Effects of Competing Vegetation on Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) Populations in Loblolly Pine Plantations in Arkansas 1

Abstract

The effects of vegetation on the abundance of the Nantucket pine tip moth, Rhyacionia frustrana (Comstock) (Lepidoptera: Tortricidae), and its parasites, were examined in three 2.25-ha plots with low, medium, and high levels of vegetation density in 3-year-old loblolly pine plantations. Pine tips apparently infested with late-instar larvae and pupae were monitored in each tip moth generation to estimate abundance of tip moth and natural enemies within the plots. Differences in vegetation levels between the three plots were apparently not a major factor in determining tip moth population levels. A significant but predictively weak linear relationship was detected between tip moth density and total tips available for oviposition on the tree. Utilization of available tips was highly variable, and the abundance of available tips did not appear to be a limiting factor to tip moth population growth in this study. Six species comprised 89% of the total parasite complex. Percent parasitism was not consistently different or predictable through time between plots with different vegetation levels. Regression analysis suggested that neither a direct nor delayed density dependent-relationship existed between tip moth and its parasite complex.