Monday, March 28, 2016

Shot Hole Borer Control in Fruit Trees

Shot hole borers are tinny reddish-black to brown beetles that attack most pome fruit trees like apples and pears and stone fruit trees like cherries, peaches, nectarines, plums, and apricots.

Identifying this pest is difficult because of their small size and their illusive life cycle. Adult shot hole borers are approximately 2 mm in length and they lay their eggs in tunnels that they create under your fruit tree's bark. The larva hatch and continue feeding on the cambium layer between the bark and the sapwood. Once the larva matures it pupates and then emerges from beneath the surface of the bark leaving small pin holes throughout your tree. Because of their numbers, their exit holes make your fruit trees that are infested appear to have been hit by a shot gun. The exit holes on your fruit tree's bark is the only way to know if your trees are being attacked by shot hole borers. Once they are identified by their exit holes the damage has already been done.

Exit Holes Signify Shot Hole Borer Activity
Shot Hole Borer Exit Holes are Approximately 1 mm in Diameter
Large infestations of shot hole borers can kill a fruit tree when the feeding larva girdles your trees. When the cambium is eaten around the entire circumference of the trunk, this leaves your fruit tree unable to recover from this pest's destructive feeding habits. Shot hole borers can have two generations in one season and branches or trees with large numbers of exit holes should be removed in order to prevent this pest from attacking other healthy trees on their second generation.

Shot Hole Borer Galleries Can Girdle Mature Fruit Trees
Trees that are under stress are more susceptible to shot hole borers. The best way to prevent shot hole borers from infesting your fruit trees is by using good cultural practices. Make sure your fruit tree is planted in a location in your garden where it can receive full sun. Prune your fruit trees every year to improve light and air flow. Avoid drought conditions by regular, consistent watering, mulching, and fertilization. A healthy fruit tree can thwart shot hole borers efforts to enter your tree through the bark and will allow fruit trees with shot hole damage to recover quickly and heal from this pest so that it will not be girdled by the feeding larva.
Shot Hole Borers Can Kill Mature Fruit Trees That Are Under Stress

For any questions regarding shot hole borers, fruit tree pest control, or other fruit tree care and pruning practices please comment below or email me at

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