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College of Food, Agricultural, and Environmental Sciences


It's Gypsy Moth Time Again

April 24, 2002

WOOSTER, Ohio - Gypsy moths have begun emerging throughout Ohio and forestry officials speculate the invasive insects will continue to spread throughout the southeastern half of the state.

Dan Herms, an Ohio State University Extension entomologist and researcher with the Ohio Agricultural Research and Development Center (OARDC), has been monitoring egg hatch in some parts of the state to accurately time management practices.

"Gypsy moth eggs begin hatching when redbud trees bloom. With the unseasonably warm weather last week, gypsy moth eggs began hatching throughout the state," said Herms. "We believe defoliation will be low in northeast Ohio this season, but will continue to increase in the eastern and southeastern parts of the state." According to Ohio Department of Agriculture (ODA) statistics, the gypsy moth has already established itself in nearly half of Ohio's 88 counties, encompassing the uppermost western counties and spreading east through central Ohio to the southern boundaries of Hocking and Athens counties.

The insect feeds on more than 100 species of deciduous and evergreen trees, severely stressing the trees, and in some cases killing them. Oak, which is the dominant tree in forests throughout eastern and southeastern Ohio, is its favorite host.

"Populations will continue to build in those oak forests. The moths are still spreading into new habitats," said Herms. He speculates that the ridge and valley system of the Appalachian foothills will also facilitate rapid increases in population. "Newly hatched larvae will be able to spread faster as wind currents carry them from the tree canopies on the ridges into the valleys below." The ODA will begin gypsy moth suppression treatments starting May 1. Aerial treatments will cover 16,000 acres in Ashland, Belmont, Carroll, Coshocton, Fulton, Guernsey, Harrison, Hancock, Holmes, Knox, Licking, Lorain, Lucas, Muskingum, Ross, Stark, Trumbull, Tuscarawas, Washington, Wayne and Williams counties.

Egg hatch occurs over two to three weeks. Larvae then feed throughout May and June before entering the pupal stage to emerge as adults in July. For more information about ODA's suppression treatments, log on to

Candace Pollock
Dan Herms