Aerial spraying planned to combat invasive spongy moths in Delta, Squamish

A spongy moth is seen in this CTV News file photo.

The B.C. government will carry out an aerial spray treatment plan in parts of Delta and Squamish this spring, as part of efforts to eradicate invasive spongy moths, and limit the damage they can cause to forests and agriculture.

In a news release Monday, the province’s agriculture ministry said it will spray 36 hectares around Delta’s Beach Grove, and 121 hectares in Squamish, west and south of the Buckley Avenue and Third Avenue intersection.

The ministry added that the treatment poses no known risk to people, pets or wildlife, and is scheduled to take place between April 1 and June 15.

“B.C.’s ecosystems and economy are at risk from invasive spongy moths. Also known as Lymantria dispar, formerly known as gypsy moths, spongy moths are a serious pest in their caterpillar form,” the province said in the release. “Caterpillars feed on tree leaves, which can defoliate forests, parks, crops and residential areas.”

Officials warn that without treatment, spongy moths could spread to other parts of B.C., causing serious harm to agriculture and forestry, and negatively impacting imports and exports.

The measure is part of B.C.’s Integrated Pest Management Act, which the province says targets areas where spongy moth populations have been increasing.

Moth numbers have been on the rise in both Delta and Squamish for more than two years.

The province said treatment is only used when necessary, and that failing to act could allow the pests to become permanent in B.C.

The treatment uses Bacillus thuringiensis var kurstaki or “btk” — a naturally occurring bacteria found in soil that targets caterpillars specifically.

The province added that the treatment has been approved for spongy moth control in Canada since 1961. It has been used regularly in B.C. since 1979, and most recently, in 2024.