Gypsy Moth Defoliation in Virginia: 2002

Total defoliation by gypsy moth caterpillars declined substantially from more than 440,000 acres in 2001 to just over 51,000 acres this year. The decrease resulted from a combination of adverse weather during egg hatch, larval disease and an effective cooperative suppression program.

The greatest change was in northern Virginia. Total defoliation decreased dramatically in most counties and a majority of what occurred was only moderate in severity. Light defoliation is not mapped. Page County was somewhat exceptional in having about the same amount of defoliation this year as last, although much of it was in different locations.Click here to enlarge the map.

Central mountain counties sustained the greatest impact, both in acres and severity. Despite the prevalence of larval disease, a significant percentage of the population completed development. There are plenty of egg masses present to pose the threat of heavy defoliation again next spring in some of these areas. Much hinges on weather and the incidence of disease.

Elsewhere, gypsy moth activity was not greatly different from last year. Small, local infestations were scattered across the Piedmont and into the Coastal Plain. Individual and small groups of trees were defoliated, but none of the affected areas was large or severe enough to be mapped from the air. Larval disease was present in varying degrees. The possibility of a noticeable increase remains, but extensive defoliation is still unlikely to occur in these locations next spring.