EFFECTS OF COLD TEMPERATURES ON HATCHING OF THE FOREST TENT CATERPILLAR, MALACOSOMA DISSTRIA (LEPIDOPTERA: LASIOCAMPIDAE)

Abstract

AbstractEgg masses of the forest tent caterpillar, Malacosoma disstria Hübner, were collected from new and old infestation areas of northern Minnesota before development started in the spring. Mortality of embryos was recorded after laboratory exposure to −10°, −15°, −20°, −25°, and −30° C for 12, 24, and 72 hours at 1, 2, 3, and 4 days before anticipated hatch. Length of treatment and temperatures of −10° and −15°C had minimal effect on survival. Mortality of embryos varied with days before hatch in an erratic cyclic pattern with temperatures and years. Temperature treatments of −20°, −25°, and −30 °C caused about 50%, 66%, and 100% embryo mortality. Mortality in new infestation areas was consistently higher than in older areas for all treatments.