This is Week 2 of the 2023 Prairie Pest Monitoring Network Weekly Updates!
Spring weather continues to be hot and dry across the prairies, bringing some challenging conditions for #Plant2023. Please stay safe.
Grasshoppers thrive in warm, dry conditions and there are reports that first instar nymphs are already hatching. Diamondback moths are appearing in pheromone traps across the prairies, albeit in low numbers so far. For more information, check out the posts in the Weekly Update! The Insect of the Week is about cutworms this week – read on and check out the links for more information.
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 target 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.
Similar to the previous week, this past week (May 8-14, 2023) was warmer and drier than normal. The average temperature across the prairies was 5°C warmer than normal (Fig. 1). This week, the warmest temperatures were observed across southern Manitoba, the northern Peace River region, and across a region that extended between Saskatoon and Edmonton. The coolest weekly temperatures were observed over southern regions of Alberta and Saskatchewan.
Figure 1. Seven-day average temperature (°C) observed across the Canadian prairies for the period of May 8-14, 2023.
Since April 1, the 2023 growing season has been marginally cooler than average across eastern Saskatchewan and Manitoba (Fig. 2). 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 has been 4.7°C warmer than normal and Manning has been 3°C warmer than normal.
Figure 2. Growing season average temperature (°C) observed across the Canadian prairies for the period of April 1 to May 14, 2023.
Seven-day cumulative rainfall was greatest across the southern prairies and central regions of Alberta (Fig. 3). Central regions of Saskatchewan received minimal rain over the past seven days. Growing season rainfall (April 1 to May 14) has been below normal across most of the prairies (Fig. 4). A large region, extending from Lethbridge to Saskatoon to the Peace River region has received well below normal rainfall accumulations so far in 2023.
Figure 3. Seven-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 8-14, 2023.Figure 4. Growing season cumulative rainfall (mm) observed across the Canadian prairies for the period of April 1 to May 14, 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. 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’ 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.
Wind Trajectory Summary to May 16, 2023
Since May 1, 2023, the majority of the reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1).
Figure 1. The average number (based on a 5-day running average) of reverse trajectories (RT) that have crossed the prairies for the period of May 1-16, 2023.
Mexico, California and Texas – Very few reverse trajectories that originated from Mexico, California or Texas have passed over the Canadian prairies so far in May 2023.
Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories 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 16, 2023.
Oklahoma and Texas – Since April 1, reverse trajectories from Oklahoma and Texas were reported to cross the southern prairies (Fig. 3).
Figure 3. The total number of dates with reverse trajectories originating over Texas and Oklahoma that have crossed the prairies between May 1 and May 16, 2023.
Kansas and Nebraska – Since April 1, reverse trajectories were reported to cross southeastern Saskatchewan and southern Manitoba (Fig. 4).
Figure 4. The total number of dates with reverse trajectories originating over Kansas and Nebraska that have crossed the prairies between May 1 and May 16, 2023.
Model simulations were used to estimate development of grasshopper eggs as of May 14, 2023. Compared with average spring temperatures, temperatures in Alberta and western Saskatchewan have been well above average so far in 2023. Unseasonably warm temperatures continue to contribute to rapid grasshopper egg development (Fig. 1). Compared to egg development expected if temperatures were like long-term to climate normals (Fig. 2), egg development in 2023 is well ahead of average (Fig. 1). 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 14, 2023. Figure 2. Long-term average predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 14, based on climate normals data.
As a result of above normal temperatures, model outputs predict that grasshopper eggs have already started to hatch across Alberta and western Saskatchewan (Fig. 3). We have received reports of grasshopper nymphs from both provinces. This spring, grasshopper eggs are hatching approximately 10 days earlier than normal. Areas with highest densities of adult grasshoppers in summer of 2022 overlap with regions with greatest predicted egg development so far in spring of 2023 (Fig. 4), including a large region extending from south of the Yellowhead Highway corridor to the Canada-USA border. Prairie farmers should be scouting for grasshoppers early this spring and summer, especially if conditions remain warmer and drier than normal over the next few weeks.
Figure 3. Predicted grasshopper (Melanoplus sanguinipes) hatch (%) across the Canadian prairies as of May 14, 2023.Figure 4. Estimated grasshopper population densities in late summer and early fall 2022 in western Canada; areas with high grasshopper densities in 2022 are at risk of high grasshopper densities and associated damage in 2023, based on knowledge of the life history of the primary pest species, including Melanoplus sanguinipes (migratory grasshopper) (map by Ross Weiss, AAFC-Saskatoon).
Test your grasshopper knowledge by taking the Canola Watchquiz!
It has been suggested the overwintering mortality of diamondback moth (DBM) is high on the prairies. DBM, carried on upper air currents, may be introduced to the prairies from overwintering sites in southern USA and the US Pacific Northwest. Analysis of wind trajectory data (from Environment and Climate Change Canada) indicated that a number of upper air currents, originating over the US Pacific Northwest, passed over the Peace River region during the last week of April and first two weeks of May. DBM development can be rapid during periods of warm weather. Shelley Barkley (Alberta Agriculture and Irrigation) reports that DBM adults have been collected from a number of traps across Alberta. In Alberta, trap captures of DBM have been highest near Grande Prairie. Similarly, Carter Peru and James Tansey (Saskatchewan Ministry of Agriculture) note that adult DBM have been collected on traps located across Saskatchewan.
During the growing season, results from the DBM monitoring program in Saskatchewan will be available here (scroll to the bottom of the page) and results from Alberta will be available here.
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)
DBM were collected during the first and second weeks of May. Thus, the DBM model was initialized for May 1, 2023 and run to May 14. Though canola may not be present, results indicate that females may have started to lay eggs on brassicaceous plants (e.g., volunteer canola, flix weed) and larvae may have hatched from early-laid eggs. In the Grande Prairie area, for example, both eggs and first instar larvae may already be present (Fig. 1).
Figure 1. Predicted development of diamondback moth (Plutella xylostella) near Grande Prairie, AB as of May 14, 2023.
Growers are out seeding, and the cutworms are ready for it – the time to start scouting for cutworms is now! Scouting occurs by manually examining plant foliage and digging in the soil near damaged or missing plants – focus on transition zones between damaged and healthy plants. Even if you have not started seeding a field yet, 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 Cutworm Pests of Crops on the Canadian Prairies.
There are over 20 cutworm species that can cause economic damage to your crop, each with different feeding behaviour, preferred hosts, and lifecycle. Cutworms will feed on prairie-grown commodities including canola, mustard, wheat, barley, triticale, peas, alfalfa, clover, fescue, and timothy. Species identification is especially important! It helps growers determine how and when to scout, whether the cutworm species is found above-ground (climbing) or below-ground, recognize damage, and choose appropriate control options. The species of cutworm will also determine the time of day for monitoring and applying controls.
Action and economic thresholds exist for many of the cutworm species – please use them. Thresholds help control costs by eliminating unnecessary and non-economic spraying and reduce your impact on non-target insects. These non-target insects include the natural enemies that work in the background to control cutworm populations!
Pale western cutworm, Phil Sloderbeck, Kansas State University, Bugwood.org (cc-by-nc 3.0)
This week’s Insect of the Week is the Pale Western Cutworm. This cutworm feeds below ground, with larvae hatching in late April through early May. Young larvae tunnel through the soil, producing holes on newly emerged shoots and furled leaves. Older larvae will sever plants just below the soil surface and may pull and eat the severed shoots underground. Mature larvae are a pale greenish gray, with a yellow, black striped head.
Catch Monday’s Insect of the Weekfor Week 2- it’s the NEW Wireworm Field Guide!
NEW for this growing season – the website has been updated to create a Field Guides page linking to free, downloadable, AND searchable PDF copies of some of the key field guides used to support in-field insect monitoring in field crops on the Canadian prairies.
Review the historicalRisk Maps for our most economically important insect pests of field crops on the Canadian prairies. 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 target 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 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 marginally cooler than normal. 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 9-16, 2022), the average temperature across the prairies was 0.5 °C cooler than normal (Fig. 1). Temperatures were warmest across southern Manitoba. The average 30-day temperature (April 16-May 15, 2022) was 1.5 °C less than climate normal values (click to view Fig. 2) and the growing season (April 1-May15, 2022) has been 1.8 °C cooler than average (click to view Fig. 3). The growing season and 30-day temperatures have been coolest in Manitoba (Fig. 2 and Fig. 3).
Figure 1. Seven-day average temperature (°C) across the Canadian prairies for the period of May 9-15, 2022.
Growing degree day (GDD) maps for Base 5 ºC and Base 10 ºC (April 1-May 15, 2022) can be viewed by clicking the hyperlinks. Over the past 7 days (May 10-16, 2022), the lowest temperatures recorded across the Canadian prairies ranged from < -7 to >2 °C while the highest temperatures observed ranged from <12 to >24 °C. Even at this early point in the growing season, a few areas in Alberta and Saskatchewan have experienced a few days >25 °C (view map). Access these maps and more using the AAFC Maps of Historic Agroclimate Conditions interface.
PRECIPITATION: Average seven-day cumulative rainfall ranged between 0 and 76 mm with the highest rainfall amounts occurring across eastern Saskatchewan and western Manitoba (Fig. 4). Western Saskatchewan and most of Alberta have received little or no rain over the past seven days. Rain accumulation over the past 30 days has been well above average across the eastern prairies, particularly in southeastern Manitoba (click to view Fig. 5). Growing season rainfall for April 1-May 15, 2022, has been greatest across Manitoba and eastern Saskatchewan. Conditions have been drier across most of Saskatchewan and Alberta (click to view Fig. 6).
Figure 4. Seven-day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 9-15, 2022.
Cutworm scouting spans April to late June across the Canadian prairies! 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 either very early or late in the day when some cutworm species (or climbing cutworms) move above-ground to feed. Start to dig below the soil surface (1-5 cm deep) near the base of symptomatic plants and also any healthy plants immediately adjacent to missing rows or wilting or clipped plants. Some cutworms feed by remaining just below the soil surface, clipping then pulling the plant below as they munch away! If the plant is well-established (e.g., perennial grass or legume), check within the crown in addition to the adjacent soil. The culprits could be cutworms, wireworms, or more!
Important: Several species of cutworms (Lepidoptera: Noctuidae) can be present in fields. They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning. A field guide is available to help growers scout and manage the various species of cutworms that can appear in field crops grown on the Canadian prairies. Cutworm Pest of Crops is available free in either English or French! Download a searchable PDF copy to access helpful diagnostic photos plus a table showing which larvae are active at different points in the growing season!
Other vital resources to scout and manage cutworms include:
● For anyone on the Canadian prairies, Manitoba Agriculture and Rural Development’s Cutworms in Field Crops fact sheet includes action and economic thresholds for cutworms in several crops, important biological information, and great cutworm photos to support in-field scouting.
● For Albertans….. If you find cutworms, please consider using the Alberta Insect Pest Monitoring Network’s “2022 Cutworm Reporting Tool” then view the live 2022 cutworm map updated daily. Review the live map to see where cutworms are appearing then prioritize in-field scouting accordingly.
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 15, 2022. Model results indicate that egg development ranges between 55 and 71 % across most of the prairies (average=61 %) (Fig. 1). Based on climate normals data, long-term average egg development should be 60 % (Fig. 2). Cool conditions in Manitoba and the Peace River region have resulted in slower development rates. The simulation indicates that egg development is greater than average across southern Alberta (Fig. 2). This region has had the least amount of rain over the past 30 days.
Grasshopper risk can be greater when conditions are warm and dry. The initial hatch may begin this week near Medicine Hat and Brooks in Alberta.
Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 15, 2022.Figure 2. Long-term average predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 15 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 that oviposition should be well underway across the prairies as of May 15, 2022. The following graphs indicate, based on potential number of eggs, that development is slower near Lethbridge (Fig. 1) than Saskatoon (Fig. 2).
Development for both locations is ahead of average. The model predicts that eggs may begin hatching next week.
Figure 1. Predicted status of alfalfa weevil (Hypera postica) populations near Lethbridge AB as of May 15, 2022.Figure 2. Predicted status of alfalfa weevil (Hypera postica) populations near Saskatoon SK as of May 15, 2022.
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 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 overwintered adults are active and that oviposition is underway across southern regions across the southern prairies. Compared to simulations for climate normals, development is generally slower than average. The following graphs provide a comparison of development for Swift Current (Fig. 1) and Winnipeg (Fig. 2). Warmer conditions in southwestern Saskatchewan are expected to have contributed to more rapid development of CLB populations whereas cool conditions have contributed to slower development of CLB populations in southern Manitoba.
The simulation predicts that first instar larvae may occur during the third or fourth week of May.
Figure 1. Predicted status of cereal leaf beetle (Oulema melanopus) populations near Swift Current SK as of May 15, 2022.Figure 2. Predicted status of cereal leaf beetle (Oulema melanopus) populations near Winnipeg MB as of May 15, 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 crossing the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1).
Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of May 1-16, 2022.
a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories have passed over south-central Alberta and western Saskatchewan (link to view Fig. 2).
b. Mexico and southwest USA (Texas, California) – Since April 1, reverse trajectories were reported for Manitoba (Portage, Selkirk, Brandon, Carman, Russell) and eastern Saskatchewan (Gainsborough, Grenfell) (link to view Fig. 3).
c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan (link to view Fig. 4).
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. 5). Results indicate that the greatest number of forward trajectories entering Canada originated from the Pacific Northwest (Idaho, Oregon, Washington).
Figure 5. 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 16, 2022.
The Pests and Predators Field Guide is filled with helpful images for quick insect identification and plenty of tips to manage the pests AND natural enemies in your fields. Claim your free copy at http://fieldheroes.ca/fieldguide/ or download a free copy to arm your in-field scouting efforts!
Review the Sweep-net Video Series including: • How to sweep a field. Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon). Published online 2020. • What’s in my sweep-net? Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon). Published online 2020. • Why use a sweep-net? Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon). Published online 2020.
Continued surveillance is important and enables tracking of Lyme disease incidence and risk. Follow the links to learn more and to submit ticks if you live in British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, or Quebec.
Another option is the free eTick APP, a public platform for image-based identification and population monitoring of ticks in Canada. Both Google Play and iOS versions of the App enable users to upload tick photos for help with identification.
Public Health Agency of Canada’s 2018 infographic (published 2021; retrieved 2022May18 for downloading) summarizing Lyme disease surveillance in Canada is worth a quick scan (see image snip below).
Figure 1. Screenshot of Public Health Agency of Canada’s infographic summarizing Lyme disease surveillance in Canada (2018; retrieved 2022May18).
The European corn borer (ECB; Ostrinia nubilalis), can be an important pest of corn. Despite its name, ECB is actually a generalist feeder, having a wide range of hosts.
The recent confirmation of ECB resistance to Cry1F Bt corn in Nova Scotia has increased the need to monitor this pest across Canada. With so many new emerging crops being grown in Canada that are also hosts for ECB (e.g. hemp, cannabis, quinoa, hops, millet and others), there is no better time for us to look at this pest across the Canadian ag landscape.
European corn borer larva. Photo: J. Smith, University of Guelph, Ridgetown Campus.
To monitor for ECB nationwide, the Insect Surveillance Community of Practice of the Canadian Plant Health Council has developed a harmonized monitoring protocol for European corn borer across all hosts. The protocol can be used to report ECB eggs, larvae or damage in any host crop across Canada. Our goal is to better understand the distribution and abundance of ECB in Canada, detect significant infestations, capture observations on any hosts and determine if ECB is shifting to other emerging crops like hops, quinoa, millet, hemp, and others. This harmonized protocol has been designed to complement protocols that are already in use to make management decisions.
Whether you are scouting corn, quinoa, hemp, millet, potatoes, apples, or other crops susceptible to ECB, we encourage you to try the harmonized monitoring protocol and report the data from your field or research plots using the free Survey123 app (available for both desktop and mobile devices):
You do not need a login in to use the survey. Simply download the Survey123 Field App and click on the third option “Continue without logging in”, once on the login screen. To see the French version, click on the button on the top right corner, once in the survey to switch from English to French. A hardcopy version to take out to the field before entering it into Survey123 is also available here in English and French.
Looking for help online to identify unusual flora and fauna? Apps aplenty exist but consider iNaturalist.ca because there are underlying benefits!
iNaturalist.ca helps users identify terrestrial organisms by connecting to online “experts” able to identify and provide information to users but there’s an underlying secondary benefit:Researchers, institutions, and active research projects can set up Lists and access observations within iNaturalist.ca. This is citizen science in action!
“Every observation can contribute to biodiversity science, from the rarest butterfly to the most common backyard weed”, to quote from iNaturalist.ca’s webpage.
Here’s how Canadian Food Inspection Agency (CFIA) who are already using and accessing valuable data from this resource to aid in the early detection of invasive species.
What’s best – iNaturalist.ca OR iNaturalist.com? Canadian Food Inspection Agency (CFIA) and the team that focuses on the detection of invasive species generally recommends iNaturalist.ca because it allows Canadians better access to Canadian experts and Canadian data.
Is iNaturalist.ca worth using to identify unknown insects encountered in field crops?iNaturalist.ca is going to be the leader in early detections and is a fairly intuitive and usable tool for everyone. It’s not perfect for all organisms but works well for many. CFIA staff are actively monitoring it and, in the near future, CFIA hopes to set up an account that might allow users to flag observations for their team to see more rapidly.
How does CFIA mine iNaturalist and what is the value? CFIA uses a script through the Intauralist API to query for any mentions of our targeted list under the project here: Important Pest Species List for Canada – Lookout · iNaturalist. CFIA staff members receive a daily email of all the target list mentions (i.e., includes insects, plants, and mollusks). In order to increase early detections, CFIA’s also trying to retrieve data from comments such as when someone mentions a new record or new detection. At this point, only a few pathogens are listed in our pest lookout because many of CFIA’s regulated pests would need more than a picture (so we didn’t add them). CFIA staff believe iNaturalist.ca is a great tool for early detection because the number of observations is very large and growing like crazy AND they are geographically widespread.
The basic steps to get you going are: ◦ Create an account at iNaturalist.ca (https://inaturalist.ca/signup). ◦ Watch your Inbox for a basic how-to guide. ◦ Upload photos or videos (e.g., bird calls) to create an “Observation”. ◦ iNaturalist subscribers considered to be experts will help identify your observation.
Could be coming to a field near you….. Many of Canada’s economically important species of insect pests originated as invasive species that managed to relocate and establish self-sustaining populations. Over time, they become increasingly widespread and so frequently abundant that they are part of the annual list of species we monitor and attempt to manage.
Examples of invasive species existing presently throughout large areas of the Canadian prairies include wheat midge, cereal leaf beetle, cabbage seedpod weevil, pea leaf weevil, swede midge – in fact, the list of invasive species is far longer! Consider the impact of invasive species AND recognize that a growing list of species will likely affect field crops in Canada. Globalization, adaptation, and the development of new cultivars suited to Canada’s growing regions, climate change, plus many other factors will contribute to the reality: we can expect more invasive species to continue to arrive.
Where can you play a role??? Early detection and accurate identification are key steps involved in mitigating the risks associated with new invasive species. Many levels of government are active in the ongoing battle against invasive species. Even so, initial detections often arise from keen in-field scouting by producers or agrologists so access these resources to help identify the “that’s weird” or “I haven’t seen that before”. And be sure to thank the many entomologists – regional, provincial, federal, and some amazing amateurs PLUS the folks at Canadian Food Inspection Agency (CFIA) who ALL work to stand on guard for thee!
• Canadian Food Inspection Agency’s (CFIA) main Plant Health sectioncan be accessed here.
• More specifically, CFIA’s Plant Pests and Invasive Species informationis accessible here.
• Did you know…. CFIA’s top field crop invasive species include anything falling under the List of Pests Regulated by Canada which is accessible here. Caveats are that (i) some species may be on the list (e.g., codling moth) that are not necessarily a high priority but remain to maintain regulatory policy or (ii) list may include species yet to be removed.
HERE’S WHERE YOU CAN HELP – Experienced producers and agrologists make important discoveries every day! Keep Canadian agriculture strong and support the detection of invasive species when encountering unusual damage symptoms or unknown insect species. How and what to report plus 3 different pathways to submit your sightings are all described here.
Every year, these guides are updated with product information and so much more! Hard copies can be purchased via the above websites. Alternatively, the 2022 Crop Production Guides are available as a FREE downloadable PDF for Alberta, Saskatchewan, and Manitoba.
A few other helpful tools to keep at your finger tips:
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.
Wireworms are the larvae of click beetles (Coleoptera: Elateridae). They are serious pests of many field crops across Canada, particularly cereals, pulses, root crops. Wireworms live for multiple years in the soil, eating crops from below – their underground habitat can make them difficult to detect and diagnose. Damage in cereals and pulse crops will appear as early season crop thinning or yellowing, weakened plants. Root crops may look fine aboveground but at harvest, produce will have feeding holes or disfigurations, decreasing market value.
When crop thinning is seen, post-emergence scouting by digging up plants and soil can reveal if wireworms are there. Photos: H. Catton, AAFC-Lethbridge.
There are several pest wireworm species in the Prairies and they are different than in other regions of Canada. A 2004-2019 survey of Prairie crop fields published by Wim van Herk and colleagues collected 5,704 specimens. This survey revealed that 97% of specimens belonged to 4 native species: 58% were Hypnoidus bicolor (no common name), 22% were Prairie grain wireworm (Selatosomus aeripennis destructor), 15% were sugarbeet wireworm (Limonius californicus), and 2% were flat wireworm (Aeolus mellillus). Importantly, the invasive wireworm species dominating coastal BC and the Atlantic provinces (Agriotes obscurus, Agriotes lineatus, Agriotes sputator) were NOT found in the survey. Over the next several weeks our Insect of the Week articles will highlight the main pest wireworm species on the Prairies.
Main pest wireworm species on the Canadian Prairies: larval stages (top), adult (click beetle) stages (bottom). Photos: J. Saguez, CEROM
Monitoring for wireworms can be done in different ways. Before seeding, bait traps can be placed in the soil. After crop emergence, hand digging in thinned areas of crop may reveal wireworms. Finally, monitoring for adult click beetles may be able to indicate if wireworm populations are high – this method is still in development. Unfortunately, there are no economic thresholds developed for wireworms, farmers need to judge yield loss from thin or bare patches caused by wireworms.
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.
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@agr.gc.ca to request your copy.
Reference:
van Herk WG, Vernon RS, Labun TJ, Sevcik MH, Schwinghamer TD (2021) Distribution of pest wireworm (Coleoptera: Elateridae) species in Alberta, Saskatchewan, and Manitoba (Canada). Environmental Entomology 50:663-672. doi: 10.1093/ee/nvab006
Week 2 and it’s time to get busy with in-field scouting for insects – cutworms, wireworms, flea beetles, and more are all active! In addition to the Weekly Update, be sure to catch the Insect of the Week.
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.
This past week (May 3-9, 2021), the average temperature across the prairies was 1.3 °C cooler than normal (Fig. 1). Similarly, the average 30-day temperature (April 10-May 9) was 1.7 °C less than climate normal values (Fig. 2). Temperatures have been warmest in southern Alberta (Table 1; Fig. 1-2).
Figure 1. Seven-day average temperature (°C) across the Canadian prairies for the period of May 3-9, 2021.Figure 2. 30-day average temperature (°C) across the Canadian prairies for the period of April 10-May 9, 2021.
The growing degree day map (GDD) (Base 5 ºC, April 1-May 2, 2021) is provided below (Fig. 3) while the growing degree day map (GDD) (Base 10 ºC, April 1-August 9, 2020) is shown in Figure 4.
Figure 3. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-May 11, 2021). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (12May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=trueFigure 4. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-May 11, 2021). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (12May2021). 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 incredible stress on newly germinating plants in field crops. The lowest temperatures recorded ranged from <-59 to >-6 °C (Fig. 5) while the highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <11 to >26 °C (Fig. 6). Wow, what an amazing range – spring is tough!
Figure 5. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (May 5-11, 2021). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (12May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=trueFigure 6. Highest temperatures (°C) observed across the Canadian prairies the past seven days (May 5-11, 2021). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (12May2021). Access the full map at https://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
Seven-day cumulative rainfall indicates that below normal rain (86% of average) was reported for the prairies (Fig. 7). Over the past seven-days rain totals across most of Alberta and the extreme southwest region of Saskatchewan was 10-20 mm. The rest of the prairies received little or no rain. Rain (30-day accumulation) amounts have been less than average for most of the prairies (81% of average). Rainfall for April 10-May 9, 2021, has been greatest for southeastern Manitoba, southwestern Saskatchewan and across most of Alberta (Table 1; Fig. 8). Average growing season (April 1 to May 9) precipitation has been well below average for most of the prairies. The two large regions (Swift Current to Prince Albert to Vegreville and the western two-thirds of Manitoba) have had less than 40 % of normal precipitation.
Figure 7. Seven-day cumulative rainfall (mm) observed across the Canadian prairies the past 30 days (May 3-9, 2021).Figure 8. 30-day cumulative rainfall (mm) observed across the Canadian prairies the past 30 days (April 10-May 9, 2021).
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’ 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’ have a similar purpose; however, the modeling 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.
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. Read a brief overview of this strategy plus the definitions and applications of both ‘Reverse’ and ‘Forward’ trajectories.
1. REVERSE TRAJECTORIES (RT) Since May 1, 2021, the majority of reverse trajectories crossing the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington). This week, an increasing number of reverse trajectories have been moving north from Kansas and Nebraska (Fig. 1).
Figure 1. The average number (based on a 5-day running average) of reverse trajectories (RTs) that have crossed the prairies for the period of May 1-13, 2021.
a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories have been reported to pass over southern Alberta (Fig. 2).
Figure 2. Total number of dates with reverse trajectories originating over the Pacific Northwest (PNW including Idaho, Oregon, and Washington) that have crossed the prairies between March 24 and May 13, 2021.
b. Mexico and southwest USA (Texas, California) – Since last week there have not been any trajectories that originated in these areas that have crossed the prairies.
c. Oklahoma and Texas – Since last week there have not been any trajectories originating in Oklahoma or Texas that have crossed the prairies.
d. Kansas and Nebraska – This week reverse trajectories were reported for Alberta (Andrew, Sedgewick), Saskatchewan (Gainsborough, Grenfell, Kindersley, Regina, Yorkton) and Manitoba (Brandon) (Fig. 3).
Figure 3. The total number of dates with reverse trajectories originating over Kansas and Nebraska that have crossed the prairies between March 24 and May 13, 2021.
2. FORWARD TRAJECTORIES (FT) Forward trajectories, originating from Mexico and USA have crossed a number of prairie locations since May 1, 2021. Based on average totals (averaged across a five day period), the greatest number of forward trajectories were observed to originate between May 5 and 8 (blue bars) and entered the prairies between May 6-9 (Fig. 4).
Figure 4. The average number (based on a 5 day running average) of forward trajectories that have crossed the prairies for the period of May 1- 13, 2021.
The following map presents the total number of dates (since March 24, 2021) with forward trajectories that have crossed the Canadian prairies (Fig. 5). Results indicate that the greatest number of forward trajectories entering Canada originated from the Pacific Northwest (Idaho, Oregon, Washington).
Figure 5. The total number of dates with forward trajectories, originating from various regions of the United States and Mexico, that crossed the prairies between March 24 and May 13, 2021.
‘Tis the season…. to scout for cutworms! 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, cutworms, or more!
Important: Several species of cutworms (Lepidoptera: Noctuidae) can be present in fields. They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning. A field guide is available to help growers scout and manage the various species of cutworms that can appear in field crops grown on the Canadian prairies. Cutworm Pest of Crops is available free in either English or French! Download a searchable PDF copy that includes great photos plus a table showing which larvae are active at different points in the growing season!
Other vital resources to scout and manage cutworms include:
● For anyone on the Canadian prairies, Manitoba Agriculture and Rural Development’s Cutworms in Field Crops fact sheet includes action and economic thresholds for cutworms in several crops, important biological information, and great cutworm photos to support in-field scouting.
● For Albertans….. If you find cutworms, please consider using the Alberta Insect Pest Monitoring Network’s “2021 Cutworm Reporting Tool” then view the live 2021 cutworm map which is updated daily. Review the live map to see where cutworms are appearing then prioritize in-field scouting accordingly.
Newly seeded fields should be scouted throughout the germination and emergence periods for a variety of insect pests – one of the most difficult to detect can be wireworms! Wireworms are the juvenile stages of a complex comprised of several species of Elateridae, commonly referred to as ‘Click beetles’. On the Canadian prairies, wireworm collections from field crops indicate that three economically important species of wireworms or click beetles can be present; Selatosomus destructor, Limonius californicus, and Hypnoides bicolor. According to van Herk and Vernon (2014), a wide variety of Elateridae have been described from across the Canadian prairies; Alberta 144 species described in Alberta, 108 species described from Saskatchewan, and 109 species described from Manitoba.
Review these two wireworm posts to learn more and supplement in-field scouting:
Newly emerging Brassicaceae but especially canola is attractive to overwintered flea beetles that emerge and become active early in the spring. As canola seedlings emerge, in-field scouting becomes crucial! If flea beetle densities are high, seedling damage levels can advance quickly – even within the same day! The cotyledon stage of canola is vulnerable to flea beetle feeding. Be sure to check out the Insect of the Week – Week 2 featured flea beetles!
Several species of flea beetles are present across North America. Be on the lookout for flea beetle damage resulting from feeding on canola cotyledons but also on the stem (Fig. 1). Two species, Phyllotreta striolata (Fig. 1) and P. cruciferae, will feed on all cruciferous plants but they can cause economic levels of damage in canola during the seedling stages.
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 (Figs. 2 and 3; copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon) – take it scouting!
Figure 2. Canola cotyledons with various percentages of leaf area consume owing to flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).
Figure 3. Percent leaf area consumed by flea beetles feeding on canola seedlings (Photo: Soroka & Underwood, AAFC-Saskatoon).
Two other favourite flea beetle resources relevant to field crop protection include:
Those armed with a stereomicroscope who are keen to monitor flea beetle species may wish to bookmark the “Common flea beetles of North Dakota” (Fauske 2003) which an excellent online resource and includes many of the commonly observed species of flea beetles also present across the Canadian prairies.
Soroka, J., Grenkow, L., Otani, J., Gavloski, J., & Olfert, O. (2018). Flea beetle (Coleoptera: Chrysomelidae) species in canola (Brassicaceae) on the northern Great Plains of North America. The Canadian Entomologist,150(1), 100-115. doi:10.4039/tce.2017.60
The cereal leaf beetle (CLB) model output suggests that overwintered adults are active and that oviposition is underway across the prairies. The graphs provide a comparison of development for Saskatoon (Fig. 1) and Winnipeg (Fig. 2). The simulation indicates that first instar larvae may occur during the third week of May.
Figure 1. Predicted status of cereal leaf beetle populations near Saskatoon, SK as of May 9, 2021.Figure 2. Predicted status of cereal leaf beetle populations near Winnipeg MB as of May 9, 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.
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 embryonic (egg) development as of May 9, 2021. The simulation predicts that development has now begun across southern areas of the Peace River region. Results indicate that egg development has been greatest for Lethbridge and Regina regions. Cool conditions in Manitoba have resulted in slower development rates (Figs. 1 and 2).
Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 9, 2021. Figure 2. Predicted percent embryonic development of overwintered grasshopper eggs across the Canadian prairies as of May 9, 2021.
Model simulations for alfalfa weevil (AAW) indicate that oviposition should be well underway across the prairies. The following graphs indicate, based on potential number of eggs, that development is more advanced near Lethbridge (Fig. 1) than Brandon (Fig. 2). The model predicts that hatch may occur during the last week of May.
Figure 1. Projected predicted status of alfalfa weevil populations near Lethbridge AB as of May 9, 2021.Figure 2. Projected predicted status of alfalfa weevil populations near Brandon MB as of May 9, 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).
Diamondback moth pheromone trap monitoring update for MB – So far (as of 12May2021). only one moth has been intercepted on a pheromone trap deployed near Austin.
Diamondback moth pheromone trap monitoring update for SK – 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. Additionally, 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 zero moths (as of 13May2021).
Cutworm reporting tool for AB – Refer to the Live Map which reports two sites with cutworms (as of 13May2021).
In canola, the most common flea beetles are either bluish black (crucifer flea beetle or Phyllotreta cruciferae) or black with two wavy yellow lines running down the length of its back (striped flea beetle or P. striolata). They overwinter as adults under plant material along field margins and females lay eggs in the soil near host plants.
Striped and crucifer flea beetles feed on canola, mustard and related cruciferous plants and weeds. Canola is highly susceptible to feeding damage at the cotyledon stage – damage appears as ‘shot-holes’ in cotyledon leaves. Flea beetles also feed on stems and very young seedlings may wilt or break off under windy or damp conditions. New generation adults feed on maturing pods late in the summer. Remember, the Action Threshold for flea beetles on canola is when 25% of cotyledon leaf area is consumed (see post from 2019 on estimating flea beetle damage and action threshold and the Flea Beetle Monitoring Protocol).
According Dr. Tyler Wist (@TylerWist1), who makes it his business to know, striped flea beetles are already active.
ECCC trajectory models indicate that air trajectories, originating over the Pacific Northwest (Idaho, Oregon, Washington), have crossed one Saskatchewan location (Unity) and a number of Alberta locations including Lethbridge, Beiseker, Olds, Provost, Vegreville, Andrew, Grande Prairie, Rycroft and Fort Vermillion.
Access this DAILY one-page report to learn more. Albertans and Saskatchewanians please take note!
Areas highlighted green in this alert may receive incoming winds from the Pacific Northwest of the USA very shortly! Remember, 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.
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.
Equipment is moving in fields across the prairies this week. In addition to the Weekly Update, the Insect of the Week is back for 2020’s growing season. Please access the complete Weekly Update either as a series of Posts for Week 2 OR a downloadable PDF .
This year, we’re doing things a bit differently for our Insect of the Week. Instead of focussing on a single insect (pest or natural enemy), we’re looking at it from a crop perspective. Each week, we’ll pick a crop and list the insects that attack it along with additional helpful information. The insect list is based on the information found in the Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Management field guide. The field guide offers information describing lifecycle, damage description, monitoring/scouting strategies, economic thresholds (where available) and control options) for each economic pest.
In addition to an Insect of the Week, we’ll also feature one of the entomologists that help support the PPMN, either directly or indirectly.
This week’s feature crops are the Brassica oilseeds (mustard and canola) and Dr. Owen Olfert is our starring entomologist.
Canola Field cc by 2.0 George Hodan
Canola has been gaining ground over wheat in terms of production area, yield and value since it was first introduced on the Prairies. In 2019, 20.4 million tons (18.5 million tonnes) were harvested from 20.4 million acres (8.3 million hectares). Mustard, typically grown in warmer and drier regions than canola, was grown on 398,000 acres (161,000 hectares) across the Prairies to produce 148,000 US tons (134,000 tonnes) across the prairies.
Diamondback moth – Alberta Agriculture and Forestry
ENTOMOLOGIST OF THE WEEK: Owen Olfert
Name: Owen Olfert Affiliation: Saskatoon Research and Development Centre, Emeritus Contact Information: owen.olfert@agr.gc.ca
How do you contribute to insect monitoring or surveillance on the Prairies?
Before I retired, I was the Chair of the PPMN. In collaboration with provincial, federal and industry colleagues, the PPMN makes decisions on insect priorities, develops standardized monitoring protocols, determines timing of surveillance activities, provides appropriate survey tools to collaborators, conducts field surveys, assembles and analyzes data, drafts and presents visual survey results to the agriculture industry. As an Insect Ecologist, I was involved in all of the field and laboratory activities mentioned above. Over the many years, the crop growing season activities have provided amazing professional opportunities in insect ecology, which overlapped strongly with my farming background. I have been fortunate to explore all of the agro-ecosystems of the Prairies in search of insect populations that threaten field crops.
In your opinion, what is the most interesting field crop pest on the Prairies?
Not to offend other insect groups, but I think grasshoppers (Acrididae) are most interesting! My interest in our prairie grasshopper complex began as a summer student with Dr. Roy Pickford (AAFC-Saskatoon) in the early 1970s. Coincidentally, my first assignment as a research scientist with AAFC involved developing surveillance and management strategies for grasshopper pest species in field crops. Over the years, my colleagues and I have published about 30 scientific papers related to grasshoppers.
What is your favourite beneficial insect?
My favourite is Macroglenes penetrans (Pteromalidae), a parasitoid of wheat midge (Sitodiplosis mosellana). It is the dominant parasitoid of wheat midge in western Canada. It is an egg-larval parasitoid; the female wasp oviposits into the egg of its host. It was discovered very early during the first major outbreak of wheat midge in the early 1980s. All of the pest management tools developed for wheat midge have taken this parasitoid into account. As a result, our estimated total saving in pesticide costs alone due to this parasitoid in the 1990’s was $248.3 million.
Tell us about an important project you are working on right now.
Our most recent project is related to an important agricultural pest – parasitoid – host plant complex, involving wheat midge and its parasitoid mentioned above. The project assesses the interactive population dynamics of the host plant (wheat), wheat midge, and M. penetrans, based on their respective life cycles and weather. These simulation models helped to detail our understanding of the tri-trophic population dynamics. The models will help guide pest management decisions prior to and during the growing season.
What tools, platforms, etc. do you use to communicate with your stakeholders?
In addition to the suite of communication tools used by the PPMN, I still attend conferences and get contacted to conduct interviews by the agricultural news media.
This week we share the prairie-wide risk maps to prepare for the 2019 growing season and we continue to evolve how the wind trajectory data is available.
Happy Easter!
Questions or problems accessing the contents of this Weekly Update? Please e-mail either Dr. Meghan Vankosky or Jennifer Otani. Past “Weekly Updates” can be accessed on our Weekly Update page.
Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990s.
In a continuing effort to produce timely information, the wind trajectory reports 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.
Economically significant insect pests are monitored across the Canadian prairies each year, thanks to extensive networks of collaborators and cooperators. In 2018, that effort culminated in 5764 survey stops across Manitoba, Saskatchewan, Alberta and the BC Peace!
Here’s what’s included in the PDF file:
Average tempature, average precipitation, and modeled soil moisture for 2018.
A series of geospatial maps are included for each of the target species; the current map is followed by the previous 4 years.
For some species, the geospatial maps represent 2018 distributions used to infer risk in the coming 2019 growing season. Data is included for bertha armyworm, cabbage seedpod weevil, pea leaf weevil, wheat stem sawfly and diamondback moth.
For wheat midge and grasshoppers, the geospatial maps forecast or predict expected populations or risk for the 2019 growing season.
These maps help the agricultural industry prepare to manage insect pests across the prairies and helps growers make crop choices and anticipate scouting priorities within their growing region. From May to July, the Weekly Updates will provide in-season updates, predictive model outputs plus scouting tips and links to relevant information.
Thank you to the many people who monitor each growing season!
In 2018, swede midge pheromone traps were deployed at 41 sites across the Prairie region of Canada to monitor adult populations of this brassica pest. Of the 41 trap sites, 16 were located in Alberta, 19 in Saskatchewan (where positive swede midge identifications were made in 2007 and 2009), and 6 in Manitoba.
None of the traps were positive for swede midge in 2018.
We are grateful to all of the producers, agronomists, and cooperators who participated in the 2018 swede midge monitoring project. Without your assistance, we could not have supported such a thorough and widespread pheromone monitoring program.
We also extend our thanks to Jonathon Williams for organizing the program, distributing trapping materials, and processing returned sticky cards for adult swede midge.
Because of the serious threat that swede midge poses to canola production, it is vital that monitoring for swede midge continues across the Prairies. At this time, plans are being made for the 2019 swede midge monitoring program. We hope that we can count on your support and cooperation in 2019.
At this time, plans are being made for the 2019 swede midge monitoring program. Agrologists or growers interested in performing weekly monitoring in 2019 are encouraged to contact Jonathon Williams, Boyd Mori, or Meghan Vankosky for more information.
Weather synopsis – This past week (May 6-13), the average temperature was approximately 2 °C cooler than long term average (Fig. 1). The warmest weekly temperatures occurred across Alberta. The 30-day average temperature (April 13-May 13) was very similar to long term average temperatures with the warmest conditions occurring across Alberta (Fig. 2).
Figure 1. Average temperatures across the Canadian prairies these past seven days (May 6-13, 2018).
Figure 2. Average temperatures across the Canadian prairies this past month (April 13-May 13, 2018).
Weekly precipitation was well below average and 30-day total rainfall is approximately 50% less than average (Figs. 3 and 4). The lowest precipitation amounts have occurred across eastern Saskatchewan and most of Manitoba.
Figure 3. Cumulative precipitation (mm) these past seven days (May 6-13, 2018).
Figure 4. Cumulative precipitation (mm) this past month (April 13-May 13, 2018).
The map below reflects the Highest Temperatures occurring over the past 7 days across the prairies.
The map below reflects the Lowest Temperatures occurring over the past 7 days across the prairies.
The growing degree day map (GDD) (Base 10ºC, March 1 – May 13, 2018) is below:
The growing degree day map (GDD) (Base 5ºC, March 1 – May 13, 2018) 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.
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!
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. 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 15, 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 indicates that CLB oviposition has begun in many locations, and that larvae may begin to appear in the next 7-10 days. As of May 13th, CLB model runs indicated that oviposition was similar Lethbridge, Swift Current, Saskatoon and Brandon (Fig. 1).
Figure 1. Predicted cereal leaf beetle (O. melanupus) oviposition at four prairie locations. Values represent
predicted values based on 2018 weather and for model predictions based on long term average
weather (model simulations for April 1-May 13, 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.
The alfalfa weevil model predicts that oviposition is well underway in southern Saskatchewan. Figure 1 shows model output for Swift Current where first instar larvae should appear early next week.
Figure 1. Predicted alfalfa weevil (Hypera postica) phenology at Swift Current SK.
Values are based on model simulations for April 1-May 6, 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 adults are beginning to fly. This is similar to model output based on long term (climate) data. Model output estimates that oviposition should begin in late May or early June (Fig. 1).
Figure 1. Predicted PLW phenology at Swift Current based on long term climate data.
Values are based on model simulations (April 1 – May 6).
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).
As of May 13, 2018, predicted mean egg development was 68% (62% last week) and model output indicates that embryological development was 5% greater than long term average. Greatest development was predicted to be across southern Alberta with potential for hatch occurring near Medicine Hat and Bow Island (Fig. 6).
Figure 1. Grasshopper (M. sanguinipes) embryological development (%) based on
model simulations for April 1-May 13, 2018.
Reminder – The Prairie Pest Monitoring Network’s 2018 Grasshopper Forecast Map was released in March (Fig. 2). 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.
Bertha armyworm (Lepidoptera: Mamestra configurata) – Bertha armyworm pupal development is predicted below. The map illustrates that overwintered BAW are beginning to develop within their pupa located in the soil but are still several weeks away from emerging as moths.
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 15, 2018) highlights the importance of wireworms in field crops and describes how growers can collaborate with AAFC entomologists (Dr. Haley Catton) by baiting grain fields in an effort to obtain wireworm specimens to further their research efforts.
It’s spring, so it’s cutworm season. This week’s insect is the darksided cutworm. Mature larvae are hairless, greyish with a prominent white stripe on either side just above their legs. It is a climbing cutworm with feeding occurring at night. They have a broad host range including cereals, canola, corn, flax, sunflower, vegetables berry and tree fruits.
Find out more about the darksided cutworm at the Insect of the Week page. Other important species include dingy, army, redbacked and pale western cutworms (See Insect of the Week: 2017 – May 1, 8, 15 and 29).
Darksided cutworm
Photocredit John Gavloski, Manitoba Ministry of Agriculture
In addition, Cutworm Pests of Crops on the Canadian Prairies – Identification and Management Field Guide was recently published (2017). This new handy manual has chapters on general biology, history of outbreaks, scouting techniques, natural enemies and general control options. The meat of the manual is descriptions of 24 cutworm species, their lifecycle, hosts, damage, monitoring and economic thresholds. To download a copy, go to the Cutworm Field Guide page.
Background. 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 1990’s. 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 (RT) and forward trajectories (FT): (i) Reverse trajectories refer to air currents that are tracked back in time from specified Canadian locations over a five-day period prior to their arrival date. Of particular interest are those trajectories that, prior to their arrival in Canada, originated over northwestern and southern USA and Mexico, anywhere diamondback moth populations overwinter and adults are actively migrating. If diamondback adults are present in the air currents that originate from these southern locations, the moths may be deposited on the Prairies at sites along the trajectory, depending on the local weather conditions at the time that the trajectories pass over our area (e.g. rain showers, etc.). RTs are the best available estimate of 3D wind fields at a specific point. They are based on observations, satellite and radiosonde data. (ii) Forward trajectories 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 to us are the winds that eventually end up passing over the Prairies. Current Data
Pacific Northwest (PNW) –The number of RTs, predicted to cross the prairies, has increased over the past week (Fig. 1). Though there has been an increase, results for May 1-14 predicted that 38 PNW reverse trajectories (RT) have crossed the prairies. This total is less than the average number 107 (based on 2007-2017) and well below last year’s results (155).
Figure 1. Daily total of reverse trajectories (RT) originating over the Pacific Northwest that
have entered the prairies during April 2018.
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 redbacked cutworm. This is an above ground species. Young larvae feed on newly-emerging shoots and furled leaves, creating small holes. Older larvae cut off leaves and sever plants just below the soil surface. Occasionally, the larvae pull the plants underground to feed on them.
For more information about Redbacked Cutworms, go to the Insect of Week page.
Redbacked cutworms – John Gavloski, Manitoba Agriculture
Weather synopsis – Many locations across southern Saskatchewan and Alberta experienced temperatures above 25°C this week. Average temperatures were warmest across southeastern Saskatchewan from May 1-8, 2017.
The map below reflects the Accumulated Precipitation for the Growing Season so far for the prairie provinces (i.e., April 1-May 10, 2017):
Whereas the seven-day precipitation accumulations were greatest across Saskatchewan:
The map below shows the Lowest Temperatures the Past 7 Days (May 4-10, 2017) across the prairies:
Whereas the map below shows the Highest Temperatures the Past 7 Days (May 4-10, 2017):
The updated growing degree day map (GDD) (Base 5ºC, March 1 – May 7, 2017) is below:
While the growing degree day map (GDD) (Base 10ºC, March 1 – May 7, 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 1, 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 9, 2017: Reverse trajectories (RT) Wind trajectories have been monitored since April 1 this year. This week there was an increase in the number of RT winds that crossed the prairies from the Pacific Northwest (PNW) of USA. In Alberta, Grande Prairie and Beiseker had a significant increase in the number of RT winds over this past week (Fig. 1 and 2). In addition to the PNW, there were three prairie locations (Selkirk MB, Unity SK and Olds AB) that had winds originating from California and Texas.
Figure 1. Weekly cumulative counts of Reverse Trajectories (RT) from the Pacific Northwest (PNW) from May 3-9, 2017 (2017 Olfert et al.).
Figure 2. Total number of RT winds from the Pacific Northwest from April 1-May 9, 2017.
Forward trajectories (FT) Similar to Reverse Trajectories, most of the model output of Forward Trajectories (FT) have originated from the Pacific Northwest (PNW). However, a few winds have been forecasted to cross the prairies from the southern USA since April 1, 2017 (Fig. 3).
Figure 3. Source destinations and number of FT winds originating from the USA between April 1-May 9, 2017.
Diamondback moth (Plutellidae: Plutella xylostella) – Pheromone traps attracting male Diamondback moths are being deployed across the prairies. High altitude air masses are tracked by AAFC-Saskatoon Staff (forward and backward trajectories). These wind events have the potential to aid the movement of diamondback moth and aster leafhoppers northward on to the Canadian prairies from Mexico, southern and central USA as well as the Pacific Northwest. Diamondback moth pheromone traps deployed across the prairies confirm their arrival – many thanks to the people who deploy and do the weekly monitoring!
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.
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. 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 Redbacked cutworms.
Figure 1. Redbacked cutworms retrieved from a Manitoban field (Photo: J. Gavloski)
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 8, 2017, CLB model output predicted that oviposition is underway in populations
that may be present in the Lethbridge, Swift Current and Brandon areas. Compared
to 2016, phenological development in 2017 is approximately 1 week later.
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. The aim or the modelling is to predict the development of Alfalfa weevil (Hypera postica) across the prairies and to help growers time their in-field scouting as second-instar larvae are predicted to occur. Compare the following predicted development stages and degree-day values copied below (Soroka 2015) to the map below.
This week, alfalfa growers in southern Alberta and southern Saskatchewan (areas of the map highlighted tan) are on the verge of predicted egg hatch of the alfalfa weevil.
Use the figure below as a visual reference to identify alfalfa weevil larvae. Note the white dorsal line, the tapered shape and the dark head capsule.
Pea Leaf Weevil (Sitona lineatus) – This species was one of the “big” insects of 2016’s field crop growing season. The distribution of pea leaf weevil increased dramatically based on both damage assessments AND collection of adults in 2016 (Fig. 1) compared to previous years (Fig. 2).
Figure 1. Distribution of pea leaf weevil (Sitona lineatus) based on surveying conducted in 2016 (Olfert et al. 2017).
Figure 2. Distributions of pea leaf weevil based on surveying conducted between 2012-2015 (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 8, 2017, predicted mean embryological development was 62% (56% last week); the greatest development was predicted to be across southern Saskatchewan. Embryological development was very similar to long term averages (60%) though well behind 2016 (74%). Hatch was not predicted for any locations.
Reminder – The Prairie Pest Monitoring Network’s 2017 Grasshopper Forecast Map (Figure 1) 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 1. Prairie Pest Monitoring Network’s 2017 Grasshopper Forecast Map.
Field scouting is critical – it enables the identification of potential risks to crops. Field crop 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.
For 2017, we offer TWO generalized insect pest scouting charts to aid in-field scouting on the Canadian prairies:
Growers can access biological information about the pest and its natural enemies, the type of damage it causes, how to monitor, and what pest management strategies might apply to help protect yield and quality (Fig. 1).
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!
Figure 1. Example of Bertha armyworm pages from the above field guide:
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 11, 2017). Cutworms, flea beetles and alfalfa weevil were noted as being insects to watch at this point in Alberta.
We again track the migration of the Monarch butterflies and they move north by checking the 2017 Monarch Migration Map! A screen shot of the map has been placed below as an example (retrieved 11May2017) but follow the hyperlink to check the interactive map! They’re getting closer to Canada!
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.
As of May 9, 2016, Reverse Trajectories (RTs) originating from Mexico and southwest USA have crossed most prairie locations:
Whereas Reverse Trajectories (RTs) originating from northwest USA have arrived over a greater area of the prairies with more RTs arriving in Alberta and the BC Peace:
Review the 2016 Wind Trajectory Updates in PDF format.
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.
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) – 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”. An excerpt of ONLY Cutworm pagesfrom 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.
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 (10May2016) below for your reference.
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 8, 2016, model indicated that oviposition is well underway and that larvae should be appearing across southern Alberta and a week later in southern Saskatchewan. Larval populations are predicted to peak in mid-June in southern Alberta and one to two weeks later at the Saskatchewan and Manitoba locations.
Predicted dates of peak emergence of CLB eggs and larvae:
Output suggests that it’s parasitoid, Tetrastichus julis, should be emerging during the period when CLB eggs are most abundant. The model run for Swan River MB showed potential symmetry for both species, though phenologies would be two weeks later than for southern Alberta.
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”.
Grasshoppers (Acrididae) – Warm conditions over the past seven days have resulted in rapid grasshopper development. Predicted mean embryological development was 74% (last week was 62%) with greatest development predicted to be in southern AB. Embryological development is predicted to be 16% ahead of long term average values (prairie wide). The model predicts that 4% of the hatch is complete (AB, SK and MB).
Recall that the 2016 Grasshopper Forecast Map circulated in January predicted the following risk areas.
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.
Degree-day maps of base 9°C are now being produced by Soroka, Olfert, and Giffen (2015) using the Harcourt/North Dakota models predicting the development of Alfalfa weevil (Hypera postica) across the Canadian prairies. The model output is mapped below to help alfalfa growers time their in-field monitoring.
Watch this map for the predicted occurrence of second-instar alfalfa weevil larvae. The economic threshold for alfalfa weevil targets third- and fourth-instar larvae but, in the event that second-instar larval densities exceed either the forage or seed production thresholds, control is appropriate to prevent third-instar peaks.
The model predicted egg hatch began the week of May 14, 2015, in the Brooks AB area (note area below shaded brown corresponding to 165 DD base 9°C). Growers in that area should be monitoring for alfalfa weevil this week.
Wind trajectories Related to Diamondback Moth (DBM) and Aster Leafhopper Introductions to the Canadian
Prairies in 2015
BACKGROUND:Potential wind events capable of carrying insect
pests from source areas in the USA can be identified by following trajectories
for air parcels through time. High altitude air masses,
originating from southern locations, frequently 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).
Wind trajectory data processing by AAFC-Saskatoon Staff began in April. Reverse
Trajectories track air masses arriving across the prairies back to
their point of origin. Forward Trajectories predict
favourable winds expected to arrive across the Canadian Prairies.
Updated: May 13, 2015
1. Reverse trajectories (RT)– During April and early
May, reverse trajectories winds were originating over the Pacific Ocean and
tracking in a west to east direction across North America. Since May 8th
most are now originating over the Arctic.
a. Pacific Northwest (PNW) –
Nothing to report.
b. Mexico and southwest USA (SW)
– Nothing to report.
2. Forward trajectories (FT)
There are
a number of forward trajectories from southern USA and Mexico predicted to
cross the prairies over the next five days. The Imperial Valley and Mexicali
FTs are predicted to cross southern Saskatchewan and Manitoba. The Santa
Maria FT is predicted to cross into central Alberta.
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.
This year we offer a generalized canola
scouting chart to aid in-field scouting on the Canadian prairies. Two versions
are offered 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.
See this week’s Insect of the Week for descriptions and pictures of the crucifer and striped flea beetles (Phyllotreta cruciferae and P. striolata) from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide
