Life History and Habits of the Elm Spanworm, Ennomos subsignarius, in the Southern Appalachian Mountains (Lepidoptera: Geometridae)1

Abstract

The elm spanworm, Ennomos subsignarius (Hubner), is a hardwood defoliator, currently epidemic in the southern Appalachian Mountains. Observations on the life history and habits were obtained during 1961 and 1962 to facilitate proper timing of aerial spray programs in Western North Carolina. Eggs are laid in early July and the winter is passed in the egg stage. Hatching occurs in late April or early May, and the larvae feed for approximately 1½ months. Pupation occurs in a loose cocoon between leaves in mid-June, and adults emerge in early July. There is 1 generation a year. Descriptions of the immature stages and short notes on natural enemies are also presented.