Cutworm, flea beetle pressure piling on Prairie crops

Flea beetle feeding (Photo courtesy Canola Council of Canada)

CNS Canada — High levels of cutworms and flea beetles are damaging crops in Western Canada this spring, according to Manitoba’s crop entomologist.

Manitoba growers started noticing damage from cutworms this week, said John Gavloski, extension entomologist for Manitoba Agriculture, Food and Rural Development in Carman.

“They were there in the fields, but they were very small caterpillars. Just doing some minor defoliation,” he said.

“They’re larger caterpillars now, and when some of the species get bigger they start clipping stems, and that really draws attention to their feeding. Also they’re taking bigger chunks of plant tissue.”

Cutworm is a term encompassing several species of caterpillar which below soil during the day and come out to feed at night on several kinds of crops, including corn and sunflower.

Gavloski said he knows of multiple cases where it has been necessary to spray fields for cutworms.

Flea beetles feed on Manitoba crops almost every year but, due to this year’s chilly conditions, pose an extra threat.

“Typically farmers use an insecticide-treated seed which repels the beetles, but that doesn’t always work. Especially with the cool weather,” he said.

Cool weather in the spring also means it takes plants longer to finish their seedling stage and become more resistant to flea beetles.

“That seed treatment basically wears down, and then the farmers have to go in and do a full spray of insecticide. That’s what we’re seeing this year,” Gavloski said.

Flea beetles, small black bugs which feed on plants in the mustard family, are present in parts of Canada as well as the U.S. Plains. Annual crop losses in North America from flea beetles are likely more than $300 million, according to the Canola Council of Canada.

Saskatchewan is also experiencing crop damage due to flea beetles and cutworms, according to a May crop report from the province. Farmers have done some reseeding, but say most crops are in relatively good condition.

An Alberta government crop report added that some areas in northwestern Alberta — for example, around Barrhead, Edmonton, Leduc, Drayton Valley and Athabasca — have started spraying for flea beetles.

Jade Markus writes for Commodity News Service Canada, a Winnipeg company specializing in grain and commodity market reporting.


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