Fruits Affected

Peach, Plum, Nectarine, Cherry, Apricot

Also See

Both peach tree borer and lesser peach tree borer are caterpillars of clearwing moths (Lepidotera: Sesiidae). These pests are extremely destructive to all types of stone fruit tree, as they feed on the cambium (inner bark) of the tree, which is essential to the tree's growth and health.

Symptoms

Visible holes or damaged areas in tree bark that ooze gum.

Organic Treatments

Limit the chance of borers in your trees by removing nearby wild trees that might be infested, and being careful not to damage your trees. The best solution is to use Isomate PTB dual mating disruption ties.

Conventional Treatments

Same as organic treatments.

Insect Cycle

Both peach tree borer and lesser peach tree borer are caterpillars of clearwing moths (Lepidotera: Sesiidae). These pests are extremely destructive to all types of stone fruit tree, as they feed on the cambium (inner bark) of the tree, which is essential to the tree's growth and health. The larvae overwinter in the cambium, emerging as adults from mid-June to early September (PTB) or May-September (LPTB). They begin breeding at once, and soon after emergence females will start laying eggs, up to 400 each. Hatched larvae tunnel into the bark until the following spring.

PTB live in the trunk of the tree, from a few inches above the soil line to six inches below, while LPTB can be found in any part of the trunk or on major branches. The lesser borer, unlike its colleague, requires a wound or other damage, such as a canker, in order to enter the tree. The adult insects of both pests actually look more like wasps than moths. The LPTB is about 1/2 inch long and its narrow abdomen is metallic blue-black with yellow bands. The PTB differs mainly in that the female has wide, orange bands rather than narrow, yellow ones. An infestation of PTB is often identifiable from the oozing gum around the base of a tree. This gum may be mixed with dirt and frass (excrement), and empty cocoons may also be found at the base of a tree. Similarly, the LPTB will create an oozing hole in a preexisting wound, and cocoons may be found nearby. If you think you have an active borer, you should be able to cut away the bark and find the caterpillar beneath. Because it infests the base of a tree, one or two PTB are enough to weaken a tree and it only takes a handful to outright kill it.

For more information, see the Utah State University Factsheet on Greater Peachtree Borer and the University of Missouri Factsheet on Insect Borers of Fruit Trees.