Hickory horned devils are impressive pea green to blue green caterpillars that are 4 to 5 inches long when full grown. They have two pairs of yellow to orange curved horns just behind the head and paired rows of spines down the back. These caterpillars will lash around when disturbed but are not dangerous. HHD are present from July to September. They spend the winter as pupae in the soil. These caterpillars eat a lot of leaf tissue but only pose a threat to small trees. They are rarely numerous enough to defoliate medium to large trees.
HHD can feed on butternut, ash, sweet gum, and persimmon. Photo: Daniel Herms, The Ohio State University, Bugwood.org
At its largest, the Redhumped caterpillar is 1-1.5 inches long. The head and first abdominal segment are red, the rest of the body is yellow with black and white stripes. Black tubercles extend from the back. These caterpillars initially feed as a group on a single leaf, skeletonizing it, and use a collective warning display to ward off predators. As they grow, they will spread out as individuals and consume entire leaves. Mature larvae overwinter in the soil and pupate in the spring. Adults fly from June till July and caterpillars feed July to September. Photo © 2006 Tom Murray Fall cankerworm is a looper caterpillar that can vary from light green with yellow stripes to green with a dark stripe down the back. Over-wintering masses of about 100 eggs hatch in later April or early May; small caterpillars chew small holes in young leaves at branch tips. Larger loopers leave only the midrib and major veins. Fall cankerworms are about an inch long when full grown. Mature larvae descend from trees on silk threads to pupate in the soil. They emerge as adults during periods of freezing temperatures to mate and lay eggs on host plants. There is one generation each year. Photo: A. Steven Munson, USDA Forest Service, Bugwood.org Yellownecked caterpillars are black caterpillars with thin longitudinal yellow stripes and some fine white hairs. The head is black and a plate just behind the head is yellow-orange. Eggs are laid in clusters of about 100 so there may be many individuals on a single tree. YNC caterpillars feed for about 4 weeks and tend to remain together. Mature larvae are about 2 inches long. Most of the damage is done in August and September. These caterpillars also feed on oak and other hardwoods. YNC overwinters in the soil as pupae. Photo: Gerald J. Lenhard, Louisiana State Univ., Bugwood.org
Fall cankerworm is a looper caterpillar that can vary from light green with yellow stripes to green with a dark stripe down the back. Over-wintering masses of about 100 eggs hatch in later April or early May; small caterpillars chew small holes in young leaves at branch tips. Larger loopers leave only the midrib and major veins. Fall cankerworms are about an inch long when full grown. Mature larvae descend from trees on silk threads to pupate in the soil. They emerge as adults during periods of freezing temperatures to mate and lay eggs on host plants. There is one generation each year. Photo: A. Steven Munson, USDA Forest Service, Bugwood.org
Yellownecked caterpillars are black caterpillars with thin longitudinal yellow stripes and some fine white hairs. The head is black and a plate just behind the head is yellow-orange. Eggs are laid in clusters of about 100 so there may be many individuals on a single tree. YNC caterpillars feed for about 4 weeks and tend to remain together. Mature larvae are about 2 inches long. Most of the damage is done in August and September. These caterpillars also feed on oak and other hardwoods. YNC overwinters in the soil as pupae. Photo: Gerald J. Lenhard, Louisiana State Univ., Bugwood.org
Leafhoppers are small, active insects that live on the underside of the leaves. They use sucking mouthparts to feed on plant sap. Usually large numbers are present by the time the injury is obvious. Heavily damaged leaves may drop early but this insect usually does not cause serious problems. Photo: Whitney Cranshaw, Colorado State U., Bugwood.org