Monitoring and Temperature-Based Prediction of the Whitemarked Tussock Moth (Lepidoptera: Lymantriidae) in Blueberry

Abstract

Larvae of the whitemarked tussock moth, Orgyia leucostigma (J.E. Smith) (Lepidoptera: Lymantriidae), defoliate and contaminate blueberries, Vaccinium corymbosum L., in eastern North America, but infestations are often not detected until economic damage has been caused. To improve monitoring techniques and understand the phenology of the whitemarked tussock moth in blueberry, we compared four trap types and determined temperature-based phenology of this pest over two growing seasons. Large delta traps captured the greatest number of male moths, and similar moth captures were found with or without monthly lure changing. Traps placed at field perimeters adjacent to woods trapped significantly more moths than those inside fields, whereas position in the canopy (high versus low) did not affect captures. Under laboratory conditions, the lower developmental threshold for larvae was 12.3 degrees C, in close agreement with field studies indicating a 12.8 degrees C threshold. Using the 12.8 degrees C threshold, monitoring of O. leucostigma cohorts on caged blueberry plants revealed a spring generation with egg hatch starting at 206 +/- 3 growing degree-days (GDD) and a late-summer generation with egg hatch starting at 1,157 +/- 52 GDD. Combined use of optimized monitoring methods and the phenology model for O. leucostigma is expected to improve integrated management of this pest in blueberry.