Not all grasshoppers are farmers' enemy

Although they’re often identified as locusts, not all grasshoppers are a plague, says John Gavloski, an entomologist with Manitoba Agriculture.

“Grasshoppers get the bad rap as being destructive when it’s really just a few species that are destructive to the crop plants,” said Gavloski, who works out of Carman, Man.

“I don’t think you want to make the assumption, off the hop, that because there are grasshoppers in the crop that they’re feeding on the crop.”

Many grasshoppers will munch on weeds instead of cereal, oilseed and pulse crops.

Read Also

VIDEO: Green Lightning and Nytro Ag win sustainability innovation award

Nytro Ag Corp and Green Lightning recieved an innovation award at Ag in Motion 2025 for the Green Lightning Nitrogen Machine, which converts atmospheric nitrogen into a plant-usable form.

“To give you a couple of examples, we had a field of soybeans and corn nearby (Carman)… there were a lot of grasshoppers in the field but the crops weren’t being touched,” he said. “They were feeding on the lambs-quarters, the pigweed and a lot of the weeds in the field.”

Knowing which species of grasshoppers are a threat to crops, and which are harmless, is a key component of integrated pest management, according to a handbook published by Agriculture Canada and the Saskatchewan Pulse Growers.

The book, titled Grasshopper Identification and Control Methods, notes there are 80 species of hoppers on the Prairies, but six species cause most of the damage to crops. It also explains how to differentiate pests, like the two-striped grasshopper, from the Russian thistle grasshopper, which as its name suggests, prefers to feed on the weed.

“Some of the non-pest species are often quite visible and I think they can worry farmers into thinking there is a problem.”

An example of that misperception is the Carolina grasshopper. That species likes to sunbathe on gravel roads and can be identified by how it flies. A flash of black is visible, similar to a butterfly, when it flies.

If a farmer is rolling down a road in a pickup, many Carolina hoppers may dart out of the way as the truck approaches, Gavloski said. Producers might conclude that there’s an infestation and a threat to crops. But that species prefers to feed on grassland.

Another example of misidentification is confusing leafhoppers with grasshoppers, said Scott Meers, an insect management specialist with Alberta Agriculture in Brooks.

“This year we have a lot of leafhoppers,” said Meers. They are much smaller than adult grasshoppers and a different species.

“Sometimes people just say those are baby grasshoppers and don’t look into it far enough…. For the most part, leafhoppers are not a concern for annual crops.”

Aside from identifying species, it’s also important to recognize the best time to spray for hoppers.

Grasshoppers hatch from eggs in the soil in mid-May to mid-June. They then go through five phases, called instars, before they reach adulthood.

Between phases they molt, or shed skin, to reveal the next state of development. The third instars phase is critical to recognize because that’s the best time to control pest species.

While it may be challenging for people to recognize the wingbuds that signify a third instar, Meers said the general rule is to spray before hoppers become adults.

“Grasshoppers when they reach adulthood they are able to fly. And before that, they are unable to fly,” he said, which means that immature hoppers are easier to kill with insecticide.

However, if producers are willing to make the effort, Gavloski said identifying a hopper in the third instar phase is doable.

“It’s like a lot of things. With practice it’s not really that difficult,” he said “What the wingbuds look like is little miniature wings… that cover a segment or two of the insect’s body.”

In a typical year, grasshoppers would already be past the third instar phase now, but because it’s been cold this spring, the insects’ development is delayed.

If producers want more information, Meers said a great resource is Dan Johnson, an entomologist at the University of Lethbridge.

His website, people.uleth.ca/~dan.johnson/index.htm, has a link called Recognizing Grasshoppers, located at the bottom of his webpage.

Pest or not?

Though there are about 80 species of grasshoppers on the Prairies, only five cause severe damage to cereals. Two species, the two-striped and the clear-winged grasshopper, are the most prevalent destructive species. But how can you tell the good from the bad?

These grasshoppers ARE pests:

Grasshoppers that hatch in late May- early June, are brown-black, and have tiny triangular wing buds.
Those that are silent during flight or on the ground.

These grasshoppers

are NOT pests:

Any that are flying before June.
Those that have large wings by early June that can be folded back when examined closely.
Those with colourful hind wings (red, yellow, orange or black) and are highly visible in flight.

Hoppers that sing, call or clatter in flight or on the ground.

These are not a

threat that merits control:

Any that inhabit a crop on a warm day without feeding on the surrounding vegetation. These are likely temporary visitors that will soon move on to more preferred vegetation.
Those that remain in grassland or other areas will not likely damage crops. Monitoring during warm weather will help determine this.

Lethargic grasshoppers that hang on vegetation in mid- or late summer may be infected with naturally occurring pathogens that reduce their numbers.

Alternative control methods

Heavy grasshopper infestations cause damage unless chemically controlled, but these steps may lower risk of damage while reducing pesticide use:

Crop selection

Some crops are less palatable to grasshoppers – oats are usually less damaged than barley or wheat; chickpeas and green peas are often not damaged while roadside grass, alfalfa and cereal crops are attacked. The timing of damage is relevant when deciding whether to spray. Immature grasshoppers may damage flowering pulses early in the season, but cause less damage to leaves or pods later in the year.

Early seeding

Good weather may allow early seeding, which may reduce grasshopper damage to crops. Older, more vigorous plants can withstand more feeding damage than younger plants.

Weed control

Tillage or chemical fallow to eliminate weed cover can reduce grasshopper egg laying in late summer and reduce hatchling survival in May and June.

Trap strips

Grasshoppers move quickly and range widely, stopping at the discovery of acceptable plants. Damage at the edge of a growing crop often forms a sharp line visible from the road. Leave green strips one or two swaths wide around the outside of a field to concentrate them in narrow zones, where they can be economically killed with insecticide.