The European gypsy moth was brought to North America in 1869 by an entrepreneur who hoped to cross breed it with the silk worm, to create a hardy silk-producer that would be easy to raise and inexpensive to feed. He was unsuccessful, and unfortunately, several gypsy moths escaped and established a wild population. By 1890, they had begun defoliating trees in his Massachusetts neighborhood. More than a century later, the gypsy moth has expanded its range throughout Northeastern United States and Canada, west to Minnesota and south to North Carolina to be one of the most significant pest of shade trees and forests.
There are many telltale signs that gypsy moths are invading your trees. The most obvious is gypsy moth egg masses, which are fuzzy, tan in color, and about the size of a nickel or quarter. The eggs masses are laid individually or in large clumps in protected places. Although there are a few native predators of the colorful caterpillars that hatch (including mice, shrews, and some birds), these insects can ravage a tree, feeding on unripe tissues of annual shoots, flowers and buds, and killing about 15% of the trees. In the long term, this mortality and defoliation can cause changes in tree species composition of the forest. Regenerating tree species may be less valuable to wildlife and less valuable as timber. This then causes a ripple effect throughout the ecosystem.
The Maryland Department of Agriculture has a Forest Pest Management Section (FPM) which manages this pest using an integrated management approach. The purpose of the integrated pest management approach is to have maximum impact on the pest species with minimum impact on non-target organisms, including humans. FPM monitors the presence and severity of gypsy moth infestations using surveys. Based upon surveys, integrated management is used to determine the best strategies to help minimize moth and caterpillar populations and damage. These strategies include biological, cultural, manual, and chemical controls.