Bionomics of Tufted Apple Bud Moth (Lepidoptera: Tortricidae) in Apple Orchard Ground Cover

Abstract

Tufted apple bud moth, Platynota idaeusalis (Walker), larval movement, host utilization, and spatial and temporal distribution were examined in ground covers of apple orchards in south-central Pennsylvania. Larvae were placed in arenas 0 or 30-50 cm from host material of dandelion, Taraxacum officinale Weber, or fallen apples in the autumn. The number and location of exuvia were recorded in the spring. Survival was greater on dandelion than on fallen apples with neither the distance nor distance by host effects being significant. Larval fitness was measured on apple root suckers; broadleaf weeds; tall fescue, Festuca acundinacea Schreber 'Kentucky 31'; and dead organic matter (fallen leaves and apples). Survival and adult weight were low on dead organic matter. Adult weight was low for larvae caged on tall fescue. Larval density before and after orchard raking and mowing was examined. Raking moved larvae into the tree row middles, although raking and mowing did not cause significant mortality. In a 2-yr orchard survey, larval density declined 85% between autumn and spring samples. Larval distribution in ground cover zones varied by season. In the autumn, most larvae were in the herbicide strip and associated with fallen leaves and root suckers. In the spring, 1/3 of the larvae were located in the border between the herbicide strip and the drive row (tree row middles), and association with fallen leaves was still strong. In the summer, larval distribution was most uniform between zones and larvae were associated with root suckers and broadleaf weeds. Ground cover management tactics are discussed.