The week of May 22-26 saw the arrival of some much needed precipitation to parts of Alberta and Saskatchewan, but hot weather up to May 21 across most of the prairies has affected insect development so far this spring.
Grasshoppers thrive in warm, dry conditions and we continue to hear about high numbers of nymphs along roadsides and field edges. Diamondback moths have been captured in pheromone traps across the prairies, generally in low numbers. In preparation for bertha armyworm monitoring, we ran the model for pupal development this week and unsurprisingly, development is ahead of schedule. For more information, check out the posts in the Weekly Update! The Insect of the Week is about parasitoids of cutworms this week – read on and check out the links for more information. Finally, Dr. Kevin Floate has written a new book about dung beetles that is available for free download!
The prairie-wide maps summarizing the results from the 2022 growing season are online and available for review, as are the historical insect pest distribution maps. These prairie-wide geospatial maps offer insight into potential risk and help growers prioritize their scouting lists.
Remember, insect Monitoring Protocols containing helpful insect pest biology, how and when to plan for in-field scouting, and even thresholds to help support in-field management decisions are all available for review or download.
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.
***Special thanks to Mark Berry, AAFC-Geomatics, for providing up-to-date weather information for the prairies that is summarized here and used to predict insect development. Mark provides this information for every Weekly Update, but I’m new to running the website and have not yet figured out how to add him to the author list for the posts***
During the week of May 15-21 average prairie temperatures continued to be well above average. The average daily temperature was 4°C warmer than normal (Fig. 1). The warmest temperatures were observed across Alberta and western Saskatchewan. Dawson Creek, BC was 8°C warmer than average temperatures for mid-May. The coolest weekly temperatures were observed over eastern Saskatchewan and Manitoba.
Figure 1. Seven-day average temperature (°C) observed across the Canadian prairies for the period of May 15-21, 2023.
Average temperatures over the past 30 days (April 22 – May 21, 2023) have been 3°C above normal with the warmest values being reported for Alberta and western Saskatchewan (Fig. 2).
Figure 2. 30-day average temperature (°C) across the Canadian prairies for the period of April 22-May 21, 2023.
Since April 1, the 2023 growing season has been coolest across eastern Saskatchewan and Manitoba (Fig. 3). Alberta temperatures continue to be above average. Relative to climate normals, growing season temperatures have been well above normal in the Peace River region. Fort Vermillion, AB has been 5°C warmer than normal and Fort St. John, BC has been 4°C above normal. Temperatures have been below normal for many locations in Manitoba. For example, the average temperature near Melita has been 2.25°C cooler than average.
Figure 3. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1 to May 21, 2023.
Seven-day cumulative rainfall (May 15-21) was very low for Alberta and Saskatchewan (Fig. 4). Over the past 30 days (April 22 – May 21, 2023), rainfall has been minimal for Saskatchewan and Alberta (Fig. 5). For example, Saskatoon has had 12 mm of rain in that time, which is only 9% of what the Saskatoon area normally receives in the same period. On average, the prairie region has received about 40% of the precipitation normally expected for this time of year. For more information, visit the Agriculture and Agri-Food Canada Agroclimate site (https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true).
Figure 4. Seven-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 15-21, 2023. Figure 5. 30-day average cumulative rainfall (mm) observed across the Canadian prairies for the period of April 22-May 21, 2023.
Growing season rainfall has been below normal across most of the prairies so far in 2023 (Fig. 6). A large region, extending from Lethbridge to Saskatoon to the Peace River region continues to have well below normal rainfall accumulations (Fig. 6). Meadow Lake rainfall has been 34% of normal and Kindersley has reported only 15 mm (42% of normal).
Figure 6. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1 to May 21, 2023.
Agriculture and Agri-Food Canada (AAFC; Ross Weiss, Meghan Vankosky) and Environment and Climate Change Canada (ECCC; Serge Trudel) 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.
‘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 moth 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.
Wind Trajectories, May 1 to May 23, 2023:
Since May 1, 2023, the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Very few reverse trajectories that originated in Mexico, California or Texas passed over the Canadian prairies between May 1 and May 23. No reverse trajectories, originating over Oklahoma or Texas crossed over the prairies this week.
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 1-23, 2023.
The majority of reverse trajectories originating in the Pacific Northwest have been reported to pass over south-central Alberta and southwestern Saskatchewan (Fig. 2).
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 May 23, 2023.
Since April 1, reverse trajectories that originated in Kansas and Nebraska were reported to cross southeastern Saskatchewan and southern Manitoba (Fig. 3).
Figure 3. The total number of dates with reverse trajectories originating over Kansas and Nebraska that have crossed the prairies between May 1 and May 23, 2023.
Model simulations were used to estimate development of grasshoppers as of May 21, 2023. Compared with average spring temperatures, well above normal temperatures in Alberta and western Saskatchewan have contributed to rapid grasshopper egg development (Fig. 1) that is well ahead of what we would expect at this time in an average growing season (Fig. 2). Average egg development for the prairies is 81% complete. The model predicts that egg development is well ahead of the long-term value of 67% complete for this time of year. Cool conditions in Manitoba have resulted in slower development rates that are similar to long-term average development rates.
Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 21, 2023. Figure 2. Long-term average predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 21, based on climate normals data.
As a result of above normal temperatures, model predictions indicate that grasshopper eggs have already started to hatch, especially in Alberta and western Saskatchewan (Fig. 3). Model simulations suggest that hatch rates are 15-35% across the Peace River region. This is well ahead of long-term average hatch rates and we already have reports of grasshopper nymphs found along roadsides and field edges in Alberta and Saskatchewan. Prairie farmers should be prepared to scout for grasshoppers for the next 2-3 weeks, especially if conditions remain warmer and drier than normal.
Figure 3. Predicted grasshopper (Melanoplus sanguinipes) hatch (%) across the Canadian prairies as of May 21, 2023.
Analysis of wind trajectory data (from Environment and Climate Change Canada) indicates that a number of upper air currents, originating over the USA Pacific Northwest, passed over Alberta and Saskatchewan during the last week of April and first three weeks of May. These wind currents could have been carrying adult diamondback moths into the prairies. In fact, adult diamondback moths have been collected in traps located across Alberta (information courtesy of Shelley Barkley, Alberta Agriculture and Irrigation) and Saskatchewan (information courtesy of Carter Peru and James Tansey, Saskatchewan Ministry of Agriculture) during the first three weeks of May.
DBM development can be rapid during periods of warm weather. This week, the diamondback moth model was initialized for May 1, 2023 and run to May 21. Though canola may not be present, model results indicate that females may have begun to lay eggs on cruciferous plants like volunteer canola and weeds. Larvae could now also be found feeding on these host plants. The model simulation indicates that populations near Grande Prairie, AB (Fig. 1) are likely to be more advanced in terms of development than populations near Cadillac, SK (Fig. 2) reflecting differences in growing season weather so far in 2023 at the two locations.
Figure 1. Predicted development of diamondback moth (Plutella xylostella) near Grande Prairie, AB as of May 21, 2023. Figure 2. Predicted development of diamondback moth (Plutella xylostella) near Cadillac, SK as of May 21, 2023 (Biofix date = May 1, 2023).
Spring Pheromone Trap Monitoring of Adult Males: Across the Canadian prairies, spring monitoring is initiated to acquire weekly counts of adult moths attracted to pheromone-baited delta traps deployed in fields. Weekly trap interceptions are observed to generate cumulative counts. Summaries or maps of cumulative male diamondback moth counts will be available for each province as the monitoring season progresses. These cumulative count estimates are broadly categorized to help producers prioritize and time in-field scouting for larvae.
In-Field Monitoring:Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.
The life stages of diamondback moth, Plutella xylostella: (A) eggs, (B) early instar larva, (C) late instar larvae, (D) pupa, and (E) adult moth. Photo credit: Jonathon Williams, AAFC-Saskatoon (all pictures)
Based on model simulations, development of overwintered BAW pupae this spring (Fig. 1) is expected to be significantly ahead of normal for most of the prairies (Fig. 2). BAW pupal development in Alberta is 10-14 days faster than average development for this time of year.
Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development (%) across the Canadian prairies as of May 21, 2023. Figure 2. Long-term average predicted bertha armyworm (Mamestra configurata) pupal development (%) across the Canadian prairies as of May 21, 2023.
To best detect the initial flight of adult BAW, pheromone traps should be placed in fields when pupal development is 75-80% complete. This ensures that traps are deployed before adults emerge and the mating period begins. Based on current BAW development, as predicted by the model, it is advisable that pheromone traps in Alberta be placed in fields this week or early next week (week of May 29). Pheromone traps should be installed later next week in most of Saskatchewan. At trap sites in eastern Saskatchewan and Manitoba, the pheromone traps should be placed in fields before June 9th.
Provincial entomologists provide insect pest updates throughout the growing season. Visit the links below to read their updates and to find other valuable information about prairie crop insects and beneficial insects.
The first Manitoba Crop Pest Update for 2023 is now available! Looking for historical information? Links are available for past Updates too.
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.
Visit the Alberta Insect Pest Monitoring Network page for information about insect monitoring in Alberta, including live maps from the 2023 monitoring season for diamondback moth, bertha armyworm, cutworms and others.
Entomologist Dr. Kevin Floate aims to answer ‘what critters are found in a cow patty?’ and ‘what do they do?’ His hope is to spark the interest of ranchers and farmers, and to stir the minds of students studying insects. In his own words, ‘This is the guide I wish I had when I started my career.’
Cover and sample content of Cow Patty Critters
Insects serve an outsized role in many ecosystem services. For dung on Canadian pastures, there are over 300 species of insects helping to break down and cycle nutrients through the soil and food webs. Understanding what insects are present in a cow patty provides insights into livestock health and ecological processes.
Dr. Kevin Floate speaking about insects to a captivated audience. Photo credit: Cam Goater, University of Lethbridge
Download your copy of Cow Patty Critters in English or in French.
This new 224-page, full color guide provides the ‘doorway’ to learn more about the critters one can find in cow dung: how to identify them, how they can be beneficial, and additional information on the biology and morphology of multiple insect groups. Also included is an extensive reference list for those who wish to pursue detailed insect identification.
While you’re out scouting for cutworms, tachinids flies and ichneumonid wasps are scouting for them too! We have two Insects of the Week this week and both are parasitoids of cutworm pests. Parasitoids complete part of their lifecycle inside another organism, in this case cutworms, eventually killing them.
Adult tachinid flies are pale or dark brown in colour with long, bristly hairs covering their bodies. Females typically lay one to several eggs on a host. Upon hatching the larvae burrow into the host, develop inside, and then exit to pupate in the soil. Adult flies feed on flower nectar, honeydew from aphids, scale insects, and mealybugs. The tachinid, Athrycia cinerea (Coq.), is a parasitoid of the Bertha armyworm.
An adult tachinid fly (Tachinia algens) reared from glassy cutworm. Photo credit: Shelby Dufton, AAFC-Beaverlodge Research Farm.
Ichneumonidae adults vary in size and colouration but all have a narrow waist, a long abdomen, and long antennae. Females have long ovipositors that they use to inject eggs into their hosts, including cutworm larvae. Adults eat nectar and aphid honeydew. Ichneumonid larvae (including Banchus flavescens) are parasitoids of Lepidoptera, Coleoptera, Diptera, Hymenoptera, and some spiders.
An adult Ichneumonid parasitoid of the genus Banchus, reared from a dingy cutworm. Photo credit: Shelby Dufton, AAFC-Beaverlodge Research Farm.
For more information about these parasitoids, the other pests they control and other important crop and forage insects, see the Field Crop and Forage Pests and their Natural Enemies in Western Canada guide. The guide has helpful information about the life cycle of these and other parasitoids. The guide also has tips for conserving parasitoids and pictures to help with identification.
The weather report is a bit longer than usual owing to unusual conditions summarized broadly as cool and wet in the east, cool and dry in the west, and cool and wet in the Peace River region! This all has an impact on the progression of insect development as well as crop growth.
Catch Monday’s Insect of the Weekfor Week 3- it’s the most common wireworm, Hypnoidus bicolor!
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: Since April 1, the 2022 growing season has been cooler than normal, particularly across Manitoba. Conditions continue to be dry across Alberta and western Saskatchewan while rainfall amounts have been well above normal for eastern Saskatchewan and Manitoba. This past week (May 16-22, 2022), the average temperature across the prairies was 2 °C cooler than normal (Fig. 1). Temperatures were warmest in an area extending from Regina to Lethbridge and north to Edmonton.
Figure 1. Seven-day average temperature (°C) across the Canadian prairies for the period of May 16-22, 2022.
The average 30-day temperature (April 23-May 22, 2022) was 0.5 °C less than climate normal values (Fig. 2) and the growing season (April 1-May 22, 2022) has been 1.7 °C cooler than average (Fig. 3). Compared with climate normal values or average growing season temperatures, temperatures in 2022 have been 2-4 °C cooler than average across southeastern Saskatchewan and Manitoba (Fig. 4; Table 1).
Figure 2. 30-day average temperature (°C) across the Canadian prairies for the period of April 23 to May 22, 2022.Figure 3. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1 to May 22, 2022.Figure 4. Growing season average temperature anomaly (°C difference from climate normals) observed across the Canadian prairies for the period of April 1-May 22, 2022.Table 1. Growing season temperature and rainfall summary for specific locations across the Canadian prairies (April 1- May 22, 2022).
PRECIPITATION: Seven-day cumulative rainfall ranged between 0 and 54 mm with highest rainfall amounts occurring across Manitoba and the Parkland region of Saskatchewan (Fig. 5).
Figure 5. Seven-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 16-22, 2022.
Western Saskatchewan and most of Alberta have received little or no rain over the past seven days. Rain (30-day accumulation) amounts have been well above average across the eastern prairies, particularly southeastern Manitoba; rain amounts have been minimal in Alberta and western Saskatchewan (Fig. 6).
Figure 6. 30-day cumulative rainfall (mm) observed across the Canadian prairies the past 30 days (April 23 to May 22, 2022).
Growing season rainfall for April 1-May 22, 2022 has been greatest across Manitoba and eastern Saskatchewan; precipitation has been well below normal across most of Saskatchewan and Alberta (Figs. 7 and 8; Table 1).
Figure 7. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1 to May 22, 2022.Figure 8. Growing season cumulative rain anomaly (% if climate normals) observed across the Canadian prairies for the period of April 1-May 22, 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 embryonic (egg) development as of May 22, 2022. Egg development ranges between 55 and 75% across most of the prairies (average=64%) (Fig. 1). Based on climate normals data, long term average development should be 64% (Fig. 2). Cool conditions in Manitoba and the Peace River region continue to result in slower than average development rates. Across southern Alberta, the simulation indicates that egg development is similar to average values. This region has had the least amount of rain during the growing season.
Grasshopper risk can be greater when conditions are warm and dry. Initial hatch is predicted to have begun near Medicine Hat and Brooks Alberta.
Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 22, 2022.Figure 2. Long-term average predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 22 based on climate normals data.
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 thatoviposition should be well underway across the prairies. The following graphs indicate, based on potential number of eggs, that development is marginally slower near Lethbridge, Alberta (Fig. 1) than Saskatoon, Saskatchewan (Fig. 2). The model predicts that hatch should begin next week.
Figure 1. Predicted status of alfalfa weevil (Hypera postica) populations near Lethbridge AB as of May 22, 2022.Figure 2. Predicted status of alfalfa weevil (Hypera postica) populations near Saskatoon SK as of May 22, 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.
Cereal leaf beetle (CLB) model output suggests that oviposition is underway across the southern prairies. The following graphs provide a comparison of development for Lethbridge, Alberta (Fig. 1) and Brandon, Manitoba (Fig. 2). Warmer conditions in southern Alberta are predicted to result in more rapid development of CLB populations than for southern Manitoba. The simulation predicts that first instar larvae may occur next week in southern Alberta and 7-10 days later across southern Manitoba.
Figure 1. Predicted status of cereal leaf beetle (Oulema melanopus) populations near Lethbridge AB as of May 22, 2022.Figure 2. Predicted status of cereal leaf beetle (Oulema melanopus) populations near Brandon MB as of May 22, 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.
1. REVERSE TRAJECTORIES (RT) Since May 1, 2022, the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Relative to previous weeks, this past week (May 17-23, 2022) there were fewer trajectories passing over the prairies.
Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of May 1-23, 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).
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 May 23, 2022.
b. Mexico and southwest USA (Texas, California) – This past week there were no reverse trajectories originating from Mexico, California or Texas. Since April 1, reverse trajectories were reported for Manitoba (Portage, Selkirk, Brandon, Carman, Russell) and eastern Saskatchewan (Gainsborough, Grenfell) (Fig. 3).
Figure 3. The total number of dates with reverse trajectories originating over Mexico, California and Texas that have crossed the prairies between April 1 and May 23, 2022.
c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan (Fig. 4). No trajectories were predicted for May 17-23, 2022.
Figure 4. The total number of dates with reverse trajectories originating over Texas and Oklahoma that have crossed the prairies between May 1 and May 23, 2022.
d. Nebraska and Kansas – Reverse trajectories, originating from Kansas and Nebraska have crossed southeastern Saskatchewan and southern Manitoba (April 1 – May 23, 2022) (Fig. 5).
Figure 5. The total number of dates with reverse trajectories originating over Kansas and Nebraska that have crossed the prairies between April 1 and May 23, 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) predicted to cross the Canadian prairies (Fig. 6). 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 May 23, 2022.
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 May 25, 2022 issue here. Bookmark their Crop Pest Update Index to readily access these reports and also bookmark their insect pest homepage to access fact sheets and more! • Diamondback moth pheromone trap monitoring update for MB – “So far, diamondback moth has only been found in 14 traps.” Review page 5 of the above report for greater detail.
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. • Cutworm live monitoring map for AB – Cumulative counts arising from weekly data are available so refer to the Live Map.
Continuing our series on Prairie wireworms, this week we highlight Hypnoidus bicolor.
This species is the most abundant in Prairie crop fields and is a native species. Despite its abundance, it has no common name. Hypnoidus bicolor larvae are relatively small (10-12 mm long when mature) and are often found in the same fields as next week’s PPMN Insect of the Week, Prairie grain wireworm (Selatosomus aeripennis destructor, up to 23 mm long when mature).
Size of resident wireworms can vary with species. Selatosomus aeripennis destructor (left) and Hypnoidus bicolor (right). Photo: W. van Herk, AAFC-Agassiz
Although this species is abundant, it may not be as aggressive of a feeder than its cousin the Prairie grain wireworm. An interesting feature of this species is that it has different populations, some of which are all females. What we call H. bicolor today may actually be several species or subspecies based on genetic differences. We estimate that the larvae of this species live in the soil for 2-3 years but this has not been verified.
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 the Hypnoidus bicolor pages of the new wireworm guide here.
Free digital copies in both official languages can be downloaded at these links.
Free hard copies are also available while supplies last. Email Haley Catton at haley.catton@agr.gc.ca to request your copy.
Main pest wireworm species on the Canadian Prairies: larval stages (top), adult (click beetle) stages (bottom). Photos: J. Saguez, CEROM
Did you know ?
– H. bicolor is in the same genus as the main pest species in Quebec, the abbreviated wireworm Hypnoidus abbreviatus.
Reference:
Drahun, I., Wiebe, K.F., Koloski, C.W., van Herk, W.G. and Cassone, B.J. (2021), Genetic structure and population demographics of Hypnoidus bicolor (Coleoptera: Elateridae) in the Canadian Prairies. Pest Manag Sci, 77: 2282-2291. https://doi.org/10.1002/ps.6255
Week 3 and scouting continues for cutworms, flea beetles and wireworms plus there’s more information this week to help prepare for in-field scouting. Be sure to catch the Insect of the Week – it’s wireworms!
Now, more than ever, we wish everyone a safe and productive field season! Stay Safe!
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) Since May 1, 2021 the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington). This week there have been an increasing number of reverse trajectories that moved north from Texas, Oklahoma and Kansas and Nebraska (Fig. 1). Though these US regions can be a source of diamondback moths, the ECCC models predict air movement, not actual occurrence of diamondback moths. It should also be noted that host plants of diamondback moth include all plants in the Brassicacea family, including cruciferous weeds and volunteer canola. These plants are suitable hosts until canola emerges.
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 1- 20, 2021.
a. Pacific Northwest (Idaho, Oregon, Washington) – This week there have been 44 trajectories (27 last week) that have crossed Alberta, Manitoba, and Saskatchewan. The majority of Pacific Northwest reverse trajectories usually have been reported to pass over southern Alberta. This growing season, PNW trajectories have crossed all of the prairies (Fig. 2).
Figure 2. Total number of dates with reverse trajectories originating over Pacific Northwest (Idaho, Oregon, and Washington) and have crossed the prairies between March 24 and May 20, 2021.
b. Mexico and southwest USA (Texas, California) – This week there have been 15 trajectories that originated in Mexico and the southwestern US that have crossed Manitoba and Saskatchewan.
c. Oklahoma and Texas – This week there have been 16 trajectories that have passed over Manitoba and Saskatchewan (Fig. 3) that originated in Oklahoma or Texas. These are the first trajectories, that originated over Oklahoma and Texas, to enter the prairies during the month of May.
Figure 3. The total number of dates with reverse trajectories originating over Oklahoma and Texas and have crossed the prairies between March 24 and May 20, 2021.
d. Kansas and Nebraska – This week there have been 35 trajectories (8 last week) that originated in Kansas or Nebraska that have passed over Manitoba and Saskatchewan (Fig. 4).
Figure 4. The total number of dates with reverse trajectories originating over Kansas and Nebraska and have crossed the prairies between March 24 and May 20, 2021.
2. FORWARD TRAJECTORIES (FT) a. Forward trajectories, originating from Mexico and USA, have crossed a number of prairie locations since May 1, 2021. This week, there has been a steady increase in the number of trajectories that are predicted to cross the prairies (Fig. 5). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line). The data suggests that, compared to this week, there may be increased potential for the introduction of DBM to the prairies.
Figure 5. The average number (based on a 5 day running average) of forward trajectories that have crossed the Canadian prairies for the period of May 1- 20, 2021.
The following map presents the total number of forward trajectories that have crossed the Canadian prairies (since March 24, 2021) (Fig. 6). Results indicate that the greatest number of forward trajectories entering Canada originated from the Pacific Northwest (Idaho, Oregon, Washington).
Figure 6. The total number of dates with forward trajectories, originating from various regions of the United States and Mexico, crossed the prairies between March 24 and May 20, 2021.
Earlier in the week, an Alert related to wind trajectories assessed over May 18-19, 2021, was shared by the PPMN. It communicated the anticpated arrival of several air masses arriving across the Canadian prairies over the next few days that originated from multiple areas of USA. Remember, the current WEEKLY REPORT (above) summarizes daily data over a longer, more comprehensive period.
TEMPERATURE: This past week the average temperature across the prairies was 2.5 °C warmer than normal (Fig. 1). Temperatures were warmest across the Parkland region in Manitoba, Saskatchewan, and Alberta.
Figure 1. 7-day average temperature (°C) observed across the Canadian prairies for the period of May 10-16, 2021.
The prairie-wide average 30-day temperature (April 17- May 16) was 0.9 °C less than climate normal values. A region from Winnipeg to Saskatoon has been 2 to 4 °C cooler than average. Temperatures have been warmest across southern Alberta (Table 1; Fig. 2).
Figure 2. 30-day average temperature (°C) observed across the Canadian prairies for the period of April 17-May 16, 2021.
The 2021 growing season (April 1 – May 16) has been characterized by near normal temperatures. Warmest temperatures were observed in a region between Lethbridge, Saskatoon and Edmonton while coolest temperatures were reported from Manitoba (Table 2; Fig. 3).
Figure 3. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1-May 16, 2021.
The growing degree day map (GDD) (Base 5 ºC, April 1-May 2, 2021) is provided below (Fig. 4) while the growing degree day map (GDD) (Base 10 ºC, April 1-August 9, 2020) is shown in Figure 5.
Figure 4. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-May 17, 2021). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (19May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=trueFigure 5. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-May 17, 2021). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (19May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
At this early point in the growing season, cool temperatures pose the risk of frost but the differences between low and high temperatures can exert stress on plants, particularly when field conditions are dry. The lowest temperatures recorded ranged from <-8 to >6 °C (Fig. 6) while the highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <3 to >28 °C (Fig. 7).
Figure 6. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (May 12-18, 2021). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (19May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=trueFigure 7. Highest temperatures (°C) observed across the Canadian prairies the past seven days (May 12-18, 2021). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (19May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
PRECIPITATION: Seven-day cumulative rainfall amounts indicate that most of the prairies had less than 2 mm of rain in the past week (Fig. 8). Rainfall amounts for the period of April 17-May 16 (30-day accumulation) were 56 % of long-term average values. Rainfall was greatest for southwestern Saskatchewan and across most of Alberta (Table 1; Fig. 9).
Figure 8 . 7-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 10-16, 2021.Figure 9. 30 day cumulative rainfall (mm) observed across the Canadian prairies for the period of April 17-May 16, 2021.
Average growing season (April 1 – May 16) precipitation has been well below average for most of the prairies (35 % less than normal). Saskatoon has reported 4.3 mm (15 % of normal) and most of Saskatchewan and Manitoba have had less than 15 mm (40 % of normal precipitation) (Table 1; Fig. 10).
Figure 10. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1-May 16, 2021.
Access Environment and Climate Change Canada’s weather radar mapping interface. Options to access preceding 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.
The pea leaf weevil is a slender greyish-brown insect measuring approximately 5 mm in length (Fig. 1, Left image). 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 1. Comparison images and descriptions of four Sitona species adults including pea leaf weevil (AAFC-Otani).
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 (Fig. 2). Females lay their eggs in the soil either near or on developing pea or faba bean plants from May to June.
Figure 2. Examples of adult pea leaf weevil damage on field pea seedlings, (A) seedling with notches on all nodes, (B) stereotypical crescent shaped notches on the leaf margin, (C) clam or terminal leaf of the pea seedling with arrows indicating the feeding notches. All photos courtesy of Dr. L. Dosdall.
Larvae develop under the soil and are “C” shaped and milky-white with a dark-brown head capsule ranging in length from 3.5-5.5 mm (Figure 3). Larvae develop through five instar stages. After hatching, larvae seek and enter the roots of a pea plant. Larvae will enter and consume the contents of the nodules of the legume host plant. It is the nodules that are responsible for nitrogen-fixation which affect yield plus the plant’s ability to input nitrogen into the soil. Consumption of or damage to the nodules (Figure 4) results in partial or complete inhibition of nitrogen fixation by the plant and results in poor plant growth and low seed yields.
Figure 3. Larva of pea leaf weevil in soil (Photo: L. Dosdall).Figure 4. Damaged pea nodules (Photo: L. Dosdall).
The cereal leaf beetle (CLB) model output predicts that oviposition is underway across the prairies. The graphs provide a comparison of development at Saskatoon (Fig. 1) and at Lacombe (Fig. 2). The simulation indicates that first instar larvae may occur during the third week of May near Saskatoon and one week later at Lacombe.
Figure 1. Predicted status of cereal leaf beetle populations near Saskatoon, SK as of May 16, 2021 (projected to May 31, 2021).Figure 2. Predicted status of cereal leaf beetle populations near Lacombe, AB as of May 16, 2021 (projected to May 31, 2021).
Lifecycle and Damage:
Adult: Adult cereal leaf beetles (CLB) have shiny bluish-black wing covers (Fig. 3). The thorax and legs are light orange-brown. Females (4.9 to 5.5 mm) are slightly larger than males (4.4 to 5 mm). Adult beetles overwinter in and along the margins of grain fields in protected places such as in straw stubble, under crop and leaf litter, and in the crevices of tree bark. They favour sites adjacent to shelterbelts, deciduous and conifer forests. They emerge in the spring once temperatures reach 10-15 ºC and the adults are active for about 6 weeks. They usually begin feeding on grasses, then move into winter cereals and later into spring cereals.
Figure 3. Adult Oulema melanopus measure 4.4-5.5 mm long (Photo: M. Dolinski).
Egg: Eggs are laid approximately 14 days following the emergence of the adults. Eggs are laid singly or in pairs along the midvein on the upper side of the leaf and are cylindrical, measuring 0.9 mm by 0.4 mm, and yellowish in colour. Eggs darken to black just before hatching.
Larva: The larvae hatch in about 5 days and feed for about 3 weeks, passing through 4 growth stages (instars). The head and legs are brownish-black; the body is yellowish. Larvae are usually covered with a secretion of mucus and fecal material, giving them a shiny black, wet appearance (Fig. 4). When the larva completes its growth, it drops to the ground and pupates in the soil.
Figure 4. Larval stage of Oulema melanopus with characteristic feeding damage visible on leaf (Photo: M. Dolinski).
Pupa: Pupal colour varies from a bright yellow when it is first formed, to the colour of the adult just before emergence. The pupal stage lasts 2 – 3 weeks. Adult beetles emerge and feed for a couple of weeks before seeking overwintering sites. There is one generation per year.
Model simulations for alfalfa weevil (AAW) predict that oviposition should be well underway across the prairies. The following graphs indicate that development is similar near Swift Current (Fig. 1) and Brandon (Fig. 2). The model predicts that that hatch may occur during the last week of May.
Figure 1. Projected predicted status of alfalfa weevil populations near Swift Current SK as of May 16, 2021 (projected to May 31, 2021).Figure 2. Projected predicted status of alfalfa weevil populations near Brandon MB as of May 16, 2021 (projected to May 31, 2021).
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 grasshopper simulation model will be used to monitor grasshopper development across the prairies. Weekly temperature data collected across the prairies is incorporated into the simulation model which calculates estimates of grasshopper development stages based on biological parameters for Melanoplus sanguinipes (Migratory grasshopper).
Model simulations were used to estimate percent grasshopper egg development as of May 16, 2021. Average development of eggs is 68 % and is well ahead of the long term average of 59 %. Since last week, developmental rates have increased at all locations (Fig. 1). The simulation predicts that development is greatest in the region that includes Regina, Saskatoon and Lethbridge (Fig. 2).
Figure 1. Predicted percent embryonic development of grasshopper eggs across the Canadian prairies as of May 16, 2021.Figure 2. Predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 16, 2021.
Recent warm temperatures near Winnipeg have resulted in faster development rates. The model was projected to May 31 to determine potential development at Saskatoon and Regina (Figs. 3 and 4). Results suggest that initial hatch may occur in the next few days with increased hatch occurring in late May. Current drought conditions tend to favour development of grasshopper populations while delaying crop development. Crop development may be delayed across southern and central regions of Saskatchewan. This may result in conditions conducive for crop damage from grasshoppers as hatch progresses in late May and early June.
Figure 3. Projected predicted development of M. sanguinipes populations near Regina SK as of May 16, 2021 (projected to May 31, 2021).Figure 4. Projected predicted development of M. sanguinipes populations near Saskatoon SK as of May 16, 2021 (projected to May 31, 2021).
Early in the growing season many of the native and introduced species of ladybird beetles become active and are easily observed (Fig. 1). These adults give rise to a whole new legion of voracious larvae and adults so preserve and protect them in fields – it could pay off!
Figure 1. Ladybird beetle (Coleoptera: Coccinellidae) hunting on wheat head (photo: AAFC-Otani).
Coccinellids are recognized as general predators with a real taste for aphids. Many species exist in North America but introduced species (either released or adventively establishing on this continent) have displaced many native species. With such a fantastic array of colours, sizes, shapes, and spots, we’re providing a few resources to help you recognize the amazing diversity in fields: ● Access “Bug Guide” and their entries falling within the Family Coccinellidae. ● “Key to the lady beetles of Saskatchewan“, released by D.J. Larson in 2013 – a technical key that includes colour photos of ladybird beetle adults. Species included in this key will most closely resemble what’s present across the Canadian prairies. ● “Ladybugs of South Dakota” is a PDF visual example of several species of coccinellids, some of which will also occur on the Canadian prairies. The poster was produced in conjunction with the “Lost Ladybug Project” and other supporting institutions. ● Consider participating in citizen-science – the Lost Ladybug Project has been in place for many years but the group welcomes reports of coccinellids from anywhere in North America and helps identify from submitted photos. The goal is to keep track of native species in comparison to the helpful but fairly competitive introduced species like Coccinella semptempunctata or Harmonia axyridis (Pallas). ● The Canadian portal of iNaturalist.ca was launched in 2015 and is connected to iNaturalist.org but the premise is the same: By signing up and submitting photos with relevant brief observations (e.g., date, location, e-contact info), users can communicate online with creditable and knowledgeable resources that help identify flora and fauna. Watch their YouTube video to learn more. Download the App (Android Google Play OR iOS App Store).
Reminder – Field scouting is critical – it enables the identification of potential risks to crops. Accurate identification of insect pests PLUS the application of established monitoring methods will enable growers to make informed pest management decisions.
We offer TWO generalized insect pest scouting charts to aid in-field scouting on the Canadian prairies:
1. CANOLA INSECT SCOUTING CHART (click chart to access downloadable PDF copy)
2. FLAX INSECT SCOUTING CHART(click chart to access downloadable PDF copy)
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. Check the recently updated Field Heroes website for scouting guides, downloadable posters, and videos. Learn about these important organisms at work in your fields!
Two NEW Field Heroes resources for 2021 include:
The NEW Pests and Predators Field Guideis filled with helpful images for quick insect identification and plenty of tips to manage the pests AND natural enemies in your fields. Claim your free copy at http://fieldheroes.ca/fieldguide/ or download for free to arm your in-field scouting efforts!
Diamondback moth pheromone trap monitoring update for MB – Refer to the summary updated twice a week. So far extremely low numbers have been intercepted at only 8 sites (e.g., when present, only max. of 2 moths per site) in Manitoba. Read the details towards the end of the May 19, 2021, report.
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. Two moths were reported (2021May13 Tansey, pers. comm.); one moth near Shaunavon (RM78) and one moth near Raymore (RM 278).
• ALBERTA’SAlberta Insect Pest Monitoring Network webpage links to insect survey maps, live feed maps, and insect trap set-up videos and more. Reminder – NEW for 2021 – AAF’s Shelley Barkley has gathered and streamlined information into a Major Crops Insect webpage. The new webpage does not replace the Alberta Insect Pest Monitoring Network page. However, the new Major Crops Insect webpage serves as a table of contents, connecting users to crop insect pest information on alberta.ca. It offers links to specific insect identification, life cycle, damage, monitoring and management. Users will hopefully find pertinent insect information with fewer clicks! Remember, AAF’s Agri-News occasionally includes insect-related information or Twitter users can connect to #ABBugChat Wednesdays at 10:00 am.
Diamondback moth pheromone trap monitoring update for AB – Refer to the Live Map which reports six sites with very low numbers of moths intercepted (as of 19May2021).
Cutworm reporting tool for AB – Refer to the Live Map which reports two sites with cutworms (as of 20May2021).
Access background information for how and why wind trajectories are monitored in this earlier post.
Alert: Yesterday and today ECCC models produced results that suggest a number of RT’s for prairie locations. Compared to previous dates, the ECCC model output predicts that trajectories are passing almost the entire prairie region over a very short period of time. The weather forecast may result in downward movement of DBM.
Details: There has been a significant increase in the number of trajectories, originating over a number of states in the USA, that have crossed the prairies (Fig. 1). These air currents may introduce diamondback moths to the prairies. ECCC trajectory models indicate that air trajectories, originating over the Pacific Northwest (Idaho, Oregon, Washington), have crossed Alberta, Saskatchewan and western Manitoba (Fig. 2). Trajectories originating over Texas and Oklahoma have passed over eastern Saskatchewan and Manitoba (Fig. 3). A third group of trajectories, originating across Kansas and Nebraska have also crossed eastern Saskatchewan and Manitoba (Fig. 4).
Though these US regions can be a source of diamondback moths, the ECCC models predict air movement, not actual occurrence of diamondback moths. It should also be noted that host plants of diamondback moth include all plants in the Brassicaceae family, including cruciferous weeds and volunteer canola. These plants are suitable hosts until canola emerges.
Action: The ECCC model output predicts that trajectories are passing almost the entire prairie region over a very short period of time. Areas highlighted in green in Figures 2, 3, and 4 of this alert may receive downward movement of DBM very shortly. The presence of any Brassicaceae plant will provide a host for incoming DBM so scout volunteers and emerging canola. If DBM were carried north on air currents it may take a few days for DBM to show up in traps.
Figure 1. Summary of the average number (5 day running average) of reverse trajectories that have crossed the Canadian prairies (May 1-19, 2021) Figure 2. The green region indicates the potential for introduction of diamondback moths from the Pacific Northwest (Idaho, Oregon, and Washington) to the Canadian prairies (May 18-19, 2021).Figure 3. The green region indicates the potential for introduction of diamondback moths from Texas and Oklahoma to the Canadian prairies (May 18-19, 2021). Figure 4. The green region indicates the potential for introduction of diamondback moths from Kansas and Nebraska to the Canadian prairies (May 18-19, 2021).
This week’s instalment is a sneak peak at the soon-to-be published manual “Field Guide of Pest Wireworms in Canadian Prairie Crop Production,” written by Haley Catton, Wim van Herk, Julien Saguez, and Erl Svendsen! (stay tuned to this channel)
Wireworms are soil-dwelling insects that have challenged crop production on the Canadian Prairies since farming began in this region. They damage crops by feeding on seeds, roots or lower stems of almost all field crops, and are especially damaging to cereals. Since wireworms are often the only reason growers use insecticide-treated seed in cereals on the Prairies, understanding more about these pests can save costs and reduce unnecessary pesticide use.
Despite their common name and worm-like appearance, wireworms are not actually “worms.” Rather, they are the larval stage of a group of beetles called click beetles (Elateridae family). Their “clicking” is a defensive behaviour that when placed on their backs, projects them up to 30 centimetres (12 inches) or more into the air to escape danger and literally get them back on their legs
Selatosomus aeripennis destructor, or the Prairie grain wireworm, is the largest of Prairie pest wireworms, reaching up to 23 millimetres (1 inch). It is hard-bodied, segmented and yellowish in colour, with three pairs of legs. Adults are 8-13 mm long, black, hairless and have distinct hind angles.
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.
A bit of sun, some snow, some rain, a bit too hot and still too cold in other areas – typical spring weather for our prairie producers!
This week the incredible team working to provide weather-related data for PPMN forecasting is coping with technical difficulties so several of the normal updates are not available but stay tuned!
This week’s Insect of the Week feature crop is wheat (durum, spring and winter) and Dr. Meghan Vankosky is our starring entomologist.
Wheat Field cc by 2.0 Sean MacEntee
Wheat is King on the Prairies and has been since the early 1900s (with recent rivalry for top spot by canola, the Queen of the Prairies). There are many challenges to overcome: droughts, pests, soils and agronomy and scientists and extension specialists have been working alongside farmers to improve the genetics, production practices, equipment and infrastructure. In 2019, despite weather challenges, the area seeded to wheat and the harvest remains impressive:
How do you contribute in insect monitoring or surveillance on the Prairies?
I am a co-chair of the Prairie Pest Monitoring Network. In addition to participating in insect monitoring of cabbage seedpod weevil, pea leaf weevil, and grasshoppers, I help provide supplies for diamondback moth, swede midge, and bertha armyworm monitoring across the prairies. In addition to the Prairie Pest Monitoring Network, I am involved with the Canadian Plant Health Council in the Surveillance Working Group and a member of the new AAFC Prairie Biovigilance Network.
In your opinion, what is the most interesting field crop pest on the Prairies?
The pea leaf weevil is very interesting. I started researching pest management options for pea leaf weevil during my MSc program in 2008. We are still working on this pest and learning so much about it. I like working with this species because it is usually easy to find specimens for lab work, they are fairly large (by insect standards) which makes them easy to handle, and I have to admit that they are kind of cute – for a pest.
What is your favourite beneficial insect?
Parasitoids in general are very cool. I spent a year in southern California working on a biological control program for Asian citrus psyllid. During that time, I worked with two parasitoids and studied how they interact with each other and their host. Of the two, I worked most with Diaphorencyrtus aligarhensis. It is an endoparsitoid that lays its eggs inside its host and kills the host from the inside out. There are many interesting parasitoids on the prairies that help manage field crop pests and I look forward learning more about them.
Tell us about an important project you are working on right now.
I just finished two projects (co-led by Dr. Boyd Mori) studying the newly discovered canola flower midge (Contarinia brassicola). We are currently working on writing papers to describe our work, but in three years we learned a great deal about the distribution of this insect in western Canada, its development, population genetics, and potential impact on canola production.
What tools, platforms, etc. do you use to communicate with your stakeholders?
I use the Prairie Pest Monitoring Network Blog (soon to be website), Twitter, and extension events to communicate research and insect monitoring results. I am getting better about using Twitter, both in terms of posting and replying, and am looking forward to helping with #abbugchat in 2020.
We shift back into the more traditional end of the week release of the “Weekly Update”.
Thanks to David Giffen and Ross Weiss (AAFC-Saskatoon) who again have begun to stream data that enables the generation of the various predictive model updates on a weekly basis throughout the growing season. This week, their efforts include pea leaf weevil, alfalfa weevil, and grasshopper predictive model outputs.
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. 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. We receive two types of model output from ECCC: reverse trajectories and forward trajectories.
‘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. 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.
‘Forward trajectories’ (FT) have a similar purpose; however, the modelling process begins at sites in USA & Mexico. The model output predicts the pathway of a trajectory. Again, of interest to us are the winds that eventually end up passing over the Prairies.
Ross Weiss (AAFC), Meghan Vankosky (AAFC) and Serge Trudel (ECCC)
DATE: APRIL 24, 2019
Reverse trajectories (RT)
a. Pacific Northwest (PNW) – For the period of April 17-23, 2019, there have been 55 RT’s (originating over ID, OR and WA) that have crossed over prairie locations (Figs. 1 and 2). By comparison, for the period of April 10-16, 2019, there were 31 RT’s. The majority PNW RT’s have been reported to pass over southern AB. Since March 23rd, Lethbridge AB has reported the highest number of PNW RT’s (n=20), Beiseker AB (n=15) and Gainsborough SK (n=11).
Figure 1. Daily total number of reverse trajectories originating over ID, OR, and WA that have crossed the prairies.Figure 2. Total number of dates with PNW reverse trajectories originating over ID, OR, and WA that have crossed the prairies (since March 23, 2019).
b. Mexico and SW USA (TX, CA) – No trajectories, originating over Mexico or southwest USA have crossed the prairies for the period of April 17-23, 2019. Since March 23, 2019 there have been 5 reverse trajectories that originated over Mexico, CA and TX. All five occurred on April 7, 2019.
c. Texas and Oklahoma – No trajectories, originating over TX or OK have crossed the prairies for the period of April 17-23, 2019. Since March 23, 2019 there have been 18 reverse trajectories that have originated over OK and TX (Fig. 3). Most of these trajectories have crossed eastern SK and MB.
Figure 3. Total number of dates with reverse trajectories originating over OK and TX that have crossed the prairies (since March 23, 2019).
d. Nebraska and Kansas – No trajectories, originating over KS or NE have crossed the prairies for the period of April 17-23, 2019. Since March 23, 2019 there have been 18 reverse trajectories that have originated over KS and NE (Fig. 4).
Figure 4. Total number of dates with reverse trajectories originating over KS and NE that have crossed the prairies (since March 23, 2019).
In a continuing effort to produce timely information, wind trajectory reports will be available both DAILY and WEEKLY:
DAILY REPORTS, as they can be generated, will be put up as a downloadable PDF file on this page.
As the spring weather improves and people are active outdoors, remember to watch for ticks Blacklegged (deer) ticks are important because they can carry Lyme Disease. Continued surveillance activities conducted by Health Canada and the provinces remain important and you can help by identifying / removing / submitting your ticks!
Weather synopsis – Temperatures (30 day average) have been warmest in southern AB and western SK.
Rainfall (30 day accumulation) amounts have been well below average for most of the prairies.
Percent of normal precipitation for the past 30 days (as of April 23, 2019) across the Canadian prairies. Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (24Apr2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
The soil moisture model indicates that soil moisture levels are low across most of southern and central AB and western SK.
Pea Leaf Weevil (Sitona lineatus) – The PLW model was run for Lethbridge AB (Fig. 1) and Saskatoon SK (Fig. 2). Output suggests that PLW are beginning to become active.
Figure 1. Predicted PLW phenology at Lethbridge AB based on long term climate data. Values are based on model simulations (April 1 – April 23, 2019).Figure 2. Predicted PLW phenology at Saskatoon SK based on long term climate data. Values are based on model simulations (April 1 – April 23, 2019).
Pea leaf weevils emerge in the spring primarily by flying (at temperatures above 17ºC) or they may walk short distances. Pea leaf weevil movement into peas and faba beans is achieved primarily through flight. Adults are slender, greyish-brown measuring approximately 5 mm in length (Fig. 3, Left).
The pea leaf weevil resembles the sweet clover weevil (Sitona cylindricollis) but the former is distinguished by three light-coloured stripes extending length-wise down thorax and sometimes the abdomen. All species of Sitona, including the pea leaf weevil, have a short snout.
Figure 3 Comparison images and descriptions of four Sitona species adults including pea leaf weevil (Left).
Adults will feed upon the leaf margins and growing points of legume seedlings (alfalfa, clover, dry beans, faba beans, peas) and produce a characteristic, scalloped (notched) edge. Females lay 1000 to 1500 eggs in the soil either near or on developing pea or faba bean plants from May to June.
Reminder – The risk map for pea leaf weevils was released in March 2019. The map is based on the number of feeding notches observed in peas (Fig. 4).
Figure 4. Estimates of pea leaf weevil (S. lineatus) densities based on feeding notches observed in peas grown in Alberta and Saskatchewan in 2018.
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) – 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 (Hypera postica) across the prairies are updated weekly to help growers time their in-field scouting for second-instar larvae. Compare the following predicted development stages and degree-day values from Soroka (2015) to the map below (Fig. 1).
Alfalfa weevil (AAW) model runs indicate that oviposition may have begun in fields near Swift Current SK.
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.
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).
Model runs were conducted for Lethbridge AB and Saskatoon SK. As of April 23, 2019, predicted development was 57% for both locations and is similar to long term average values. The following graph illustrates that gradual development has occurred during the past three weeks. Hatch is expected to occur in mid to late May.
More information can be found by accessing the grasshopper pages within the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” as an English-enhanced or French-enhanced version.
Weather synopsis – Across most of the prairies, weather conditions continue to be warmer and dryer than average. This past week (May 14-21, 2018), the average temperature was approximately 2 °C warmer than long-term average temperatures (Fig. 1). The warmest weekly temperatures occurred across AB and west-central Saskatchewan. The 30-day average temperature (April 21-May 21) was 1-2 °C warmer than long term average temperatures with the warmest conditions occurring the western half of the prairies (Fig. 2).
Figure 1. Weekly (May 14 – May 21, 2018) average temperature (°C) .
Figure 2. 30-day (April 21 – May 21, 2018) average temperature (°C).
Weekly precipitation was well below average and 30 day total rainfall is approximately 50% less than average (Figs. 3 and 4). Manitoba continues to be very dry, though this week southeast Manitoba did receive rainfall amounts that were greater than 30 mm.
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
Pacific Northwest (PNW) –The total number of RT’s from the Pacific Northwest of the United States, for the period between May 1 – 22, 2018, was n=67. This was significantly less than in 2017 (n=226), as well as the long term average (n=166) (Fig. 1).
Figure 1. Daily total number of reverse trajectories originating over the Pacific Northwest of
the United States that have entered the prairies (May 1-22, 2018).
Cutworms (Noctuidae) – A field guide is now available to help growers scout and manage Cutworms! Cutworm Pest of Crops is available for free in either English or French and is posted on the Cutworm Field Guide page! Also be sure to check the Insect of the Week through May – it highlights cutworms. Several species of cutworms can be present in fields. They range in colour from shiny, opaque, to tan, to brownish-red with chevron patterning. Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol. Also refer to Manitoba Agriculture cutworm fact sheet which includes action and economic thresholds for cutworms in several crops. Scout fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look. Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed. Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant. If the plant is well-established, check within the crown in addition to the adjacent soil. The culprits could be wireworms or cutworms.
The following page extracted from the new “Cutworm Pests of Crops on the Canadian Prairies” (Floate 2017; Page 5) shows the seasonal occurrence of lifecycle stages for different species of cutworms. To aid scouting, the seasonal chart outlines what time of year larvae of different pest species are present (i.e., when to scout) but it also describes larval feeding habit (i.e., where to look for them relative to the plant host).
For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2018 Cutworm Reporting Tool”. Once data entry occurs, growers can view the live 2018 cutworm map which is updated daily (see below for the map retrieved May 24, 2018).
Flea Beetles (Chrysomelidae: Phyllotreta species) – Be on the lookout for flea beetle damage resulting from feeding on canola cotyledons but also on the stem. Two species, Phyllotreta striolata and P. cruciferae, will feed on all cruciferous plants but they can cause economic levels of damage in canola during the seedling stages.
Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed. Watch for shot-hole feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding. Estimating flea beetle feeding damage can be challenging. Using a visual guide to estimate damage can be helpful. Canola Watch circulated this article but also use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon) – take it scouting!
Figure 1. Canola cotyledons with various percentages of leaf area consume owing to flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).
Figure 2. Percent leaf area consumed by flea beetles feeding on canola seedlings (Photo: Soroka & Underwood, AAFC-Saskatoon).
Refer to the flea beetle page from the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” as an English-enhanced or French-enhanced version.
Cereal leaf beetle (Oulema melanopus) – Model output predicts that CLB larvae should be appearing at many locations across the southern prairies. An example of CLB predicted phenology for Lethbridge AB is presented in Figure 1.
Figure 1. Predicted CLB phenology at Lethbridge. Values are based on model
simulations, for April 1 – May 21, 2018 (projected to June 21, 2018).
Lifecycle and Damage:
Adult: Adult cereal leaf beetles (CLB) have shiny bluish-black wing-covers (Fig. 2). The thorax and legs are light orange-brown. Females (4.9 to 5.5 mm) are slightly larger than the males (4.4 to 5 mm). Adult beetles overwinter in and along the margins of grain fields in protected places such as in straw stubble, under crop and leaf litter, and in the crevices of tree bark. They favour sites adjacent to shelter belts, deciduous and conifer forests. They emerge in the spring once temperature reaches 10-15 ºC and are active for about 6 weeks. They usually begin feeding on grasses, then move into winter cereals and later into spring cereals.
Figure 2. Adult Oulema melanopus measure 4.4-5.5 mm long (Photo: M. Dolinski).
Egg: Eggs are laid approximately 14 days following the emergence of the adults. Eggs are laid singly or in pairs along the mid vein on the upper side of the leaf and are cylindrical, measuring 0.9 mm by 0.4 mm, and yellowish in colour. Eggs darken to black just before hatching. Larva: The larvae hatch in about 5 days and feed for about 3 weeks, passing through 4 growth stages (instars). The head and legs are brownish-black; the body is yellowish. Larvae are usually covered with a secretion of mucus and fecal material, giving them a shiny black, wet appearance (Fig. 3). When the larva completes its growth, it drops to the ground and pupates in the soil.
Figure 3. Larval stage of Oulema melanopus with characteristic feeding damage visible on leaf (Photo: M. Dolinski).
Pupa: Pupal colour varies from a bright yellow when it is first formed, to the colour of the adult just before emergence. The pupal stage lasts 2 – 3 weeks. Adult beetles emerge and feed for a couple of weeks before seeking overwintering sites. There is one generation per year.
Fact sheets for CLB are published by the province of Alberta and available from the Prairie Pest Monitoring Network. Also access the Oulema melanopus page from the new “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide”.
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 (Hypera postica) across the prairies are updated weekly to help growers time their in-field scouting for second-instar larvae. Compare the following predicted development stages and degree-day values from Soroka (2015) to the map below (Fig. 1).
The AAW model runs suggest thatoviposition should be well underway in southern Saskatchewan. Larvae should be in the first and second instars.
Figure 1. Predicted development of alfalfa weevil as of May 21, 2018.
The larval stage of this weevil feeds on alfalfa leaves in a manner that characterizes the pest as a “skeletonizer”. The green larva featuring a dorsal, white line down the length of its body has a dark brown head capsule and will grow to 9mm long.
Use the photo below as a visual reference to identify alfalfa weevil larvae. Note the white dorsal line, the tapered shape of the abdomen and the dark head capsule.
Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon). Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (Philip et al. 2015). The guide is available in both a free English-enhancedor French-enhanced version.
Pea Leaf Weevil (Sitona lineatus) – The PLW model predicts that adult weevils should be out and that oviposition may be occurring in fields with emerging peas. An example of PLW predicted phenology for Swift Current SK is presented in Figure 1.
Figure 1. Predicted PLW phenology at Swift Current, SK. Values are based on model simulations,
for April 1 – May 21, 2018 (projected to July 1, 2018).
Pea leaf weevils emerge in the spring primarily by flying (at temperatures above 17ºC) or they may walk short distances. Pea leaf weevil movement into peas and faba beans is achieved primarily through flight. Adults are slender, greyish-brown measuring approximately 5 mm in length (Fig. 2, Left). The pea leaf weevil resembles the sweet clover weevil (Sitona cylindricollis) but the former is distinguished by three light-coloured stripes extending length-wise down thorax and sometimes the abdomen. All species of Sitona, including the pea leaf weevil, have a short snout.
Figure 2. Comparison images and descriptions of four Sitona species adults including pea leaf weevil (Left).
Adults will feed upon the leaf margins and growing points of legume seedlings (alfalfa, clover, dry beans, faba beans, peas) and produce a characteristic, scalloped (notched) edge. Females lay 1000 to 1500 eggs in the soil either near or on developing pea or faba bean plants from May to June. Reminder – The 2017 risk map for pea leaf weevils was released in March 2018. The map is based on the number of feeding notches observed in peas (Fig. 3).
Figure 3. Estimates of pea leaf weevil (S. lineatus) densities based on feeding notches observed in
peas grown in Alberta and Saskatchewan in 2017.
Biological and monitoring information related to pea leaf weevil in field crops is posted by the province of Alberta and in the PPMN monitoring protocol.
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).
Recent warm conditions have advanced egg development. As of May 21, 2018, predicted mean egg development was 78% (68% last week) and model output indicates that embryological development was 10% greater than long term average. Greatest development was predicted to be across Alberta, particularly in an area extending from Lethbridge to Edmonton (Fig. 1 and 2). Last week first instar grasshoppers were collected near Rosetown SK.
Figure 1. Grasshopper embryological development (%) for
April 1 – May 21, 2018, based on model simulations.
Figure 2. Grasshopper hatch (%) for April 1 – May 21, 2018, based on model simulations.
Reminder – The Prairie Pest Monitoring Network’s 2018 Grasshopper Forecast Map was released in March (Fig. 3). Spring temperatures, soil moisture conditions, and precipitation all have an impact on survival of overwintered grasshopper eggs. Growers in areas highlighted orange or red in the map below should be vigilant this spring.
Field scouting is critical – it enables the identification of potential risks to crops. Accurate identification of insect pests PLUS the application of established monitoring methods will enable growers to make informed pest management decisions. We offer TWO generalized insect pest scouting charts to aid in-field scouting on the Canadian prairies: 1. CANOLA INSECT SCOUTING CHART 2. A NEW FLAX INSECT SCOUTING CHART These charts feature hyperlinks directing growers to downloadable PDF pages within the “Field crop and forage pests and their natural enemies in western Canada: Identification and management field guide“. 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. Good luck with your scouting!
Remember – If your fields are near one of Environment Canada’s PRAIRIE Radar Stations, consider accessing weather radar maps in video format show either the past 1 OR 3 hours of spatio-temporal maps of precipitation events. These maps can help growers review where and how much precipitation fell nearby. 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.
As the spring weather improves and people are active outdoors, remember to watch for ticks. Blacklegged (deer) ticks are important because they can carry Lyme Disease. Continued surveillance activities conducted by Health Canada and the provinces remain important and you can help by identifying / removing / submitting your ticks!
Bertha armyworm (Lepidoptera: Mamestra configurata) – Bertha armyworm (BAW) – BAW pupae, developing in the soil, are predicted to be ahead of average development. Pupal development is predicted at approximately 50% (Fig. 1) whereas the long term average is 36%.
Figure 1. Predicted bertha armyworm pupal development across the prairies as of May 21, 2018.
Model output predicts that emergence may begin as early as June 9th for the Regina area. Development is expected to be 5-6 days faster than average (Fig. 2; Table 1).
Figure 2. Predicted bertha armyworm phenology at Regina SK. Values are based on
model simulations, for April 1 – May 21, 2018 (projected to June 30, 2018).
Table 1. Projected dates for bertha armyworm adult emergence.
Reminder – Review the 2017 bertha armyworm distribution map for the Canadian prairies which reports cumulative pheromone trap counts intercepting male moths during the 2017 growing season.
Remember – Health Canada’s Pest Management Regulatory Agency launched a new mobile app to access pesticide labels registered for use in Canada. The App helps homeowners, farmers, industry, provincial and federal organizations access details for pest control products from a smartphone or tablet (Fig. 1). Users can save searches, download product labels to their ‘Favourites’ which can even be accessed while offline. ‘Favourites’ will also auto-update when accessed online. Pesticide labels can be searched based by product name or active ingredient (e.g., to review detailed explanations on proper product use and necessary precautions). Users can download the app on their mobile device. If you have any questions, please contact the PMRA’s Information Service.
Provincial entomologists provide insect pest updates throughout the growing season so we have attempted to link to their most recent information:
Manitoba’s Insect and Disease Update for 2018 will be posted soon. Watch for updates prepared by John Gavloski. Saskatchewan’s Crop Production News for 2018 will be posted soon. Watch for updates prepared by James Tansey and Carter Peru. Watch for Alberta Agriculture and Forestry’s Call of the Land for insect pest updates from Scott Meers. The most recent Call of the Land (posted on May 24, 2018) highlighted flea beetles and need to scout carefully to apply the action threshold of 25% of the cotyledon leaf area consumed, use of the online cutworm reporting tool, and low numbers of diamondback moth so far this spring.
This week’s Insect of the Week is a large group of insects called ground beetles, also known as carabid beetles. Many species feed on cutworms as well as other pests.
Almost 400 different species of ground beetles occur on the Prairies, ranging in size from just a few millimetres to more than 2 centimetres. A field may contain 50 or more species, with densities ranging up to 10 beetles per square meter.
Ground beetles are characterized with long threadlike antennae, have a body that is flattened top-to-bottom, and have strong legs designed for running, large eyes, and obvious jaws (mandibles). Smaller ground beetle species can be important predators of cutworm eggs. Larger species attack and kill fully-grown cutworm larvae.
With all the work they do protecting your crop, ground beetles are real @FieldHeroes.
For many, seed isn’t even in the ground yet, but the cutworms are ready for it when it is. So the time to start scouting for cutworms is now! Even if it is too wet to seed, consider checking volunteer plants for cutworms or feeding damage. General cutworm monitoring protocols can be found on the Monitoring Protocols page. Species-specific protocols can be found in the new Cutworm Pests of Crops on the Canadian Prairies (see below for download details).
There are over 20 cutworm species that may cause economic damage to your crop, each with different feeding behaviour, preferred hosts and lifecycle. This is why species identification is so important: it helps growers understand what they are up against: determining how and when to scout, knowing whether the cutworm species is found above-ground (climbing) or below-ground, recognizing damage, choosing control options. Species also impacts the most appropriate time of day for monitoring and applying controls.
Action and economic thresholds do exist for many of the cutworm species – please use them. This will help control costs by eliminating unnecessary/un-economic sprays and reduce your impact on non-target insects – insects that include cutworm natural enemies that work in the background to control cutworm populations.
This week’s Insect of the Week is the army cutworm. This is an above ground species. Young larvae chew holes in leaves and notch leaf margins. Older larvae will consume entire leaves. They get their name from the fact that when food is scarce, larvae move as a large group in the same direction to locate more host plants.
For more information about army cutworms, go to the Insect of Week page.
Army cutworm larva (cc-by 3.0 Whitney Cranshaw, bugwood.org)
Weather synopsis – This week’s average temperatures were approximately 2°C cooler than normal and seven-day precipitation accumulations were above normal.
Over the past month, precipitation was below average in Manitoba, but above average in northwest Alberta.
The map below reflects the Accumulated Precipitation for the Growing Season so far for the prairie provinces (i.e., April 1-May 17, 2017):
The map below shows the Lowest Temperatures the Past 7 Days (May 11-17, 2017) across the prairies:
Whereas the map below shows the Highest Temperatures the Past 7 Days (May 11-17, 2017):
The updated growing degree day map (GDD) (Base 5ºC, March 1 – May 14, 2017) is below:
While the growing degree day map (GDD) (Base 10ºC, March 1 – May 14, 2017) is below:
The maps above are all produced by Agriculture and Agri-Food Canada. Growers may wish to bookmark the AAFC Drought Watch Maps for the growing season.
THE WEEK OF MAY 15, 2017: Wind trajectory data processing by AAFC-Saskatoon Staff began in April. Reverse Trajectories track arriving air masses back to their point of origin while Forward Trajectories predict favourable winds expected to arrive across the Canadian Prairies for the week of May 15, 2017: Reverse trajectories (RT) Wind trajectories have been monitored since April 1 this year. Wind patterns continue to be similar to previous weeks. The first graph (Fig. 1) indicates that winds from the Pacific Northwest (PNW) passed over Carman MB each day of the past week. Though the number of RTs increased over the past week, the overall pattern has not changed across the prairies.
Figure 1. Number of Reverse Trajectories (RT) originating in the Pacific Northwest that have arrived at sites across the Canadian prairies from May 9-15, 2017.
Figure 2 shows that the greatest number of RTs continue to be settling at sites across southern Alberta (e.g., areas highlighted red).
Figure 2. Total number of reverse trajectories originating from the Pacific Northwest of the USA arriving at sites across the Canadian prairies (April 1-May 15, 2017).
Flea Beetles (Chrysomelidae: Phyllotreta species) – Be on the lookout for flea beetle damage resulting from feeding on canola cotyledons but also on the stem. Two species, Phyllotreta striolata and P. cruciferae, will feed on all cruciferous plants but they can cause economic levels of damage in canola during the seedling stages.
Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed. Watch for shot-hole feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.
Estimating flea beetle feeding damage can be challenging. Using a visual guide to estimate damage can be helpful. Canola Watch circulated this article but also use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon) – take it scouting!
Figure 1. Canola
cotyledons with various percentages of leaf area consume owing to flea beetle
feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).
Figure 2.
Percent leaf area consumed by flea beetles feeding on canola seedlings
(Photo: Soroka & Underwood, AAFC-Saskatoon).
Refer to the flea beetle page from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” as an English-enhanced or French-enhanced version.
Cutworms (Noctuidae) – NEW – Just in time for spring scouting! A new field guide is now available to help growers scout and manage Cutworms! Cutworm Pest of Crops is now available for free in either English or French and is featured at our newCutworm Field Guide! Also be sure to check the Insect of the Week throughout May – it highlights cutworms! Be sure to read more about Army cutworms.
Army cutworm larva (cc-by 3.0 Whitney Cranshaw, bugwood.org)
Several species of cutworms can be present in fields. They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning. Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol. Also refer to the Manitoba Agriculture cutworm fact sheet which includes action and economic thresholds for cutworms in several crops. Keep an eye on fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look. Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed. Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant. If the plant is well-established, check within the crown in addition to the adjacent soil. The culprits could be wireworms or cutworms. For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2017 Cutworm Reporting Tool”. Once data entry occurs, growers can view the live 2017 cutworm map which is updated daily.
Cereal leaf beetle (Oulema melanopus) – As of May 15, 2017, the CLB model predicts that oviposition should be underway in the Lethbridge, Swift Current and Brandon areas. Compared to southern Alberta and Saskatchewan, populations in southern Manitoba are predicted to be delayed by approximately a week.
Lifecycle and Damage: Adult: Adult cereal leaf beetles (CLB) have shiny bluish-black wing-covers (Fig. 1). 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 1. Adult Oulema melanopus (~4.4-5.5 mm long).
Egg: Eggs are laid approximately 14 days following the emergence of the adults. Eggs are laid singly or in pairs along the mid vein on the upper side of the leaf and are cylindrical, measuring 0.9 mm by 0.4 mm, and yellowish in colour. Eggs darken to black just before hatching. Larva: The larvae hatch in about 5 days and feed for about 3 weeks, passing through 4 growth stages (instars). The head and legs are brownish-black; the body is yellowish. Larvae are usually covered with a secretion of mucus and fecal material, giving them a shiny black, wet appearance (Fig. 2). When the larva completes its growth, it drops to the ground and pupates in the soil.
Figure 2. Larval stage of Oulema melanopus with characteristic feeding damage visible on leaf.
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) – 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).
Degree-day maps of base 9°C are now being produced by Soroka, Olfert, and Giffen (2016) using the Harcourt/North Dakota models. Models predicting the development of Alfalfa weevil (Hypera postica) across the prairies are updated weekly to help growers time their in-field scouting for second-instar larvae. Compare the following predicted development stages and degree-day values from Soroka (2015) to the map below.
This week, the predictive model output for Brooks AB suggests that oviposition is well underway (i.e., in areas of the map below highlighted chocolate-brown). The initial first instar larvae may occur by next week.
Use the figure below as a visual reference to identify alfalfa weevil larvae. Note the white dorsal line, the tapered shape of the abdomen and the dark head capsule.
Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (Philip et al. 2015). The guide is available in both a free English-enhancedor French-enhanced version.
Pea Leaf Weevil (Sitona lineatus) – The pea leaf weevil simulation model will be used to monitor weevil development across the prairies. Weekly temperature data collected across the prairies is incorporated into the simulation model which calculates estimates of weevil development stages based on biological parameters for Sitona lineatus.
Model output predicted that flight of pea leaf weevil adults was significantly earlier in Lethbridge than Saskatoon in 2017. In the figure below, note the red line predicting adults emerging from overwintering then the yellow line predicting overwintered adults taking flight this spring for Lethbridge AB (Fig. 1, Upper) and Saskatoon SK (Fig. 1, Lower).
Figure 1. Model output predicting development of pea leaf weevil in Lethbridge AB (Upper) and Saskaton SK (Lower) in the spring of 2017.
Reminder – In 2016, the distribution of pea leaf weevil increased dramatically based on both damage assessments AND collection of adults in 2016 (Fig. 2).
Figure 2. Distribution of pea leaf weevil (Sitona lineatus) based on surveying conducted in 2016 (Olfert et al. 2017).
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.
Grasshopper Simulation Model Output – The grasshopper simulation model will be used to monitor grasshopper development across the prairies. Weekly temperature data collected across the prairies is incorporated into the simulation model which calculates estimates of grasshopper development stages based on biological parameters for Melanoplus sanguinipes (Migratory grasshopper).
As of May 15, 2017, the predicted mean embryological development was only slightly ahead of last week at 66% (compared to 62% last week), and similar to long term averages (64%; Fig. 1). Although it is still early in the growing season, grasshopper hatch can vary across the prairies. For example, model output indicated that the hatch in Vauxhall AB was predicted to be about a week ahead of Saskatoon SK. As a result, timing of peak hatch could be 10-14 days earlier in Vauxhall than Saskatoon.
Figure 1. Simulation model outputs mapped to predict the embryological development of Migratory grasshopper (Melanoplus sanguinipes) eggs across the Canadian prairies as of May 15, 2017).
Reminder – The Prairie Pest Monitoring Network’s 2017 Grasshopper Forecast Map (Fig. 2) was released in January. While spring temperatures, soil moisture conditions, and precipitation can all have an impact on overwintered grasshopper eggs, growers in areas highlighted orange or red in the map below should be vigilant as nymphs begin to hatch this season.
Figure 2. Prairie Pest Monitoring Network’s 2017 Grasshopper Forecast Map.
Bertha armyworm (Lepidoptera: Mamestra configurata) – The first map (Fig. 1) shows that predicted pupal development is well underway (average 27%).
Figure 1. Predicted stage of pupal development of overwintered Bertha armyworm set to emerge in 2017.
The second map (Fig. 2) indicates that predicted development this year is ahead of long term averages in Manitoba and Saskatchewan.
Figure 2. Pupal development of overwintered Bertha armyworm in 2017 compared to long-term averages observed across the Canadian prairies.
These maps will be updated weekly to aid those who deploy and monitor this moth using pheromone traps. The video below posted by Alberta Agriculture and Forestry’s Scott Meers describes how pheromone traps are used to monitor this important pest of canola.
Field scouting is critical – it enables the identification of potential risks to crops. However, the identification of these insect pests PLUS the application of established monitoring methods will enable growers to make informed pest management decisions.
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.
Provincial entomologists provide insect pest updates throughout the growing season so we have attempted to link to their most recent information:
Manitoba’s Insect and Disease Update for 2017 will be posted soon. Watch for updates prepared by John Gavloski and Pratisara Bajracharya). Saskatchewan’s Crop Production News for 2017 will be posted soon. Watch for updates prepared by Scott Hartley and Danielle Stephens. Watch for Alberta Agriculture and Forestry’s Call of the Land for updates from Scott Meers who recently provided an update (posted on May 18, 2017). Flea beetles and seed-feeding carabids and fungus beetles in harvested grain were noted as being insects to watch at this point in Alberta.
We again track the migration of the Monarch butterflies as they move north by checking the 2017 Monarch Migration Map! A screen shot of the map has been placed below as an example (retrieved 18May2017) but follow the hyperlink to check the interactive map! They’ve migrated into the extreme south of Ontario!
Across the prairies, meteorological conditions for the period May 8-15, 2016, were similar to long term average values for the first half of May.
The average temperature was 8.7 °C (12 °C last week) and was 0.7 °C warmer than the average temperature for May 8-15.
This past week, rainfall amounts were minimal across most of Alberta and southern Manitoba. Most of Saskatchewan received normal or above normal rainfall. This week rainfall amounts greater than 30 mm were reported for a number of locations across southern Saskatchewan.
The 30-day rainfall amounts were similar to long term average values.
Compared to last week, soil moisture levels were predicted to improve across most of Saskatchewan. Low soil moisture values were predicted across central and northern Alberta.
Unfortunately, there were some cool temperatures just as seedlings were emerging….. The map below reflects the Lowest Temperatures occurring over the past 7 days across the prairies.
Whereas the map below reflects the Highest Temperatures occurring over the past 7 days across the prairies.
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.
2016 Wind Trajectories – High altitude air masses originate from southern locations and continuously move northerly to Canadian destinations. Insect pest species such as Diamondback moth and Aster leafhoppers, traditionally unable to overwinter above the 49th parallel, can utilize these air masses in the spring to move north from Mexico and the United States (southern or Pacific northwest). Data acquired from Environment Canada is compiled by Olfert et al. (AAFC-Saskatoon) to track and model spring high altitude air masses with respect to potential introductions of insect pests onto the Canadian prairies.
Reverse Trajectories track arriving air masses back to their point of origin while Forward Trajectories predict favourable winds expected to arrive across the Canadian Prairies.
This week, Reverse Trajectories (RT) originating from southwest USA and Mexico have crossed over more than half of the prairie locations (18 of 29 locations). This week, first reports of these RT’s occurred for Russel MB, Gainsborough SK, Yorkton SK, Grenfell SK, Watrous SK, and Kindersley SK.
Review earlier 2016 Wind Trajectory Updates in PDF format.
Field scouting is critical because it enables the identification of potential risks to crops. Canola production systems across the Canadian prairies will suffer insect pest outbreaks. However, the identification of these insect pests PLUS the application of established monitoring methods will enable growers to make informed pest management decisions.
We first offered the chart below in 2015 but we again post our generalized canola scouting chart to aid in-field scouting on the Canadian prairies. Two versions are below – the first version contains hyperlinks to help growers learn more about some of our insect pests and how to monitor while the second version may be easier to view or print.
Whenever possible, monitor and compare to established economic thresholds so pollinators and beneficial arthropods are preserved. Economic thresholds, by definition, can help growers avoid crop losses due to an insect pest.
More information about Diamondback moths can be found by accessing the pages from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide”. View ONLY the Diamondback moth page but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.
Reminder – Flea Beetles (Chrysomelidae: Phyllotreta species) – Be on the lookout for flea beetle damage resulting from feeding on canola cotyledons but also on the stem.
Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed. Shot-hole feeding is the traditional damage in seedling canola but watch the growing point and stems of seedlings.
Estimating flea beetle feeding damage can be challenging. Using a visual guide to estimate damage can be helpful. Canola Watch circulated this article but also use the images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon) – take it scouting!
Figure 1. Canola cotyledons with various percentages of leaf area consume owing to flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).
Figure 2. Percent leaf area consumed by flea beetles feeding on canola seedlings (Photo: Soroka & Underwood, AAFC-Saskatoon).
Refer to the flea beetle page from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” as an English-enhanced or French-enhanced version.
Reminder – Cutworms (Noctuidae) – Keep an eye on fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look. Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed. Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant. If the plant is well-established, check within the crown in addition to the adjacent soil. The culprits could be wireworms or cutworms. Several species of cutworms can be present in fields. They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning. Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol. Also refer to Manitoba Agriculture and Rural Initiatives cutworm fact sheet which includes action and economic thresholds for cutworms in several crops.
More information about cutworms 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 an excerpt of ONLY the Cutworm pagesfrom the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide”. The guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.
For ALBERTANS….. If cutworms are spotted in Albertan fields, please consider using the Alberta Pest Surveillance Network’s “2016 Cutworm Reporting Tool”. Once data entry occurs, your growers can view the live 2016 cutworm map.
A screen shot of the live map has been retrieved (18May2016) below for your reference.
Reminder – Pea Leaf Weevil (Sitona lineatus) – 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. The pea leaf weevil resembles the sweet clover weevil (Sitona cylindricollis) yet the former is distinguished by three light-coloured stripes extending length-wise down thorax and sometimes the abdomen (Access the Pea leaf weevil monitoring protocol). All species of Sitona, including the pea leaf weevil, have a short snout.
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.
Information related to Pea leaf weevil in Alberta and the forecast for 2016 is posted here.
Cereal leaf beetle (Oulema melanopus) – Based on last week’s warm weather, our bioclimate model predicted rapid development of cereal leaf beetle (CLB) populations.
As of May 15, 2016, the CLB model indicated that oviposition is well underway, though this week’s development was slower than the previous week. Model output predicted that egg populations should be peaking this week in both Alberta and Saskatchewan and next week at Swan River MB. Larval populations are predicted to peak in mid-June in southern Alberta and Saskatchewan and one week later at Swan River MB locations.
Predicted dates of peak emergence of CLB eggs and larvae:
The following model outputs have been updated this week and reflect the predicted stages of CLB present in fields in relation to its parasitoid, Tetrastichus julis.
Fact sheets for CLB are published by the province of Alberta and by 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”.
