Grasshoppers are swarming pastures in the heat of B.C.’s Interior, causing worry for ranchers

Record-setting temperatures in B.C. this summer have had consequences other than wildfires, smoke and drought. Swarms of grasshoppers have descended on portions of the province’s Interior, and they are making life difficult for ranchers. 

Ranchers in the Vanderhoof area, around 100 kilometres west of Prince George, have recorded as many as 40 grasshoppers per square metre, according to Mike Pritchard with the B.C. Cattlemen’s Association.

This is well above the threshold at which ranchers lose money on their herds. As well as eating agricultural crops such as wheat and barley, they also consume pasture grass, which puts them in direct competition with cattle for food.

“They are actually eating and consuming the grass as much as cattle are,” said Pritchard, a rancher himself. “And so that’s where you basically lose production or productivity on your pasture land because the grass is gone.”

Pritchard said the situation has forced ranchers to consider selling their stock early to secure a return on their investment. Earlier in July, he facilitated the sale of 150 head of cattle for a rancher — at just over a quarter of a million dollars — because grasshoppers had consumed their pasture land, he said.

Record heat creates perfect conditions

This summer’s prolonged high temperatures are the cause of the problem, experts say. 

Grasshoppers thrive in temperatures of around 36-37 C, says Dan Johnson, a professor at the University of Lethbridge with expertise in entomology and pest control.

Females bury their eggs and those eggs can remain dormant for years until conditions are right for them to hatch.

A Bruner’s spurthroated grasshopper laying eggs. Once laid, eggs remain dormant until temperatures and other conditions are optimal for them to hatch. (Dan Jonson/University of Lethbridge)

Johnson said he has seen similar explosions in the Prairies, where ideal conditions have resulted in populations as high as 150 grasshoppers per square metre. 

Preparing for the future

He said it’s too late to do anything about grasshoppers this year because they’re difficult to kill once they reach maturity.

But he is hoping to work with ranchers and farmers like Pritchard to collect samples of the grasshoppers in their fields so that he can learn more about their migration patterns. 

Climate change could also be a factor. Johnson said there will continue to be spikes in grasshopper populations if hot, dry summers continue to lengthen in B.C.

“If you have more of a warm sequence one after another without breaks, that’s when they will really expand,” he said.

Leave comment

Your email address will not be published. Required fields are marked with *.