Limiting spread of the poplar-and-willow borer weevil and the damage it’s doing to some deciduous stands in the region will be difficult if not impossible, according to an insect expert with the Ministry of Forests, Lands and Natural Resource Operations (FLNRO).
Ken White, FLNRO’s regional entomologist for the Skeena Resource Region, said Friday the province doesn’t have an action plan in place to combat the bug.
“The ministry has no plans to do anything specific, as control of this insect is extremely difficult, and in most cases, impractical,” he said. “Individual homeowners can try and protect their trees, but that is also very difficult.”
B. Staffan Lindgren, professor of ecosystem science and management at the University of Northern BC, agrees. “To my knowledge there are no specific control measures, as the larvae are protected from pesticides, etc., unless (you’re) using a systemic pesticide, which becomes quite expensive and also damages the tree.”
Lindgren added that because the insect is not native to this continent, willows, poplars, and other trees haven’t developed natural defenses against it.
“My guess is that if we wait long enough, resistant varieties of willow will start taking over, creating a balance with the insect,” he stated. “This could take hundreds of years, because the susceptible willows are often not killed outright and therefore persist.”
Lindgren and White say that unlike the mountain pine beetle epidemic that devastated pine stands across the province, this latest insect infestation likely won’t have a significant economic impact here. They point out that willow, poplar, black cottonwood – the tree species hit hardest by the bug – are for the most part not harvested commercially.
Both men suggest, though, that the insect’s latest outbreak could have an effect on wildlife that rely on willows for sustenance.
“It may affect moose habitat by reducing availability of browse, which may in turn affect the moose population,” noted Lindgren.
“If it is anything like the increased attack we saw six years ago, a lot of willows could be killed, and people will notice this,” said White. “(We’re) not sure what the impacts will be, except that species that rely on willow forage may have to switch to other food plants for a while.”
Both men stress than any impact the infestation has on local deciduous trees and wildlife that rely on them will likely be short-term.
“You have to remember that willow is a very resistant tree,” stressed White. “They will re-sprout profusely from their base when the upper stems are killed. In some areas, willows grow so well after pruning/girdling that they are considered a weed problem. We have seen a good recovery of willow that was killed six years ago in the Smithers area.”