Manitoba’s pest grasshopper species are out, and with the heat and dry weather they’re having a good time.
“There’s some control currently going on,” provincial entomologist John Gavloski said. “A lot of it is edge spraying, so people doing their ditches and their field edges, but there has been some full-field spraying.”
Why it matters: Interlake farmers say grasshoppers are cutting into their already precious forage.
Not every field is fighting the problem, he added, but populations are thick in some patches, and the issue is widespread in that almost every region has some field where there is a problem.
Populations were “just starting to build” in 2019, according to Gavloski, another infamously dry year.
“I would say this is probably our fourth consecutive drier summer and we’ve seen this almost progressive build as we’ve had these hotter, drier summers,” he said.
Those dry conditions dodge some of the pest’s natural controls. Cool, wet weather can help kill nymphs, the July 7 Manitoba Crop Pest Update noted, while humidity is also friendly to a fungal infection that serves as another natural control.
At the same time, the report noted, lack of vegetation during drought may cause grasshoppers to move into crops to feed.
Gavloski singled out two species responsible for most damage in the field. Both the clear-winged grasshopper, a species that generally targets grassy plants, and two-striped grasshopper, typically not as picky, have been noted this year, he said.
According to the July 7 update, grasshoppers in southern Manitoba were generally in the fourth or fifth instar and 10 to 30 per cent were estimated to be adults. Heat had accelerated grasshopper development, the report also noted.
Gavloski urged producers to be scouting their field edges.
Reports have been most dramatic in the Interlake, where producers say drought conditions left them with little forage even before the grasshoppers got hungry.
Tyler Fulton, president of the Manitoba Beef Producers, says damage varies, but has been generally widespread.
“In our area, we have them, for sure, and we have them worse than I’ve seen them in the last several years, but it’s not to the same degree that they’re seeing in the Interlake and, for that matter, I think farther south to the southwest,” he said.
As bad as issues are, however, Gavloski says this may not yet be Manitoba’s grasshopper peak.
“Weather can change things. Natural enemies can change things, but they do tend to build their populations up when we get these kinds of consecutive hot, dry summers,” he said.
David Koroscil, manager of claims services with the Manitoba Agricultural Services Corporation, says the organization is aware that the Interlake has been hit hard by lack of rainfall and grasshopper damage.
“It’s just starting to come in, so we haven’t really been out there too much yet,” he said.