The senior author has seen egg clusters as early as April 7 at Gainesville. Division of Plant Industry records show that larvae have been collected from May to November 14. It seems probable that some larvae appear in April. Adults are diurnal and nocturnal. Damage and Detection Initial symptoms include the appearance of brown, necrotic, skeletonized leaf tissue, resulting from young larvae eating some but not all layers of the leaf.
Later instars devour the leaf, leaving only a few large veins.
Larvae attract attention by feeding in groups, usually side by side in a row. This is the only pertinent lepidopterous insect that feeds in a gregarious manner upon grape foliage. As the larvae of the colony become mature they tend to disperse as isolated individuals or in small groups. Among cultivated grapes, grapeleaf skeletonizer seems to prefer exotic or the more choice and tender varieties. Adults have been collected in Steiner traps several times.