Summer 2023 Spongy Moth Update

The spongy moth (Lymantria dispar dispar), formerly known as gypsy moth, is a destructive pest which defoliates and destroys many tree species, especially oak trees.

The spongy moth is an invasive species which originated in Europe and was introduced to the Northeast US in 1869. Spongy moths have been causing significant forest damage in Pennsylvania since the 1970s.

Female spongy moths lay their eggs as light tan egg masses on trees, stones, and flat sheltered areas in the months of June and July. The eggs then hatch the following spring between mid April to early May.

The Pennsylvania Department of Conservation and Natural Resources (DCNR) conducts spraying of spongy moths in State Parks, State Forest Lands, and some forest lands in the Allegheny National Forest were being sprayed this summer, targeting 275 sites covering 290,819 acres. DCNR Spraying Information

DCNR does not spray on private lands. DCNR's Spongy Moth Informational Page offers a number of resources to help private landowners identify and combat spongy moth infestations.

Residents may refer to the following resources for additional information on spongy moths:

Penn State Extension - Preparing for High Spongy Moth Densities

PA Game Commission - Spongy Moth Spraying Information

US Department of Agriculture -  National Invasive Species Information Center (Spongy Moth) 

Centre County Government - Spongy Moth Outlook 2023