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.
This past week, cooler temperatures were observed across most of the prairies. Growing season temperatures have been lower than average while rainfall amounts continue to be above average. This past week (June 3-9, 2024) temperatures were 1.2 °C below climate normal values. The average temperature across the prairies was 12.5 °C (Figure 1). Warmest temperatures were observed across a large area that extended west of Winnipeg to Saskatoon and Lethbridge. Seven day cumulative rainfalls were highly variable (Figure 2). Average cumulative seven day rainfall was 16.3 mm. Lowest rainfall values were observed across southern and western regions of the prairies, while the Parkland region had higher rainfall amounts.
Figure 1. Seven day average temperature (°C) observed across the Canadian prairies for the period of June 3-9, 2024.Figure 2. Seven day cumulative rainfall (mm) observed across the Canadian prairies for the period of June 3-9, 2024.
The average 30 day temperature (May 11 – June 9, 2024) was 11.4 °C and was 0.5 °C cooler than the long term average temperature. Warmest temperatures were observed south of an area extending from Winnipeg to Saskatoon and southwest to Lethbridge (Figure 3). Most of the prairies have reported 30 day rainfall amounts were normal to above normal. Average cumulative rainfall (mm) over the past 30 days was 65 mm and was 152% of climate normal values. The Peace River region continues to report lowest rainfall totals (Figure 4). Cumulative rainfall continues to be greatest across most of Manitoba.
Figure 3. 30 day average temperature (°C) observed across the Canadian prairies for the period of May 11 – June 9, 2024.Figure 4. 30 day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 11– June 9, 2024.
Since April 1, the 2024 growing season has been 0.6 °C warmer than average. Warmest average temperatures were observed across the southern prairies (Figure 5). Growing season rainfall has been above normal across most of the prairies. Rain amounts have been 184% of climate normals (Figure 6). Highest cumulative rainfall has been greatest for most of Manitoba and southern Alberta (Figure 7).
Figure 5. Growing season average temperature difference from climate normal (°C) observed across the Canadian prairies for the period of April 1 – June 9, 2024.Figure 6. Growing season percent of normal rain (%) observed across the Canadian prairies from April 1 to June 9, 2024.Figure 7. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1 – June 9, 2024.
Nymphs of economically important grasshopper species have been observed at multiple locations in southern Alberta and southern Saskatchewan since mid-May. On Jun 6, few grasshopper nymphs were active at sentinel sites between Saskatoon and Rosetosn SK, likely due to cool, wet, and windy conditions.
Scout for grasshoppers to keep informed of their developmental stage and population density.
Grasshopper Scouting Tips: ● Review grasshopper diversity and photos of nymphs, adults, and non-grasshopper species to aid in-field scouting from egg hatch and onwards. ● It is best to scout on warm days when grasshopper nymphs are more active and easier to observe. ● Carefully check roadside ditches and along field edges but also check the edge of the crop and into the actual field. ● Younger or earlier instar nymphs are easier to manage – visit sites every few days to stay on top of local field conditions. ● A sweep-net can ‘detect’ grasshopper nymphs, however, economic thresholds for grasshoppers are based on the number of grasshoppers per square-metre counts. ● Access the PPMN’s Grasshopper Monitoring Protocol as a guide to help implement in-field monitoring. ● Review grasshopper lifecycle, damage and scouting and economic thresholds to support sound management decisions enabling the preservation of beneficial arthropods and mitigation of economic losses.
Important – A preliminary summary of available thresholds for grasshoppers has been kindly shared by Dr. J. Tansey (Saskatchewan Agriculture) in Table 1. When scouting, compare in-field counts to the available threshold value for the appropriate host crop AND for field or ditch situations. Available thresholds (nominal and economic) help support producers while protecting beneficials (i.e., predators, parasitoids, and pathogens) that regulate natural populations of grasshoppers.
Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.
The week of May 27, 2024, very mature larvae were retrieved in flixweed in southern Alberta (Barkley, pers.comm. 2024). Thus, a second generation of adult diamondback moth is likely active in southern parts of the prairies.
Pheromone-baited Delta traps housing sticky cards are used to monitor diamondback moth across the Canadian prairies. Research has shown that cumulative counts > 25 moths indicate elevated risk. In those areas, it then becomes important to scout and assess larval densities.
Please refer to this week’s Provincial Insect Pest Report Links to find the most up-to-date information summarizing weekly cumulative counts compiled by provincial pheromone trapping networks across the Canadian prairies in 2024.
Provincial entomologist (Barkley, Tansey, Peru, Gavloski) have kindly provided the following summary for this week: • Alberta – two traps have caught > 25 adult diamondback moths; one trap deployed in the County of Warner (as of June 15, 2024) and one trap deployed in the County of Grande Prairie (as of June 8, 2024). • Saskatchewan – 6 RMs have observed cumulative counts >25 (as of June 6, 2024); traps are located near Regina (RM 129), Macroie (RM 285), Buchanan (RM 304), Laura (RM 315), Delisle (RM 345) and Makwa (RM 428). As of June 6, 2024, the highest cumulative count was 61 moths. • Manitoba – pheromone traps at 20 locations have captured > 25 moths, with cumulative trap catches ranging form 28 to 187. All of the traps with elevated risk are located in the Central, Eastern, South Interlake and North Interlake regions of Manitoba.
Scouting and pest management for diamondback moth depends on in-field counts of larvae per metre2! This means plants need to be pulled and tapped off to assess the number of larvae! Use Figure 1 below to help identify the different stages of diamondback moth.
Figure 1. The life stages of the diamondback moth (Plutella xylostella), which can have multiple generations per year. Photos: AAFC-Saskatoon-J. Williams.
Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture, Saskatchewan Agriculture, and the Prairie Pest Monitoring Network. Also, refer to the diamondback moth pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (2018) accessible as a free downloadable PDF in either English or French on our new Field Guides page.
Pheromone traps used to monitor bertha armyworm are typically set up along canola fields when pupal development reaches 75-80%; the 2024 monitoring season started the week of June 10, 2024.
Use the images below (Fig. 1) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.
Figure 1. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).
Please refer to this week’s Provincial Insect Pest Report Links to find the most up-to-date information summarizing weekly cumulative counts compiled by provincial pheromone trapping networks across the Canadian prairies in 2024.
Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (2018) accessible as a free downloadable PDF in either English or French on our new Field Guides page.
The cereal leaf beetle (Chrysomelidae: Oulema melanopus) has a broad host range. Wheat is the preferred host, but adults and larvae also feed on leaf tissue of oats, barley, corn, rye, triticale, reed canarygrass, ryegrass, fescue, wild oats, millet and other grasses. Yield quality and quantity is decreased, if the flag leaf is stripped. Fun fact: Cereal leaf beetle larvae carry their own fecal waste above their body to help protect themselves from predators.
Fortunately, the parasitoid wasp, Tetrastichus julis Walker (Hymenoptera: Eulophidae), is an important natural enemy of cereal leaf beetle larvae. Learn more about this beneficial insect species featured in Week 9 of 2023’s Insect of the Week!
Cereal Leaf Beetle Lifecycle and Damage:
Adult: Adult cereal leaf beetles (CLB) have shiny bluish-black wing covers (Fig. 3). The thorax and legs are light orange-brown. Females (4.9 to 5.5 mm) are slightly larger than males (4.4 to 5 mm). Adult beetles overwinter in and along the margins of grain fields in protected places such as in straw stubble, under crop and leaf litter, and in the crevices of tree bark. They favour sites adjacent to shelterbelts, deciduous and conifer forests. They emerge in the spring once temperatures reach 10-15 ºC and the adults are active for about 6 weeks. They usually begin feeding on grasses, then move into winter cereals and later into spring cereals.
Figure 3. Adult Oulema melanopus measure 4.4-5.5 mm long (Photo: M. Dolinski).
Egg: Eggs are laid approximately 14 days following the emergence of the adults. Eggs are laid singly or in pairs along the midvein on the upper side of the leaf and are cylindrical, measuring 0.9 mm by 0.4 mm, and yellowish in colour. Eggs darken to black just before hatching.
Larva: The larvae hatch in about 5 days and feed for about 3 weeks, passing through 4 growth stages (instars). The head and legs are brownish-black; the body is yellowish. Larvae are usually covered with a secretion of mucus and fecal material, giving them a shiny black, wet appearance (Fig. 4). When the larva completes its growth, it drops to the ground and pupates in the soil.
Figure 4. Larval stage of Oulema melanopus with characteristic feeding damage visible on leaf (Photo: M. Dolinski).
Pupa: Pupal colour varies from a bright yellow when it is first formed, to the colour of the adult just before emergence. The pupal stage lasts 2 – 3 weeks. Adult beetles emerge and feed for a couple of weeks before seeking overwintering sites. There is one generation per year.
Access scouting tips for cereal leaf beetle or find more detailed information by accessing the Oulema melanopus page from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (2018; accessible as a free downloadable PDF in either English or French on our new Field Guides page.
Reminder – Early detection is critical for slowing the spread of invasive insects.
A collaborative project developed by the Insect Surveillance Community of Practice and Canadian Plant Health Council has led to a series of posters featuring invasive insects of concern. Each poster includes a QR Code that users can scan to report observations of these priority invasive and migratory insects. Posters are free, printable PDF copies and highlight species of concern across Canada’s regions: • Prairies (English or French) • British Columbia (English or French) • Ontario & Quebec (English or French) • Atlantic (English or French)
The English version of the Prairies poster is below to view (Front and Back) Use the QR code to report detections or observations of these invasive species.
Reminder – Last week, the Prairie Pest Monitoring Network is excited to promote the official launch of the Prairie Weed Monitoring Network’s official website, PrairieWeeds.com!
The Western Grains Research Foundation (WGRF) is excited to announce the official launch of Prairieweeds.com, a comprehensive online platform designed to support the Prairie Weed Monitoring Network (PWMN) through the Integrated Crop Agronomy Cluster.
Led by Dr. Charles Geddes and Julia Leeson from Agriculture and Agri-Food Canada (AAFC), the PWMN is a pioneering initiative aimed at implementing an all-inclusive weed biovigilance strategy across the Canadian prairies. The PWMN is a coordinated collaboration among federal, provincial, and academic weed science experts.
“The launch of Prairieweeds.com marks a significant milestone in the development of the PWMN,” says Dr. Charles Geddes, Weed Scientist, AAFC. “Prairieweeds.com will serve as the digital home of the PWMN, offering a wealth of resources and up-to-date information on weed abundance, herbicide resistance, and integrated weed management specific to the Canadian prairies.”
The PWMN will build on the existing and highly successful models of the Prairie Pest Monitoring Network, and Prairie Crop Disease Monitoring Network, and will formalize and coordinate weed awareness, detection/identification, and assessment activities for the Prairie region.
Laura Reiter, WGRF Board Chair, expressed enthusiasm for the project, stating, “Prairieweeds.com will be a great resource for farmers, agronomists, and researchers. The website is a great opportunity to provide the agricultural industry with the information required to manage weeds effectively, anticipate new threats, and mitigate herbicide-resistant weeds.”
The Prairie Weed Monitoring Network (PWMN) is supported by funding from Agriculture and Agri-Food Canada through the Sustainable Canadian Agricultural Partnership’s AgriScience Program – Clusters Component, WGRF, Alberta Grains, Alberta Canola, SaskCanola, Saskatchewan Wheat Development Commission, Saskatchewan Pulse Growers, Manitoba Crop Alliance, Manitoba Pulse and Soybean Growers, Manitoba Canola Growers Association, and Prairie Oat Growers Association.
Prairie-wide provincial entomologists provide insect pest updates throughout the growing season. Follow the hyperlinks to readily access their information as the growing season progresses:
MANITOBA’SCrop Pest Updates for 2024 have started! Access the online June 13, 2024 report (or PDF copy). Bookmark the insect pest homepage to access fact sheets and more! Highlights pulled from the latest report include: • Flea beetles in MB – Dr. J. Gavloski reported that, “flea beetels have been a concern in some fields resulting in some foliar insecticide applications and reseeding. Spraying for flea beetles this week was reported from the Northwest, Central and Eastern regions. In the Northwest region there are reports of some canola fields having been sprayed twice for flea beetles, and one field having been sprayed three times for flea beetles. Some reseeding of canola was reported from the Northwest region, and a couple of fields near Portage la Prairie in the Central region were reseeded because of flea beetle damage.” • Cutworms in MB – “Cutworms have been causing damage in several crops. Insecticide applications for cutworms over the past week have occurred in canola, sunflowers, peas, and flax, with most of these reports coming from the Southwest or Central regions. Some canola and a small area of corn in the Southwest region were reseeded because of cutworms.” • “Wireworm damage to corn was noted in a field in the Central region.” • “Seedcorn maggots have been reported in sunflowers, but no serious damage.” • Diamondback moth pheromone trap monitoring in MB – Reports that diamondback moth were present “in 73 out of 89 traps” and that, “trap counts have generally been low so far in the Northwest and Southwest regions” but “some moderate counts have occurred in the Eastern, Interlake and Central regions. The highest cumulative trap count so far is 187 from a trap near Riverton in the Interlake region.” • True armyworm in MB – “Counts have been low so far in the western regions of Manitoba, with some moderate counts in the Central region” while “some higher counts occurred in some traps in the Eastern and Interlake regions”. “The highest cumulative count is 360, from a trap near Dencross in the Eastern region. There are some areas in the Central, Eastern and Interlake regions where
Dr. John Gavloski (Manitoba Agriculture) reported that, “”Some moderate to high counts have occurred from traps in the Eastern and Interlake regions of Manitoba. The highest cumulative count is 222, from a trap near Dencross in the Eastern region” and “(it) would be good to prioritize looking for armyworm larvae while scouting cereals and forage grasses” in “some areas of the Central, Eastern and Interlake regions”.
ALBERTA’SInsect Pest Monitoring Network webpage links to insect survey maps, live feed maps, insect trap set-up videos, and more. There is also a Major Crops Insect webpage. Remember, AAF’s Agri-News occasionally includes insect-related information, e.g., how to manage stem feeding from flea beetles, keep canola bins malathion-free, scout for grasshoppers and other pests (June 10, 2024); scout for insect pests (June 3, 2024), scout for grasshoppers (May 27, 2024), flea beetle control (May 6, 2024); cereal insect pests, latest on insects in canola, and post-emergence wireworm scouting (May 13, 2024). • Diamondback moth pheromone trap monitoring update for AB – Cumulative counts arising from weekly data are available so refer to the Live Map. So far, cumulative trap counts have been recorded from 31 reporting sites and 28 remain in the “no risk” category as of June 13, 2024). Three sites report “elevated risk” (as of June 13, 2024); they occur within the County of Grande Prairie, County of Warner, and Vulcan County. • Cutworm live monitoring map for AB – Cumulative counts arising from weekly data are available so refer to the Live Map. So far, 10 surveyed sites have reported from across the province, nine falling within southern Alberta and one report from the County of Grande Prairie.
This year it is as important as ever to scout and to monitor insect populations at the field-scale.
Grasshoppers thrive in warm, dry conditions. Some 5th instar nymphs were spotted in ditches in southwestern Saskatchewan in the past week, although there are many first, second, third, and fourth instar nymphs active as well. Signs of damage in the roadsides and field edges are being reported.
Diamondback moths develop rapidly when it is warm and their population densities can build up quickly with each generation. Be ready to scout if pheromone traps in your area have detected diamondback moths this spring and watch the provincial websites and PPMN updates for pheromone trap results.
Bertha armyworm development is also well ahead of schedule. Watch the provincial websites in Alberta, Saskatchewan, and Manitoba for reports on bertha armyworm pheromone trap captures for your area over the next few weeks; these provide an estimate of regional risk and are meant to guide in-field scouting.
This week, the Insect of the Week featured the strawberry blossom weevil. This is an invasive insect to Canada that is currently found in BC, but it is important to watch for it on the prairies in raspberry and strawberry patches.
Please read this week’s posts in the Weekly Update for more information about the insects listed above and for a sneak peak of wheat midge development!
Remember, insect Monitoring Protocols containing 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.
The week of June 5-11, 2023 was characterized by average prairie temperatures that continue to be well above average. The prairie average daily temperature was 3.5°C warmer than normal (Fig. 1). Like last week, the warmest temperatures were observed across Manitoba and eastern Saskatchewan. 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 5 – 11, 2023.
Average temperatures over the past 30 days (May 13 to June 11, 2023) have been 4°C above normal with the warmest values being reported across Manitoba and Saskatchewan (Fig. 2). Average 30-day temperatures ranged from 14.2°C at High Level, Alberta to 20°C at Morden, Manitoba.
Figure 2. 30-day average temperature (°C) across the Canadian prairies for the period of May 13 to June 11, 2023.
Seven-day cumulative rainfall was nominal for most of Alberta and western Saskatchewan while significantly higher rainfall amounts were reported for eastern Saskatchewan and Manitoba (Fig. 3). Southern Alberta, including Lethbridge and Taber reported weekly rainfall totals that were greater than 25mm up to June 11. Winnipeg and Minnedosa, Manitoba reported more than 45mm.
Figure 3. Seven-day cumulative rainfall (mm) observed across the Canadian prairies for the period of June 5-11, 2023.
Eastern Saskatchewan has generally had the highest rainfall totals over the past 30 days. Rainfall amounts continue to be low across Alberta and Manitoba (central and eastern regions) (Fig. 4). In Alberta, a large region that extends from Lethbridge to Edmonton, is extremely dry – this area has received only 40% of the precipitation normally expected for this time of year in the last 30 days. Central and eastern regions of Manitoba have also had less than 40% of normal precipitation. A large region extending north from an area that extends from Brandon, Manitoba to North Battleford, Saskatchewan has had above normal precipitation.
Figure 4. 30-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 13 to June 11, 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). Central and southern regions of Alberta are categorized as relatively cool/dry. The Peace River region has been cool and wet. Eastern Saskatchewan and a number of western Manitoba locations are now categorized as warmer and wetter.
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 13 to June 11, 2023. The red line indicates average temperature and the blue line represents average rainfall (for the period of May 13 to June 11, 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.
There was a significant decrease in the number of reverse trajectories that entered the Canadian prairies during the week of June 7-13, 2023 as compared to the previous week (Fig. 1).
Figure 1. The average number (based on a 5-day running average) of reverse trajectories (RT) that have crossed the prairies for the period of May 14 to June 13, 2023.
Mexico, California and Texas: Only 5 reverse trajectories crossed into the prairies from Mexico, California, and Texas from June 7-13. These trajectories were expected to cross into southeastern Saskatchewan and Manitoba (Fig. 2).
Figure 2. Total number of dates with reverse trajectories originating over Mexico, California and Texas that have crossed the prairies between April 1 and June 13, 2023.
Pacific Northwest (Idaho, Oregon, Washington): This week 40 reverse trajectories were predicted to cross the prairies from the Pacific Northwest. The majority of the reverse trajectories from the Pacific Northwest passed over Alberta and western Saskatchewan (Fig. 3).
Figure 3. Total number of dates with reverse trajectories originating over the Idaho, Oregon, and Washington that have crossed the prairies between April 1 and June 13, 2023.
Oklahoma and Texas: There were 17 reverse trajectories that originated over Texas and Oklahoma and passed through the prairies in the past week. These reverse trajectories largely passed over Manitoba and southeastern Saskatchewan and (Fig. 4).
Figure 4. The total number of dates with reverse trajectories originating over Oklahoma and Texas that have crossed the prairies between May 1 and June 13, 2023.
Kansas and Nebraska: Since April 1, reverse trajectories originating in Kansas and Nebraska were reported to cross southeastern Saskatchewan and southern Manitoba (Fig. 5). This week (June 7-13), there were 46 reverse trajectories, originating over Kansas and Nebraska that were predicted to pass over Saskatchewan and Manitoba.
Figure 5. The total number of dates with reverse trajectories originating over Kansas and Nebraska that have crossed the prairies between May 1 and June 13, 2023.
Model simulations were used to estimate development of grasshoppers as of June 11, 2023. Well above normal temperatures across the prairies continue to result in rapid grasshopper development. Model runs suggest that this spring’s hatch is almost complete. As of June 11, grasshopper nymphs should range from the first to fourth instar in many locations on the prairies. Based on average instar, development is most advanced across the southern prairies where populations should consist of mainly third and fourth instar nymphs (Fig. 1).
Figure 1. Predicted grasshopper (Melanoplus sanguinipes) development, presented as average instar, across the Canadian prairies as of June 11, 2023.
At some locations between in central Saskatchewan (between Saskatoon and Swift Current), some fifth instar grasshopper nymphs have been captured in sweep net samples and the number of nymphs in the fourth instar has increased. Two-striped grasshoppers continue to be most prevalent in this region, but more first instar nymphs of the other primary pest species were observed in ditches in Saskatchewan this week. From the roadsides, there were some signs of grasshopper damage to crop plants, including canola, along field edges.
Models and geospatial maps are tools to help time in-field scouting on a regional scale but grasshopper development can vary and is only accurately assessed through scouting. Producers are advised to monitor roadsides and field margins to assess the development and densities of local grasshopper populations. Due to the small size, it may be difficult to visually observe first and second instar grasshoppers in roadside vegetation and field margins. If possible, grasshopper assessments should be conducted with sweep nets. This will permit assessment of grasshopper densities, stage and species present.
Diamondback moths (Plutella xylostella) are a migratory invasive species; after initial migration into the prairies, diamondback moths can have multiple non-migratory generations during the growing season. Typically, there are three to four non-migrant generations of diamondback moths on the prairies.
Diamondback moth development can be rapid during periods of warm weather. Model simulationsto June 11, 2023, indicate that the second generation of non-migrant adults (based on early-May arrival dates) is currently occurring across the southern prairies (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 11, 2023.
On the prairies, we use a network of pheromone traps to detect the first spring appearance of diamondback moths. In the June 7 and June 14 issues of the Manitoba Crop Pest Update, some diamondback moth trap locations in the central and eastern parts of the province reported catching between 100-200 adult moths. At least three sites in central and southern Alberta (use the link to see the live map) have also caught between 100-200 moths so far this year. Lower numbers have been recorded so far in Saskatchewan in 2023.
Now, 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.
Based on model simulations, development of overwintered bertha armyworm (Mamestra configurata) continues to be 7-10 days ahead of normal. Where present, we expect the majority of the prairie population of bertha armyworm to now be in the adult stage (Fig. 1) and females have likely already begun to lay eggs (Fig. 2).
Figure 1. Proportion (%) of the bertha armyworm (Mamestra configurata) population that is expected to be in the adult stage across the Canadian prairies as of June 11, 2023.Figure 2. Proportion (%) of the bertha armyworm (Mamestra configurata) population that is expected to be in the egg stage across the Canadian prairies as of June 11, 2023.
Bertha armyworm populations were very low in 2022. So far, trap catches in Alberta in 2023 have also been very low (most traps with less than 20 adult male moths). A few trap locations in Saskatchewan and at least one in Manitoba have reported more than 100 moths caught since the traps were set up in late May or early June.
Pheromone trap monitoring for bertha armyworm provides a regional picture of potential risk. Cumulative trap catches below 300 generally represent low risk. To know if a specific field is at risk of economic yield losses, scouting for larvae in that field is required. The PPMN protocol for bertha armyworm monitoring provides information about scouting for adult and larval bertha armyworm and about economic thresholds for this pest.
Wheat midge (Sitodiplosis mosellana) overwinter as larval cocoons in the soil. Adequate rainfall in May and June is a signal to larval cocoons to end their diapause and move to the soil surface to pupate. Insufficient rainfall in May and June can result in delayed movement of larvae to the soil surface. Wheat midge emergence may be delayed or erratic if rainfall does not exceed 20-30 mm during May. The Olfert et al. (2020) model indicated that dry conditions may result in delayed adult emergence, delayed oviposition by female wheat midge, fewer adults, and fewer eggs laid.
In the last few weeks, rainfall events over parts of the prairies may have provided the cue to end wheat midge larval diapause. Cumulative rainfall from May 1 to June 11 across western Manitoba, most of Saskatchewan and northwestern Alberta now exceeds the threshold of 30 mm of rain required to terminate the larval diapause of wheat midge (Fig. 1).
Figure 1. Areas in western Canada where cumulative rainfall from May 1 to June 11, 2023 is equal to or greater than 30 mm, which is the threshold required to promote movement of wheat midge (Sitodiplosis mosellana) larvae to the soil surface where they will pupate.
The wheat midge model indicates that, where wheat midge populations are present, larvae have begun to move to the soil surface in some areas of the prairies (Fig. 2).
Figure 2. Percent of the wheat midge larval population (Sitodiplosis mosellana) that has moved to the soil surface across western Canada, as of June 11, 2023.
In contrast to the wet areas on the prairies, wheat midge adult emergence might be delayed in 2023 in areas that have not yet received much rain. It is also possible that the wheat midge larval cocoons will remain in a diapause state in the dry areas of the prairies until a future year when spring moisture is more suitable for wheat midge development.
Scouting for adult wheat midge usually starts in late June or early July. Over the next few weeks, the Prairie Pest Monitoring Network will continue to use phenology models to predict that status of wheat midge development and provide additional updates.
Visit the Alberta Insect Pest Monitoring Network and Crop Insects pages for information about insects and monitoring in Alberta, including links for live maps from the 2023 monitoring season for diamondback moth, bertha armyworm, cutworms and others.
Watch for new issues of the Saskatchewan Crop Production News coming soon in 2023 and browse the articles from 2022 for information from the past.
The latest Manitoba Crop Pest Update for 2023 was posted on June 14. Watch their website for new Crop Pest Updates as the season continues and check out the archives to read past Updates.
Strawberry blossom weevil (Anthonomus rubi), a recent invader of the Fraser Valley of British Columbia (BC), has been busy clipping buds this spring in strawberry and raspberry fields. This weevil was first spotted in raspberries in Abbotsford, BC in 2019. Native to Europe, Asia, and parts of North Africa, this weevil is now established in the Fraser Valley of BC and northwestern Washington state. It has not yet been found in the prairie provinces.
Damage to strawberry buds from the strawberry blossom weevil. Photo credit: Michelle Franklin, AAFC-Agassiz.
Different from many of the nocturnal root feeding weevils that damage roots and stunt plant growth in berries, strawberry blossom weevil is active during the day. It is small (2-3 mm long) with a small white patch of scales on the scutellum (back) and a long slender rostrum (snout). The female weevil is the main source of damage, as she deposits her eggs inside of green developing buds. She first chews a hole in the bud and then turns around and lays an egg inside, after which she clips the stem below.
A female strawberry blossom weevil laying an egg into a Himalayan blackberry bud. Photo credit: Warren Wong.
Typically a single c-shaped larvae develops inside of a bud. The larvae then pupates and the adult weevil emerges from the bud by chewing an exit hole.
A strawberry blossom weevil larva, about 2.5 mm long, inside a berry bud. Photo credit: Warren Wong.
We are currently investigating the impact of this new weevil on strawberry and raspberry crops in the Fraser Valley of BC. Reports from its native range in Europe indicate that bud losses associated with strawberry blossom weevil range widely from 5 to 90% and yield losses over 60% have been reported. Despite the name, strawberry blossom weevil uses a wide range of host plants in the family Rosaceae – including the invasive Himalayan blackberry and ornamental plants such as rose and potentilla. The United States Department of Agriculture Animal and Plant Health Inspection Service (APHIS) put a Federal Order in place in September 2021 and continues to require a phytosanitary certificate to move Fragaria, Rubus, and Rosa plants from Canada into the USA (Federal Order DA-2021-25).
We need your help surveying for this pest! Although strawberry blossom weevil has not been detected beyond the Fraser Valley of BC, we are continuing a nation-wide survey in summer 2023 for this pest. Adult weevils naturally drop when disturbed so they can be detected by a method called beat sampling – where plants are tapped from above and weevils are collected into a tray below. Like many other insects, they are also attracted to the colour yellow and can be collected on yellow sticky cards. Visual surveys for damaged buds with severed stems can also be useful when searching for strawberry blossom weevil. In collaboration with Agriculture and Agri-Food Canada’s Geomatics Team we have developed a Story Map for Strawberry Blossom Weevil to summarize our survey efforts thus far.
Questions or problems accessing the contents of this Weekly Update? Please contact us so we can connect you to our information. Past “Weekly Updates” can be accessed on our Weekly Update page.
TEMPERATURE: The 2022 growing season has been cooler than normal. Rainfall has been below normal for Alberta and western Saskatchewan while rainfall amounts have been well above normal for eastern Saskatchewan and Manitoba. This past week (June 6-12, 2022) average daily temperatures were generally warmer than in the previous week. The warmest conditions occurred across southern Manitoba, a region extending from Regina to Saskatoon and southwest to Lethbridge, and in the northern Peace River region (Fig. 1). The average temperature across the prairies was 2 °C warmer than normal.
Figure 1. Seven-day average temperature (°C) across the Canadian prairies for the period of June 6-12, 2022.
Though the prairie-wide average 30-day temperature (May 14 – June 12, 2022) was similar to the long-term average value, the average was 1.5 °C warmer than the previous week. Average temperatures have increased across most of the prairies (Fig. 2).
Figure 2. 30-day average temperature (°C) across the Canadian prairies for the period of May 14-June 12, 2022.
The prairie-wide average growing season (April 1-June 12, 2022) temperature was 1 °C warmer than last week; the average growing season temperature for the prairies has been 1 °C cooler than climate normal values. The growing season continues to be cooler in Manitoba than Saskatchewan and Alberta (Fig. 3).
The growing season (April 1 – June 5, 2022) has been cooler in Manitoba than in Saskatchewan and Alberta (Fig. 4; Table 1). The average growing season temperature for the prairies has been 1.5 °C cooler than climate normal values.
Figure 3. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1 to June 12, 2022.
PRECIPITATION: Seven-day cumulative rainfall ranged between 0 and 42 mm across the prairies, with highest rainfall amounts (20-40 mm) occurring in a region extending from Hanna to Calgary and south to Lethbridge (Fig. 4). Rainfall amounts were generally less than 10 mm for most of Saskatchewan.
Figure 4 Seven-day cumulative rainfall (mm) observed across the Canadian prairies for the period of June 6-12, 2022.
30-day accumulation amounts have been well above average across Manitoba but well below normal across southern and western Saskatchewan (Fig. 5). Growing season rainfall for April 1 – June 12, 2022, continues to be greatest across Manitoba and eastern Saskatchewan; rain amounts have been below normal across most of western Saskatchewan and Alberta (Fig. 6).
Figure 5. 30-day cumulative rainfall (mm) observed across the Canadian prairies the past 30 days (May 14-June 12, 2022).Figure 6. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1 to June 12, 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. Review lifecycle and damage information for this pest. Review the historical grasshopper maps based on late-summer adult in-field counts performed across the prairies.
Model simulations were used to estimate percent grasshopper egg development and hatch as of June 12, 2022. Warmer temperatures over the past 30 days have resulted in increased rates of grasshopper development across Saskatchewan and Alberta; wetter/cooler conditions across eastern Saskatchewan and Manitoba have resulted in delayed development.
Last week, average embryological development was 76 %. This week, average egg development is predicted to be 83 % and is 1 % greater than the long-term development rate. Hatch is progressing across southern and central regions of Alberta and Saskatchewan with hatch rates that range between 15 and 60% (Fig. 1). First to third instar nymphs should be occurring across southern and central regions of Alberta and Saskatchewan. Simulations indicate that 5-10% of the population has hatched across southern and central regions of Manitoba.
Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development (%) across the Canadian prairies as of June 12, 2022.
Risk estimates, based on meteorological inputs, were used to assess the impact of weather on grasshopper development and population growth potential (Fig. 2). Grasshopper risk is greatest in areas that are warmer and drier than normal. As of June 12, 2022, model output indicates that potential risk is greatest across a region that extends from Lethbridge to Swift Current and Saskatoon. Relative to last week,risk has increased for localized areas across the Peace River region. The simulation indicates that even though temperatures are suitable for grasshopper development, excessive moisture across most of Manitoba has reduced the potential risk from grasshoppers. Overall risk is predicted to be similar to long-term average risk and is currently well below potential risk predictions that were produced for the 2021 growing season.
Figure 2. Predicted risk for the migratory grasshopper (Melanoplus sanguinipes) across the Canadian prairies as of June 12, 2022.
The alfalfa weevil (AAW) (Curculionidae: Hypera postica) model predicts development using biological parameters known for the pest species and environmental data observed across the Canadian prairies on a daily basis. Review lifecycle and damage information for this pest.
Model simulations for alfalfa weevil (AAW) indicate third instar larvae should now be appearing across the prairies. Development is similar to long-term average values. AAW development in central Saskatchewan (Fig. 1) is slower than AAW development in southern Alberta (Fig. 2).
Figure 1. Predicted status of alfalfa weevil (Hypera postica) populations near Saskatoon SK as of June 12, 2022.Figure 2. Predicted status of alfalfa weevil (Hypera postica) populations near Medicine Hat AB as of June 12, 2022.
Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (2018) accessible as a free downloadable PDF in either English or French on our new Field Guides page.
The cereal leaf beetle (CLB) (Chysomelidae: Oulema melanopus) model predicts larval development using biological parameters known for the pest species and environmental data observed across the Canadian prairies on a daily basis. Review lifecycle and damage information for this pest.
Warmer conditions in southern Alberta and western Saskatchewan are predicted to result in more rapid development of cereal leaf beetle (CLB) populations in those regions than in southern Manitoba. CLB model output predicts that hatch should be nearly complete for southern Alberta and western Saskatchewan. First to third instar larvae are predicted to be present in these areas (Fig. 1). As a result of cooler conditions, the model predicts that egg development has been delayed in southern Manitoba; first instar and second instar larvae may be appearing this week (Fig. 2).
Figure 1. Predicted status of cereal leaf beetle (Oulema melanopus) populations near Lethbridge AB as of June 12, 2022.Figure 2. Predicted status of cereal leaf beetle (Oulema melanopus) populations near Winnipeg MB as of June 512 2022.
Access scouting tips for cereal leaf beetle or find more detailed information by accessing the Oulema melanopus page from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (2018; accessible as a free downloadable PDF in either English or French on our new Field Guides page.
Pupal development of bertha armyworm (BAW) is progressing across the prairies with the most rapid development occurring across southern and central regions of Alberta and western Saskatchewan (Fig. 1). Over the next week, adults should be emerging across Alberta, Saskatchewan and localized areas in southern Manitoba.
Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development (%) across the Canadian prairies as of June 12, 2022.
Use the images below (Fig. 2) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.
Figure 2. 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.
Wheat midge (Sitodiplosis mosellana) overwinter as larval cocoons in the soil but soil moisture conditions in May and June largely determine whether or not the larva exits their cocoon to move to the soil surface to continue development (i.e., to pupate then emerge as a midge this season). Adequate rainfall promotes termination of diapause and movement of larvae to the soil surface where pupation occurs. Insufficient rainfall in May and June can result in delayed movement of larvae to the soil surface. Wheat midge emergence may be delayed or erratic if rainfall does not exceed 20-30 mm during May. The Olfert et al. (2020) model indicated that dry conditions may result in: a. Delayed adult emergence and oviposition b. Reduced numbers of adults and eggs
Compared to last week, the wheat midge model indicates that the development of larval populations has advanced considerably across the eastern prairies and Peace River region. Normal to above-normal rain in Manitoba, eastern Saskatchewan and the Peace River region should be sufficient to promote the movement of wheat midge larvae to the soil surface (Fig. 1). Insufficient rainfall across central Alberta and western Saskatchewan will limit the development of larval populations that are in the soil.
Wheat midge simulations suggest that greater than 60 % of the larval population has moved to the soil surface in some areas of the prairies. Larval populations should begin to transition to the pupal stage over the next seven days. Current development for eastern Saskatchewan and Manitoba is similar to long-term average rates.
Figure 1. Percent of wheat midge larval population (Sitodiplosis mosellana) that has moved to the soil surface across western Canada,as of June 12, 2022.
Risk estimates, based on meteorological inputs, were used to assess the impact of weather on wheat midge development and potential population growth potential (Fig. 2). Wheat midge risk is greatest in areas that have received normal to above-normal rainfall. As of June 12, 2022, model output indicates that potential risk is greatest across eastern Saskatchewan and Manitoba. Risk in these areas is predicted to be similar to long-term average risk.
Figure 2. Predicted risk for wheat midge (Sitodiplosis mosellana) outbreaks across the Canadian prairies as of June 12, 2022.
Additional information can be accessed by reviewing the Wheat midge pages extracted from the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide” (2018) accessible as a free downloadable PDF in either English or French on our new Field Guides page.
1. REVERSE TRAJECTORIES (RT) Since May 1, 2022, the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). This past week (June 7-13, 2022) the number of reverse trajectories originating from Mexico, California, Texas, Oklahoma, Nebraska and Kansas continued to be low. This week reverse trajectories generally originated over the Pacific Ocean before entering the prairies.
Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of June 1-13, 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 7-13, 2022) the ECCC model predicted that 134 reverse trajectories would cross the prairies. This is a significant increase over the previous week (n=26).
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 13, 2022.
b. Mexico and southwest USA (Texas, California) – This past week (June 7-13, 2022) the model reported that zero reverse trajectories that originated from Mexico, California or Texas crossed over the Canadian prairies. Since May 1, 2022, these trajectories have been restricted to Manitoba and eastern Saskatchewan (Fig. 3).
Figure 3. The total number of dates with reverse trajectories originating over Mexico, California and Texas that have crossed the prairies between April 1 and June 13, 2022.
c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan. This past week (June 7-13, 2022) one trajectory crossed over Edmonton, Alberta.
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 13, 2022.
d. Nebraska and Kansas – Until this week, reverse trajectories originating from Kansas and Nebraska have been associated with southeastern Saskatchewan and southern Manitoba (Fig. 5). This past week (June 7-13, 2022) the ECCC model predicted that 8 reverse trajectories passed over the prairies. Six of these reverse trajectories passed over parts of Alberta, including Beiseker, Olds, Edmonton, Rycroft, and Fort Vermilion and Fort St. John in British Columbia.
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 13, 2022.
2. FORWARD TRAJECTORIES (FT) The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) that were predicted to cross the Canadian prairies (Fig. 6). This week (May 31 to June 6, 2022) there 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 7-13, 2022) there was an increase in the number of forward trajectories (n=34) predicted to cross the prairies compared to last week (n=12). 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 13, 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 15, 2022 issue here. Bookmark their Crop Pest Update Index to readily access these reports and also bookmark their insect pest homepage to access fact sheets and more! • Flea beetles, cutworms and grasshopper nymphs in MB – Review the above June 15 issue to find greater details but the summary reads as, “Flea beetles levels are at quite high levels in many areas. Some growers have applied up to three insecticide applications for flea beetles, and there has been some reseeding. Some fields of small grains and sunflowers have been sprayed for cutworms. Hatch of the potential pest species of grasshoppers is occurring; some control has occurred in the Central region.” • Diamondback moth pheromone trap monitoring update for MB – “So far, diamondback moth has been found in 29 traps.” Read the report on Page 5 of the June 15, 2022 issue OR review a more detailed summary of cumulative trap counts from 48 sites deployed across the province. • Armyworm pheromone trap monitoring is underway in MB – “So far, counts have generally been quite low, with armyworm moths only being caught in 6 traps.” Read the report on Page 6of the June 15, 2022 issue.
ALBERTA’SInsect Pest Monitoring Network webpage links to insect survey maps, live feed maps, insect trap set-up videos, and more. There is also a Major Crops Insect webpage. The new webpage does not replace the Insect Pest Monitoring Network page. Remember, AAF’s Agri-News occasionally includes insect-related information. Twitter users can connect to #ABBugChat Wednesdays at 10:00 am. • Diamondback moth pheromone trap monitoring update for AB – Cumulative counts arising from weekly data are available so refer to the Live Map. So far, low numbers of diamondback moth have been intercepted across the province. • Cutworm live monitoring map for AB – Reports continue to come in so refer to the Live Map to review areas where cutworms are being found. So far, black army, pale western, and dingy cutworms have been reported. Use this online form to report cutworms in Alberta.
The 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 a free copy to arm your in-field scouting efforts!
Review the Sweep-net Video Series including: • How to sweep a field. Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon). Published online 2020. • What’s in my sweep-net? Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon). Published online 2020. • Why use a sweep-net? Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon). Published online 2020.
This week wraps up our series on Prairie wireworms, and we are ending with a bit of an odd one, the flat wireworm (Aeolus mellillus).
The flat wireworm is not found in huge abundance on the Prairies, but it is worth knowing about because it’s different than the other 3 main species. First, it is quite recognizable with its dark reddish-brown head and stripe below its head.
A. mellillus (arrow)
Second, if you ever get one of these in the palm of your hand, it is very active, it will be hard to hold on to it before it crawls away. This activity may be because the flat wireworm is also a predacious species, in fact it might eat other wireworms! But it also eats plants, and the literature says it cuts plants rather than the shredding type of feeding shown by other species. The flat wireworm can grow fast to its mature size of 15 mm. Unlike other wireworm species, Aeolus mellillus has a short 1-2 year life cycle and can pupate anytime between spring and late summer. This species also does not need to mate to reproduce – as far as we know, Canadian populations of A. mellillus are all females!
AAFC has recently released a new field guide on Prairie pest wireworms. It has information on biology, monitoring and management and research on wireworms on the Prairies. Preview pages extracted from the guide highlighting Aeolus mellillus by clicking here.
Free digital copies in both official languages can be downloaded at these links.
Week 6 and things are hopping – literally! Be sure to catch the Insect of the Week – it’s bertha armyworm! This week find updates to predictive model outputs for grasshoppers, wheat midge, bertha armyworm, cereal leaf beetle, and alfalfa weevil plus a lot more to help prepare for in-field scouting!
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.
Access background information for how and why wind trajectories are monitored in this post.
1. REVERSE TRAJECTORIES (RT) This past week (in particular June 9 and 10) there were an increasing number of reverse trajectories moving north from the Pacific Northwest (Idaho, Oregon and Washington), Texas, Oklahoma, Kansas and Nebraska (Fig. 1). Though these US regions 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 10 2021.
a. Pacific Northwest (Idaho, Oregon, Washington) – This week there have been 106 trajectories (53 last week) that have crossed Alberta, Manitoba and Saskatchewan. This growing season, PNW trajectories have crossed all parts of the prairies (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 10, 2021.
b. Mexico and southwest USA (Texas, California) – Compared to previous years, there has been a noticeable increase in the number of trajectories from the southern US. The majority of these trajectories have crossed Manitoba and eastern Saskatchewan (Fig. 3). This week there have been 10 trajectories (0 last week) that originated in Mexico or the southwest USA that have crossed the prairies (Fig. 3).
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 10, 2021.
c. Oklahoma and Texas – This week there have been 13 trajectories (0 last week) originating in Oklahoma or Texas that have passed over the prairies (Fig. 4).
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 10, 2021.
d. Kansas and Nebraska – This week there were 19 trajectories (versus 1 last week) that originated in Kansas or Nebraska that passed over the prairies (Fig. 5). Relative to the reverse trajectories associated with Oklahoma and Texas (Fig. 4), the trajectories from Kansas and Nebraska have crossed further into Alberta (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 10, 2021.
2. FORWARD TRAJECTORIES (FT) a. Continuing a trend that began last week, this week there was an increase 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 10, 2021.
TEMPERATURE: This past week (May 31 – June 6, 2021) extremely warm conditions resulted in weekly average temperatures that were well above normal (Fig. 1). The warmest temperatures were observed across Manitoba and eastern Saskatchewan (Fig. 1).
Figure 1. 7-day average temperature (°C) observed across the Canadian prairies for the period of May 31 – June 6, 2021.
Across the prairies, the average 30-day (May 8 – June 6) temperature was almost 2.5 °C warmer than the previous week and 1.3 °C greater than climate normal values. Warmest temperatures were observed across southern Manitoba (Table 1; Fig. 2).
Figure x. 30-day average temperature (°C) observed across the Canadian prairies for the period of May 8 – June 6, 2021.
The 2021 growing season (April 1 – June 6) has been characterized by near-normal temperatures. Temperatures have been warmest for southern Manitoba and southern Alberta (Table 2; Fig. 3).
Figure 3. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1 – June 6, 2021.
PRECIPITATION: This week, the highest rainfall amounts were reported across northwest Saskatchewan and central Alberta while weekly rainfall amounts less than 2 mm was reported across a large area that extended from western Manitoba, across most of Saskatchewan, to southern Alberta. Extreme dry conditions were reported across the Peace River region (Fig. 4).
Figure 4 . 7 day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 31 – June 6, 2021.
Rainfall amounts for the period of May 8 to June 6 (30-day accumulation) were above normal (110 % of long-term average values). Rainfall amounts have been near normal to above normal for large areas of Alberta as well as northwest and southeast Saskatchewan. Well-above-normal rain was reported for Edmonton and Regina. Below normal rainfall amounts were reported for central and northern areas of the Peace River region and across Manitoba (Table 1; Fig. 5).
Figure 5. 30-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 8 – June 6, 2021.
Average growing season (April 1 – June 6) precipitation was 94 % of normal with the greatest precipitation occurring near Edmonton and across eastern Saskatchewan, including Regina. Most of Manitoba and the Peace River region have had 60 % or less than normal precipitation during the 2021 growing season (Table 2; Fig. 6).
Figure 6. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1 – June 6, 2021.
Access Environment and Climate Change Canada’s weather radar mapping interface. Options to access preceeding precipitation events include clicking off either an 1 or 3 hours time interval, using an 8-colour or 14-colour index. or changing the base map.
Model simulations were used to estimate grasshopper (Melanoplus sanguinipes) development as of June 6, 2021. Average development of eggs is 86 % and is well ahead of the long term average of 73 %. Last week’s warm conditions across southeastern SK and southern Manitoba have been responsible for advanced development of eggs near Regina, Saskatoon, Brandon, and Winnipeg. Egg development is predicted to exceed 90 % across most of the southern prairies (Fig. 1).
Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development (%) across the Canadian prairies as of June 6, 2021.
As of June 6, hatch was predicted to be occurring across most of the prairies (overall average was 26 %) with hatch rates approaching 30-45 % across southern Manitoba and Saskatchewan (Fig. 2). The model was projected to June 22 to determine potential development at Regina and Swift Current over the next two weeks (Figs. 3 and 4). Results suggest that by June 22, Regina populations will primarily be in the third instar, with first appearance of fourth instars. Development near Swift Current is predicted to be slower, with populations being mostly in the first and second instars.
Warm, dry conditions continue to persist across Manitoba. This may result in conditions conducive to crop damage from grasshoppers as hatch progresses in June. Producers are advised to monitor roadsides and field margins to assess development and densities of local grasshopper populations.
Figure 2. Predicted grasshopper (Melanoplus sanguinipes) hatch (%) across the Canadian prairies as of June 6, 2021.Figure 3. Predicted development of Melanoplus sanguinipes populations near Regina, Saskatchewan as of June 6, 2021 (projected to June 22, 2021).Figure 4. Predicted development of Melanoplus sanguinipes populations near Swift Current, Saskatchewan as of June 6, 2021 (projected to June 22, 2021).
Wheat midge (Sitodiplosis mosellana) overwinter as larval cocoons in the soil. Soil moisture conditions in May and June can have significant impacts on wheat midge emergence. Adequate rainfall promotes termination of diapause and movement of larvae to the soil surface where pupation occurs. Insufficient rainfall in May and June can result in delayed movement of larvae to the soil surface. Elliott et al. (2009) reported that wheat midge emergence was delayed or erratic if rainfall did not exceed 20-30 mm during May. Olfert et al. (2016) ran model simulations to demonstrate how rainfall impacts wheat midge population density. The Olfert et al. (2020) model indicated that dry conditions may result in: a. Delayed adult emergence and oviposition b. Reduced numbers of adults and eggs
As of June 6, 2021, wheat midge model runs indicate that recent rainfall in central Alberta and northwestern and southeastern Saskatchewan has resulted in movement of more than 30 % of the larval population to the soil surface (Fig. 1). Dryer conditions in other parts of Saskatchewan, Manitoba and most of the Peace River region continue to delay movement of larvae to the soil surface. If dry conditions persist, this should result in delayed pupation and adult emergence.
Figure 1. Percent of wheat midge larval population (Sitodiplosis mosellana) that has moved to the soil surface across western Canada, based on weather conditions up to June 6, 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.
Model simulations to June 6, 2021, indicate that bertha armyworm (BAW) (Mamestra configurata) pupal development ranges from 60-90 % across the prairies (Fig. 1). BAW traps should be placed in fields when pupal development exceeds 80 %. Table 1 provides guidelines to determine when traps should be deployed. Based on weather data up to June 6, 2021, BAW adults should begin to emerge by mid to late June.
Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development across the Canadian prairies as of June 6, 2021.
Model projections to June 30 predict that development near Winnipeg will be more advanced than at Lacombe (Figs. 2 and 3, respectively). The model predicts that egg hatch will begin in mid-June near Winnipeg.
Figure 2. Predicted development of bertha armyworm (Mamestra configurata) populations near Winnipeg, Manitoba as of June 6, 2021 (projected to June 30, 2021).Figure 3. Predicted development of bertha armyworm (Mamestra configurata) populations near Lacombe, Alberta as of June 6, 2021 (projected to June 30, 2021).
Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.
The cereal leaf beetle (CLB) (Oulema melanopus) model predicts that larval development is progressing across the prairies. The graphs below provide a comparison of development at Saskatoon (Fig. 1) and at Lethbridge (Fig. 2). The simulation indicates that populations are mostly in the second instar with the initial occurrence of third instar stages expected to occur this week. The simulation predicts that larval development will be complete by the end of the month across central Saskatchewan.
Figure 1. Predicted status of cereal leaf beetle (Oulema melanopus) populations near Saskatoon, Saskatchewan as of June 6, 2021 (projected to June 22, 2021).Figure 2. Predicted status of cereal leaf beetle (Oulema melanopus) populations near Lethbridge, Alberta as of June 6, 2021 (projected to June 22, 2021).
Model simulations for alfalfa weevil (AAW) (Hypera postica) predict, as of June 6, that alfalfa weevil populations should be primarily in the second larval instar (Fig. 1). The following graph indicates the predicted development near Brandon (Fig. 2). This week, larval populations in southern Manitoba should be primarily in the second instar. Simulation runs indicate that by June 22, southern Manitoba populations will be in the fourth instar with initial appearance of pupae.
Figure 1. Predicted development of Hypera postica (alfalfa weevil) populations across the prairies as of June 6, 2021.Figure 2. Predicted status of alfalfa weevil (Hypera postica) development for populations near Brandon, Manitoba as of June 6, 2021 (projected to June 22, 2021).
The larval stage of this weevil feeds on alfalfa leaves in a manner that characterizes the pest as a “skeletonizer” (Fig. 3). 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 3. Developmental stages of the alfalfa weevil (Hypera postica). Composite image: J. Soroka (AAFC-Saskatoon).
Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon). Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (2018; accessible in either English-enhanced or French-enhanced versions).
The 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 Guideis filled with helpful images for quick insect identification and plenty of tips to manage the pests AND natural enemies in your fields. Claim your free copy at http://fieldheroes.ca/fieldguide/ or download for free to arm your in-field scouting efforts!
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 10Jun2021) but follow the hyperlink to check the interactive map. They have reached Dauphin MB!
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 9, 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 – Cooperators are deploying pheromone traps and 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 38 traps have intercepted moths and only double-digit cumulative counts! Access the summary (as of June 8, 2021).
SASKATCHEWAN’SCrop Production News will soon be available. Be sure to bookmark their insect pest homepage to access important information! • Bertha armyworm pheromone trap monitoring update for SK – Cooperators are deploying pheromone traps at sites across the province. • Diamondback moth pheromone trap monitoring update for SK – follow this link to find current DBM counts. At this point, extremely low numbers have been intercepted but monitoring continues. 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 – Cooperators are deploying pheromone traps so refer to the Live Map as data becomes available. • Diamondback moth pheromone trap monitoring update for AB – Refer to the Live Map which reported extremely low numbers of moths intercepted so far (<45 province-wide as of 10Jun2021). • Cutworm reporting tool – Refer to the Live Map which reported four sites with cutworms (as of 10Jun2021).
This week’s Insect of the Week is the bertha armyworm (Mamestra configurata), a crop pest with the potential to do serious damage when populations run high. Though these insects are harmless to crops as adults, bertha armyworm larvae primarily consume canola, mustard, and alfalfa. Larvae may also consume plants like flax, peas and potatoes. The bertha armyworm is prevalent across the Prairies.
Prior to reaching their mature larval size, bertha armyworms feed on the underside of leaves. In canola and other plants that drop their leaves prior to the bertha armyworms’ larval maturation, the growing larvae move on to eat seed pods, stripping the pods and in extreme cases, consuming the seeds inside them. Even when the seed pods are not eaten through, stripped pods risk shattering and can hinder crop development.
bertha armyworm damage to seed pods (AAFC)
Adults are 20 millimeters long moths with a greyish body and 40 mm wingspan. Wing markings on the forewing include prominent white, kidney-shaped markings near the midpoint, and an olive and white irregular marking extending along the wing tip. Mature larvae are 40 mm long black (though sometimes light green or light brown) caterpillars with a light brown head and an orange stripe along each side, with three broken white lines down their backs.
bertha armyworm moth (Alberta Agriculture and Rural Development)
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 week cutworms, flea beetles, diamondback moths, grasshopper nymphs, alfalfa weevil larvae and bertha armyworm pheromone-baited traps will be going out – a busy week! Several economic pests Canadian growers contend with are now developing into the more damaging stages so get in to those fields!
This week’s Insect of the Week feature crop is dry bean, one of a number of important Prairie pulse crops. Our feature entomologist this week is Jennifer Otani (Agriculture and Agri-Food Canada).
Fava Bean Crop cc by 2.0 Phillip Halling
Dry bean, an important pulse crop, has seen modest but steady gains over the last five years. On the Prairies, Manitoba leads in both area (71%) and production (60%) (2019, StatsCan). Total Prairie production was 184,200 tonnes (203,046 US tons) on 96,000 hectares (237,400 acres).
How do you contribute in insect monitoring or surveillance on the Prairies?
The Pest Management Program based at the Beaverlodge Research Farm monitors and studies economic insect pests in annual crops, perennial grasses and legumes grown for seed. Our projects have focused on monitoring Lygus and root maggots in canola, red clover casebearer and clover-feeding weevils in clover seed production systems, and wheat midge. The program also monitors pests and beneficial insects in canola, alfalfa, wheat, clovers and grasses grown throughout the BC and Alberta portions of the Peace River region. Data collection supports the development of integrated pest management strategies suited to the region and supports regional and provincial insect pest surveillance and growers. I am the co-chair of the Prairie Pest Monitoring Network, and have supported the Network for many years as a researcher, collaborator, and editor for the PPMN’s Weekly Update and Blog.
In your opinion, what is the most interesting field crop pest on the Prairies?
I have two – one that’s kept me employed and one that scares me! Lygus bugscontinue to intrigue on so many levels. There are several species (a “complex”), that are native to the Canadian prairies. They affect a diverse range of plants and they can adjust to a region by producing more or less generations per season. My other favourite is the red clover casebearer (Coleophora deauratella) – I have tremendous respect for any larva that carries its home around and can chew through plexiglass glue to escape from cages!
What is your favourite beneficial insect?
I love dragonflies – both the aquatic and aerial life stages are simply amazing! Dragonflies are important indicators of ecosystem health. Both the nymphs and adults are fierce predators. I’m also tremendously fond of the Peristenus formerly known as Otaniaea. After years of collecting, rearing and forwarding beautiful specimens to support Dr. Henri Goulet’s work to revise the genus, he generously named this native braconid parasitoid after me. The species was later synonymized but, after so many years studying this pest-parasitoid complex, I’m still very honoured to have a beneficial wasp that attacks Lygus linked to my name!
Tell us about an important project you are working on right now.
Our program continues to work towards making the most of our samples by addressing species of both pest and beneficial insects. We are fortunate to work in a variety of host crops including canola, wheat, peas, alfalfa, creeping red fescue, plus red and alsike clover. This growing season, we now have an enhanced opportunity to continue more of this work in perennial grasses and legumes grown for seed. It’s important because perennials grown for seed, turf and forage markets are common throughout the region with fields remaining in crop 3-5 years and they may be an important reservoir for beneficial insects who traverse beyond field edges. Projects like these, involving our long-term monitoring and surveying research in both annual and perennial field crops, produce data sets we can direct towards the first iteration of the Beneficial Insects project lead by Dr. Haley Catton. We are working to make multiple years of canola survey data, some of our field plot data, and portions of our natural enemies data available to better define interactions and the economic value associated with the interaction of pests and beneficial insects in our fields.
What tools, platforms, etc. do you use to communicate with your stakeholders?
In addition to normal project reporting and publishing results, I actively support tech-transfer events at regional, provincial and national levels. The Pest Management Program has an unofficial lab Blog (http://insectpestmanagement.blogspot.com) to help communicate our activities to producer-cooperators, collaborators and potential students. I am also responsible for the Prairie Pest Monitoring Network (prairiepest.ca) which is a vital tool used to communicate with the Canadian agricultural industry. I also communicate using Twitter (@Bugs5132) during the growing season to highlight our research activities and the PPMN, often with the hashtags #PPMNblog and #WestCdnAg.
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.
Figure 1. Average Temperature (°C) across the Canadian prairies the past seven days (May 8-15, 2019).
Average 30-day temperatures were approximately 2 °C cooler than average (Fig. 2). Across the prairies, average temperatures (April 9-May 6) were 0 to -3 °C below normal (Fig. 3).
Figure 2. Mean temperature differences from Normal across the Canadian prairies from April 16-May 13, 2019. Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (16May2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true Figure 3. Average Temperature (°C) across the Canadian prairies the past 30 days (April 15- May 15, 2019).
Seven-day cumulative rainfall indicated that minimal rain was observed across large areas in AB and MB. Most locations reported less than 5mm (Fig. 4).
Figure 4. Cumulative precipitation observed the past seven days across the Canadian prairies (May 8-15, 2019).
Across the prairies, rainfall amounts for the past 30 days (April 15-May 15, 2019) have been approximately 50% of normal (Fig. 5). Growing season rainfall amounts have been well below average for most of the prairies. Only two areas, southern SK and the Peace River region were the only two areas that had normal to above normal rainfall (Fig. 6).
Figure 5. Percent of Average precipitation across the Canadian prairies the past 30 days (Up to May 15, 2019). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (16May2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true Figure 6. Cumulative precipitation observed the past 30 days across the Canadian prairies (April 15-May 15, 2019).
Soil moisture values are low across most of the prairies (Fig. 7).
Figure 7. Modeled soil moisture (%) across the Canadian prairies (up to May 15, 2019).
The growing degree day map (GDD) (Base 5 ºC, April 1-May 15, 2019) is below (Fig. 8):
Figure 8. Growing degree day (Base 5 ºC) across the Canadian prairies for the growing season (April 1-May 15, 2019). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (16May2019). 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. 9):
Figure 9. Growing degree day (Base 10 ºC) across the Canadian prairies for the growing season (April 1-May 15, 2019). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (16May2019). 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. 10).
Figure 10. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (May 8-15, 2019). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (16May2019). 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.
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.
New for 2019 – The Prairie Crop Disease Monitoring Network (PCDMN) represents the combined effort of our prairie pathologists who work together to support in-field disease management in field crops.
In 2019, the PCDMN will release a series of weekly Cereal Rust Risk Reports throughout May and June. Information related to trajectory events based on forecast and diagnostic wind fields and cereal rust risk is experimental, and is OFFERED TO THE PUBLIC FOR INFORMATIONAL PURPOSES ONLY.
Background: Agriculture and AgriFood Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990s. Trajectory models are used to deliver an early-warning system for the origin and destination of migratory invasive species, such as diamondback moth. In addition, plant pathologists have shown that trajectories can assist with the prediction of plant disease infestations and are also beginning to utilize these same data. An introduction will be presented of efforts to identify wind trajectory events that may bring rust urediniospores into Western Canada from epidemic areas in the central and Pacific northwest (PNW) regions of the USA. Identification of potential events as well as an assessment of epidemic severity from source locations, and prairie weather conditions, will be used to assess the need for prompt targeted crop scouting for at-risk regions of the Canadian Prairies.
This week, two documents are available from the PCDMN:
Synopsis of May 14, 2019, Weekly Cereal Rust Risk Report:
Wind trajectory and cereal rust risk assessment and need for in-crop scouting in the Prairie region, May 14, 2019
1. Pacific Northwest – Given limited stripe rust development in the PNW, a low number of recent wind trajectories from the PNW, cool Prairie weather conditions, and early stages of Prairie crop development, as of May 14, 2019, the risk of stripe rust appearance from the PNW is limited and scouting for this disease is not urgent.
2. Texas-Nebraska corridor – Although leaf and stripe rust development continues in this corridor, the disease is mainly affecting the lower canopy at generally low levels. There has been a low number of recent wind trajectories from this area, cool Prairie weather conditions, and early stages of Prairie crop development. As of May 14, 2019 the risk of leaf and stripe rust appearance from the Texas-Nebraska corridor is low and scouting for these diseases is not urgent.
3. Where farmers or consultants noticed stripe rust development on winter wheat in the fall of 2018, it is recommended to scout winter wheat fields that have resumed growth this spring. Scouting is especially critical where the variety being grown is susceptible to stripe rust. Currently, there are no early spring reports of stripe rust on winter wheat.
Flea Beetles (Chrysomelidae: Phyllotreta species)– As newly seeded stands begin to emerge, the need for in-field scouting increases. Review Wk05 for flea beetle information, visual guides to help estimate percent of cotyledon damage, and links to the Insect Field Guide.
Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed. Watch for shot-hole feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.
Cereal leaf beetle (Oulema melanopus) – The CLB model was run for Lethbridge AB and projected to June 15, 2019 (Fig. 1). The cereal leaf beetle model indicates that eggs may begin to hatch later next week Lethbridge.
Figure 1. Projected predicted status of cereal leaf beetle populations near Lethbridge 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”.
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 runs for Brooks AB (Fig. 1) and Swift Current SK (Fig. 2) were projected to June 15, 2019. Model output indicates that initial hatch should occur late next week in fields near Brooks. Hatch should be 5-7 days later in the Swift Current region. Compared to last year’s runs for Swift Current, development is predicted to be 10 days later than 2018. Compared with long term normal weather data, egg development is 1 – 2 days later than average.
Figure 1. Projected predicted status of alfalfa weevil populations near Brooks AB to June 15, 2019 using long term average temperatures. Figure 2. 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.
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).
Compared to last week, near normal temperatures have resulted in expected development of grasshopper eggs. This week, as of May 15, 2019, predicted development was 63% and is similar to long term average values (Fig. 1).
Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development acrossthe Canadian prairies as of May 15, 2019.
Model runs for Lethbridge (Fig. 2) and Saskatoon (Fig. 3) were projected to June 15, 2019. Results indicated that eggs should begin to hatch next week. Model predictions, based on long term normal weather data predict that initial hatch near Saskatoon should occur on May 25th.
Figure 2. Predicted status of Melanoplus sanguipes populations near Lethbridge AB as of May 15, 2019. Figure 3. Predicted status of Melanoplus sanguipes populations near Saskatoon SK as of May 15, 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.
Whenever possible, monitor and compare pest densities to established economic or action thresholds to protect and preserve pollinators and beneficial arthropods. Economic thresholds, by definition, help growers avoid crop losses related to outbreaking insect pest species.
The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops.
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 valuable arthropods occurring in field crops.
Have you seen the “Check the Net” infographics that helps growers understand just how many organisms are present in cereals, oilseeds, and pulses and that ONLY A SMALL PROPORTION are considered economic pests? A great many of the other insects, spiders, and mites are beneficial organisms that work to regulate crop pests! Protect and enhance their impact on crop pests by performing in-field assessments and use economic thresholds to help decide when control is warranted and find out more about the Cereal Avengers, Oilseed Avengers and Pulse Avengers!
Be sure to follow @FieldHeroes on Twitter for practical tips and information.
Thanks to Western Grains Research Foundation for their support of this important campaign. This initiative has been made possible through the support and advice of enthusiastic members of the Prairie Pest Monitoring Network.
Crop Protection Guides – If you don’t have a copy of your province’s Crop Protection Guide, please make use of these links to access the PDF version of the:
Remember – If your fields are near one of Environment Canada’s PRAIRIE Radar Stations, consider accessing weather radar maps in video format to access either the past 1 OR 3 hours of precipitation events displayed as spatio-temporal maps. These maps can help growers review where and how much precipitation fell nearby and can help when trying to time pesticide applications.
Screen shots of Environment Canada’s webpages are below for reference and red text and arrows have been added to help you navigate the webpage.
Provincial entomologists provide insect pest updates throughout the growing season so we link to their most recent information:
• Manitoba‘s Insect and Disease Updates for 2019 will be posted here and include updates from Dr. John Gavloski.
• Saskatchewan‘s Crops Blog Posts includes a segment on “Early season scouting of cutworms” by Sara Doerksen posted for April 2019. Watch for updates from Dr. James Tansey and Mr. Carter Peru.
• Alberta Agriculture and Forestry’s Call of the Land regularly includes insect pest updates from Mr. Scott Meers. The most recent Call of the Land was posted March 18-22, 2019 but did not include an insect update.
The lily leaf beetle (Lilioceris lilii) is a native of Europe and was originally found in Canada at Montreal in 1945. Since then, it has spread throughout Eastern Canada and has now established itself as far west as Alberta. Long distance movement of the beetle is facilitated by movement of plant material; locally, they move on their own as they are strong flyers.
The lily leaf beetle lays its eggs and develops only on true lilies (Tiger, Easter, Asiatic and Oriental lilies) and fritillaries. They can feed (but not develop) on other perennials like lily-of-the-valley. Adult and larval feeding will ruin true lilies. The feeding damage can be so severe that many gardeners have removed lilies from their landscapes.
The adult beetle overwinters in the soil or leaf litter, not necessarily near host plants. They emerge on the first warm spring days and will begin feeding on the early emerging lilies, as early as mid-April on the Prairies. Shortly after emergence, they start to mate and lay orange eggs in rows of 3-12 on the undersides of the lily leaves or on the emerging lily shoots (late April to early May). Egg laying (up to 450 per female) can continue well into July. Eggs will hatch in 4-8 days.
The larva is a soft, hump-backed, orange to brownish slug-like animal with a black head and legs. For protection from predation, desiccation and camouflage, it covers its body with a layer of its own fecal matter. The larval stage most destructive phase of the beetle’s life cycle, as larvae feed for 16-24 days. They devour leaves leaving only the plant stems, and chew into flower buds. Larvae drop to ground to pupate and emerge as adults 16-22 days later.
Tetrastichus setifer, a small parasitoid wasp (harmless to humans), is being introduced as biological control agent for the beetle. T. setifer overwinters in the soil in a cocoon. It then emerges in the spring and the female will lay up to nine eggs in one lily leaf beetle larva. She can lay eggs in all four larval instars of the lily leaf beetle.
There have been successful T. setifer releases in Ottawa with establishment and good suppression of lily leaf beetles. Releases have been done in gardens in Manitoba and Quebec as well natural sites in Quebec where the native lilies Lilium canadense, and Lilium michiganense grow. Successful establishment of T. setifer in the natural locations is uncertain at this time. Recently, there have been releases in Calgary, Alberta and Olds, Alberta. In 2018 additional releases were made in 2 gardens in Brooks, Alberta.
This week’s insect is the ground beetle, Pterostichus melanarius (Coleoptera: Carabidae). This large (12-19 mm), shiny black beetle originates from Europe and probably arrived to North America in the 1920s in ships’ ballasts. It has become a widespread insect throughout North America, particularly in habitats used by humans: urban areas, forests, and agricultural land.
Flight has been the main method of colonization and dispersal for this species. In newly arrived populations of P. melanarius, individuals generally have longer hind wings which allow for more efficient dispersal. After a population has become established in an area, short-winged morphs of the species become dominant.
This species is an excellent example of a generalist predator. Generalist predators include many species of ground beetles, some rove beetles, ants, centipedes and spiders. These arthropods are not picky when it comes to choosing a meal. For example, P. melanarius will eat nearly anything including many different arthropods, earthworms, slugs and even some small vertebrates. Generalist predators are effective in keeping some insects from reaching high numbers that can damage agricultural crops.
Find out more about ground beetles and Pterostichus melanarius at the Insect of the Week page!
Pterostichus melanarius Photo credit: Henri Goulet (retired), Agriculture and Agri-Food Canada
Photograph of Pterostichus melanarius catching a fourth-instar P. xylostella in a plastic container (LRC, Photo credit: A. Mauduit)
Weather synopsis – This past week (June 4 – 11, 2018), the average temperature (13.3 °C) was very similar to long term average (Fig. 1). The warmest weekly temperatures occurred across MB. The 30-day (May 12 – June 11) average temperature (12.9 °C) was approximately 2 °C warmer than long term average (Fig. 2).
Figure 1. Weekly (June 4 – 11, 2018) average temperature (°C) . Figure 2. The 30-day (May 12 – June 11, 2018) average temperature (°C).
Weekly and 30-day total precipitation was above average. The wettest region was across eastern areas in SK (Figs. 3 and 4).
Background: Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories to deliver an early-warning system for the origin and destination of migratory invasive agricultural pests.
We receive two types of model output from ECCC: reverse trajectories (RT) and forward trajectories (FT):
(i) ‘Reverse trajectories’ (RT) refer to air currents that are tracked back in time from specified Canadian locations over a five-day period prior to their arrival date.
(ii) ‘Forward trajectories’ (FT) have a similar purpose; however, the modelling process begins at sites in USA and Mexico. The model output predicts the pathway of a trajectory. Again, of interest are the winds that eventually end up passing over the Prairies.
Current Data
Since April 1. 2018, the majority of Pacific Northwest (PNW) air currents have crossed over southern AB (Fig. 1). The cumulative number of wind dispersal events for June 1 – 11, 2018 (181) is greater than the long term (2007 – 2017) average (98).
Figure 1. Total reverse trajectories (originating from US – PNW) April 1 – June 11, 2018.
Since April 1, the majority of air currents from southwest USA and Mexico have crossed over eastern SK and western MB (Fig. 2). So far there have been 18 RT’s (June 1 – 11, 2018) and compares with 2017 (3) and the long term average (24).
Figure 2. Total number of reverse trajectories (originating from southern USA) April 1 – June 11, 2018.
Reminder – Last week turned out to be our wireworm blitz! This complicated group of insect species was featured in the Insect of the Week AND we include the survey results again this week!
The following maps summarize the main results of a survey of pest species of wireworms of the Canadian Prairie Provinces. Samples (both larvae and beetles) were submitted to Dr. Bob Vernon’s lab in Agassiz, BC, from 2004 to 2017, and identified by Dr. Wim van Herk (Fig. 1). Species identifications were confirmed with barcoding.
Figure 1. Sampling locations for click beetles and wireworm larvae (Coleoptera: Elateridae) submitted for wireworm surveying from 2004-2017.
Approximately 600 samples were submitted, with the number of larvae per sample typically less than five (Fig. 1). More samples are welcome, particularly from areas currently not well represented on the maps.Please provide either the legal land description or latitude and longitude coordinates with a sample. Any information on the cropping history or whether fields were irrigated is helpful.
Review the complete survey summary posted in Week 05 (for Jun 7, 2018).
Disclaimer: Please do not distribute or use the contents of this post, including any maps, without obtaining prior permission.
Obtain further information or arrange shipment of wireworm or click beetle samples by contacting: Dr. Wim van Herk Agriculture and Agri-Food Canada Agassiz Research and Development Centre 6947 Highway 7, Agassiz, BC, V0M 1A0 wim.vanherk@agr.gc.ca
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 11, 2018, predicted hatch was 74% (long term average was 28%). The average development is almost at second instar (Fig. 1) with 30, 28, 12 and 2% in the first, second, third and fourth instar stages, respectively.
Figure 1. Grasshopper development (average instar) on model simulations, for April 1 – June 11, 2018.
Model output for Saskatoon illustrates that populations are primarily in the first and second instars with third and fourth instar stages beginning to appear (Fig. 2). This agrees with last week’s survey conducted south of Saskatoon SK.
Figure 2. Predicted grasshopper phenology at Saskatoon SK. Values are based on model simulations, for April 1 – June 11, 2018.
Bertha armyworm (Lepidoptera: Mamestra configurata) – BAW development continues to be 7-10 days ahead of normal development (Fig. 1).
Figure 1. Percentage of pupal stage heat requirements for emergence of bertha armyworm (as of June 20, 2018).
Near Saskatoon SK, adult emergence is well underway and oviposition is predicted to have begun this week. Based on climate data, oviposition near Saskatoon should begin around the third week of June.
Reminder –Table 1. Projected dates for BAW adult emergence for June 4, 2018 (projected to June 30, 2018).
For those who are now checking a bertha armyworm pheromone trap on a weekly basis, we provide an excellent photo 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 so check carefully and thanks for your help!
Wheat Midge (Sitodiplosis mosellana) – Simulation modelling is used to predict wheat midge emergence across the Canadian prairies. The wheat midge model indicates that wheat midge larvae should be moving to the soil surface (Fig. 1). Adequate moisture has resulted in expected emergence patterns.
Figure 1. Predicted wheat midge phenology at Saskatoon SK. Values are based on model simulations, for April 1 – June 11, 2018 (projected to July 15, 2018).
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.
Pea Leaf Weevil (Sitona lineatus) – The PLW model predicts that oviposition is nearly complete and PLW are primarily in the adult and egg stages (Fig. 1). Larvae should begin to appear later this week.
Figure 1. Predicted pea leaf weevil phenology at Red Deer AB. Values are based on model simulations, for April 1-May 28, 2018 (projected to July 15, 2018).
Pea leaf weevils emerge in the spring primarily by flying (at temperatures above 17ºC) or they may walk short distances. Pea leaf weevil movement into peas and faba beans is achieved primarily through flight. Adults are slender, greyish-brown measuring approximately 5 mm in length (view weevil adult photos here).
Adults 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 (Fig. 4). Females lay 1000 to 1500 eggs in the soil either near or on developing pea or faba bean plants from May to June.
Figure 4. Scalloped notching along leaf margins of pea plant (Photo: L. Dosdall).
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. 5 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. 5 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 5. 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.
Alfalfa Weevil (Hypera postica) – Approximately 70% of the population should be in the third or fourth instar stages and pupae may be occurring as well. AAW populations near Winnipeg, Brandon, Regina, Saskatoon and regions in southern Alberta are predicted to be primarily in the fourth instar (Fig. 1).
Figure 1. Average predicted development stages of alfalfa weevil. Values are based on model simulations (April 1-June 11, 2018).
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.
Lygus bugs (Lygus spp.) – Lygus development is well underway. Adults have moved in to the fields and oviposition should be almost complete. The Lygus model suggests that populations near Brandon MB should consist of first to third instar stages (Fig. 1).
Figure 1. Predicted Lygus phenology at Brandon MB. Values are based on model simulations, for April 1 – June 11, 2018.
On average, prairie populations are predicted to be in the first or second instar stages with development being greatest across the southern prairies (Fig. 2).
Figure 2. Predicted average developmental Lygus stage. Values are based on model simulations, for April 1 – June 11, 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.
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.
Cabbage seedpod weevil (Ceutorhynchus obstrictus) – There is one generation of CSPW per year and the overwintering stage is the adult which is an ash-grey weevil measuring 3-4mm long (Refer to lower left photo). Adults typically overwinter in soil beneath leaf litter within shelter belts and roadside ditches.
Monitoring:
Begin sampling when the crop first enters the bud stage and continue through the flowering.
Sweep-net samples should be taken at ten locations within the field with ten 180° sweeps per location.
Count the number of weevils at each location. Samples should be taken in the field perimeter as well as throughout the field.
Adults will invade fields from the margins and if infestations are high in the borders, application of an insecticide to the field margins may be effective in reducing the population to levels below which economic injury will occur.
An insecticide application is recommended when three to four weevils per sweep are collected and has been shown to be the most effective when canola is in the 10 to 20% bloom stage (2-4 days after flowering starts).
Consider making insecticide applications late in the day to reduce the impact on pollinators. Whenever possible, provide advanced warning of intended insecticide applications to commercial beekeepers operating in the vicinity to help protect foraging pollinators.
High numbers of adults in the fall may indicate the potential for economic infestations the following spring.
Damage: Adult feeding damage to buds is more evident in dry years when canola is unable to compensate for bud loss. Adults mate following a pollen meal then the female will deposit a single egg through the wall of a developing pod or adjacent to a developing seed within the pod (refer to lower right photo). Eggs are oval and an opaque white, each measuring ~1mm long. Typically a single egg is laid per pod although, when CSPW densities are high, two or more eggs may be laid per pod.
There are four larval instar stages of the CSPW and each stage is white and grub-like in appearance ranging up to 5-6mm in length (refer to lower left photo). The first instar larva feeds on the cuticle on the outside of the pod while the second instar larva bores into the pod, feeding on the developing seeds. A single larva consumes about 5 canola seeds. The mature larva chews a small, circular exit hole from which it drops to the soil surface and pupation takes place in the soil within an earthen cell. Approximately 10 days later, the new adult emerges to feed on maturing canola pods. Later in the season these new adults migrate to overwintering sites beyond the field.
Provincial entomologists provide insect pest updates throughout the growing season so we link to their most recent information:
Manitoba‘s Insect and Disease Update for 2018 will be posted soon. Review the most recent update (June 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 7, 2018) and identified concerns with stem feeding by flea beetles with the cooler weather this past week, reports of dung beetle larvae in some irrigated fields, continuation of pea leaf weevil surveying into central Alberta, and transient presence of some blister beetles. Updated June 14, 2018.
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 12Jun2018) but follow the hyperlink to check the interactive map. Last week monarchs were spotted in Manitoba and this week they’ve entered Saskatchewan!
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 Rove Beetle (Delia spp.). This beetle feeds on aphids, mites, eggs and larvae of many other insects present under plant debris, rocks, stones, carrion, dung, and other materials. It is also an important natural enemy of the pea leaf weevil. One species of the rove beetle, Aleochara bilineata, is an important natural enemy of cabbage, seedcorn, onion and turnip maggots.
Follow @FieldHeroes to learn more about the Natural Enemies that are working for you for FREE to protect your crops!
For more information on the Rove Beetle, see our Insect of the Week page.
Weather synopsis – Meteorological conditions for the past month of May were generally warmer and dryer than normal. Average May temperatures were in the range of 0 to 2°C warmer than long term averages.
May precipitation was below average across Manitoba and Saskatchewan; rainfall amounts were greatest across Alberta. The overall precipitation this growing season has been below normal to normal in Saskatchewan and Manitoba, but normal to well above normal in Alberta.
Over this past week, average temperatures across the prairies were 2°C warmer than last week, and marginally warmer than long term averages for early June. Weekly average temperatures were greatest in southern regions of Manitoba and Alberta. Precipitation over the past week was greatest in central and northern Alberta. Most of Saskatchewan was dry over the past week.
The map below reflects the Accumulated Precipitation for the Growing Season so far for the prairie provinces (i.e., April 1-June 5, 2017):
The map below shows the Lowest Temperatures the Past 7 Days (May 30-June 5, 2017) across the prairies:
Whereas the map below shows the Highest Temperatures the Past 7 Days (May 30-June 5, 2017):
The updated growing degree day map (GDD) (Base 5ºC, March 1 – June 4, 2017) is below:
While the growing degree day map (GDD) (Base 10ºC, March 1 – June 4, 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.
