Apple ermine moth
Yponomeuta malinellus
14 host plants
Last updated
In late spring you will notice white silken webbing on serviceberry or native crabapple branches, with small dark caterpillars visible inside tents. These caterpillars strip leaves within webs, leaving skeletonized foliage and unsightly silk webbing. Look for tents in April and May.
Remove silk tents by hand while caterpillars remain inside; simply prune branch tips and dispose of webbing. Pruning eliminates the problem entirely and avoids pesticide use. If you miss larval stage, damaged foliage typically drops and branches regrow with fresh leaves by mid-summer. Cosmetic pest with no long-term impact on tree health.
Quick Reference
The apple ermine moth is an imported pest which feeds exclusively on apples. The adult moth has silver-white wings spotted with black. Larvae are gray, cream-colored, or greenish with dark spots along the sides. They may reach 3⁄4" long at maturity. Young larvae feed on developing leaves, mining out leaf tissues. They later move into the foliage and feed as tent caterpillars. Several leaves are tied together with webbing to make nests up to 3" across. Each nest contains several caterpillars. New nests are made as leaves in old ones are consumed. The caterpillars pupate in clusters within webbi
Cultural Controls
- -cultural control Pick off or prune out any egg masses observed on the bark in the fall.
- Prune out and destroy nests (in May) when practical.
- Also remove any pupating clusters when noticed.
- Management-