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Spring ’hopper threat remains high

Spring 2023 may repeat, when grasshoppers emerged sooner than usual, causing havoc.
A lot will depend on weather, but if it is warm and dry in April and May, grasshoppers will be noticeable.

WESTERN PRODUCER — On Jan. 12, the temperature in Saskatoon dropped to – 41 C. The cold snap lasted five days, with night-time lows between -30 and -40 C.

In theory, that widespread blast of winter should have killed grasshopper eggs buried in soil across the province, but most of them likely survived.

“We don’t have hard data on the status of those eggs right now. Once again, they are cold hardy, they are in those protected egg cases ….They’re in the soil,” said James Tansey, provincial pest management specialist with the Saskatchewan Ministry of Agriculture.

“I think we’re still looking at a pretty significant hatch this spring.”

Tansey shared an overview of the grasshopper situation during a mid-March webinar hosted by his department.

Spring may be a repeat of 2023, when grasshoppers emerged sooner than usual and caused havoc for farmers in the early growing season. A lot depends on weather, but if it is warm and dry in Saskatchewan in April and May, grasshoppers will be noticeable.

“Very likely we’re going to (have) an early hatch again this year,” Tansey said. “We’re looking at probably warm and probably on the dry side (this spring).”

Dan Johnson, a University of Lethbridge professor and a grasshopper expert, delivered a similar message earlier this winter. Last fall featured warm and dry conditions in southern Alberta that were ideal for egg laying.

Most species of rangeland grasshoppers have one generation per year and have an embryonic diapause that occurs several weeks after the eggs are laid, says a U.S. Department of Agriculture document on grasshopper development.

“Through diapause, these grasshoppers avoid hatching in the late summer and fall, when conditions would be unfavourable for growth and development.”

Sometimes the appearance of grasshoppers in spring is staggered. A portion of the population emerges early and others come later.

Weather conditions last fall could cause a different phenomenon, in which most grasshoppers emerge at the same time, Johnson said.

“(In late 2023) it kept warming up off and on and what I think, is those embryos have been evened up (in development),” he said. “Some years they come out in a sharp flush and that’s what this year is probably going to present to us.”

Again, a lot depends on spring weather. Cold and rain could mess with emergence.

That said, grasshoppers were a major problem in Saskatchewan last year and the next generation of hoppers could potentially be similar or worse.

A grasshopper survey map from 2023 shows that populations were moderate to severe in a large region of western and southwestern Saskatchewan stretching from Kindersley to the U.S. border and eastward to Assiniboia. Many likely succeeded in breeding the next generation of crop pests.

“It looks very much like there were a lot of eggs…. Conditions were conducive for a lot of eggs going into the soil,” Tansey said.

Last year, two-striped grasshoppers were the most common species in many parts of Saskatchewan, he added. That is a bit unusual because previous outbreaks in the province were dominated by migratory grasshoppers.

Looking south, experts predict a bad year for grasshoppers in eastern Montana. The U.S. Department of Agriculture grasshopper hazard map shows bright red and orange colours across a large swath of that state.

“Right now, there’s no indication on any of these weather patterns I’ve seen right now, including cold weather … that’s going to be sufficient to turn the tide on some of these grasshopper populations,” Gary Adams of the USDA told Montana Public Radio in late January.

A big population of hoppers in Montana is a risk to cattle ranching and crop production in southern Saskatchewan and Alberta.

Young grasshoppers, known as nymphs, have wing pads instead of wings and cannot fly, says a Manitoba Agriculture website. But wings develop after they mature into adults. Once that happens, grasshoppers are “very, very mobile” and can migrate from Montana into Canada, Tansey said.

“We do have some substantial populations … in some regions (in) our southern neighbour. Why is this long distance migration important for us? They (grasshoppers) don’t have much in way of passport respect.”