Pest Profile: Grasshopper

Description: 

Many different grasshopper species can be found in Canada—roughly 85 species—but four are considered problematic across the prairies:

• Migratory grasshopper – Distinguished by the spur on its throat. Adults have black bands on their hind legs and are smaller in size (1”–1¼”). They eat almost anything.
• Two-striped grasshopper – Distinguished by two pale stripes that run from the back of the eyes to the tip of the forewings. Adult coloration can range from green to black, often with a mix of green and black markings. Prefers broadleaf plants and lush habitats. Rarely flies but is a strong walker.
• Packard's grasshopper – Distinguished by the lack of any prominent stripes in its grey appearance. There are two light-colored stripes behind the eyes, but they do not extend further.
• Clear-winged grasshopper – Distinguished by mottled forewings and transparent hindwings, which provide a camouflage pattern. Adults appear yellow to brown in color and primarily feed on cereal crops.

There has been a shift in populations over the past two years, with migratory and two-striped grasshoppers causing a significant portion of the damage. Early grasshoppers typically feed on pastures and rangelands and are not usually a problem in cereal crops. If they take flight before June, they are generally not considered pests. Warm and dry conditions accelerate their development.

Damage (caused by both nymphs and adults):

• Feed by removing all types of plant material.
• Damage increases as nymphs progress through their instars toward adulthood.
• Several consecutive years of hot, dry weather can lead to significant population increases.

Lifecycle:

• Grasshoppers overwinter as eggs, laid in pods in the soil. Each pod can contain anywhere from 8 to 150 eggs, which hatch the following spring when temperatures reach approximately 4°C.
• There is one generation per year.
• Problematic species typically hatch in late May to early June.
• Multiple hatching periods can occur due to temperature fluctuations.
• Nymphs progress through several instars before reaching adulthood. Advance thru instars as nymphs reaching adulthood.

Economic Thresholds and Control Options