Gypsy Moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), Egg Eclosion: Degree-day Accumulation1

Publisher Website
Google Scholar
Abstract
Twenty-five gypsy moth, Lymnntria dispar (L.) (Lepidoptera:Lymantriidae), egg masses were sampled at ca. 10-day intervals from 11 February 1980 to initial field eclosion in May 1980. Samples were dehaired and classified as nonfertile, fertile, or parasitized, and fertile eggs were reared under constant conditions (24.5°C, 45% relative humidity [RH], 14-h photoperiod) until hatching was complete. Number hatched, duration of hatch, days to initial, median, and final hatch, and percent hatch were recorded. A degree-day (°D) accumulation model based on a modified sine wave approximation to temperatures recorded at a weather station ca. 2 km south of the study site fit the data well. A threshold of 3°C produced a model predicting egg mass eclosion at 282 ± 29°D(x ± Sx), with 95% confidence limits of 277 and 287 °D. Validation studies of the model against field eclosion of egg masses at the study site in 1980 and 1981 resulted in an excellent fit, but initial eclosion on the study site in 1982 occurred earlier than expected.

This publication has 0 references indexed in Scilit: