Insects
Bertha Army Worm
The Bertha Army worm is one of the most significant insect pests of canola in Canada. The larval form of the Bertha Army worm causes damage to crops like Canola by chewing on the undersides of the leaves as a small larvae, and by feeding directly on the seed pods as the larvae matures.
Bertha Army worms have two parasitoids that can act as biological controls: an ichneumonid wasp and a tachinid fly. Chemical controls are recommended to be used once the economic threshold has been reached.
For more information on the life cycle of Bertha Army worms and best management practices, visit
Bertha armyworm – Overview | Alberta.ca
Grasshoppers
Grasshoppers are a provincially designated pest and are widespread across Alberta. Grasshoppers are the most prevalent in dry areas and can cause significant damage to cereal crops. There are 85 species of grasshoppers in Alberta, but only 5 are considered pest species.
Hatching of pest grasshopper species occurs between early May and mid-June. The grasshoppers immediately begin to forage on the surrounding plants.
In large numbers, grasshoppers can reduce crop yields. Best management practices for grasshopper control include early seeding of crops, crop rotation, tillage, trap strips, and chemical control.
For more information on the life cycle of grasshoppers and best management practices, visit
Diamondback Moth
Diamondback moths are an introduced insect. The larvae feed heavily on the leaves and green tissue of plants in the Brassicaceae family, including canola and mustard. Larval damage can be most significant when the buds and flowers are being targeted. There are three species of parasitic wasps that attack diamondback moths, and multiple insect predators like flies, wasps, beetles, spiders, and birds can reduce larvae populations.
Some best management practices for Diamond back moth larvae control include:
- Control of Brassicaceous weeds, including volunteer canola, early in the season to eliminate host plants for early arriving diamondback moth.
- Scout for early arriving diamondback moth and larvae damage on seedlings.
- In July and August, monitor crops at least twice per week, scouting for larvae.
- The nominal threshold when control is required in canola is if larvae exceed:
- 100 to 150 per square meter (1 to 2 larvae/plant) in immature to flowering plants
- 200 to 300 per square meter (2 to 3 larvae/plant) in plants with flowers and pods
- Minimize the effect on beneficial insects by using economic thresholds to ensure insecticide application is made only when warranted.
Visit Diamondback moth | Alberta.ca for more information.
Alberta’s Insect Pest Monitoring Network
Alberta’s insect monitoring program completes monitoring for multiple insect pests and beneficial insects throughout the summer and into the fall. This program can give a snapshot of insect populations within a region, which can better inform producers about current and future risks.
Insects that are monitoring include:
Bertha Army Worm
Diamondback Moth
Cabbage seedpod weevil
Grasshopper
Cutworm
Wheat Midge
Wheat stem sawfly
To learn more and see live maps of the survey results, visit
Alberta Insect Pest Monitoring Network | Alberta.ca