The gypsy moth is an introduced forest insect. It was brought into this
country from Europe in 1869 and has been restricted to the Northeast.
The gypsy moth feeds aggressively on oak, alder, apple, basswood,
willow, and birch. As the caterpillars reach maturity they will also
feed on hemlock, cedar, pine, and spruce.
[Illustration: Gypsy moth larvae.]
In the Northeast, the gypsy moth has a single generation per year,
overwintering in the egg stage. Eggs hatch in late April and May and
larvae are present for approximately two months. Full-grown caterpillars
measure more than two inches long and are easily identified by the five
pairs of blue spots and six pairs of red spots arranged in a double row
along the back. The adult moths are active from late June to early
September. Female moths, their bodies heavy with eggs, are unable to fly
and must rely on a powerful sex attractant to lure male moths. This sex
attractant has been chemically synthesized and is used as a trap bait in
surveys designed to determine the presence of gypsy moths in areas
suspected to be infested. Each female deposits from 200 to 800 eggs in a
buff-colored mass which she attaches to any convenient surface including
cars, trailers, and other vehicles.
[Illustration: Female gypsy moths depositing egg masses.]
During the past 75 years the gypsy moth has been the target of many
large-scale control programs, and much money has been spent trying to
reduce the impact of gypsy moth infestations. Current control efforts
are handicapped by the unavailability of a safe and effective persistent
chemical. In the North two predators and nine parasites have been
successfully established to help control the gypsy moth. The greatest
problem in controlling gypsy moth spread, however, lies in the fact that
recreational vehicles transport egg masses and larvae from infested
sites into uninfested areas.