Department of Agriculture
Cherry Scallop Shell Moth
The cherry scallop shell moth, Hydria prunivorata (Ferguson) is a defoliator of black cherry, and occasionally other native cherries, throughout its range in eastern North America. The moth's name is derived from the pattern of alternating dark and light scalloped lines on the wings. The adults, which emerge from late May to early August, have a wingspread of about 37 mm. After mating, the females lay their eggs in clusters on the underside of cherry leaves. The eggs hatch from July through early August. The young larvae construct a tube-like nest by webbing together leaf margins. They then feed gregariously on the leaf surface within the nest. When the leaf's surface is completely stripped, the larvae move at night to other leaves where they construct a new nest and continue to feed.
Full-grown larvae are about 20 mm long, pale yellow with four brown dorsal longitudinal stripes, and have an orange-brown head capsule. Pupation of most larvae does not occur until they reach the ground, either by descending on silken thread they spin, or falling with the nest when it is dislodged by wind or rain. However, some larvae have also been observed to pupate within the nest before it falls. Pupae overwinter either in leaf litter or just below the soil surface. Only one generation per year has been reported throughout the moth's range.
Attacked foliage exhibits a bright red-brown color as the remaining leaf tissue of the nest dies. When populations are high, the entire crown of the tree may be affected. If severe cherry scallop shell moth damage coincides with, or follows, other stress events (such as drought, a late spring frost, or defoliation by other insects), crown dieback, loss of radial growth or tree mortality may result.
Cherry scallop shell moth populations that remain at epidemic levels for two or more years are usually significantly reduced by an egg-parasitizing wasp of the genus Telenomus.
Photo Credit: John R. Omer and Robert E. Acciavatti