The gypsy moth is a non-native, invasive species that has been advancing into Ohio from Pennsylvania and Michigan over the past decade. In its caterpillar stage, it feeds on the leaves of over 300 different tree and shrub species and is especially fond of oak. A healthy tree can usually withstand only two years of defoliation before it is permanently damaged or dies.
To date, 51 of Ohio's 88 counties have established gypsy moth populations.
There are three defined zones in a spreading infestation. One is the "Infested Zone", in which the pest population is well established and colonies overlap. The second zone is the "Transition Zone", in which isolated pest populations have developed, but are not generally overlapping. The third zone is the "Uninfested Zone", in which no pest populations have developed.