Tent caterpillars: Tips to help control the outbreak

The rising number of tent caterpillars over the last couple of years could be a sign Saskatchewan is in the middle of an outbreak.

Specialist says outbreaks happen every 10 to 15 years and last up to six years

Tent caterpillars crawl up the wall in Raymore, Sask. (Todd Deutsch/Submitted to CBC)

The rising number of tent caterpillars over the last couple of years could be a sign Saskatchewan is in the middle of an outbreak.

That's according to the province's Ministry of Agriculture insect specialists who said tent caterpillar outbreaks happen every 10 to 15 years and last anywhere from three to six years.

Scott Hartley, an insect specialist with the ministry, said its usually around this time of the year when people start to notice tent caterpillars. However, he says the astonishing number of caterpillars for this time of year suggests the mild winter and hot spring may have sprung more caterpillars, quicker.

"But a combination of factors have allowed it to build up to this point and be this widespread," Hartley said. "Certainly in 2015 there was problems in a number of areas, some parks and urban areas did see outbreaks last year as well."

Both the City of Regina and the City of Saskatoon have seen a noticeable increase in the amount of tent caterpillars, cankerworms and leafrollers this year. In a release, the City of Saskatoon said it believes the city is in the third year of an outbreak period for tent caterpillars.
A tent caterpillar infestation is happening across Saskatchewan. (Todd Deutsch/Submitted to CBC)

The city added it does not control tent caterpillars, cankerworms or leafrollers because the critters don't impact the health of the trees they attack.

For homeowners interested in battling the outbreak, Hartley said they should reach for a product known as bacillus thuringiensis kurstaki (BTK), a safe caterpillar killer that won't kill other insects or damage trees or plants.
This graphic shows the progression of a tent caterpillar outbreak. (CBC)

Should farmers fear caterpillar outbreaks?

While tent and forest caterpillars tend to target and feed off deciduous trees, Hartley said farmers shouldn't be too worried of the outbreak reaching their fields.

"This is a forestry pest, so it's not a concern to farmers as far as crops go," he said.

The Ministry of Agriculture added the caterpillars' natural predators include birds, and the sarcophagid fly, which actually lays its eggs in the caterpillar. Hartley added that disease also tends to wipe out tent caterpillars.


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