Date: 3/30/99

Time: 10:00

Type: Symposium

Number: 96

Factors contributing to composition of gypsy moth natural enemies in resident and newly established North American forests

*W. Kauffman, Niles Biological Control Lab, USDA-PPQ, Niles, MI 49120
Contact e-mail: pek4@cornell.edu

In 1996 and 1997, we sampled gypsy moth eggs, small larvae and large larvae at 13 forest sites in the Upper Midwest and East Coast to determine the distribution of natural enemies in resident populations of gypsy moth (6 sites in NJ), later established populations (5 sites in MI) and newly established populations (2 sites in NC). The egg parasitoid Ooencyrtus kuvanae was present at all sites. The egg parasitoid Anastatus disparis was present at all NJ sites, present in only 1 site in MI, and absent in NC. At least one larval parasitoid was collected from each site in NJ and MI but none in NC. Cotesia melanoscelus was present at all NJ sites, present at two MI sites, and absent in NC. Compsilura concinnata was present at only 1 site in NJ, present at all MI sites, and absent in NC.Phobocampe disparis was present only at two NJ sites. We also determined the occurrence of nuclear polyhedrosis virus (NPV) and the fungal pathogen Entomophaga maimaiga from these gypsy moth larvae. NPV was present at all sites, whereas Entomophaga maimaiga was present at all sites in NJ and MI but none in NC. Clearly, the parasitoid guild in older, resident populations of gypsy moth has greater species richness and higher abundance compared to later established populations. This disparity may warrant efforts to establish these and other specialized, low host density parasitoids like Ceranthia samarensis in newer gypsy moth populations to effect more stable biological control.

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