Appearance times Larvae begin to feed in April and continue to feed until pupation in May to early June. There is one generation per year. Natural enemies Five or possibly six species of wasp parasites have been recorded for army cutworm in Canada, mostly from Alberta. The egg produces multiple embryos from which over a thousand offspring may be produced. Sixty per cent or more of army cutworm larvae were parasitized by this organism during an outbreak in Alberta in 1990.
Damage can be of any severity up to complete defoliation.
In severe infestations, the area defoliated has ranged from an individual field to thousands of acres with larval densities of up to 200 per square metre. The first signs of damage are holes in leaves and semi-circular notches eaten from the edges of leaves. Army cutworm moths have been monitored in southern Alberta with pheromone traps since 1978. Sample larvae as for other subterranean cutworm species. Mark an area of soil 50 cm by 50 cm.