The B.C. government plans to conduct aerial-spray treatments in three locations on southern Vancouver Island in spring 2022 to prevent Lymantria moths from becoming established and to minimize the risk they pose to forests, farms, orchards and urban trees.

The Ministry of Forests, Lands, Natural Resource Operations and Rural Development has applied for an amendment to its existing pesticide use permit issued in March 2021 for Lymantria moths (formerly known as gypsy moths). 

The planned 2022 treatment areas on Vancouver Island are:

• View Royal (50 hectares south of Thetis Lake Regional Park and the Trans-Canada Highway)
• Nanoose Bay (1,068 hectares south of Nanoose Bay to the northern boundary of the City of Nanaimo)
• Cowichan Lake (402 hectares at the easternmost tip of the lake and part of the Town of Lake Cowichan)

These planned treatment locations are in addition to five areas in the Fraser Valley and the Lower Mainland. Last year’s monitoring program trapped 98 male moths in these eight areas, indicating that the moths could become established in those locations if the proposed pesticide spraying is not done.

Trapping and monitoring results from 2021 show evidence that Lymantria moth populations have increased dramatically in the areas slated for treatment this spring, likely because of outbreaks in Ontario and Quebec over the past three years. Egg masses are commonly transported to B.C. on recreational vehicles and outdoor household articles originating from affected areas outside of the province.

If left untreated, the invasive Lymantria moths could spread to other areas of British Columbia and pose a threat to native forests, orchards and urban trees. Trees such as Garry oak, arbutus, red alder, aspen, cottonwood, maple, orchard fruit trees, nut trees and many species of urban ornamental trees would be affected, as well as food crops such as apples, blueberries and other fruits.

The ministry is planning as many as four applications of Foray 48B in the specified areas between April 15 and June 30, 2022, to control the moths. Foray 48B is used in organic farming and the active ingredient Bacillus thuringiensis var kurstaki (Btk) is naturally present in urban, agricultural and forest soils throughout the province. It only affects the stomachs of caterpillars such as Lymantria moth caterpillars, and is specific to their digestive systems.

Btk has been approved for the control of Lymantria moth larvae in Canada since 1961. It does not harm humans, mammals, birds, fish, plants, reptiles, amphibians, bees or other insects. It only affects Lymantria moth caterpillars after they ingest it.

Residents in the planned spray areas are invited to submit their comments about this application to amend the existing pesticide use permit (refer to Permit No. 738-0032-21/24) for evaluation by the Integrated Pest Management Act administrator, Ministry of Environment and Climate Change Strategy, Suite 200-10470 152 St., Surrey, B.C. V3R 0Y3, by March 12, 2022.

Quick Facts:

• The Lymantria moth is an introduced pest. The caterpillars feed on tree leaves and can damage forests, farms and orchards.
• Large Lymantria moth populations have defoliated sections of forests and residential areas in Ontario and the eastern United States in recent years.
• These moths are unintentionally brought to B.C. on vehicles and equipment from eastern North America.
• Infested locations are often subject to agriculture and transportation quarantines, as well as additional treatments that may include vehicle checks, product certification and increased pesticide use.

Learn More:

To learn more about Lymantria moths, visit www.gov.bc.ca/lymantriamoth or call 1 866 917-5999 (toll-free).

For information about the pesticide use permit application or to see a map of planned treatment areas, visit: www.gov.bc.ca/lymantria-news  

The pesticide use permit application and treatment area maps are available for viewing at the relevant city or municipal hall and/or on the websites of the affected communities.