common names: Bark Beetle, Shot Hole Borer
scientific name: Order Coleoptera, family Scolytidae, Scolytus rugulosus
identification: Adult beetles are dark brown to black and blunt on each end. They have well-developed wings. They drill small holes in tree trunks about the size of pencil lead. Larvae are snow white.
biology and life cycle: Adult beetles appear from April through June. Mated females seek out trees that are in somewhat unhealthy or stressed condition. They enter the cambium layer, excavate a gallery, and deposit white eggs. The female usually dies with the tip of her body blocking the entrance to the egg gallery. Young grubs (larvae) hatch and burrow into the inner bark. Their tunnels are full of frass, unlike the clean parent gallery. When fully grown after six to eight weeks, the larvae change into pupae and later into adult beetles. One to three generations a year.
habitat: Apple, peach, pear, plum, cherry, quince, serviceberry, chokeberry, and many other stressed trees.
feeding habits: Eat small holes in the twigs, branches, and trunks of stressed trees.
economic importance: Not much. This is not a serious pest if the soil and trees are managed properly.
natural control: Keep trees healthy by improving the soil.
organic control: Tree Trunk Goop (see Appendix C).
insight: Native to Europe but has naturalized across the United States.