Late spring makes Man. canola more vulnerable to flea beetles

CNS Canada — Canola crops are more vulnerable to flea beetle damage in Manitoba this spring as cool, wet conditions have caused seed treatments to wear off.

“Most of the canola has seed treatments that contain insecticide which protects the canola from the flea beetles. What is happening is the fields that were planted around mid-May are starting to see the seed treatments wear out,” said John Gavloski, entomologist with Manitoba Agriculture, Food and Rural Development.

“They’re (seed treatments) not protecting the plant anymore.”

Another reason canola crops are more vulnerable to flea beetle damage in Manitoba this year is because the late spring has slowed development, and earlier-stage crops can’t defend themselves as well against the pest, said Gavloski.

“Once the canola gets three or four true leaves on its own, it can compensate really well for flea beetle feeding,” he said. “But prior to that, when it’s just a couple cotyledons, or one or two true leaves, there’s not enough material there for the plant to really compensate well.”

There has already been some spraying of insecticide in some parts of the province in order to protect canola crops from flea beetle damage — and there may need to be more over the next couple of weeks until the flea beetles die off, said Gavloski.

“Farmers should look at the number of pits and the feeding damage. If they’re going above about 25 per cent defoliation and there are still a lot of flea beetles around, that’s when we tell them, ‘You may need to consider applying an insecticide’,” he added.

Farmers in Saskatchewan and Alberta have also been dealing with flea beetles this spring, with both striped and crucifer species present, according to a Canola Council of Canada update.

Flea beetles are the most pressing problems for farmers in the early part of the growing season, but cutworms are also an issue.

Farmers in Manitoba should be checking their fields for cutworms, as they feed on sunflowers, corn and some cereal crops, Gavloski added.

— Terryn Shiells writes for Commodity News Service Canada, a Winnipeg company specializing in grain and commodity market reporting.


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