Identification

• The eggs of the moth are light yellow before changing to a dark red in the span of approximately two weeks, then fade to a gray that makes them difficult to see within the bark of the apple tree. The larval caterpillar measures approximately 3/4 inch in length and takes on a green, gray or cream color with dark spots dotting its body. Upon reaching maturity, the adult apple ermine moth shows off silver wings with tiny, black spots.
  
  

Life Cycle

• The female moth deposits eggs in the bark of the apple tree during summer and the emerging larvae of the apple ermine moth overwinter in the tree, feeding on the bark before emerging in the spring and moving on to the foliage. Large numbers of the larvae build communal webs that serve as a protective covering. These webs can grow nearly as large as a human fist, often with several of the structures dotting the tree. The larvae begin to pupate in June inside cocoons that hang within the webs.
  
  

Management

• Pheromone-based traps are available to help capture the moth and reduce the number of eggs that it deposits. These should be placed shoulder high in the tree and the bait replaced every 14 days or, in extremely hot weather, more frequently. In smaller trees, hand removal of the webs and tents is an option to capture and destroy the larvae and pupae of the pest before they begin to feed on the leaves of the apple tree. Encourage the presence of flies, birds and spiders as they are natural predators of the apple ermine moth.
  
  

Considerations

• Because of the manner in which they build webs and cocoons, the apple ermine moth is often confused with two separate species: the fall webworm and the tent caterpillar. However, nests of the fall webworm are larger and occur later in the summer, while tent caterpillars tend to build their silky residences on the limbs and trunk of a tree, rather than the leaves. The webbing of the apple ermine moth is not as dense or thick as that of other similar insects.