Effects of Vegetation Control on Parasitoids of the Nantucket Pine Tip Moth, Rhyacionia frustrana (Lepidoptera: Tortricidae)

The Nantucket pine tip moth (Rhyacionia frustrana (Comstock)) is host to numerous parasitoid species that can cause substantial moth mortality. Little is known regarding the effects of forest management practices on these parasitoids. Abundance of parasitoids and parasitism rates, based on rearing of adult moths and parasitoids, were compared in herbicide-treated and untreated loblolly pine, Pinus taeda L., stands in the southeastern Georgia coastal plain. Three parasitoids, Lixophaga mediocris Aldrich, Eurytoma pini Bugbee, and Hyssopus rhyacioniae Gahan accounted for over 70% of total parasitism. Parasitism rates did not differ significantly between treated and untreated plots. Tip moth damage was higher in the untreated plots. Malaise trapping of parasitoids yielded no significant difference in numbers of tip moth parasitoids or total parasitoids captured in treated and untreated plots, suggesting a functional response of parasitoids to tip moth densities. Higher levels of naturally occurring vegetation did not improve tip moth control through increased parasitism rates.