Pest description and crop damage Large white grub (1 to 3 inches), bores holes 0.5 inch in diameter in trunk and main branches, and eventually kills trees. Adult moth, which is speckled gray, causes no damage. Three-year life cycle.
Keep trees vigorous.
Apply to major branches and trunk; to trunk and crown of small trees. Apply in early June and in 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).