York Region readies for battle against spongy moth caterpillars

Newmarkettoday.ca
May 18, 2022

York Region is readying itself for another year of addressing the spongy moth outbreak, with “heavy to severe” defoliation anticipated in patches in all of its municipalities.

The egg masses for the moths are beginning to hatch this month and the region is asking residents to take measures to address any infestations for their own trees this year.

Region invasive species specialist Dayna Laxton said they are hopeful it is “the beginning of the decline” for the outbreak, but residents will still have to be wary this year.

"Residents should expect some feeding of their trees again this year,” she said. “They can expect some level of heavy to severe defoliation in very localized areas.”

Municipalities have combated the invasive moths as their population has surged over the past couple of years, part of a naturalized cycle. A virus naturally causes the moths to decline over time, but until then, the caterpillars can cause substantial damage to trees, particularly vulnerable ones.

Laxton said there has been a noticeable decline in egg mass surveys this year, and the cold temperatures of the winter might mean some egg masses also do not hatch.

“I am hopeful that the overall levels of defoliation that we see this year will be significantly less than last year,” she said.

The methods to combat the moth have not changed, Laxton said. Residents can scrape egg masses off their trees and plunge them into soapy water. But as the eggs start to hatch, you can put a burlap band on a tree to gather the caterpillars and then also kill them in soapy water, wearing protective equipment.

Laxton said it is key to note that the band will not on its own stop caterpillars from feeding, but is a way to gather them together as they seek shade from the sun.

“They are an effective control,” she said. “The burlap band is actually a collective tool.”

She added that you can also look to consult a tree care company on control methods, which can include some chemicals.

The region, meanwhile, will be taking care of its regional forests and street trees on regional roads. Municipalities have done targeted protection of vulnerable trees with control measures like scraping.

Laxton said it is hard to predict what the moths could be like next year. But she said many trees adapt to the creatures, bringing back their leaves once the caterpillars go into cocoons.

“The trees are highly resilient, and they have a natural defence mechanism,” she said. “A lot of the trees came back no problem.”

More information is available at york.ca/lddmoth.

The Town of Newmarket offers free burlap kits to Newmarket residents until the end of May, with information available at heynewmarket.ca/lddmoth.