Warm spring brings more insects to Prairies

By: Terryn Shiells

A warm spring across the Prairies is bringing larger insect populations to crop-growing regions this season.

Manitoba and Alberta canola crops are seeing increasing populations of flea beetles this spring. The insects feed on multiple parts of the plant and can be very damaging for canola in its early development stages. Both provinces have already received reports of damage from the insects this year.

"The problem with the flea beetles in canola is some individuals seeded quite early this year and the seeds they put in the ground have a seed treatment that's supposed to protect the plant from flea beetles. But, that seed treatment only lasts for about a month," said John Gavloski, entomologist with Manitoba Agriculture, Food and Rural Initiatives at Carman.

Scott Hartley, entomologist with Saskatchewan Agriculture in Regina, said the province hasn't seen any flea beetles yet because seeding in many areas was delayed due to wet fields and crops aren't developed enough to be affected by the insects.

Leafhoppers and aphids overwintered in Minnesota because of mild temperatures in the U.S. Midwest. They're now blowing into Manitoba and Saskatchewan but entomologists from both provinces said it's not a big concern for their crops.

"There were some worries that there were aster leafhoppers, which are the ones that are responsible for disease, but so far it hasn't been affecting fields," Hartley said.

Saskatchewan and Alberta are worried about pea leaf weevil right now. The insect only feeds on the growing points and leaves of pea crops but can cause significant damage.

"They've been moving in to the fields because it's been above their flight threshold temperatures," said Scott Meers, insect management specialist with Alberta Agriculture and Rural Development at Brooks.

Cutworms have been present in scattered areas across the Prairies this season, but Meers said the pest numbers are way down compared to this time last year.

Some cutworm species feed on canola stems while others feed on the leaves, but they can all cause significant damage to plants.

Hartley recommends farmers scout fields often for all insects in order to protect their crops.

"It's not one of those things that you can just walk through the fields and observe. You might have to get down and actually look at undersides of leaves, and at young stems for flea beetles. Farmers also need to watch for feeding notches from pea leaf weevil," he said.

Higher populations of diamondback moths, which target canola and mustard crops, were also detected across the Prairies this spring and entomologists will be monitoring their activity throughout the season.

Diamondbacks have the potential to cause a lot of damage because they feed on multiple parts of plants.

Hartley said bertha armyworms, whose larvae feed on the undersides of leaves, are also expected to be an issue for canola and mustard crops later in the growing season.

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