Larva - The partly grown larva (caterpillar) is approximately 10 mm long and reddish to brownish black with white and yellow stripes. The mature caterpillar is about 50 mm long and black with eight near-white, longitudinal, broken stripes; the head and legs are mahogany red (Color Plate 1C).
Host Plants - An important pest of azaleas, azalea caterpillars have also been reported on blueberry in Delaware, on red oak in Maryland, and occasionally on Andromeda and apple in Atlantic states.
Damage - Often the caterpillars defoliate much of the plant before they are detected.
Life History - The azalea caterpillar is gregarious, feeding in groups; all members raise head and posterior in unison when disturbed. Comparatively little is known about the biology of this insect. Apparently there is only one generation per year. Eggs are deposited by the female moth in masses of 80 to 100 on the underside of the leaf. The first-instar caterpillars feed in a cluster side by side unless disturbed. Most of the damage occurs in August and September.
Because the caterpillar is harmless to humans, it can be removed by hand. For specific chemical controls, see the current state extension service recommendations.
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