THE WINTER MOTH, OPEROPHTERA BRUMATA (LEPIDOPTERA: GEOMETRIDAE), A NEW PEST ATTACKING APPLE ORCHARDS IN NOVA SCOTIA, AND ITS COLDHARDINESS

Abstract

The winter moth, Operophtera brumata(L.), a recent introduction to North America, is a serious pest of apple in Nova Scotia. Natural controls, mainly the parasite Cyzenis albicans(Fall.), reduce its rate of increase, and selective chemical controls are applied to maintain economic levels. Its maximum density is limited by its food supply in neglected orchards. The mean freezing point of O. brumatawinter eggs is −31°F. Egg mortality increases appreciably with increase of duration of exposure to low temperatures in the −26°F to −34°F vulnerable range. It seems probable that winter moth will continue to spread slowly over much of Eastern North America.