Week 3 and scouting continues for cutworms, flea beetles and wireworms plus there’s more information this week to help prepare for in-field scouting. Be sure to catch the Insect of the Week – it’s wireworms!
Now, more than ever, we wish everyone a safe and productive field season! Stay Safe!
Questions or problems accessing the contents of this Weekly Update? Please contact us so we can connect you to our information. Past “Weekly Updates” can be accessed on our Weekly Update page.
Access background information for how and why wind trajectories are monitored in this post.
1. REVERSE TRAJECTORIES (RT)
Since May 1, 2021 the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington). This week there have been an increasing number of reverse trajectories that moved north from Texas, Oklahoma and Kansas and Nebraska (Fig. 1). Though these US regions can be a source of diamondback moths, the ECCC models predict air movement, not actual occurrence of diamondback moths. It should also be noted that host plants of diamondback moth include all plants in the Brassicacea family, including cruciferous weeds and volunteer canola. These plants are suitable hosts until canola emerges.
a. Pacific Northwest (Idaho, Oregon, Washington) – This week there have been 44 trajectories (27 last week) that have crossed Alberta, Manitoba, and Saskatchewan. The majority of Pacific Northwest reverse trajectories usually have been reported to pass over southern Alberta. This growing season, PNW trajectories have crossed all of the prairies (Fig. 2).
b. Mexico and southwest USA (Texas, California) – This week there have been 15 trajectories that originated in Mexico and the southwestern US that have crossed Manitoba and Saskatchewan.
c. Oklahoma and Texas – This week there have been 16 trajectories that have passed over Manitoba and Saskatchewan (Fig. 3) that originated in Oklahoma or Texas. These are the first trajectories, that originated over Oklahoma and Texas, to enter the prairies during the month of May.
d. Kansas and Nebraska – This week there have been 35 trajectories (8 last week) that originated in Kansas or Nebraska that have passed over Manitoba and Saskatchewan (Fig. 4).
2. FORWARD TRAJECTORIES (FT)
a. Forward trajectories, originating from Mexico and USA, have crossed a number of prairie locations since May 1, 2021. This week, there has been a steady increase in the number of trajectories that are predicted to cross the prairies (Fig. 5). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line). The data suggests that, compared to this week, there may be increased potential for the introduction of DBM to the prairies.
The following map presents the total number of forward trajectories that have crossed the Canadian prairies (since March 24, 2021) (Fig. 6). Results indicate that the greatest number of forward trajectories entering Canada originated from the Pacific Northwest (Idaho, Oregon, Washington).
Earlier in the week, an Alert related to wind trajectories assessed over May 18-19, 2021, was shared by the PPMN. It communicated the anticpated arrival of several air masses arriving across the Canadian prairies over the next few days that originated from multiple areas of USA. Remember, the current WEEKLY REPORT (above) summarizes daily data over a longer, more comprehensive period.
TEMPERATURE: This past week the average temperature across the prairies was 2.5 °C warmer than normal (Fig. 1). Temperatures were warmest across the Parkland region in Manitoba, Saskatchewan, and Alberta.
The prairie-wide average 30-day temperature (April 17- May 16) was 0.9 °C less than climate normal values. A region from Winnipeg to Saskatoon has been 2 to 4 °C cooler than average. Temperatures have been warmest across southern Alberta (Table 1; Fig. 2).
The 2021 growing season (April 1 – May 16) has been characterized by near normal temperatures. Warmest temperatures were observed in a region between Lethbridge, Saskatoon and Edmonton while coolest temperatures were reported from Manitoba (Table 2; Fig. 3).
The growing degree day map (GDD) (Base 5 ºC, April 1-May 2, 2021) is provided below (Fig. 4) while the growing degree day map (GDD) (Base 10 ºC, April 1-August 9, 2020) is shown in Figure 5.
At this early point in the growing season, cool temperatures pose the risk of frost but the differences between low and high temperatures can exert stress on plants, particularly when field conditions are dry. The lowest temperatures recorded ranged from <-8 to >6 °C (Fig. 6) while the highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <3 to >28 °C (Fig. 7).
PRECIPITATION: Seven-day cumulative rainfall amounts indicate that most of the prairies had less than 2 mm of rain in the past week (Fig. 8). Rainfall amounts for the period of April 17-May 16 (30-day accumulation) were 56 % of long-term average values. Rainfall was greatest for southwestern Saskatchewan and across most of Alberta (Table 1; Fig. 9).
Average growing season (April 1 – May 16) precipitation has been well below average for most of the prairies (35 % less than normal). Saskatoon has reported 4.3 mm (15 % of normal) and most of Saskatchewan and Manitoba have had less than 15 mm (40 % of normal precipitation) (Table 1; Fig. 10).
The maps above are all produced by Agriculture and Agri-Food Canada. Growers can bookmark the AAFC Current Conditions Maps for the growing season. Historical weather data can be access at the AAFC Drought Watch Historical website, Environment Canada’s Historical Data website, or your provincial weather network.
Access ALL the PPMN’s Wind Trajectory reports (Weekly and Daily).
Access Environment and Climate Change Canada’s weather radar mapping interface. Options to access preceding precipitation events include clicking off either an 1 or 3 hours time interval, using an 8-colour or 14-colour index. or changing the base map.
The pea leaf weevil is a slender greyish-brown insect measuring approximately 5 mm in length (Fig. 1, Left image). Pea leaf weevil resembles the sweet clover weevil (Sitona cylindricollis) but the former is distinguished by three light-coloured stripes extending length-wise down thorax and sometimes the abdomen. All species of Sitona, including the pea leaf weevil, have a short snout.
Adults will feed upon the leaf margins and growing points of legume seedlings (alfalfa, clover, dry beans, faba beans, peas) and produce a characteristic, scalloped (notched) edge (Fig. 2). Females lay their eggs in the soil either near or on developing pea or faba bean plants from May to June.
Larvae develop under the soil and are “C” shaped and milky-white with a dark-brown head capsule ranging in length from 3.5-5.5 mm (Figure 3). Larvae develop through five instar stages. After hatching, larvae seek and enter the roots of a pea plant. Larvae will enter and consume the contents of the nodules of the legume host plant. It is the nodules that are responsible for nitrogen-fixation which affect yield plus the plant’s ability to input nitrogen into the soil. Consumption of or damage to the nodules (Figure 4) results in partial or complete inhibition of nitrogen fixation by the plant and results in poor plant growth and low seed yields.
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. Also access the Pea leaf weevil page from the Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Management field guide. (en français : Guide d’identification des ravageurs des grandes cultures et des cultures fourragères et de leurs ennemis naturels et mesures de lutte applicables à l’Ouest canadien).
The cereal leaf beetle (CLB) model output predicts that oviposition is underway across the prairies. The graphs provide a comparison of development at Saskatoon (Fig. 1) and at Lacombe (Fig. 2). The simulation indicates that first instar larvae may occur during the third week of May near Saskatoon and one week later at Lacombe.
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.
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.
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 “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).
Model simulations for alfalfa weevil (AAW) predict that oviposition should be well underway across the prairies. The following graphs indicate that development is similar near Swift Current (Fig. 1) and Brandon (Fig. 2). The model predicts that that hatch may occur during the last week of May.
Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon). Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (2018; accessible in either English-enhanced or French-enhanced versions).
The grasshopper simulation model will be used to monitor grasshopper development across the prairies. Weekly temperature data collected across the prairies is incorporated into the simulation model which calculates estimates of grasshopper development stages based on biological parameters for Melanoplus sanguinipes (Migratory grasshopper).
Model simulations were used to estimate percent grasshopper egg development as of May 16, 2021. Average development of eggs is 68 % and is well ahead of the long term average of 59 %. Since last week, developmental rates have increased at all locations (Fig. 1). The simulation predicts that development is greatest in the region that includes Regina, Saskatoon and Lethbridge (Fig. 2).
Recent warm temperatures near Winnipeg have resulted in faster development rates. The model was projected to May 31 to determine potential development at Saskatoon and Regina (Figs. 3 and 4). Results suggest that initial hatch may occur in the next few days with increased hatch occurring in late May. Current drought conditions tend to favour development of grasshopper populations while delaying crop development. Crop development may be delayed across southern and central regions of Saskatchewan. This may result in conditions conducive for crop damage from grasshoppers as hatch progresses in late May and early June.
Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba Agriculture and Resource Development, Saskatchewan Agriculture, Alberta Agriculture and Forestry, the BC Ministry of Agriculture and the Prairie Pest Monitoring Network. Also refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (accessible in either English-enhanced or French-enhanced versions).
Early in the growing season many of the native and introduced species of ladybird beetles become active and are easily observed (Fig. 1). These adults give rise to a whole new legion of voracious larvae and adults so preserve and protect them in fields – it could pay off!
Coccinellids are recognized as general predators with a real taste for aphids. Many species exist in North America but introduced species (either released or adventively establishing on this continent) have displaced many native species. With such a fantastic array of colours, sizes, shapes, and spots, we’re providing a few resources to help you recognize the amazing diversity in fields:
● Access “Bug Guide” and their entries falling within the Family Coccinellidae.
● “Key to the lady beetles of Saskatchewan“, released by D.J. Larson in 2013 – a technical key that includes colour photos of ladybird beetle adults. Species included in this key will most closely resemble what’s present across the Canadian prairies.
● “Ladybugs of South Dakota” is a PDF visual example of several species of coccinellids, some of which will also occur on the Canadian prairies. The poster was produced in conjunction with the “Lost Ladybug Project” and other supporting institutions.
● Consider participating in citizen-science – the Lost Ladybug Project has been in place for many years but the group welcomes reports of coccinellids from anywhere in North America and helps identify from submitted photos. The goal is to keep track of native species in comparison to the helpful but fairly competitive introduced species like Coccinella semptempunctata or Harmonia axyridis (Pallas).
● The Canadian portal of iNaturalist.ca was launched in 2015 and is connected to iNaturalist.org but the premise is the same: By signing up and submitting photos with relevant brief observations (e.g., date, location, e-contact info), users can communicate online with creditable and knowledgeable resources that help identify flora and fauna. Watch their YouTube video to learn more. Download the App (Android Google Play OR iOS App Store).
FYI…. CABI’s Invasive Species Compendium entries contain more information about our most common introduced species of ladybird beetles in North America:
● Coccinella septempunctata (seven-spot ladybird)
● Harmonia axyridis (asian or harlequin ladybird)
Reminder – Field scouting is critical – it enables the identification of potential risks to crops. Accurate identification of insect pests PLUS the application of established monitoring methods will enable growers to make informed pest management decisions.
We offer TWO generalized insect pest scouting charts to aid in-field scouting on the Canadian prairies:
1. CANOLA INSECT SCOUTING CHART (click chart to access downloadable PDF copy)
2. FLAX INSECT SCOUTING CHART(click chart to access downloadable PDF copy)
These charts feature hyperlinks directing growers to downloadable PDF pages with photos 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.
The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops. Check the recently updated Field Heroes website for scouting guides, downloadable posters, and videos. Learn about these important organisms at work in your fields!
Two NEW Field Heroes resources for 2021 include:
Access ALL the Field Heroes links here and be sure to follow @FieldHeroes!
Access the following links to gain important pesticide application information and registered products for agricultural field crop protection on the Canadian prairies:
• Saskatchewan’s Crop Protection Guide – 2021
• Manitoba’s Guide to Crop Protection 2021
• Alberta’s 2021 Crop Protection or Blue Book
• Western Committee on Crop Pests Guide to Integrated Control of Insect Pests of Crops
Provincial entomologists provide insect pest updates throughout the growing season so link to their information:
• MANITOBA’S Crop Pest Updates for 2021 are now available! Access the May 19, 2021, report here. Be sure to bookmark their Crop Pest Update Index to readily access these reports! Also bookmark their insect pest homepage to access fact sheets and more!
Diamondback moth pheromone trap monitoring update for MB – Refer to the summary updated twice a week. So far extremely low numbers have been intercepted at only 8 sites (e.g., when present, only max. of 2 moths per site) in Manitoba. Read the details towards the end of the May 19, 2021, report.
• SASKATCHEWAN’S Crop Production News will soon be available. Access the new Crops Blog Posts and review Saskatchewan’s 2020 insect pest surveying results in order to prepare for 2021. Be sure to bookmark their insect pest homepage to access important information!
Diamondback moth pheromone trap monitoring update for SK – follow this link to find current DBM counts. At this point, extremely low numbers have been intercepted but monitoring continues. Two moths were reported (2021May13 Tansey, pers. comm.); one moth near Shaunavon (RM78) and one moth near Raymore (RM 278).
• ALBERTA’S Alberta Insect Pest Monitoring Network webpage links to insect survey maps, live feed maps, and insect trap set-up videos and more. Reminder – NEW for 2021 – AAF’s Shelley Barkley has gathered and streamlined information into a Major Crops Insect webpage. The new webpage does not replace the Alberta Insect Pest Monitoring Network page. However, the new Major Crops Insect webpage serves as a table of contents, connecting users to crop insect pest information on alberta.ca. It offers links to specific insect identification, life cycle, damage, monitoring and management. Users will hopefully find pertinent insect information with fewer clicks! Remember, AAF’s Agri-News occasionally includes insect-related information or Twitter users can connect to #ABBugChat Wednesdays at 10:00 am.
Diamondback moth pheromone trap monitoring update for AB – Refer to the Live Map which reports six sites with very low numbers of moths intercepted (as of 19May2021).
Cutworm reporting tool for AB – Refer to the Live Map which reports two sites with cutworms (as of 20May2021).
Click the provincial name below to link to online crop reports produced by:
• Manitoba Agriculture and Resource Development (subscribe to receive OR access a PDF copy of the May 18, 2021 report).
• Saskatchewan Agriculture (or access a PDF copy of the May 11-17, 2021 report).
• Alberta Agriculture and Forestry (or access a PDF copy of the May 11, 2021 report).
The following crop reports are also available:
• The United States Department of Agriculture (USDA) produces a Crop Progress Report (access a PDF copy of the May 17, 2021 edition).
• The USDA’s Weekly Weather and Crop Bulletin (access a PDF copy of the May 18, 2021 edition).
Access background information for how and why wind trajectories are monitored in this earlier post.
Alert: Yesterday and today ECCC models produced results that suggest a number of RT’s for prairie locations. Compared to previous dates, the ECCC model output predicts that trajectories are passing almost the entire prairie region over a very short period of time. The weather forecast may result in downward movement of DBM.
Details: There has been a significant increase in the number of trajectories, originating over a number of states in the USA, that have crossed the prairies (Fig. 1). These air currents may introduce diamondback moths to the prairies. ECCC trajectory models indicate that air trajectories, originating over the Pacific Northwest (Idaho, Oregon, Washington), have crossed Alberta, Saskatchewan and western Manitoba (Fig. 2). Trajectories originating over Texas and Oklahoma have passed over eastern Saskatchewan and Manitoba (Fig. 3). A third group of trajectories, originating across Kansas and Nebraska have also crossed eastern Saskatchewan and Manitoba (Fig. 4).
Though these US regions can be a source of diamondback moths, the ECCC models predict air movement, not actual occurrence of diamondback moths. It should also be noted that host plants of diamondback moth include all plants in the Brassicaceae family, including cruciferous weeds and volunteer canola. These plants are suitable hosts until canola emerges.
Action: The ECCC model output predicts that trajectories are passing almost the entire prairie region over a very short period of time. Areas highlighted in green in Figures 2, 3, and 4 of this alert may receive downward movement of DBM very shortly. The presence of any Brassicaceae plant will provide a host for incoming DBM so scout volunteers and emerging canola. If DBM were carried north on air currents it may take a few days for DBM to show up in traps.
This week’s instalment is a sneak peak at the soon-to-be published manual “Field Guide of Pest Wireworms in Canadian Prairie Crop Production,” written by Haley Catton, Wim van Herk, Julien Saguez, and Erl Svendsen! (stay tuned to this channel)
Wireworms are soil-dwelling insects that have challenged crop production on the Canadian Prairies since farming began in this region. They damage crops by feeding on seeds, roots or lower stems of almost all field crops, and are especially damaging to cereals. Since wireworms are often the only reason growers use insecticide-treated seed in cereals on the Prairies, understanding more about these pests can save costs and reduce unnecessary pesticide use.
Despite their common name and worm-like appearance, wireworms are not actually “worms.” Rather, they are the larval stage of a group of beetles called click beetles (Elateridae family). Their “clicking” is a defensive behaviour that when placed on their backs, projects them up to 30 centimetres (12 inches) or more into the air to escape danger and literally get them back on their legs
Selatosomus aeripennis destructor, or the Prairie grain wireworm, is the largest of Prairie pest wireworms, reaching up to 23 millimetres (1 inch). It is hard-bodied, segmented and yellowish in colour, with three pairs of legs. Adults are 8-13 mm long, black, hairless and have distinct hind angles.
More information about these pests (lifecycle, damage, control options, etc.) and others is available in the Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Management field guide. (en français : Guide d’identification des ravageurs des grandes cultures et des cultures fourragères et de leurs ennemis naturels et mesures de lutte applicables à l’Ouest canadien). Biological and monitoring information related to wireworms in field crops is posted by Manitoba Agriculture and Resource Development, and Alberta Agriculture and Forestry.
