By Keana Boere, AAg, Intern Extension Agrologist, Tisdale
Grasshoppers are a large group of insects; all species in the group are characterized by chewing mouth parts, slender bodies, wings that fold lengthwise and large powerful hind legs for jumping. There are about 180 grasshopper species in Canada and 85 of those are found in Saskatchewan. Of the 85 species, only four, sometimes five in northern Saskatchewan are considered pests. Distinguishing between pest and non-pest species is important to be able to manage a potential crop threat while not harming non-pest grasshoppers and other beneficial insects. The following identification characteristics can be used to differentiate between pest and non-pest grasshoppers.
Non-pest grasshoppers:
- Will have wings before late-June; “wings in the spring, not a pest;”
- Have brightly-coloured (red, orange) hind wings;
- Are noisy flyers (calls and clacks sounds.)
The four pest grasshopper species in Saskatchewan include the: 1) migratory grasshopper, 2) Packard’s grasshopper, 3) two-stripe grasshopper and 4) clear-winged grasshopper.
- Adult migratory grasshoppers can be identified by two prominent black bands on their hind legs. They are omnivores and prefer forbs, grasses, wheat, barley and other crops. They will also scavenge on dead insects, ground litter, dried manure and in an outbreak may also consume trees or ornamental plants.
- Packard’s grasshopper is one of the largest grasshoppers in Saskatchewan. Distinguishing characteristics include two light-coloured stripes that extend from just behind the eyes to the end of the thorax and the last two leg segments are a blue-green colour. They prefer legumes in open habitats with light textured soils but will also feed on other crops.
- The two-stripe grasshopper has two pale stripes extending back from the eyes to the tip of the forewings. This grasshopper prefers lush vegetation in lush habitats with heavy textured soils, specifically in sloughs and ditches. They will feed on a wide range of broad-leaf crops (often alfalfa), cereals and grasses.
- The clear-winged grasshopper is yellowish to brownish with mottled dark patches on the wings. They also have two stripes beginning at the thorax and converging at the tip of the forewings. Clear-winged grasshoppers prefer grass and rangeland areas and will feed on grasses and cereal grains. Broad-leaf plants are usually avoided.
The economic threshold to warrant grasshopper control depends on many different conditions. The stage of the insect, crop type, crop stage, growing conditions, cost of control and the current market value of the crop should all be considered. For most crops, when populations reach eight to twelve grasshoppers per square metre across the whole field, control is required. Lentils in the flowering and podding stages are sensitive to grasshopper damage. Flax bolls are also at risk, so the economic threshold in these cases are two grasshoppers per square metre.
Grasshoppers can be managed using biological, cultural and chemical methods. The 2022 Guide to Crop Protection has insecticide options if populations reach the economic threshold for specific crops. It is important to ensure that the grasshopper species of concern is in fact a pest species for your crop. Grasshoppers have host preferences and therefore can be present in a crop but will not cause any damage.
The 2022 grasshopper forecast map showed increased numbers compared to 2021 and several local hotspots, but populations remain relatively low for most areas of the province. It is important to continue to scout fields and be aware of the grasshopper pest species and the economic thresholds for your crop.
For more information, read our grasshopper web page, watch a recorded webinar, or contact your nearest crop extension specialist.