The Bug Box: Redhumped caterpillar

Peter J. Bryant

Peter J. Bryant

This bug is creeping around your property. He may be friend or foe.

Name: Schizura concinna

Alias: Redhumped caterpillar. This pest has caused problems in the county from time to time. The rather unique caterpillar grows to about 1½ inches long with a base color of yellow. The body has longitudinal white, reddish-brown or sometimes black stripes. The head is usually orange or brick red, along with the fourth segment of the body, which also has two prominent, black spines. The caterpillar rests with its hind legs elevated. After maturing, the it drops to the ground in the fall and spins a cocoon where it spends the winter. Moths emerge in the spring and mate. Adult moths have a wing span of 1 to 1⅜ inches. The forewings are reddish to gray-brown and often are darkest along the hind margin. The hind wings are off white to light gray or brown. Each female may lay more than 200 eggs. After the eggs hatch, the small caterpillars begin feeding. There may be more than one generation a year. Redhumped caterpillars seem to be more numerous after a warm winter.

Crimes: This pest attacks several different plants including plum, walnut and sweet gum trees, as well as almond, apple, apricot, birch, cherry, cottonwood, pear, prune, redbud, willow and others. Their feeding produces skeletonized leaves.

Redeeming Qualities: None known.

Sentence: There are a number of natural controls that keep this pest to manageable numbers, but at times populations can get out of hand. If they are found when young, the branch they are on can be cut off and the caterpillars can be burned or crushed. If a tree has been badly damaged, it will probably be able to overcome the damage unless it happens two or three years in a row. There are insecticides that are effective in controlling this pest.

For more information on dangerous and beneficial bugs, call agent Wayne Jones at the Bonneville County Extension Office at 208-529-1390.