The Government of British Columbia will carry out aerial spray treatments from late April to June 30, 2026, to control invasive spongy moths in selected areas of Delta and Squamish. This action is intended to protect forests, farms, crops, and trees from serious long-term damage.
Spongy Moths are invasive insects whose caterpillars feed on the leaves of many trees and plants. When large numbers are present, they can cause widespread defoliation in forests, parks, farms, and residential areas. This weakens trees and reduces crop health, making ecosystems more vulnerable.
In Delta, approximately 36 hectares will be treated, including areas near Boundary Bay and Beach Grove. In Squamish, about 121 hectares will be treated near the Squamish River and surrounding neighborhoods. These areas were selected based on long-term monitoring using pheromone-baited moth traps, which showed rising moth populations for more than two years.
Without treatment, spongy moths could spread across the province and become permanently established. This would pose serious risks to forestry and agriculture and could negatively affect domestic and international trade of agricultural and forest products.
The treatment uses Bacillus thuringiensis var. kurstaki (Btk), a naturally occurring bacteria found in soil. Btk is commonly used in organic farming to control caterpillar pests. It works only in the stomachs of caterpillars and does not harm people, pets, birds, or other wildlife. Health Canada has approved its use since 1961, and it has been safely applied in British Columbia for decades.
Three early-morning aerial applications will be carried out, each spaced seven to ten days apart. Residents may stay indoors during spraying and follow basic hygiene practices, such as washing hands and thoroughly cleaning fruits and vegetables.
Health information and support are available through official provincial resources and HealthLinkBC by calling 811.