WOOLLY-BEAR CATERPILLARS OF GRAMMIA BLAKEI (GRT.) (LEPIDOPTERA: ARCTIIDAE) — AN OCCASIONAL PEST OF NATIVE RANGE PASTURES AND ADJACENT CROPS IN SOUTHERN ALBERTA AND SOUTHWESTERN SASKATCHEWAN

Abstract

AbstractThe woolly-bear caterpillars of Grammia (= Apantesis) blakei (Grt.) are sometimes abundant on native range pastures in the short-grass region of southern Alberta and southwestern Saskatchewan and occasionally cause early season damage to adjacent cultivated crops. The larvae overwinter as mid- to late-instars in protected sites on the soil surface and begin feeding in the spring as soon as new plant growth is available. They are general feeders on both mono- and dicotyledonous plants. Larval densities exceeding 10/m2 were found at several locations from 1982 to 1985 and historical records indicate that densities sometimes exceed 50/m2. The moths are present in late May through June but are rarely observed or collected. In Canada the species is univoltine with a mid-larval summer diapause.