Winnipeg ends war on forest tent caterpillars

The Winnipeg insect control branch concluded the forest tent caterpillar control program on Tuesday.

City says crawly bugs have stopped eating, looking to spin cocoons

Tent caterpillars cling to a tree trunk in a Winnipeg park. (Darren Bernhardt)

The City of Winnipeg has ended its combat with the caterpillar. 

The Winnipeg insect control branch concluded the forest tent caterpillar control program on Tuesday.

The caterpillars have stopped feeding so the spraying no longer works, the city said in a release. 

Taz Stuart, an entomologist and director of technical operations at Poulin's Pest Control Services, said the city uses bacillus thuringiensis kurstaki, or BTK, to tackle the caterpillars. The bacterial product becomes less effective further on in the bugs' life cycle. 

"It takes a lot more BTK to kill them, so therefore BTK is not going to be very effective at this time," Stuart said. 

People can still kill the creepy crawler with contact insecticides such as permethrin, pyrethroid or malathion — or with the bottom of their shoes. 

"The old-fashioned way of broom, hockey stick or other item to knock down the remaining worms that are going to start going into the pupa stage," Stuart said. 

Forest tent caterpillars typically infest the city once every 10 to 15 years. 0:29

People will still see the caterpillars crawling around looking for a place to spin a cocoon.

If each tree in Winnipeg has 100 forest tent caterpillars and there are 5 million trees, 500 million adult moths will emerge in July, Stuart said.  

"It could be a golden storm of moths," he said.