Gypsy Moths

Early spring through mid to late May is the time frame for Gypsy moths. The moths emerge as caterpillars and feed on the tender leaves of hardwood trees. Severe infestations can and often do result in complete defoliation of trees, sometimes conifers. Trees can usually survive a defoliation of one season while conifers seldom survive defoliation.

Gypsy moths are very close to being the number one pest for leaf defoliation in the United States, costing in the area of $50 million per year in the eastern United States into Canada. We are right in the affected area. The caterpillars feed at night and start at the top of the trees and work downward.

The moths are very light and move easily in the air. However, female GM’s cannot fly. The caterpillars will continue to feed for about 8-12 weeks going through a molting phase 5 or 6 times. Be aware that a mature caterpillar can eat 1 square foot of leaves per day. At the conclusion of the feeding stage in late
June to early July the caterpillar will pupate into moths by late July. As moths the Gypsy moth does not eat but searches for a mate. Each female will lay a single buff colored egg mass consisting of 100-1000 eggs. The female cannot fly in spite of having large well developed wings.

Identifying the moths is relatively easy. As larvae, or caterpillars, the Gm is rather large with distinctive markings. At a size of 2 ½" with yellow marked black heads and having 5 pairs of blue bumps followed by 6 pair of red bumps down the back the moth is easy to identify as a caterpillar. The pupa of the moth will be found hanging upside down motionless, suspended in place with a few strands of silk.

Be on the lookout, especially if you have oak or ash trees. Contact us if you thing you have found the distinctive caterpillars on your trees. The next 6-12 weeks are critical. We can determine the type and will notify the appropriate agency. We can and do take corrective action.