OBSERVATIONS ON THE BIONOMICS OF THE DARK-SIDED CUTWORM, EUXOA MESSORIA (LEPIDOPTERA: NOCTUIDAE), IN ONTARIO

Abstract

AbstractThe dark-sided cutworm, Euxoa messoria (Harris), has a North American distribution and is commonly found in tobacco fields in Ontario. It has one generation a year, and overwinters as an egg in the soil. Hatching takes place in early April and the young larvae feed on the rye rotation crop; later they attack newly transplanted tobacco seedlings. Head width measurements of larvae collected from the field show seven instars, but individual rearing data of E. messoria larvae reveal that small numbers pass through six and an occasional larva passes through eight; however, the eighth instar has the same head width as the seventh. Pupation occurs from late July to mid-August in the soil. The adult emerges from mid-August to October, and oviposition occurs in this same period. Eggs are completely developed before winter. Behaviour and duration of the different stages are described. Natural mortality factors of the species are given.