Environment and Climate Change Canada (ECCC) trajectory models indicate that air trajectories, originating over the Pacific Northwest (Idaho, Oregon, Washington), have crossed a number of Alberta locations including Lethbridge, Beiseker, Olds, Manning, Rycroft, and Wanham.
Access this special one-page alert to learn more. Albertans please take note!
Action: Areas highlighted green in this alert may receive incoming winds from the Pacific Northwest of the USA very shortly so please deploy diamondback pheromone traps as soon as possible!
Since April 1, the 2021 growing season has been cooler and dryer than normal. This past week (April 26-May 2, 2021), the average temperature across the prairies was approximately 0.5 °C cooler than normal. Similarly, the average 30-day temperature (April 3- May 2) was 0.6 °C less than climate normal values. Temperatures have been warmest in southern Alberta. Seven day cumulative rainfall indicates that below normal rain (79% of average) was reported for the prairies.
The growing degree day map (GDD) (Base 5 ºC, April 1-May 2, 2021) is below (Fig. 3) while the growing degree day map (GDD) (Base 10 ºC, April 1-August 9, 2020) is shown in Figure 4.
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 ranged from <-14 to >0 °C (Fig. 5) while the highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <3 to >24 °C (Fig. 6).
Rain (30-day accumulation) amounts have been less than average for most of the prairies (75 % of average; Fig. 7). Rainfall for April 3-May 2, 2021, has been greatest for southeastern Manitoba and the extreme southwest of Alberta (Fig. 8).
Grasshopper Simulation Model Output – The grasshopper simulation model will be used to monitor grasshopper development across the prairies. Weekly temperature data collected across the prairies is incorporated into the simulation model which calculates estimates of grasshopper development stages based on biological parameters for Melanoplus sanguinipes (Migratory grasshopper).
Model simulations were used to estimate percent grasshopper embryonic development as of May 2, 2021. Results indicate that egg development has begun across the southern prairies (Fig. 1) and progression estimates for sites across the prairies are presented in Figure 2.
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 Lethbridge (Fig. 1) and Saskatoon (Fig. 2).
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 shelter belts, 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 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. 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.
Models predicting the development of Alfalfa weevil (AAW) across the prairies are updated weekly to help growers time their in-field scouting for second-instar larvae.
Model simulations for alfalfa weevil (AAW) indicate that oviposition should have begun across central and western areas of the prairies. The following graphs indicate, based on potential number of eggs, that development is more advanced near Regina SK (Fig. 1) than Winnipeg MB (Fig. 2).
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 9 mm long.
Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon). Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (2018; accessible in either English-enhanced or French-enhanced versions).
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!
• Alberta Agriculture and Forestry – 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 (where insect survey maps, live feed maps, and insect trap set-up videos can be found). 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.
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.
For many, seed isn’t in the ground yet, but cutworms may be in the soil ready for when it does. 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.
While they may be related and share many similarities, cutworms are not all the same, nor cause the same kind of damage. For example, the armyworm (Mythimna unipuncta) is a climbing cutworm and feeds on leaves. In contrast, young pale western cutworms (Agrotis orthogonia) feed on the surface of newly-emerging shoots and furled leaves of young plants causing small holes and older larvae sever plants just below the soil surface and occasionally pull and eat severed plants underground. In addition, there is likely more than one cutworm species present in your field.