The Overwintering Potential of True Armyworm, Pseudaletia Unipuncta (Lepidoptera: Noctuidae), Populations in Quebec

The true armyworm, Pseudaletia unipuncta (Haw.), has no evident diapausing stage, is not freeze tolerant, shows no consistent seasonal changes in either supercooling-point values or longevity at 0 °C for different developmental stages, and did not survive when held in overwintering cages in the field. These facts support the hypothesis that this species cannot overwinter in Quebec and that the adult populations observed each spring must therefore be the result of a northerly migration from sites, such as Tennessee, where overwintering is known to occur.