Kentucky Office of the State Entomologist

Gypsy Moth Information

Why be so concerned with this insect?

The European Gypsy Moth was deliberately introduced from Europe at Medford, Mass. in 1868 or 1869 by Leopold Trouvelot (he made a living as an artist, painting mostly portraits, but he had an amateur interest in entomology). Trouvelot hoped to raise this moth for silk production. Unfortunately, some of his moths escaped. Trouvelot understood the potential magnitude of this accident and notified local entomologists but no action was taken. By 1889 the Gypsy Moth was doing heavy damage in certain parts of the Boston area; it is now a serious pest throughout much of the Northeast and is expanding its range.

As a caterpillar, the gypsy moth has a voracious appetite and has been known to completely defoliate forests. The caterpillars feed on about 500 different species of plants. The most preferred host is oak followed by apple, cherry, hawthorn, hickory, maples, sassafras, sweet gum and willow. Only the caterpillar stage feeds. When fully grown, the caterpillar is about 2 inches long, very hairy and has five pairs of blue dots followed by six pairs of red dots along its back. The larval stage lasts about seven weeks.

Gypsy moths are spread in two different ways. Natural spread occurs when newly hatched larvae are dispersed by blowing wind. Over the past 10-15 years, gypsy moths have moved long distances on outdoor household articles such as cars and recreational vehicles, firewood and other items. It has been estimated that 85% of new infestations have been through the movement of outdoor household articles. Once established, gypsy moth numbers can fluctuate widely from year to year. Seasons with light damage can be followed by seasons with severe damage. In periods of heavy outbreaks, gypsy moth caterpillars crawl on walls, across roads, over outdoor furniture, and sometimes will come inside homes.

The gypsy moth has four different life stages: egg, caterpillar, pupa and adult moth. The female moth lays eggs in masses which will contain between 500 and 1,000 eggs and will have a fuzzy tan appearance. The eggs hatch in early spring, coinciding with the bud break of most hardwood trees.

Want to know more about gypsy moth? Go to: http://www.fs.fed.us/ne/morgantown/4557/gmoth/