Description
The uglynest caterpillar (Archips cerasivorana) gets its name from the unsightly silken nests it forms on the ends of branches. The nests are built around several small stems and are filled with pieces of dead leaves and black droppings from the caterpillars. Inside the webbing are numerous yellowish green caterpillars with shiny black heads. Uglynest caterpillars feed on the foliage of a variety of trees and shrubs including cherry, hawthorn, and rose, but they are seldom abundant enough to cause any lasting damage to their hosts. Other caterpillars that form webs or tents and are sometimes confused with the uglynest caterpillar include the fall webworm, which produces lighter, gauzier webs; tent caterpillars, which form silken tents at the branch crotches; and the mimosa webworm, which only attacks mimosa and honeylocust. The caterpillars feed from late spring through the summer, when they form pupae within their nests. The adult moths emerge from July to September. They are dull orange with a wingspread of just under 1 inch.
Control
Prune out and destroy the webbed portions of branches, or spray with an insecticide containing diazinon or carbaryl when the webs are first seen. Use an insecticide containing acephate on the oak webworm, a similar species. Make sure your plant is listed on the product label. Apply the spray at a high pressure to force it into the webs and improve control.
