The wretched worm that ravages spruce and fir trees and leaves a brownish mess in its wake seems to be everywhere one looks this summer, while options for trying to prevent the pest from wreaking its havoc are limited.
For some rural property owners just outside Thunder Bay, spruce budworm infestations are occurring for the second consecutive season.
It’s “everywhere in our trees,” one woman said in a social-media post. “This is the second year I’ve seen them here, definitely worse this year.”
“I see it along Highway 11 toward Atikokan, too,” she added.
The Ministry of Natural Resources says spruce budworm is a native insect in Ontario “with outbreak cycles occurring for many years.”
Though Btk (Bacillus thuringiensis kurstaki) spray is “effective . . . little can be done to reduce defoliation,” a ministry spokeswoman said in an email.
Moths that appear on impacted trees between late June and early August lay eggs on the underside of needles, causing the cycle to continue.
By mid-summer, tree needles have dried up, leaving the trees with a reddish hue and literally covered in excrement from the worms.
The resident who made the social media post said “I don’t want to use Btk because it will harm butterfly population, and the infestation is so bad, we would need aerial spray to make a difference in the forest.”
The ministry spokeswoman added: “Landowners can help by ensuring trees are well watered during the dry season.”
According to a ministry backgrounder, spruce budworm “is the most destructive pest of spruce and fir forests in North America.”
The insect’s larvae “are wasteful feeders as they only eat partial needles and then move on to other needles.”
Larvae emerge in the spring and eat previous year’s needles, unopened buds and flowers, then move to new shoots, the ministry says.
The majority of feeding occurs in mid-to-late June.
Some experts say a tree often won’t survive if an infestation occurs for three to five consecutive seasons.
