A long list of host plants including hickory, dogwood, apple, and rose are attacked by this pest. The azalea caterpillar, on the other hand, confines its feeding mainly to azaleas . . . During periodic outbreaks, all of these types of defoliating caterpillars can cause unsightly damage to ornamental trees and shrubs on which they feed. Several registered insecticides offer quick effective control if they are applied when the caterpillars are small and damage is not yet extensive. For large shade trees, it is essential to engage a commercial arborist with powerful spraying equipment.
Some caterpillars attract attention more from their large size than from the damage they do.
This imperial moth caterpillar will be four inches long when full grown. This monster, known as the hickory horned devil, grows up to six inches long. Despite its ferocious look, it is harmless to man and never occurs in large enough numbers to be considered a pest. There are a few caterpillars that should not be handled because of their stinging spines. Contacting the spines of a saddleback caterpillar is every bit as painful as a bee sting.