Researcher keeps watch for new canola pest

Pollen beetles cause extensive damage 
to crops in the Maritimes and Europe 
but haven’t been spotted in the west … yet

Entomologist Hector Carcamo has seen many, many insects in his career but he has yet to lay eyes on Brassicogethes aeneus, otherwise known as the pollen beetle.

He doesn’t want to, either.

Carcamo, a research scientist with Agriculture Canada, works in Lethbridge and a sighting of the pollen beetle in his region would mean the pest has made its way to Western Canada and could potentially be a threat to canola crops.

It has not appeared but Carcamo suggests that farmers watch for it just in case.

“I have never seen one in the flesh,” said Carcamo.

“What happens sometimes is when you start looking for something closely, we tend to find it, but hopefully that’s not the case with this beetle. It’s considered a potentially serious pest of canola.”

The pollen beetle is present in the Maritimes and Quebec, and is a major pest of canola in Scandinavia.

Carcamo said accidental human introduction would be the most likely way it could arrive in Western Canada. It could hitch a ride on a cabbage or other member of the crucifer family, for example.

The pollen beetle is easy to identify, said Carcamo. It is two to three millimeters long and about the same size as a flea beetle. It is shiny and black or greenish black.

There are two related species that look similar, Carcamo said. One of them is found in Eastern Canada and the other in Europe.

The beetles lay eggs on plants and the larvae then feed on pre-emerged blossoms. In the second larval stage, they feed on open flowers.

Carcamo said plants can generally tolerate major flower abortion and still survive and flourish, so it would take a large number of beetles to do major damage.

Research work on pesticides is underway in Canada.

Though it would be ideal to identify any pollen beetles early so they could be eliminated, Carcamo said that is unlikely.

“We have a very poor record of eradicating insects because by the time you detect them it means that they are not in low numbers. You need a method that allows detection at very low levels and I don’t think those methods exist.

“Usually by the time you find the insect, it means that it’s at a level high enough that it’s beyond the point that you can eradicate it.”

Nevertheless, identifying the insect’s presence early would provide time to figure out management methods and economic spray thresholds for prairie conditions.

Trap crops might also be an option should the beetle make its way to the Prairies.

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