Gypsy Moth Defoliation in Virginia: 2003

Cooperative aerial surveys documented 79,927 acres of defoliation by gypsy moth caterpillars this year, which is roughly 28,000 acres more than in 2002. Seventy percent of the total occurred in Alleghany, Bath and Highland Counties. The great majority of defoliation was only light to moderate because caterpillars were decimated by disease before they completed development. Poor egg hatch was also a factor in some locations. Both viral and fungal diseases occurred, but the fungus, Entomophaga maimaiga, apparently caused most of the population collapse. So far, it appears that there should be very little defoliation by gypsy moth larvae next year.

Frequent storms and persistent clouds made aerial surveys particularly difficult and prolonged. In addition, poor egg hatch, late leaf-out at high elevations, late freeze damage, hail storms, oak anthracnose, larval disease and defoliation by other insects created some confusing circumstances. Near the Peaks of Otter on the Blue Ridge Parkway, for example, most of these factors had at least some effect and a minority of symptoms observed from the air could be attributed to the gypsy moth.

Last modified: Monday, 19-Oct-2009 14:40:41 EDT