Introduced to the United States in 1869 by accident. Gypsy moth comes in cycles that can sometimes not even be noticed to high populations that can effects thousands of acres of foliage. Trees can normally withstand 2 to 3 successive years of defoliation without being killed, but the defoliation of the tree does reduce the ability of the tree to resist and become more susceptible to pests and diseases. Trees that are already stressed from other pests, diseases, fungus and nutrient issues then attacked by gypsy moth can cause death to the tree.
If you are not sure how bad the infection on your tree(s) or property give us a call to give you a free Plant health Care evaluation.