Saltmarsh Caterpillar (Estigmene acrea)

Introduction

The saltmarsh caterpillar is native to North American and can be commonly found throughout the United States, Central America and the Canadian provinces of Quebec and Ontario. In the United States, it is most commonly a pest in southern and southwestern states. It has a fairly wide host range including asparagus, bean, cotton, soybean, alfalfa, cabbage, beet, clover, carrot, tobacco and tomato. It also feeds on a wide range of weed hosts, but seems to prefer pigweed.

Saltmarsh caterpillar overwinter as hairy pupae in debris on the ground. Adults emerge in the spring. Eggs are deposited in clusters on the underside of leaves. Larvae hatch and begin feeding in mass. Feeding of young larvae frequently results in skeletonization of leaf tissue. Older larvae will disperse to find food. Large holes in leaf tissue are signs of damage from older larvae. Consumption of leaf tissue doubles with each instar.

	Image courtesy of Dan Mott and Jack Bacheler NCSU.

Saltmarsh caterpillar is frequently parasitized by tachinids and many other parasitoids. Insecticides are also effective, but broad-spectrum products should be avoided in the spring to preserve the beneficial population as long as possible. Intrepid^® insecticide is an effective chemical control.

Identification

Adult saltmarsh caterpillars are bright white moths with freckled black spots on the wings. The hindwings of females are yellow only on the underside, while males' hindwings are yellow on both top and bottom. Larvae are very hairy and may be yellow, brown or black with yellow stripes. Mature larvae can be up to two inches long.