email: uge1067@arches.uga.edu

ORANGE STRIPED OAKWORM

IDENTIFICATION:  Mature larvae (caterpillar) are 1-1/2” long.  They are black with eight orange to yellow stripes and a row of large yellow spots below the last lateral stripe.  The underside is yellow. The head is jet black and the segment just behind the head is bright orange-yellow.  The second segment behind the head has two long, slender, black horns and smaller black spines along the body. Disturbed larvae bend into a distinctive U-shape.

When the caterpillar is fully grown it crawls from trees and burrows three to four inches into the soil to pupate and overwinter.  Moths appear in early summer.  The adult moth is 1-1/4” long with wings closed. They are reddish brown, translucent with a submarginal dark stripe and a white spot on each forewing.  Over a period of a month the female will deposit up to 500 eggs in a single cluster on the underside of an oak leaf, usually on the lower branches.  The newly hatched larvae are greenish yellow. There are approximately two generations a year in Georgia. 

HOST PLANTS:  Prefers white oaks, but also feeds on maple, hickory, birch and hazelnut.

DAMAGE:  Young caterpillars feed by skeletonizing the leaf surface.  Older caterpillars are defoliators and may consume all but the leaf midrib.  Defoliation usually occurs one branch at a time when populations are small.

MONITORING:  Look for signs of localized skeletonization turning to defoliation on host tree branches.

CONTROL:  Manually destroy aggregations of young larvae when detected on small trees.  An application of Bacillus thuringiensis (Thuricide) or horticultural oil will control young larvae. Damage is seldom widespread and chemical control is rarely needed.

COMMENTS:   Harmless.  No stingers.

The University of Georgia and Ft. Valley State University, the U.S. Department of Agriculture and counties of the state cooperating. The Cooperative Extension Service offers educational programs, assistance and materials to all people without regard to race, color, national origin, age, sex or disability.