Regina begins spraying for cankerworms, tent caterpillars

The City of Regina started its annual tree spraying program on Tuesday, aimed at reducing the damage done by cankerworms and tent caterpillars.

Tent caterpillar numbers are above average this year, according to Russell Eirich, manager of forestry, pest control and horticulture for the City of Regina.

The high numbers this year are due to the cyclical nature of the pest's population, which has peaks and valleys over a seven- to 10-year stretch, Eirich said.

"They're just at their natural high," he said.

Cankerworms have a wider reach than usualin 2017. Eirich said the city will spray four city sectors, up from two the year before. Eirich said about 10,000 trees will be sprayed this year.

• Cankerworm populations may go up this year, City of Regina says

The trees will be sprayed with an organic product, DiPel, he said.When the pest larvae begin to feed on the trees, they'll get sick and die within days.

"It doesn't harm your garden... It is a very safe product out there," Eirichsaid, adding people will know when trees are being sprayed nearby just by the sound.

The decision on which areas will be sprayed for tent caterpillars is based onthe biology of the insects, Eirich said. They're more interestedin Schubert chokecherries andcertain types of ash trees.

Cankerworms, meanwhile, prefer elm trees, which are typically found in older neighbourhoods.

Mosquito populations are on par with the yearly average, Eirich said, but their numbersarelargely dependent on the weather. Drier conditions so far this year have tilted mosquito control in the city's favour.

To keep it that way, Eirich said people can help keep things dry through efforts such as draining birdbaths and making sure no water has accumulated on properties.