Pest description and crop damage Large white larva (1 to 3 inches) bores 0.5-inch-diameter holes in trunk and main branches and eventually kills trees. Adult moth is speckled gray. Three-year life cycle.
Keep trees vigorous.
Apply preventive spray to major branches and trunk as well as to crown of small trees. Apply in early June and early July.
For more information
Johnson, W.T. and H.H. Lyon (1991), Insects That Feed on Trees and Shrubs, 2nd ed., Cornell University Press (p. 256).