Gypsy Moths Active in 2005

There have been isolated outbreaks of gypsy moth activity in eastern Connecticut in June 2005, with heavy defoliation of white oaks occurring in some locations. Some white pines have had their needles clipped by the caterpillars. Roadside surveys by plant inspectors at the Connecticut Agricultural Experiment Station indicate gypsy moth caterpillars are abundant from Guilford to Waterford and appear centered in the East Haddam area. A larger number of gypsy moth egg masses were detected in this area in 2004. No gypsy moth activity has been detected or reported in western Connecticut. Aerial surveys will be conducted in July to delineate the extent of defoliation this year.

While noticeable, the heavy gypsy moth activity shouldn’t mark a return to the years of widespread gypsy moth defoliations. Our scientists suspect that relatively dry weather conditions were not ideal for the gypsy moth fungus, Entomopaga maimaiga, which was discovered killing gypsy moth caterpillars by Experiment Station scientists in 1989. It may be that in going from a cool moist May to a hot dry June this year, little precipitation was available at the right time for the fungus to infect gypsy moth larvae (caterpillars). Little fungal activity has been observed this year. Since the resting spores of the fungus can survive for seven to ten years, the fungus should continue to suppress the gypsy moth in future years if there is sufficient rainfall during late May and June. However, the fungus is not expected to prevent all outbreaks and hot spots will continue to occur. Trees should recover from this single defoliation. If there are questions or comments, please call Dr. Kirby Stafford at (203) 974-8485.

6/23/05