Gypsy Moth in British Columbia
The European gypsy moth (Lymantria dispar) was introduced from Europe to the northeastern U.S. in 1869. The North American strain of the moth was first seen in B.C. in 1978.
Biology and Behaviour
Gypsy moths are “defoliating” insects, which means their caterpillars eat the leaves of trees and shrubs.
Eggs are laid in, on or inside trees, or on any solid object found under a tree such as lawn furniture, toys, vehicles or piles of wood or lumber. Egg masses can be transported over long distances when the materials the eggs were laid on are moved. Infestations can then spread slowly, when spring breezes blow young larvae across a few kilometers at a time.
Once gypsy moths arrive in an area, they threaten extensive damage, both to the environment and economy.
- When gypsy moths are discovered in an area, B.C.'s major trading partners may set quarantine and trade restrictions for products like Christmas trees, logs with bark, or nursery plants. They may also set more stringent requirements for transporting goods. For example, in 1999, in response to a gypsy moth infestation, the U.S. threatened to refuse shipments of trees and plants from B.C.’s nurseries without additional inspection certificates.
- The gypsy moth is a direct threat to B.C. fruit producers. It will eat the leaves of fruit trees, blueberries and hazelnuts. Apple trees, in particular, are excellent hosts.
- The gypsy moth has more than 300 known hosts, including native shade trees, the rare and endangered Garry oak, and valuable ornamental trees.
Canadian and U.S. agencies have worked hard to find and eradicate this invasive pest. This vigilance has been worthwhile. Though gypsy moth populations are found in B.C. every year, so far none have become permanently established.
Read about the methods used to eradicate gypsy moths in B.C.:
Read what HealthLinkBC says about gypsy moth spraying:
Trapping & Treatment
Since 1997, the gypsy moth has been trapped in many locations across the Lower Mainland, Vancouver Island and B.C.'s southern Interior. The first spraying treatments in B.C. occurred in 1979.