If you notice large sections of your azaleas that are virtually stripped of leaves there is a good chance that you have azalea caterpillars. They mostly feed on azaleas but have also been observed on blueberry, apple, red oak, and andromeda.
Young immature caterpillars are small and green and can be found on the underside of leaves. Once they reach approximately ⅜ “ long they will change color into a shade of purple and begin feeding on entire leaves.
The older caterpillars are 2 inches long, hairy, and extremely colorful. They form bright red heads, legs, and tails, and broken longitudinal yellow and/or white stripes. Older caterpillars have a voracious appetite and often consume large areas of foliage before being noticed. Although azalea caterpillars appear menacing they are not harmful. They can easily be plucked by hand or shaken from the branches and trampled underfoot.
Bacillus thuringiensis (B. t.) may be used when the larvae are small. Products including acephate, carbaryl and pyrethrin-based insecticides may also be used. Check the North Carolina Agricultural Chemicals Manual for an up to date list of products labeled for azalea caterpillar management in ornamental landscapes.
If you have any questions about this topic or if you any other horticulture-related questions please contact Chris Blaha by email at firstname.lastname@example.org or by phone at 252-232-2262.