Blog & News

Another forest insect pest that is found on PEI! (archive)

Published on Thursday March 19, 2015
Authored by PEIISC

European or North American gypsy moth, (Lymantria dispar)

Gypsy moth was introduced to Northeastern United States in the 1860’s and has since spread to several provinces including PEI, New Brunswick, Nova Scotia, Ontario and Quebec. It is found each year in British Columbia but has not established a permanent population yet due to lots of hard work to eradicate it.

Gypsy moth is a defoliator… their larvae feed on the leaves of deciduous trees for the most part, but have been known to defoliate coniferous trees as well. The prefer to feed on oak, poplar, elm, maple and birch but are not picky, and will feed on over 300 different species of trees and shrubs. The loss of foliage causes stress to the trees making them vulnerable to attack by other insects and diseases. Repeated severe defoliation can kill a tree.

Gypsy moth overwinters in the egg stage. In the spring, eggs hatch and the gypsy moth larvae move up the tree and feed on the newly emerged leaves. They mainly feed at night so often you will see the damage to the leaves of your tree but not the larvae. Young caterpillars produce silken threads that catch in the wind and blow them to neighboring trees. More mature larvae begin to feed day and night and can very quickly defoliate your tree. You can identify them by the 5 pairs of blue spots and 6 pairs of reddish spots on their back. Once the larvae are mature (usually around July) they find a protected place such as a crevice in the tree bark, form a cocoon and pupate. Adults emerge in late summer. The males are strong fliers while females are flightless. The adults do not feed and only live for about a week… just long enough to mate and lay eggs.

The female gypsy moths will lay eggs on anything!… on or inside trees, on any solid object found under a tree like lawn furniture, toys, vehicles, trailers, boats or piles of wood or lumber. Egg masses can be transported over long distances when the materials the eggs were laid on are moved.

Not moving firewood can help prevent the spread of insect pests such as gypsy moth and many others… Burn local wood.

CFIA has more information about gypsy moth and other forest insect pests.…/e…/1330963478693/1330963579986

In PEI the gypsy moth is found mainly in the Summerside and Charlottetown areas. These areas are regulated and there are restrictions on the movement of wood from the regulated areas to a non-regulated area.…/e…/1343832991660/1343834043533

– Beth Hoar, Chair, PEIISC

Attached images:

Moth antennae are generally quite feathery. They use their antennae for “smelling” things like the pheromone from a female gypsy moth.
The male gypsy moth is brownish in color, smaller than the female and is a strong flier.
The female gypsy moth is much larger than the male and, unlike the male, it is flightless. This means it lays its eggs very close to where it pupated… mostly on branches and tree trunks but could be on anything nearby like firewood, campers, bikes, boats… things we move around and inadvertently move the gypsy moth with us!
Female gypsy moth lay eggs in the fall which then, overwinter. The egg masses are covered with fine hairs from the females abdomen. These hairs protect the eggs from predators, insulate them in cold temperatures and help to keep the eggs dry. Mild winters contribute to the eggs successfully overwintering.
The gypsy moth larva be identified by the 5 pairs of blue spots followed by 6 pairs of reddish spots that are on its back. This can vary some, but blue dots followed by red dots is a good indication you have found a gypsy moth larva.
Distribution of Gypsy moth in the Atlantic region.