A brush is sometimes useful for mechanically rubbing the insects off. Check trunk and rough branch areas of white pines for cottony white flecks of pine bark adelgid. Plan horticultural oil treatment if needed. Prune or peel off and destroy tent caterpillar egg masses. Favorite hosts include cherry, crabapple and apple.
Damaged tips are brown and hollow in the center from the feeding of the caterpillars.
On trees, shrubs, fruiting bushes and vines, prune off and destroy cankered twigs and any branches showing dieback. Prune shortly before budbreak, or wait until just after leaves have expanded. Landscape fabric can also be used as a barrier underneath mulch. Where plants have a history of infestation, apply horticultural oil treatments to control spider mites on evergreens such as hollies and spruces and on certain other trees, shrubs and vines, including apple, honeylocust and grape. You may be able to see the tiny red eggs of these mites on twigs or bud scales with a hand lens.