PEACH TREE BORER

Description: Peach tree borer is one of the most serious pests to stone fruit trees in Utah. The borer most commonly infests peaches, but can also get into cherries, apricots, and plums. Mature borers look similar to black wasps, and their eggs hatch from late June to early September. As soon as they hatch they begin to feed just under the bark of the trunk and on the roots of the tree. They will feed until it gets cold in the fall, and then go dormant for the winter. In the spring, they will continue to feed, mature, and lay their eggs that will become the next generation of borers.

Symptoms: One of the surest signs that a tree has peach tree borer is seeing clear sap running from the trunk of the tree. If the sap has a cloudy appearance or is off-colored, there is a possibility that the tree has a different disease. Other things to look for are sawdust around the base of the trunk, and shed pupa skin from the borers. If a tree has a bad infestation, whole sections of the tree may be dead.

Control: The easiest way to control peach tree borer is to maintain healthy trees through proper watering and pruning. Borers like to enter a tree through open wounds, so be sure that weed eaters, mowers, or other mechanical devices do not damage the trunk of the tree. Wrapping the trunk of a tree in the winter with white tree tape is also beneficial because it helps prevent sun damage to the trunk.

Once borers are in the trunk they are very difficult to control. It is better to prevent them from ever getting into the tree. The best time to spray for them is when the adults are laying their eggs. This occurs in Northern Utah, during the months of July and August. During this period, apply an approved pesticide to the trunk of the tree and to the soil around the base of the tree. Application rates and times vary with different types of pesticides. Speak to nursery employees or a county extension agent for specific times to apply a pesticide and what pesticide to use for borer control.