. Insect and disease conditions in the United States, 1979-83 : what else is growing in our forests?. Forest insects United States; Trees Diseases and pests United States; Plants Disease and pest resistance. Gypsy Moth A Regional Nuisance Becomes a National Dilemma Written by Robert D. Wolfe From 1979 to 1983, defolia- tion caused by the gypsy moth reached unprecedented levels: the years from 1980 to 1983 were the worst on record. Defoliation during the 5-year period 1979-83 totaled more than all the defoliation recorded during the previous 55 years (fig. 1). Few people would have predicted th
. Insect and disease conditions in the United States, 1979-83 : what else is growing in our forests?. Forest insects United States; Trees Diseases and pests United States; Plants Disease and pest resistance. Gypsy Moth A Regional Nuisance Becomes a National Dilemma Written by Robert D. Wolfe From 1979 to 1983, defolia- tion caused by the gypsy moth reached unprecedented levels: the years from 1980 to 1983 were the worst on record. Defoliation during the 5-year period 1979-83 totaled more than all the defoliation recorded during the previous 55 years (fig. 1). Few people would have predicted that this insect could cause such ex- tensive damage. The gypsy moth was introduc- ed into this country from Europe in 1869. From its toehold outside Boston, MA, the moth established itself throughout New England, New Jersey, and Pennsylvania. During the 1980's, the gypsy moth spread into Delaware, Maryland, and into portions of Virginia and West Virginia. Isolated infesta- tions have been found in many States, including Arkansas, California, North Carolina, Oregon, and Washington. Like other defoliating insects, the gypsy moth does its damage during the larval stage. In the Northeast, the larvae emerge from egg masses in late April or early May. After they hatch, some lar- vae crawl to treetops and hang suspended on silken threads. These larvae are easily picked up by the wind and can be carried for several miles or more. As they feed, the larvae pass through several instars, shedding their outer skin as they grow (fig. 2). When population levels are high, the larvae remain in the trees, feeding day and night until mature enough to pupate. The male moths, which emerge from the pupae in late June, are strong fliers; female moths cannot Figure 1. Acreage defoliated by gypsy moth. 1980 10%. fly. Instead, the females lure the males by emitting a strong sex pheromone. After they mate, the female deposits her eggs in an oval mass of as many as 1,000 eggs (fig. 3). Then, both moths die
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