Flea beetle infestation blamed on dry conditions

When things are bad, the humour usually gets dark.

Such is the case with Chris Allam, a farmer near Edmonton, who is dealing with severe insect pressure in his canola this spring.

“(I’m) thinking the Chinese should change their zodiac sign of 2019 to the year of the cutworm or flea beetle. (We) might have less canola to not trade with them,” Allam posted on Twitter June 5.

Allam isn’t alone in his frustration.

Across the Prairies, hundreds of producers are coping with high populations of flea beetles. The pests are feeding on canola plants that developed slowly because of dry conditions and cool weather this spring.

“I know a lot of (canola) seed got stranded and didn’t even germinate for two (or more) weeks after seeding,” said Angela Brackenreed, Canola Council of Canada agronomist in Manitoba.

In a June 5 note to growers, the council said Twitter comments, calls to their agronomists and sales of foliar insecticides all point to a “worse than usual flea beetle situation” in 2019.

In Manitoba, flea beetles are attacking canola crops across the province, but the situation varies from field to field, said John Gavolski, Manitoba Agriculture entomologist.

“Some fields have grown through (it),” Gavloski said from his office in Carman, Man.

“Other fields, just because of a timing issue and how slow the plants are growing, they’re being hit and (growers are) having to do foliar spraying.”

Multiple factors can influence flea beetle pressure, but it seems like dry conditions are a major issue this year.

Several growers and agronomists said on Twitter that rain is desperately needed to spur canola growth. Canola can usually withstand flea beetle pressure after the plants reach the three to four true leaf stage. In many regions it’s taking longer than normal to reach that stage of development.

Consequently, some growers are opting for a foliar spray because insecticidal seed treatments have worn off.

In Manitoba, the population of flea beetles is currently a mix of crucifer and striped beetles, Gavloski said.

Before going in with a foliar spray to kill those beetles, growers should evaluate a few factors:

• Is there more than 25 percent defoliation on canola plants?

• Does the field have an active population of fiea beetles?

• What’s the stage of the crop?

However, growers should “avoid going with the flow,” the canola council said.

In other words, spray based on conditions in your fields; don’t spray because the neighbour is doing it.

“In areas where lots of spraying seems to be happening, two of our Saskatchewan agronomists checked their own canola fields and found minimal feeding. They’re not spraying,” the council said.

“The ‘better safe than sorry’ approach may be a waste of time and money and unnecessarily threatens all the beneficial insects in a field.”

Contact robert.arnason@producer.com

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