History of Gypsy Moth Infestations
in British Columbia

Distribution | Detection History | Treatment History | Current Status

Gypsy moth (Lymantria dispar) has been found in British Columbia since 1978 but has so far they have not become permanently established due to aggressive monitoring and eradication programs conducted by the Federal and Provincial governments.  The insect is well-established in eastern North America.  The Canadian Food Inspection agency lists infested areas in North America in their directive memo D-98-09 - Appendix 1.  These areas are the potential source of new infestations in B.C. and the western states.

The following history of gypsy moth detection records and treatment efforts is copied by permission from the CFS publication Gypsy moth Pest Leaflet Number 75, Pacific Forestry Centre. The original publication is available through the Canadian Forest Service Bookstore site.  The tables have since been updated to provide the most current status of the gypsy moth trap catches and egg mass finds.  Links to more information on past treatment activities is also included in the last table.

A recent article by Dr. Vince Nealis Still invasive after all these years: Keeping gypsy moth out of British Columbia. 2009. The Forestry Chronicle 85(4): 593-603 provides a more detailed description of the gypsy moth eradication efforts and is available through the CFS Bookstore.

A description of the monitoring (trapping) protocols is also provided on this web site.

The Distribution of Gypsy Moth

The gypsy moth is a native insect of Europe and North Africa, and it occurs across Asia to Japan. In North America, the European race is established in the north eastern United States and the provinces of Quebec and Ontario, having expanded from the original introduction at Medford, Massachusetts in 1868. During the 1970s and 1980s, it was found in numbers sufficient to cause concern in the western states of California, Utah, Oregon and Washington as well as in British Columbia. These occurrences were caused by the transportation of egg-laden materials from eastern sources. In 1991, federal inspectors found egg masses of the Asian race on Russian ships at Vancouver waiting to load grain; male moths were subsequently trapped on shore. British Columbia therefore now faces the threat of gypsy moth introductions from sources to the east, south and west.

The Gypsy Moth in British Columbia

The first recorded interception of the gypsy moth in the province occurred in 1911, although unconfirmed interceptions may have been made two to three years earlier. In that year a single egg mass was found on imported European nursery stock by a provincial inspector at Vancouver. About the same time, in Vancouver, more egg masses were found on ornamental Thuja trees from Japan.

The British Columbia Gypsy Moth Detection Story, 1911-2007

1911-1989 > 1990 - 1999 > 2000 - present

The Gypsy Moth Threat to British Columbia

During the past twenty years, an assertive program to prevent permanent establishment of the gypsy moth in the southern part of the province has been successful. The program, based on comprehensive surveys and spray treatments using the biological insecticide Btk (Bacillus thuringiensis var. kurstaki), has been coordinated through the B.C. Gypsy Moth Committee of the Plant Protection Advisory Council of British Columbia. The primary challenge of the program is to deal with repeated introductions of the pest.

To date, treatment programs have been conducted at the following locations.  The majority of these treatments have been highly successful.  More detailed descriptions of the different treatment methods are provided and selection process are provided on the Gypsy Moth Management page.

Alternative treatments*  (non-spray), have been used with limited or inconclusive results.  The Ministry of Forests and Range continues to test non-spray treatments to determine their effectiveness as eradication methods and define the optimal conditions for their deployment.  Preventative measures are exercised by the Federal government's Canadian Food Inspection Agency (CFIA) who restrict movement of goods that may be infested by gypsy moth by imposing a regulated area over the known infestation.

TREATMENT HISTORY

(Btk was used for all treatments unless otherwise noted)

The battle with the moth continues.

The program to prevent establishment via intensive surveys and treatment of establishing populations will continue.

Back to the Gypsy Moth Homepage

Contact Tim Ebata if you have comments on the presentation of this information.

BC Ministry of Forests and Range
Forest Practices Branch
P.O. Box 9513 Stn. Prov. Gov.
Victoria, BC
V8W 9C2

Section phone: (250) 387-8739
Section fax: (250) 387-2136