The European Gypsy Moth is a non-native defoliating insect that was introduced to North America in 1869. The caterpillar or larva stage of the Gypsy Moth eats the leaves of trees causing the trees to be more vulnerable to disease and attack from other insects.
Gypsy moth infestations can cause moderate to severe defoliation of certain types of trees. Healthy trees can usually withstand losing their leaves for a few years. However, several years of defoliation can severely weaken or kill trees.
What You Can Do - Control Methods for Homeowners and Residents
Conservation Halton urges all residents to participate in the control program by scraping and destroying egg masses, and catching and destroying caterpillars. Your choice of control method will be closely linked to the Gypsy Moth’s stage of development, as described by season below.
November – Late April: Remove and Destroy Egg Masses
Gypsy Moth is in the egg stage between early September and late April. Egg masses can be found on tree trunks, branches, buildings and on objects around the house. One egg mass contains about 300 eggs. By destroying them you will significantly reduce the number of caterpillars that emerge in the spring.
Scrape off egg masses with a dull knife and place them in soapy water for a few days before discarding them in the garbage. If they fall on the ground crush them with your shoe.
Egg masses are easy to vacuum off trees, buildings and other objects with a portable or a household vacuum cleaner. You can reach egg masses that are located at higher elevations on the tree by adding a number of extension pipes to the vacuum hose, or with the help of a ladder. Place collected egg masses in soapy water for a few days and then discard them in the garbage.
Late April – Early May: Place Sticky Barriers or Bands on the Tree Trunk
Wrap duct tape around the tree trunk and apply a thin coat of sticky material (ready-to-use products are commercially available in most garden centres) to the duct tape. This prevents young caterpillars from crawling up the tree. This control method will effectively trap only young caterpillars that are already crawling on trees or that emerge from egg masses that are situated low on a tree trunk or on other buildings and objects.
Late May – August: Replace Sticky Bands with Burlap (Cloth) Bands
Trap and destroy caterpillars by placing burlap (cloth) bands on trees. Wrap burlap that is approximately one metre wide around the tree trunk, tie it at the middle with a rope and fold it. Caterpillars feed at night and hide during the day in shelters that protect them from the heat. They will congregate under the burlap. Destroy caterpillars that emerge from under the burlap late in the afternoon before they crawl back to the canopy to feed.
Additional Resources
Land & Forests (Forestry) 
