saskatchewan, and southwestern Manitoba (Fig. 2).
Figure 2. Proportion (%) of the wheat midge (Sitodiplosis mosellana) population that is predicted to be in the pupal stage in western Canada, as of June 18, 2023.
Model output suggests that first adults may be appearing in fields in southeastern Saskatchewan and southwestern Manitoba this week. Dr. Tyler Wist reports that adult wheat midge have been found on sticky cards baited with pheromone lures, including at the AAFC research farm in Saskatoon.
Scouting for adult wheat midge should start now. Over the next few weeks, the Prairie Pest Monitoring Network will continue to use phenology models to predict the status of wheat midge development and will provide additional updates.
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.
New issues of the Saskatchewan Crop Production News are coming soon in 2023. Use the link to browse the articles from 2022 or subscribe to receive new issues of the newsletter as they are published online.
Weekly Manitoba Crop Pest Updates for 2023 are available online with timely updates about insect pests, weeds, and plant pathogens. Watch their website for new Crop Pest Updates (usually published on Wednesdays this year).
The cereal leaf beetle (Oulema melanopus) is an invasive insect pest that feeds on oat, barley, corn, rye, triticale, reed canary grass, ryegrass, fescue, wild oat, and millet, though wheat is their preferred host. Originally from Europe, it is now found in most cereal production areas in North America. The cereal leaf beetle can be found in parts of Manitoba, Saskatchewan, and Alberta.
Adult cereal leaf beetle. Photo credit: Boris Loboda.
Adult cereal leaf beetles are about 6 mm long and bear striking coloration with an orange-red thorax, yellow-orange legs, and a metallic blue head and wing covers. Adults overwinter in field debris in the fall, typically emerging in mid-April to May in the Canadian prairies to feed and lay their eggs. Cereal leaf beetle eggs are laid singly or in clusters of two or three along upper leaf surfaces, close to the margins or mid-rib. Initially appearing bright yellow, eggs darken to orange-brown and then black before hatching.
Cereal leaf beetle larva. Photo credit: Dr. John Gavloski
Larvae are the most damaging stage of this insect, feeding on upper leaf surfaces. Larval damage appears in pale lines similar in appearance to window-panes. Severe damage is similar to frost damage, where the leaves appear white and can also be mistaken for slug damage. Larvae are yellow in color with a brown head but may appear black like an oil droplet. Black coloration results from a defense mechanism, where larvae smear themselves with a fecal coating to mask their vibrant coloration and reduce predation. After feeding for 10 to 14 days, larvae drop to the soil, entering a pre-pupal and then pupal stage. Larvae pupate below the soil near the host plant’s roots for three weeks, after which they emerge as adults to feed and move to overwintering sites.
Cereal leaf beetle damage to a cereal crop. Photo credit: Bob Hammon, Colorado State University, bugwood.org
Monitoring for this pest should first occur in the spring, when producers should be on the lookout for adults emerging to feed. Scouting continues throughout the spring and summer, before and during the boot stage to assess cereal leaf beetle populations. Egg and larval scouting should be conducted at 5 to 10 random sites throughout the field, at least three meters from the edge. 10 consecutive plants should be inspected at each location, with the number of eggs and larvae counted per plant (before tillering) or per stem (after tillering). Following this, the average number of eggs and larvae is calculated per plant. Economic thresholds have not been established in Canada but have been established for Montana and North Dakota.
Tune in next week to learn about the cereal leaf beetle’s natural enemy – Tetrastichus julis!
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 (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.
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.
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.
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.
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
Week 7 and things are about to get really busy for in-field scouting! Be sure to catch the Insect of the Week – it’s wheat midge! This week find updates to predictive model outputs for grasshoppers, wheat midge, bertha armyworm, cereal leaf beetle, alfalfa weevil, and diamondback moth plus a lot more to help prepare for in-field scouting!
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 (June 7-13, 2021), weekly temperatures were above normal and rainfall in eastern Saskatchewan and Manitoba were above normal. The warmest temperatures were observed across Manitoba and Saskatchewan (Fig. 1). Across the prairies, the average 30-day (May 15 – June 13) temperature was 1 °C warmer than climate normal values. Warmest temperatures were observed across southern Manitoba (Fig. 2). The 2021 growing season (April 1 – June 13, 2021) has been characterized by near normal temperatures (Fig. 3).
Figure 1. 7-day average temperature (°C) observed across the Canadian prairies for the period of June 7 -13, 2021.Figure 2. 30-day average temperature (°C) observed across the Canadian prairies for the period of May 15 – June 13, 2021.Figure 3. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1 – June 13, 2021.
PRECIPITATION: This week, the highest rainfall amounts were reported across eastern Saskatchewan and most of Manitoba. Minimal rainfall was reported across most of Alberta (Fig. 4). Rainfall amounts for the period of May 15-June 13 (30-day accumulation) were above normal (150% of long-term average values). Rainfall amounts have been above normal for northeastern Alberta, northwestern and southeastern Saskatchewan, and western Manitoba. Well above normal rain was reported for Lloydminster, Regina, and Brandon regions. Below normal rainfall amounts were reported for the Peace River region and southern Alberta (Fig. 5). Average growing season (April 1 – June 13) precipitation was 116% of normal with the greatest precipitation occurring across eastern Saskatchewan, including Regina and an area extending from Brandon to Winnipeg. Below normal rainfall has been reported across western Saskatchewan and southern Alberta (Fig. 6).
Figure 4 . 7-day cumulative rainfall (mm) observed across the Canadian prairies for the period of June 7 -13, 2021.Figure 5. 30-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 15 – June 13, 2021Figure 6. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1-June 13, 2021.
Access background information for how and why wind trajectories are monitored in this post.
1. REVERSE TRAJECTORIES (RT) Similar to last week, this 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 (DBM), the ECCC models predict air movement, not actual occurrence of diamondback moths. Fields (and DBM traps) should be monitored for DBM adults and larvae.
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 15, 2021.
a. Pacific Northwest (Idaho, Oregon, Washington) – This week (June 11-15, 2021) there were 109 trajectories (versus 106 last week) that crossed Alberta, Manitoba and Saskatchewan (Fig. 2).
Figure 2. 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 15, 2021.
b. Mexico and southwest USA (Texas, California) – Compared to previous years, there has been a noticeable increase in number of trajectories from the southern US. The majority of these trajectories have crossed Manitoba and eastern Saskatchewan (Fig. 3). This week (June 11-15, 2021) there have been 11 trajectories (10 last week) that originated in Mexico or the southwest USA that have crossed the prairies.
Figure 3. The total number of dates with reverse trajectories originating over Mexico, California and Texas and have crossed the prairies between March 24 and June 15, 2021.
c. Oklahoma and Texas – The majority of these trajectories passed over Manitoba and eastern Saskatchewan (Fig. 4). This week (June 11-15, 2021) there were 18 trajectories (13 last week) originating in Oklahoma or Texas that passed over the prairies.
Figure 4. The total number of dates with reverse trajectories originating over Oklahoma and Texas and have crossed the prairies between March 24 and June 15, 2021.
d. Kansas and Nebraska – This week (June 11-15, 2021) there were 20 trajectories (19 last week) that originated in Kansas or Nebraska that passed over the prairies (Fig. 5).
Figure 5. The total number of dates with reverse trajectories originating over Kansas and Nebraska and have crossed the prairies between March 24 and June 15, 2021.
2. FORWARD TRAJECTORIES (FT) a. This week there was a decrease in the number of forward trajectories predicted to cross the prairies (Fig. 6). 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 there will be increased potential for introduction of DBM to the prairies.
Figure 6. 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 15, 2021.
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. Model simulations to June 13, 2021 (using a biofix date of May 15, 2021), indicate that the first generation of non-migrant adults are currently emerging across the Canadian prairies (Fig. 1).
Fig. 1 Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of June 13, 2021.
So far, Manitoba, Saskatchewan, Alberta and the BC Peace are all reporting relatively low numbers of intercepted DBM in pheromone traps (read provincial insect pest report links) despite the fact that favourable wind trajectories have passed over the Canadian prairies from southern regions of North America (review wind trajectory reports for 2021). Even so, once DBM are present in an area, it is important to monitor individual canola fields for larvae. Warm growing conditions can quickly translate into multiple generations in a very short time so use the following photos to help identify larvae (Fig. 2), pupae (Fig. 3), or adults (Fig. 4)!
Monitoring:Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.
Figure 2. Diamondback larva measuring ~8mm long. Note brown head capsule and forked appearance of prolegs on posterior.
The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1 m² (approximately 2-3 larvae per plant). Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).
Figure 3. Diamondback moth pupa within silken cocoon.
Model simulations were used to estimate grasshopper (Melanoplus sanguinipes) development as of June 13, 2021. Average development of eggs is 90 % and well ahead of the long-term average of 80 %. As of June 13, the hatch is predicted to be underway across most of the prairies with a prairie average of 45 % (versus 26 % last week). Hatch rates were greater than 75 % across southern Manitoba, Saskatchewan and Alberta. Development in central and Peace River regions of Alberta has been significantly slower than the rest of the prairies (Fig. 1).
Figure 1. Predicted grasshopper (Melanoplus sanguinipes) hatch (%) across the Canadian prairies as of June 13, 2021.
Development of grasshopper nymphs, based on average instar, is greatest across Manitoba (Fig. 2). Above normal temperatures have resulted in the rapid development of grasshopper populations across Manitoba and Saskatchewan. Grasshopper populations south of Winnipeg are predicted to be mostly in the 3rd and 4th instar stages. Nymph development, as of June 13, 2021, is greater than long-term average values across most of the prairies (Fig. 3).
Figure 2 Predicted grasshopper (Melanoplus sanguinipes) development, presented as the average instar, across the Canadian prairies as of June 13, 2021.Fig. 3. Long-term average predicted grasshopper (Melanoplus sanguinipes) development, presented as the average instar, across the Canadian prairies as of June 15 based on climate normals data.
The model was projected to June 29 to determine potential development at Saskatoon and Winnipeg over the next two weeks. Results suggest that by June 29, Saskatoon populations will primarily be in the third and fourth instar with first appearance of fifth instar nymphs (Fig. 4) whereas near Winnipeg development is predicted to be faster, with populations being mostly in the fourth and fifth instars (Fig. 5). Producers are advised to monitor roadsides and field margins to assess the development and densities of local grasshopper populations.
Figure 4. Predicted development, presented as the average instar, of Melanoplus sanguinipes populations near Saskatoon, Saskatchewan as of June 13, 2021 (projected to June 29, 2021).Figure 5. Predicted development, presented as the average instar, of Melanoplus sanguinipes populations near Winnipeg, Manitoba as of June 13, 2021 (projected to June 29, 2021).
Grasshopper Scouting Steps: ● Measure off a distance of 50 m on the level road surface and mark both starting and finishing points using markers or specific posts on the field margin. ● Start at one end in either the field or the roadside and walk toward the other end of the 50 m, making some disturbance with your feet to encourage any grasshoppers to jump. ● Grasshoppers that jump/fly through the field of view within a one-meter width in front of the observer are counted. ● A meter stick can be carried as a visual tool to give perspective for a one-meter width. However, after a few stops, one can often visualize the necessary width and a meter stick may not be required. Also, a hand-held counter can be useful in counting while the observer counts off the required distance. ● At the endpoint, the total number of grasshoppers is divided by 50 to give an average per meter. For 100 m, repeat this procedure. ● Compare counts to the following damage levels associated with pest species of grasshoppers: 0-2 per m² – None to very light damage 2-4 per m² – Very light damage 4-8 per m² – Light damage 8-12 per m² – Action threshold in cereals and canola 12-24 per m² – Severe damage 24 per m² – Very severe damage For lentils at flowering and pod stages, >2 per m² will cause yield loss. For flax at boll stages, >2 per m² will cause yield loss.
Model simulations to June 13, 2021, indicate that bertha armyworm (BAW) (Mamestra configurata) pupal development is greater than 75% (Fig. 1). Populations are predominantly in the pupal stage (Fig. 2).
Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development (%) across the Canadian prairies as of June 13, 2021.Figure 2. Predicted percent of bertha armyworm (Mamestra configurata) population that is in the pupal stage (% of population) across the Canadian prairies as of June 13, 2021.
Model simulations indicate that BAW adult emergence has begun across southern areas of Manitoba and Saskatchewan (Fig. 3). Based on pupal development, adult emergence should occur across most of the prairies over the next few days.
Figure 3. Predicted percent of bertha armyworm (Mamestra configurata) population that is in the adult stage (% of population) across the Canadian prairies as of June 13, 2021.
Model projections to June 30 predict that development near Winnipeg is more advanced than at Lacombe (Figs. 4 and 5). The model predicts that oviposition has begun near Winnipeg and that egg hatch will begin next week in fields.
Figure 4. Predicted development of bertha armyworm (Mamestra configurata) populations near Winnipeg, Manitoba as of June 13, 2021 (projected to June 29, 2021).Figure 5. Predicted development of bertha armyworm (Mamestra configurata) populations near Lacombe, Alberta as of June 13, 2021 (projected to June 29, 2021).
Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting. Use the images below (Fig. 6) to learn to identify the various stages. Review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm!
Figure 6. The egg stage (A), larval stage (B), pupal stage (C), and adult stage (D) of bertha armyworm. Photos: Jonathon Williams (AAFC-Saskatoon).
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 cereal leaf beetle (CLB) (Oulema melanopus) model predicts that larval development varies across the prairies. The graph predicts development at Lethbridge (Fig. 1). The simulation indicates that populations in southern Alberta should be in the second and third instar. The appearance of pupae is expected to occur by the end of the month across southern Alberta.
Figure 1. Predicted status of cereal leaf beetle (Oulema melanopus) populations near Lethbridge, Alberta as of June 13, 2021 (projected to June 29, 2021).
Cereal leaf beetle scouting
Give priority to the following factors when selecting monitoring sites: □ Choose fields and sections of the fields with past or present damage symptoms. □ Choose fields that are well irrigated (leaves are dark green in color), including young, lush crops. Areas of a field that are under stress and not as lush (yellow) are less likely to support CLB. □ Monitor fields located along riparian corridors, roads and railroads. □ Survey field areas that are close to brush cover or weeds, easy to access, or are nearby sheltered areas such as hedge rows, forest edges, fence lines, etc.
Focus site selection on the following host plant priorities: □ First – winter wheat. If no winter wheat is present then; □ Second – other cereal crops (barley, wheat, oats, and rye). If no cereal crops are present then; □ Third – hay crops. If no hay crops or cereal crops are present then; □ Fourth – ditches and water corridors
Sweep-net Sampling for Adults and Larvae: ● A sweep is defined as a one pass (from left to right, executing a full 180 degrees) through the upper foliage of the crop using a 37.5 cm diameter sweep-net. ● A sample is defined as 100 sweeps taken at a moderate walking pace collected 4-5 meters inside the border of a field. ● At each site, four samples should be collected, totaling 400 sweeps per site. The contents of each sample should be visually inspected for life stages of CLB and all suspect specimens should be retained for identification. ● Because the CLB larvae are covered in a sticky secretion, they are often covered in debris and are very difficult to see within a sweep-net sample. ● To help determine the presence of CLB, place the contents of the sweep net into a large plastic bag for observation.
Visual Inspection: Both the adults and larvae severely damage plants by chewing out long strips of tissue between the veins of leaves (Fig. 1), leaving only a thin membrane. When damage is extensive, leaves turn whitish.
Lifecycle and Damage:
Larva: The larvae hatch in about 5 days and feed for about 3 weeks, passing through 4 growth stages (instars). The head and legs are brownish-black; the body is yellowish. Larvae are usually covered with a secretion of mucus and fecal material, giving them a shiny black, wet appearance (Fig. 2). When the larva completes its growth, it drops to the ground and pupates in the soil.
Figure 2. Larval stage of Oulema melanopus with characteristic feeding damage visible on leaf (Photo: M. Dolinski).
Pupa: Pupal colour varies from a bright yellow when it is first formed, to the colour of the adult just before emergence. The pupal stage lasts 2 – 3 weeks. Adult beetles emerge and feed for a couple of weeks before seeking overwintering sites. There is one generation per year.
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). 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. 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.
Figure 3. Adult Oulema melanopus measure 4.4-5.5 mm long (Photo: M. Dolinski).
Model simulations for alfalfa weevil (AAW) (Hypera postica) predict, as of June 13, that alfalfa weevil populations should be in the third larval instar (Fig. 1). Fourth instar larvae are predicted to occur across southeastern Saskatchewan and southern Manitoba.
Figure 1. Predicted percent of Hypera postica (alfalfa weevil) population in the third instar stage as of June 13, 2021.
The following graphs indicate that development is more advanced near Brandon (Fig. 2) than Swift Current (Fig. 3). Simulation runs indicate that by June 29, southern Manitoba populations will be in pupal stage whereas Swift Current populations are predicted to be in the fourth instar and pupal stages.
Figure 2. Predicted status of alfalfa weevil (Hypera postica) development for populations near Brandon, Manitoba as of June 13, 2021 (projected to June 29, 2021).Figure 3. Predicted status of alfalfa weevil (Hypera postica) development for populations near Swift Current, Saskatchewan as of June 13, 2021 (projected to June 29, 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).
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
Based on averages across the three provinces, 56% of the wheat midge population is predicted to be in the larval cocoon stage (in the soil) and 44% of the larvae have moved to the soil surface. As a result of suitable temperature and rainfall, wheat midge model simulations indicate that more than 70% of the larval population has moved to the soil surface in central Alberta and northwestern and southeastern Saskatchewan (Fig. 1). Dryer conditions in Manitoba and the Peace River region continue to delay the movement of larvae to the soil surface.
Figure 1. Percent of the wheat midge (Sitodiplosis mosellana) larval population that has moved to the soil surface across western Canada, based on weather conditions up to June 13, 2021.
More information about wheat midge can be found by accessing the pages from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide”. View ONLY the Wheat midge pages but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.
Aphids can cause significant damage to fields and increase crop losses but low densities in a grain field sometimes have little economic impact on production. This is especially true if the aphid’s natural enemies (beneficial insects) are present in the field because they can keep the aphids under control.
The Cereal Aphid Manager is an easy-to-use mobile app that helps farmers and crop advisors control aphid populations in wheat, barley, oat or rye. It is based on Dr. Tyler Wist’s (AAFC-Saskatoon) Dynamic Action Threshold model. The model treats the grain field as an ecosystem and takes into account many complex biological interactions including:
the number of aphids observed and how quickly they reproduce
the number of different natural enemies of aphids in the field and how many aphids they eat or parasitize per day
the lifecycles of aphids and their enemies taking into account developmental stages, egg laying behaviour, population growth rate, lifespan, etc.
Frequent in-field scouting, supported by the app’s dynamic threshold, allows growers to weigh the above factors and the app predicts what the aphid population will be in seven days and the best time to apply insecticide based on economic thresholds.
To learn more and to download the app (Android or iOS), go to AAFC’s CAM webpage.
The European corn borer (ECB; Ostrinia nubilalis), has been an important pest of corn and other crops in eastern Canada for nearly a century now but is also known to be a sporadic pest in western Canada. Despite its name, ECB is actually a generalist feeder, having a wide range of hosts. With so many new emerging crops being grown in Canada that are also hosts for ECB (eg. hemp, cannabis, quinoa, hops, millet and others), there is no better time to look at this pest across the Canadian agricultural landscape.
To monitor for ECB nationwide, the Surveillance Working Group of the Canadian Plant Health Council has developed a harmonized monitoring protocol for European corn borer in both English and French. The project aims to generate real-time reporting and annual maps – access a full description of the project and list of key contact persons. The protocol can be used to report ECB eggs, larvae or damage in any host crop across Canada. This harmonized protocol has been designed to complement protocols already in use to make management decisions in order to generate data to compare ECB presence across all of Canada and across host crops.
When scouting corn, quinoa, hemp, millet, potatoes, apples, or other crops susceptible to ECB, the Surveillance Working Group of the Canadian Plant Health Council encourages the use of the harmonized monitoring protocol and reporting of the data from fields or research plots using the free Survey123 app (available for both desktop and mobile devices): • Early to Mid-Season ECB Survey (Before July) – https://arcg.is/0qCCHH (applicable for use in eastern Canada). • Later Season ECB Survey (July to Pre-Harvest) – https://arcg.is/fSODf (applicable for use in both eastern AND western Canada).
The NEW Pests and Predators Field Guide is 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!
Track the migration of the Monarch butterflies as they move north by checking the 2021 Monarch Migration Map! A screenshot of the map has been placed below as an example (retrieved 17Jun2021) but follow the hyperlink to check the interactive map. They’ve reached Saskatchewan and southern Alberta!
Provincial entomologists provide insect pest updates throughout the growing season so link to their information:
MANITOBA’SCrop Pest Updates for 2021 are now available – access the June 16, 2021 report here. Be sure to bookmark their Crop Pest Update Index to readily access these reports! Also, bookmark their insect pest homepage to access fact sheets and more! • Bertha armyworm pheromone trap monitoring update for MB – Cumulative counts arising from weekly data will soon be available. • Diamondback moth pheromone trap monitoring update for MB – Refer to the summary updated twice a week. So far, only 59 traps have intercepted moths and the highest cumulative count is 135 moths near The Pas. Access the summary (as of June 8, 2021).
SASKATCHEWAN’SCrop Production News have begun to roll out for 2021 and are accessible now! Access Issue #1 online which includes a crop protection laboratory update including how to submit samples, information on curculios on fruit crops, and information for scouting flea beetles and assessing damage. Be sure to bookmark their insect pest homepage to access important information! • Bertha armyworm pheromone trap monitoring update for SK – Cumulative counts arising from weekly data will soon be available. • 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. Province-wide, <45 moths have been intercepted so far (2021Jun10 Carter, pers. comm.).
ALBERTA’SInsect Pest Monitoring Network webpage links to insect survey maps, live feed maps, and 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 or 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 starting to roll in so refer to the Live Map as data becomes available. • Diamondback moth pheromone trap monitoring update for AB – Refer to the Live Map which still reports extremely low numbers of moths intercepted so far (<45 province-wide as of 17Jun2021). • Cutworm reporting tool – Refer to the Live Map which still reports only four sites with cutworms (as of 17Jun2021).
This week’s Insect of the Week is the wheat midge. Found around the globe where wheat is grown, these small insects can pose a big problem for producers. Sizeable crop damage has been attributed to wheat midge populations across the Prairies, where it feeds on spring, winter and durum wheat, as well as triticale and spring rye.
Crop damage occurs when the wheat midge is in its larval stage. Once hatched, the wheat midge larvae eat developing wheat kernels, causing shrivelled, misshapen, cracked or scared kernels. This damage isn’t apparent at a glance and developing seeds must be inspected within the glume. Losing wheat kernels will lower crop yield, while damaged kernels will impact the grade given to the harvested wheat. The Canadian Grain Commission allows midge damage between two and five percent prior to impacting the assigned grade.
Wheat midge adult (AAFC)
Adult wheat midges are delicate orange flies that grow to 2–3 mm long, with large black eyes and long legs and antennae in relation to their otherwise small size. Mature larvae grow to 2–3 mm long. Young larvae begin as translucent white maggots and turn bright orange during the maturation process.
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.
This time it’s a BIG Weekly Update – several predictive model updates have been generated this week! Find updated information for bertha armyworm, grasshoppers, cereal leaf beetle, alfalfa weevil, wheat midge and pea leaf weevil. A new Pests & Predators podcast is available and much more. Keep scrolling down and it’s time to get in fields to scout!
This week’s Insect of the Week feature crop is barley, an important Prairie cereal (and not just because it’s an essential ingredient for beer). Our feature entomologist this week is John Gavloski (Manitoba Agriculture and Resource Development).
Barley Crop cc by 2.0 Ian Britton
Without barley, there would be no beer. And the world wept. Thankfully, plenty of barley is grown on the Prairies, not just for beer but also as feed. Roughly 96% of the barley grown on the Prairies is split equally between Alberta and Saskatchewan. In 2019, total Prairie production on 2.85 million hectares (7.05 million acres) was 9.93 million metric tonnes (10.95 million US tons).
Name: John Gavloski Affiliation: Manitoba Agriculture and Resource DevelopmentContact Information: John.Gavloski@gov.mb.ca, @Johnthebugguy
How do you contribute in insect monitoring or surveillance on the Prairies?
I organize annual monitoring programs for diamondback moth, bertha armyworm and grasshoppers in Manitoba. I am also currently monitoring the distribution and levels of cabbage seedpod weevil and pea leaf weevil in Manitoba.
In your opinion, what is the most interesting field crop pest on the Prairies?
Grasshoppers, as a group of insects, are quite interesting. In Canada there are about 180 species of grasshoppers, but only a few cause economic damage to crops. I have enjoyed the sights, sounds, and tastes of grasshoppers; yes you read that last part correctly! The pest species like dry conditions. In late-spring or early-summer we often start to see species of grasshoppers with colourful and almost butterfly-like hind wings; when they fly you get flashes of orange, yellow, and black. None of these are pest species, but cool to observe. Others are good mimics, and can blend in with sand, gravel or leaves very well. Late in the summer it is always a treat to hear the singing of grasshoppers, especially the katydids, which are not pests and are usually green with long antennae. And yes, I have eaten grasshoppers, at an entomology conference featuring an insect banquet. I did enjoy them – anything cooked in a flavourful sauce is good, but I suggest removing the wings if you ever try them – too much cuticle. I guess this bout of entomophagy makes me and the other entomologists at the banquet natural enemies of grasshoppers.
What is your favourite beneficial insect?
This is a really tough, as there are so many fascinating beneficial insects! Hover flies are a family of flies (Syrphidae) with many beneficial and interesting attributes. They are predators, pollinators, masters of mimicry, and it is fun to watch the larvae feed. There are 539 species of hover flies in Canada. Adults are good pollinators that are great at mimicking wasps and bees, come in a variety of sizes, and can often be seen hovering near flowers. The slug-like, legless larvae of many hover flies feed on aphids by impaling an aphid with its mouthparts, holding it up, sucking the fluids out of the body, and discarding the exoskeleton. It makes for a great show. I try to raise awareness about hover flies so that people know they are not wasps or bees, cannot sting and are beneficial in many ways.
Tell us about an important project you are working on right now.
I am tracking the distribution and densities of cereal leaf beetle in Manitoba. It was first found in the northwest region of Manitoba in 2009. A small parasitic wasp called Tetrastichus julis was introduced shortly after cereal leaf beetles were detected. I have been tracking the spread and densities of both the pest and the parasitoid across Manitoba. Cereal leaf beetle larvae are sent to AAFC-Lethbridge where they are dissected to determine the level of parasitism. If the level is low, parasitoids are sent to me for release in Manitoba in areas where they may be lacking. I will be assessing levels of cereal leaf beetle larvae again this year, and hopefully releasing more wasps if needed.
What tools, platforms, etc. do you use to communicate with your stakeholders?
I enjoy doing presentations for academics, producers, agronomists, and the general public. I co-produce the Manitoba Crop Pest Update from May through August. This is an opportunity to communicate current types and levels of insect activity in Manitoba. I like producing factsheets, for pests and beneficial insects, that are available on our department’s website. An information campaign that has been fun to contribute to is “Field Heroes”, which provides information to help raise awareness and provide information about beneficial insects. Until several of the rural newspapers in Manitoba closed recently, I produced a monthly column called “Incredible Creatures” that several of the rural newspapers carried.
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.
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 21, 2019, Weekly Cereal Rust Risk Report: Wind trajectory and cereal rust risk assessment and need for in-crop scouting in the Prairie region, May 21, 2019.
1. Pacific Northwest – Given limited stripe rust development in the PNW, a low number of recent wind trajectories from the PNW, cool and relatively dry Prairie weather conditions, and early stages of Prairie crop development, as of May 21, 2019, the risk of stripe rust appearance from the PNW is limited and scouting for this disease is not urgent.
2. Texas-Oklahoma corridor – Although leaf and stripe rust development continues in this corridor, especially Oklahoma, the disease is mainly affecting the lower canopy at generally low levels. In addition, crops are advancing towards maturity and thus will become less of a source of rust inoculum. There have been a low number of recent wind trajectories from this area, cool and relatively dry Prairie weather conditions, and early stages of Prairie crop development. Thus, as of May 21, 2019 the risk of leaf and stripe rust appearance from the Texas-Oklahoma corridor is low and scouting for these diseases is not urgent.
3. Kansas-Nebraska corridor – Although leaf and stripe rust development continues in this corridor, it is at low-moderate levels and mainly in the middle portions of crop canopies, recent moisture conditions may promote further development. There have been a low number of recent wind trajectories from this area, cool and relatively dry Prairie weather conditions, and early stages of Prairie crop development. Thus, as of May 21, 2019 the risk of leaf and stripe rust appearance from the Kansas-Nebraska corridor is low and scouting for these diseases is not urgent, but further development of rust in these regions may increase the risk.
4. 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.
Weather synopsis – This past week (May 8-15, 2019) the average temperature was approximately 1 °C cooler than normal (Fig. 1). The warmest temperatures were observed in AB and with conditions much cooler in SK and MB.
This week, May 15-21, 2019, cool, dry conditions continued to occur across the prairies. Though temperatures are warming up, early growing season daily average temperatures continue to be cooler than normal. This past week the average temperature was approximately 2.5 °C cooler than normal (Fig. 2). The warmest temperatures were observed in central AB, southeast SK and southwest MB (Fig. 2).
Figure 1. Average Temperature (°C) across the Canadian prairies the past seven days (May 15-21, 2019). Figure 2. Average Temperature (°C) across the Canadian prairies the past 30 days (April 21-May 21, 2019).
Average 30 day temperatures were approximately 3 °C cooler than average (Fig. 3). Across the prairies, average temperatures (April 23 – May 20, 2019) were 2 to -3 °C below normal with central SK having temperatures that were 3 to 4 °C cooler than average with well below average temperatures occurring in a large area of central SK.
Figure 3. Mean temperature differences from Normal across the Canadian prairies from April 23-May 20, 2019. Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (21May2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
This week (May 15-21, 2019), the seven-day cumulative rainfall indicated that minimal rain was observed across large areas of SK (Fig. 4). Most locations reported less than 5 mm. Wetter conditions were reported in a corridor between Lethbridge and Calgary AB.
Figure 4. Cumulative precipitation observed the past seven days across the Canadian prairies (May 15-21, 2019).
Across the prairies, rainfall amounts for the past 30 days (April 21-May 21, 2019) have been approximately 50% of normal (Fig. 5). Rainfall in southwest SK has increased. Between Brandon MB and Lloydminster SK 30-day rainfall amounts are well below average (Fig. 5). Growing season rainfall (April 1 – May 21) amounts have been well below average for most of the prairies, particularly in west central SK and eastern regions of AB (Fig. 6). For this growing season, almost all of the prairies have received rainfall that is 85 percent or less than average (Fig. 7).
Figure 5. Cumulative precipitation observed the past 30 days across the Canadian prairies (April 21-May 21, 2019). Figure 6. Cumulative precipitation observed for the growing season across the Canadian prairies (April 1-May 21, 2019). Figure 7. Percent of Average precipitation across the Canadian prairies for the growing season (April 1-May 21, 2019). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (21May2019). 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 most of the prairies. Near normal soil moisture is predicted to occur in an area extending from Swift Current, west to Lethbridge and north to Edmonton and Grande Prairie (Fig. 8).
Figure 8. Modeled soil moisture (%) across the Canadian prairies (up to May 21, 2019).
The growing degree day map (GDD) (Base 5 ºC, April 1-May 20, 2019) is below (Fig. 9):
Figure 9. Growing degree day (Base 5 ºC) across the Canadian prairies for the growing season (April 1-May 20, 2019). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (22May2019). 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, April 1-May 15, 2019) is below (Fig. 10):
Figure 10. Growing degree day (Base 10 ºC) across the Canadian prairies for the growing season (April 1-May 20, 2019). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (22May2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
The lowest temperatures (°C) observed the past seven days range from -10 to 2 °C in the map below (Fig. 11).
Figure 11. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (May 14-20, 2019). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (22May2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
The highest temperatures (°C) observed the past seven days range from -10 to 2 °C in the map below (Fig. 12).
Figure 12. Highest temperatures (°C) observed across the Canadian prairies the past seven days (May 14-20, 2019).Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (22May2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
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.
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.
Model output indicates that alfalfa weevil hatch has begun and first instar alfalfa weevils should be present across most of AB (Fig. 1). Model runs for Brooks AB (Fig. 2) and Swift Current SK (Fig. 3) were projected to June 15, 2019. Second instar larvae will begin to occur late next week in fields near Brooks and 3-5 days later in the Swift Current region.
Figure 1. Predicted percent of alfalfa weevil (Hypera postica) populations at first instar stage across the Canadian prairies (as of May 21, 2019). Figure 2. Projected predicted status of alfalfa weevil populations near Brooks AB to June 15, 2019, using long term average temperatures. Figure 3. Projected predicted status of alfalfa weevil populations near Swift Current SK to June 15, 2019, using long term average temperatures.
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) – Model runs for Red Deer AB (Fig. 1) and Swift Current SK (Fig. 2) were projected to June 15, 2019. Results indicated that oviposition should begin at the end of May. Model predictions, based on long term normal weather data, predict that initial hatch near Saskatoon should occur on May 29th.
Figure 1. Projected predicted status of pea leaf weevil populations near Red Deer AB to June 15, 2019 using long term average temperatures. Figure 2. Projected predicted status of pea leaf weevil populations near Swift Current SK to June 15, 2019 using long term average temperatures.
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 CLB model was run for Lethbridge AB (Fig. 1), Brandon MB (Fig. 2), and Grande Prairie AB (Fig. 3) and projected to June 15, 2019. The cereal leaf beetle model indicates that eggs may begin to hatch later next week in Lethbridge (Fig. 1) and Brandon (Fig. 2). Hatch is predicted to be 4-7 days later in the Peace River region (Fig. 3).
Figure 1. Projected predicted status of cereal leaf beetle populations near Lethbridge AB to June 15, 2019, generated using long term average temperatures. Figure 2. Projected predicted status of cereal leaf beetle populations near Brandon MB to June 15, 2019, generated using long term average temperatures. Figure 3. Projected predicted status of cereal leaf beetle populations near Grande Prairie AB to June 15, 2019, generated using long term average temperatures.
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).
As of May 21, 2019, predicted grasshopper egg development was 66% (63% last week) and is similar to long term average values (68%) (Fig. 1).
Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 21, 2019. Figure 2. Predicted percent of grasshopper (Melanoplus sanguinipes) population at first instar stage across the Canadian prairies (as of May 21, 2019).
Model runs for Grande Prairie (Fig. 3), Lethbridge (Fig. 4) and Saskatoon (Fig. 5) were projected to June 15, 2019. Results for Lethbridge (Fig. 4) and Saskatoon (Fig. 5) indicated that eggs should begin to hatch this week. Hatch in the Peace River region is predicted to be approximately one week later. Results also indicated that initial hatch (less than 6%) should have occurred in southwest SK and southeast AB.
Figure 3. Predicted status of Melanoplus sanguinipes populations near Grande Prairie AB as of May 21, 2019. Figure 4. Predicted status of Melanoplus sanguinipes populations near Lethbridge AB as of May 21, 2019. Figure 5. Predicted status of Melanoplus sanguinipes populations near Saskatoon SK as of May 21, 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.
• 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.
Public summer field events – Coming to a field near you – Our field crop entomologists are already scheduled to be at these 2019 field tour events from May-August (be sure to re-confirm dates and details as events are finalized):
• June 6, 2019. Farming Smarter crop walk or plot hop if you are a flea beetle! Access event information. Entomologist participating: Hector Carcamo
• June 20, 2019: Solstice Forage and Crops Field Tour to be held at the Beaverlodge Research Farm (Beaverlodge AB). View event info/registration details. Entomologists tentatively participating: Jennifer Otani, Keith Uloth
• June 26, 2019: 2019 CanolaPALOOZA to be held at the Lacombe Research and Development Centre (Lacombe AB). View event info/registration details. Entomologists tentatively participating: Jennifer Otani, Amanda Jorgensen, Meghan Vankosky, Scott Meers, Shelley Barkley, Patty Reid, Sunil Shivananjappa, Hector Carcamo, Julie Soroka, Mark Cutts, Jim Tansey, Sherrie Benson and the Junior Entomologists.
• July 9-12, July 16-18, 2019: Crop Diagnostic School. Held at the University of Manitoba Research Farm at Carman, Manitoba. An 2-week diagnostic school will complete units on entomology, plant pathology, weed science, soil fertility, pulse crop production, and oilseed production. View registration and event information. Entomologists participating: John Gavloski and Jordan Bannerman.
• July 9, 2019: CanolaPALOOZA Saskatoon, to be held at the SRDC Llewellyn Farm. Read more about this event. Entomologists presenting: Tyler Wist, James Tansey, Greg Sekulic, Meghan Vankosky
• July 23-24, 2019: Crop Diagnostic School, Scott Saskatchewan. Read more about this event. Entomologists presenting: Meghan Vankosky, Tyler Wist.
• July 24, 2019: Crops-a-Palooza. Held at Canada-Manitoba Crop Diversification Centre (CMCDC), Carberry, Manitoba. Read more about this event. Entomologist participating: John Gavloski, Vincent Hervet, Tharshi Nagalingam, Bryan Cassone.
• August 8, 2019: 2019 Wheatstalk to be held at Teepee Creek AB. View event info/registration details. Entomologists tentatively participating: Jennifer Otani, Amanda Jorgensen.
• August 8, 2019. Horticulture School. Agriculture and Agri-Food Canada Research Farm, Portage la Prairie, Manitoba. Entomologist presenting: John Gavloski, Kyle Bobiwash.
(This week’s post is provided by Dr. James Tansey, Saskatchewan Ministry of Agriculture, Provincial Specialist, Insect/Vertebrate Pest Management)
With the onset of the 2019 growing season, we decided to feature an insect that is becoming a growing problem throughout Canada: Spotted Wing Drosophila (SWD), Drosophila suzukii.
Figure 1: Spotted wing drosophila (Drosophila suzukii) adults on raspberry fruit Hannah Burrack, North Carolina State University, Bugwood.org
This invasive insect is thought to have originated in southeast Asia. The first record of SWD is from Japan in 1916. SWD is now established in small and stone fruit production areas throughout North America. SWD has been reported in British Columbia since 2009, and was first reported in Alberta in 2010. Although it has not yet been found in Saskatchewan, occurrence in Alberta and low levels in southern Manitoba suggest that SK infestations are likely imminent. Saskatchewan Ministry of Agriculture will be monitoring for this pest this summer (2019).
SWD is an economic pest of many soft fruits including raspberry, strawberry, cherry, blueberry and plum (Figure 1). Saskatoon berry has been documented as a host. Haskap is also considered susceptible but may escape major damage as SWD populations typically do not increase until after harvest. However, Ontario haskap growers have seen economic losses when a mild winter is coupled with factors that lead to delayed ripening.
SWD adults are 3-4 mm, yellow-brown with red eyes. Males have a conspicuous spot on the leading edge of each wing (Figure 2). Females lack the spots but have a characteristic large, serrated ovipositor (Figure 3).
Figure 2: Spotted wing drosophila (Drosophila suzukii) adult male cc by 2.0 – Martin Cooper
Figure 3: Spotted wing drosophila (Drosophila suzukii) adult female cc by 2.0 – Martin Cooper
SWD overwinter as adults. These become active in the spring, mate and seek egg-laying sites. Female SWD lay as many as 16 eggs per day for up to two months, averaging 384 eggs each. Female SWD deposit eggs with their serrated ovipositor under the skin of healthy, ripening fruit. Oviposition sites look like pin-holes in the skin (Figure 4). These can also serve as avenues of entry to pathogens like brown rot and botrytis. Several larvae can occur per fruit (Figure 5). Larval feeding causes fruit to become prematurely soft and unmarketable. Larvae mature in 3-13 days and pupate most commonly in the fruit. The pupal stage lasts another 3-15 days. Multiple generations per year are common.
Figure 4: Ovipositor scars in cherry fruit from Spotted wing drosophila (Drosophila suzukii) cc by 3.0 – Martin Hauser Phycus
Figure 5: Spotted wing drosophila (Drosophila suzukii) larva Hannah Burrack, North Carolina State University, Bugwood.org
Although SWD adults can be moved around by winds, movement of contaminated plant material is the major route for dispersal. Current management includes culling and destruction of soft fruit and the application of insecticides to established populations. Products registered to control SWD can be on Health Canada’s pesticide label search site (http://pr-rp.hc-sc.gc.ca/ls-re/index-eng.php). Use the search terms ‘spotted wing drosophila’. Product updates occur periodically so check this site regularly.
Weather synopsis – This past week (June 11 – 18, 2018), the average temperature (12.4 °C) was 1 °C cooler than long term average values (Fig. 1). The warmest weekly temperatures occurred across Manitoba. The 30-day (May 19-June 18, 2018) average temperature (13.1 °C) was approximately 1 °C warmer than long term average (Fig. 2).
Figure 1. Weekly (June 11 – 18, 2018) average temperature (°C) . Figure 2. The 30-day (May 19 – June 18, 2018) average temperature (°C).
Weekly and 30-day total precipitation was above average (Figs. 3 and 4). The wettest (30-day) region was across eastern areas in SK and western MB, while western Saskatchewan and most of Alberta are dry.
The map below reflects the Highest Temperatures occurring over the past 7 days (June 5-11, 2018) across the prairies and is available from Agriculture and Agri-Food Canada (Fig. 6).
The map below reflects the Lowest Temperatures occurring over the past 7 days (June 5-11, 2018) across the prairies and is available from Agriculture and Agri-Food Canada (Fig. 7).
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 18, 2018, the model output indicated that the average instar was 2.1 this week (1.7 last week), with 23, 27, 25, 8 and 2% in the 1st, 2nd, 3rd, 4th and 5th instar stages, respectively. The most rapid grasshopper development was predicted to occur across southern Manitoba and southeast Saskatchewan (Fig. 8).
Figure 8. Grasshopper development (average instar) based on model simulations, for April 1 – June 18, 2018.
Model output for Saskatoon illustrates that populations are primarily in the 2nd and 3rd instar stages with 4th and 5th instar stages beginning to appear (Fig. 9). This agrees with this week’s survey conducted between Saskatoon and Rosetown. Melanoplinae adults were collected at a few sites near Saskatoon and eastern Saskatchewan.
Figure 9. Predicted grasshopper phenology at Saskatoon SK. Values are based on model simulations for April 1 – June 18, 2018.
Grasshopper Scouting Steps:
● Measure off a distance of 50 m on the level road surface and mark both starting and finishing points using markers or specific posts on the field margin.
● Starting at one end in either the field or the roadside and walk toward the other end of the 50 m making some disturbance with your feet to encourage any grasshoppers to jump.
● Grasshoppers that jump/fly through the field of view within a one meter width in front of the observer are counted.
● A meter stick can be carried as a visual tool to give perspective for a one meter width. However, after a few stops one can often visualize the necessary width and a meter stick may not be required. Also, a hand-held counter can be useful in counting while the observer counts off the required distance.
● At the end point the total number of grasshoppers is divided by 50 to give an average per meter. For 100 m, repeat this procedure.
● Compare counts to the following damage levels associated with pest species of grasshoppers:
0-2 per m² – None to very light damage
2-4 per m² – Very light damage
4-8 per m² – Light damage
8-12 per m² – Action threshold in cereals and canola
12-24 per m² – Severe damage
>24 per m² – Very severe damage
* For lentils at flowering and pod stages, >2 per m² will cause yield loss.
* For flax at boll stages, >2 per m² will cause yield loss.
Wheat Midge (Sitodiplosis mosellana) – Recent dry conditions near Saskatoon have resulted in slower wheat midge development (compared to last week’s model output). Predictions for 2018 (Fig. 1) are similar to long term average values (Fig. 2).
Figure 1. Predicted wheat midge phenology at Saskatoon SK. Values are based on model simulations for April 1 – June 18, 2018.Figure 2. Predicted wheat midge phenology at Saskatoon SK. Values are based on model simulations for Long Term Climate Normals.
Monitoring:
When monitoring wheat fields, pay attention to the synchrony between flying midge and anthesis.
In-field monitoring for wheat midge should be carried out in the evening (preferably after 8:30 pm or later) when the female midges are most active. On warm (at least 15ºC), calm evenings, the midge can be observed in the field, laying their eggs on the wheat heads (photographed by AAFC-Beav-S. Dufton & A. Jorgensen below). Midge populations can be estimated by counting the number of adults present on 4 or 5 wheat heads. Inspect the field daily in at least 3 or 4 locations during the evening.
REMEMBER that in-field counts of wheat midge per head remain the basis of economic threshold decision. Also remember that the parasitoid, Macroglenes penetrans (photographed by AAFC-Beav-S. Dufton below), is actively searching for wheat midge at the same time. Preserve this parasitoid whenever possible and remember your insecticide control options for wheat midge also kill these beneficial insects which help reduce midge populations.
Economic Thresholds for Wheat Midge:
a) To maintain optimum grade: 1 adult midge per 8 to 10 wheat heads during the susceptible stage.
b) For yield only: 1 adult midge per 4 to 5 heads. At this level of infestation, wheat yields will be reduced by approximately 15% if the midge is not controlled.
Inspect the developing kernels for the presence of larvae and the larval damage.
The 2018 wheat midge forecast map was circulated in January and is posted below for reference. Note that areas highlighted orange or red in the map below included surveyed fields with comparatively higher densities of wheat midge cocoons last fall.
Information related to wheat midge biology and monitoring can be accessed by linking to your provincial fact sheet (Saskatchewan Agriculture or Alberta Agriculture & Forestry). A review of wheat midge on the Canadian prairies was published by Elliott, Olfert, and Hartley in 2011. Additionally, more information can be found by accessing the pages from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide”. View ONLY the Wheat midge pages but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.
Bertha armyworm (Lepidoptera: Mamestra configurata) – BAW development continues to be 7-10 days ahead of normal development (Figs. 1 and 2). Near Saskatoon, oviposition is predicted to be well underway (Fig. 1).
Figure 1. Predicted bertha armyworm phenology at Saskatoon SK. Values are based on model simulations for April 1 – June 18, 2018.
Based on climate data (LTCN), oviposition near Saskatoon should begin the third week of June (Fig. 2).
Figure 2. Predicted bertha armyworm phenology at Saskatoon SK when using Long Term Climate Normal (LTCN) data.
Many thanks to those who are checking a bertha armyworm pheromone trap on a weekly basis. Please use the reference photo below kindly shared by Saskatchewan Agriculture to aid your identification and reporting of trap interceptions. Note the kidney-bean white-patterned shape on each forewing but also know other cutworm species can resemble bertha armyworm moths. Check carefully and thanks for your help!
Monitoring:
Larval sampling should commence once the adult moths are noted.
Sample at least three locations, a minimum of 50 m apart.
At each location, mark an area of 1 m2 and beat the plants growing within that area to dislodge the larvae.
Count them and compare the average against the values in the economic threshold table below:
Scouting tips:
Some bertha armyworm larvae remain green or pale brown throughout their larval life.
Large larvae may drop off the plants and curl up when disturbed, a defensive behavior typical of cutworms and armyworms.
Young larvae chew irregular holes in leaves, but normally cause little damage. The fifth and sixth instar stages cause the most damage by defoliation and seed pod consumption. Crop losses due to pod feeding will be most severe if there are few leaves.
Larvae eat the outer green layer of the stems and pods exposing the white tissue.
At maturity, in late summer or early fall, larvae burrow into the ground and form pupae.
Keep track of the Provincial Entomologist Updates for the latest in-season pheromone trap monitoring results for 2018.
Albertans can access the online reporting map (screenshot retrieved 19Jun2018 provided below for reference:
Lygus bugs (Lygus spp.) – The model indicated that Lygus populations range between the 1st – 4th instar stages with the average being second instar stage. The greatest development is predicted to occur across southern Manitoba and Saskatchewan (Fig. 1). The model suggests that Saskatoon populations consist of first to third instar stages (Fig. 2).
Figure 1. Lygus development (average instar) based on model simulations, for April 1 – June 18, 2018.Figure 2. Predicted Lygus phenology at Saskatoon SK. Values are based on model simulations for April 1 – June 18, 2018.
Remember – The economic threshold for Lygus in canola is applied at late flower and early pod stages.
Adult L. lineolaris (5-6 mm long) (photo: AAFC-Saskatoon).
Fifth instar lygus bug nymph (3-4 mm long) (photo: AAFC-Saskatoon).
Damage: Lygus bugs have piercing-sucking mouthparts and physically damage the plant by puncturing the tissue and sucking plant juices. The plants also react to the toxic saliva that the insects inject when they feed. Lygus bug infestations can cause alfalfa to have short stem internodes, excessive branching, and small, distorted leaves. They feed on buds and blossoms and cause them to drop. They also puncture seed pods and feed on the developing seeds causing them to turn brown and shrivel.
Begin monitoring canola when it bolts and continue until seeds within the pods are firm. Since adults can move into canola from alfalfa, check lygus bug numbers in canola when nearby alfalfa crops are cut.
Sample the crop for lygus bugs on a sunny day when the temperature is above 20°C and the crop canopy is dry. With a standard insect net (38 cm diameter), take ten 180° sweeps. Count the number of lygus bugs in the net.
Repeat the sampling in another 14 locations. Samples can be taken along or near the field margins. Calculate the cumulative total number of lygus bugs and then consult the sequential sampling chart (Figure C). If the total number is below the lower threshold line, no treatment is needed. If the total is below the upper threshold line, take more samples. If the total is on or above the upper threshold line, calculate the average number of lygus bugs per 10-sweep sample and consult the economic threshold table.
Sequential sampling for lygus bugs at late flowering stage in canola.
The economic threshold for lygus bugs in canola covers the end of the flowering (Table 1) and the early pod ripening stages (Table 2). Once the seeds have ripened to yellow or brown, the cost of controlling lygus bugs may exceed the damage they will cause prior to harvest, so insecticide application is not warranted.
Consider the estimated cost of spraying and expected return prior to making a decision to treat a crop.
Remember that insecticide applications at bud stage in canola have not been proven to result in an economic benefit in production. The exception to this is in the Peace River region where early, dry springs and unusually high densities of lygus bug adults can occasionally occur at bud stage. In this situation, high numbers of lygus bugs feeding on moisture-stressed canola at bud stage is suspected to result in delay of flowering so producers in that region must monitor in fields that fail to flower as expected.
Table 1. Economic thresholds for lygus bugs in canola at late flowering and early pod stages (Wise and Lamb 1998).
1 Canola crop stage estimated using Harper and Berkenkamp 1975). 2 Economic thresholds are based on an assumed loss of 0.1235 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).
Table 2. Economic thresholds for lygus bugs in canola at pod stage (Wise and Lamb 1998).
3 Economic thresholds are based on an assumed loss of 0.0882 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).
Biological and monitoring information related to Lygus in field crops is posted by the provinces of Manitoba or Alberta fact sheets or the Prairie Pest Monitoring Network’s monitoring protocol. Also refer to the Lygus pages within the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” – both English-enhanced or French-enhanced versions are available.
Diamondback moth (Plutellidae: Plutella xylostella) – Once the diamondback moth is present in the area, it is important to monitor individual canola fields for larvae. Warm growing conditions can quickly translate into multiple generations in a very short period!
Monitoring:
Remove the plants in an area measuring 0.1 m² (about 12″ square), beat them on to a clean surface and count the number of larvae (Fig. 1) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.
Figure 1. Diamondback larva measuring ~8mm long. Note brown head capsule and forked appearance of prolegs on posterior.
Figure 2. Diamondback moth pupa within silken cocoon.
Economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1 m² (approximately 2-3 larvae per plant). Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).
Figure 3. Diamondback moth.
Across the prairies, provincial staffs coordinate diamondback pheromone trapping during the growing season. Every spring, the early arrival of diamondback moths (Fig. 3) is monitored through the tracking of high level air masses that originate from the south of North America and arrive across the Canadian prairies. Additionally, pheromone traps are deployed to intercept the initial moths. Cumulative male moth counts occurring over a 6-7 week period of trapping are used to estimate relative risk for the growing season. Vast networks of cooperators across Manitoba, Saskatchewan, Alberta, and the BC Peace work with their provincial entomologists to generate the following in-season results:
● Counts are summarized by Saskatchewan Agriculture (updated June 15, 2018, by J. Tansey):
● Manitoba Agriculture generally reports low DBM counts so far but review the specifics by region within the latest Insect and Disease Update (June 6, 2018).
More information about Diamondback moths can be found by accessing the pages from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide”. View ONLY the Diamondback moth page but remember the guide is available as a free downloadable document as both an English-enhanced or 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.
Reminder – The 2017 cabbage seedpod weevil distribution map was circulated in January and is posted below for reference. Note that areas highlighted orange or red in the map below included fields with comparatively higher densities of the weevil in 2017 so in-field scouting is particularly important in these same areas in 2018.
Researchers need your help – They are looking for LIVE cereal leaf beetle larvae from any field across the Canadian prairies in order to assess Tetrastichus julis parasitism rates.
If larvae are encountered in 2018, please carefully collect 20-30 of them and put them with some cereal leaves and a moist paper towel in a hard container (e.g. plastic yogurt container) with holes poked in the lid for air. Pack the parcel with ice packs, label with your name, date, crop type, and location, and send them to us. Email or phone us for information on how to ship for free.
What’s in it for you? Learn if cereal leaf beetle is being controlled by natural enemies in your field. If you need T. julis, we may be able provide you with some.
Pea Leaf Weevil (Sitona lineatus) – The PLW model predicted that larvae should be appearing in fields near Saskatoon (Fig. 1). Development in 2018 is faster than that predicted using long term averages (LTCN presented in Fig. 2).
Figure 1. Predicted pea leaf weevil phenology at Saskatoon SK. Values are based on model simulations for April 1 – June 18, 2018.Figure 2. Predicted pea leaf weevil phenology at Saskatoon SK. Values are based on model simulations for April 1 – June 18, 2018. using Long Term Climate Normals.
Larvae develop under the soil over a period of 30 to 60 days. They are “C” shaped with a dark brown head capsule. The rest of the body is a milky-white color (Fig. 3 A). Larvae develop through five instar stages. In the 5th instar, larvae range in length from 3.5 – 5.5 mm. First instar larvae bury into the soil after hatching, and search out root nodules on field pea and faba bean plants. Larvae enter and consume the microbial contents of the root nodules (Fig. 3 B). These root nodules are responsible for nitrogen-fixation, thus pea leaf weevil larval feeding can affect plant yield and the plant’s ability to input nitrogen into the soil.
Figure 3. Pea leaf weevil larva in soil (A) and field pea root nodules damaged by larval feeding (B). Photos: L. Dosdall).
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.
Scarabaeidae – Reminder – Each June brings scattered reports across the Prairies of white grubs associated with crop damage. In fact, several species of Aphodius, Phyllophaga, Polyphylla or even small Aetenius produce larvae described as “white grubs”.
Recently, crop damage reports have been associated with a grub identified as the larvae of the beetle Aphodius distinctus (see below). This common beetle is not known to be a pest, but there is an ongoing effort to gather information to develop a ‘pest’ profile. Additional information is online at Top Crop Manager. Please send reports of this insect and associated information to Dr. Kevin Floate (Agriculture and Agri-Food Canada, Lethbridge, AB).
What a difference a year makes! The Field Heroes campaign has been successful at raising awareness of the role of beneficial insects in Western Canadian crops. You’ll see this year’s campaign giving growers and agronomists more details on the many natural enemies they should be scouting for in cereal, oilseed and pulse crops.
Please make use of the Scouting Guides freely available on the Field Heroes website. Each guide includes valuable information and photos to help identify the contents of a sweep-net and to increase understanding of the impact of beneficial insects. Please share and encourage use of the Scouting Guides.
Be sure to follow @FieldHeroes on Twitter for practical tips and information. Please tag @FieldHeroes in your own Tweets about beneficials. Re-Tweets are great, too.
Thanks to Western Grains Research Foundation for their support of this important campaign. This initiative is not possible without the support and advice of enthusiastic members of the Prairie Pest Monitoring Network. Our research is having a tangible impact on growers’ pest management decisions.
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 can be accessed here. Review the most recent update (June 6, 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.
Alberta Agriculture and Forestry’s Call of the Land regularly includes insect pest updates from Scott Meers. The most recent Call of the Land (posted on June 21, 2018) noting that bertha armyworm moths were detected this first week of pheromone monitoring (check online map), onset of flowering in canola signalling the need for in-field monitoring for cabbage seedpod weevil, continued grasshopper calls from the south and advice to scout now while nymphs are easier to manage, Nutall’s blister beetle transiently showing up in some fields (blister beetle post), and the presence of the beneficial stiletto fly larvae which is a predator within the soil profile and targets wireworm larvae.
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 21Jun2018) but follow the hyperlink to check the interactive map. They are in Manitoba and moving west through southern Saskatchewan this week!
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 red turnip beetle (Coleoptera: Chrysomelidae). This beetle is 7-10 millimeters long and has a distinctive red body with black markings on the head and thorax, and three black stripes down its back (elytra). They feed on mustards, canola, cole crops, and cruciferous weeds (except stinkweed).
They overwinter as reddish brown oval eggs in the soil. Adults emerge in the spring to feed for 2-3 weeks before re-entering the soil to escape the summer heat. When they re-emerge, they disperse throughout the host crop, feeding, mating, and laying eggs (300-400/female). Feeding damage can cause delayed harvest or need for re-seeding to replace killed plants. Later in the season they feed on leaves, stems, and pods. Attached pods are prone to premature shelling.
For more information about the red turnip beetle, have a look at our Insect of the Week page!
Red turnip beetle adult and damage John Gavloski, Manitoba Agriculture, Food and Rural Development
This week’s Insect of the Week is the wheat midge. Larvae feed on the surface of developing wheat kernels in spring and winter wheat, durum wheat, triticale and occasionally spring rye. Damage includes aborted, shrivelled, misshapen, cracked, or scared kernels. This lowers grain yield, quality and grade.
For more information on the wheat midge, visit our Insect of the Week page.
Weather synopsis – Over this past week, average temperatures were similar to last week and only marginally cooler than long term averages for early June. Average temperatures were warmest in southern Manitoba with cooler conditions occurring across Alberta.
This second map presents the 30 Day Average Temperature. Average temperatures were greatest in southern regions of Manitoba and central Alberta.
The map below indicates that 7 Day Accumulated Precipitation was greatest across Alberta while central and southern Saskatchewan continued to be dry.
The map below indicates that the rainfall amounts for the past month (May 13 – June 11) were average to above-average in Alberta and below-average for Manitoba and Saskatchewan.
The updated growing degree day map (GDD) (Base 5ºC, March 1 – June 11, 2017) is below:
While the growing degree day map (GDD) (Base 10ºC, March 1 – June 11, 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.
Grasshopper Simulation Model Output – Simulation modelling is used to predict grasshopper development across the prairies. Weekly temperature data is incorporated into the model which calculates estimates of grasshopper development stages based on biological parameters for Melanoplus sanguinipes (Migratory grasshopper). Predicted hatch for June 11, 2017, was 52% (23% last week) with 32% of the population in the first instar, 15% second instar and 15% third instar.
The greatest development was predicted to be across southern regions in all three provinces, particularly southeastern Alberta and a region extending south from Swift Current/Regina to the US border.
Grasshopper populations near Saskatoon were predicted to be primarily in the second instar with appearance of some third and fourth instars. This week’s survey (southwest of Saskatoon) agreed with model predictions with first collections of a few fourth instars.
Model output for Grande Prairie indicates that development continues to be approximately 10 days later than locations across the southern prairies.
Bertha armyworm (Lepidoptera: Mamestra configurata) – Emergence of adult moths is well underway. The map illustrates predicted appearance of adults (percent of the population) across the southern prairies; oviposition is predicted to begin this week with first hatch beginning later next week.
For those of you monitoring BAW pheromone traps, you may want to compare trap “catches” to the following reference photo kindly shared by Saskatchewan Agriculture:
Wheat Midge (Sitodiplosis mosellana) – TheInsect of the Week features wheat midge!
Simulation modelling is used to predict wheat midge emergence across the Canadian prairies. The model predicted that wheat midge adults should emerge in July. The following graphs indicate that adult emergence at Saskatoon (Fig. 1) could be two weeks later than at Melfort (Fig. 2). Though average temperatures have been similar for both locations, model output indicates that dry conditions at Saskatoon (6 mm since June 1) may result in delayed emergence. Adequate moisture at Melfort (20 mm since June 1) has resulted in expected emergence patterns. Predicted rainfall for this week should result in emergence patterns that are more typical.
Figure 1. Predicted wheat midge development at Saskatoon SK.
Figure 2. Predicted wheat midge development at Melfort SK.
More information about Wheat midge can be found by accessing the pages from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide”. View ONLY the Wheat midge pages but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.
Pea Leaf Weevil (Sitona lineatus) – Oviposition is predicted to have peaked across central and southern regions of Alberta and Saskatchewan. Hatch should be underway in pea fields near Lethbridge while hatching is predicted to occur this week near Saskatoon.
Alfalfa Weevil (Hypera postica) – Recent warm weather has resulted in rapid alfalfa weevil development. Model output indicates that 98% of the hatch is complete (less than 80% last week). Larval populations should be predominantly in the second (35%) and third (46%) instars.
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.
Scarabaeidae – Each June brings scattered reports across the Prairies of white grubs associated with crop damage. In fact, several species of Aphodius, Phyllophaga, Polyphylla or even small Aetenius produce larvae described as “white grubs”.
Recently, crop damage reports have been associated with a grub identified as the larvae of the beetle Aphodius distinctus (see below). This common beetle is not known to be a pest, but there is an ongoing effort to gather information to develop a ‘pest’ profile. Additional information is online at Top Crop Manager. Please send reports of this insect and associated information to Dr. Kevin Floate (Agriculture and Agri-Food Canada, Lethbridge, AB).
Reverse trajectories (RT) There were 139 reverse trajectories that were predicted to pass across Alberta and Saskatchewan from the Pacific Northwest between May 26 and June 8.
Forward trajectories (FT) The following map indicates the origin of forward trajectories predicted to cross the prairies over the next five days. There have been an increased number of winds that have crossed the prairies from the southwest USA and Mexico since June 1.
Provincial entomologists provide insect pest updates throughout the growing season so we have attempted to link to their most recent information:
● Manitoba’s Insect and Disease Update for 2017 is prepared by John Gavloski and Pratisara Bajracharya the latest issue (Insect and Disease Update).
● Saskatchewan’s Crop Production News – 2017 – Issue #2 prepared by Scott Hartley and Danielle Stephens is now posted and includes the latest update on pea leaf weevil.
● Watch for Alberta Agriculture and Forestry’s Call of the Land and access the most recent Insect Update provided by Scott Meers.
Across the prairies, weather conditions were warmer and wetter than long term average values for the period of June 6-13, 2016. The average temperature was 15°C and was approximately 2°C warmer than the previous week.
This week’s rainfall was generally greater than long term average amounts. For the 30 day period of May 14-June 13, conditions were cooler in Alberta compared to Saskatchewan and Manitoba. The area extending from Swift Current to Regina and north to Saskatoon continues to be the warmest/driest region of the prairies.
The map below reflects the Accumulated Precipitation for the Growing Season so far for the prairie provinces (i.e., April 1-June 14, 2016):
The map below reflects the Accumulated Precipitation the Past 7 Days for the prairie provinces (i.e., June 8-14, 2016):
Compared to last week, overnight temperatures were warmer the past 7 days. The map below shows the Lowest Temperatures the Past 7 Days (June 8-14, 2016) across the prairies:
The map below shows the Highest Temperatures the Past 7 Days (June 8-14, 2016):
The updated growing degree day map (GDD) (Base 5ºC, March 1 – June 12, 2016) is below:
While the growing degree day map (GDD) (Base 10ºC, March 1 – June 12, 2015) 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.
Cutworms (Noctuidae) – Please refer to earlier cutworm posts describing scouting tips, monitoring protocols and fact sheets (including cutworm images plus action and economic thresholds).
For Manitobans….The earlier Insect Update included great photos of dingy and redbacked cutworms plus monitoring tips including how to discern these two species from one another. Reports of cutworm continued in the current Insect Update. For Saskatchewanians…. Cutworms were again reported in the recent Saskatchewan Insect Report. For Albertans….. Additional reports of cutworms have occurred throughout the province the past week! If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2016 Cutworm Reporting Tool”. Once data entry occurs, your growers can view the live 2016 cutworm map.
A screen shot of the live map has been retrieved (15Jun2016) below for your reference.
Grasshoppers (Acrididae) – Previous model predictions related to hatch and nymphal instar development can be reviewed here.
Reminder – Weekly surveying conducted by AAFC-Saskatoon Staff on June 2, 2016, confirmed that Melanoplines were primarily first and second instar stages although a few third instar nymphs were collected.
The following image showing various stages of the clearwinged grasshopper is provided below – note that adults have wings extending the length of the abdomen whereas nymphs lack wings but develop wing buds that will eventually mature to wings.
Swede midge (Contarinia nasturtii) – Pheromone traps captured the first swede midge of 2016 between May 25 and 31 in northeastern Saskatchewan. This is substantially earlier (6-7 weeks) compared to 2014 and 2015. The earlier emergence pattern is likely due to the mild winter and warm spring weather combined with adequate moisture levels. Emergence traps indicate a moderate number of swede midge have emerged near Carrot River, Saskatchewan, and producers should monitor their canola fields for damage symptoms.
Swede midge scouting tips for in-field monitoring: • Watch for unusual plant structures and plant discolourations then follow-up by closely scrutinizing the plant for larvae. • The growing tip may become distorted and produce several growing tips or none at all, young leaves may become swollen, crinkled or crumpled and brown scarring caused by larval feeding may be seen on the leaf petioles and stems. • Flowers may fail to open. • Young plants that show unusual growth habits should be examined carefully for damage and larvae; especially if the sticky liners have many flies resembling midges (swede midges are about the size of orange blossom wheat midge but are not orange). • Larvae can be seen with a hand lens. • Refer to the Canola Watch article by Dr. Julie Soroka for more information on swede midge and watch for a new Ontario fact sheet produced by Baute et al. 2016.
Bertha armyworm (Lepidoptera: Mamestra configurata) – Those monitoring BAW pheromone traps may want to compare trap “catches” to the following reference photo kindly shared by Saskatchewan Agriculture below:
Provincial staff coordinate BAW pheromone trapping across the prairies and summarize cumulative counts in report or map formats:
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.
They emerge from overwintering in the spring as soil temperatures warm to ~15°C. CSPW utilize several flowering hosts including wild mustard, flixweed, hoary cress, stinkweed and volunteer canola. CSPW move to canola during the bud to early flower stages and will feed on pollen and buds, causing flowers to die.
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.
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.
