Did you Know?Insects are very in tune with specific “scents” that draw them to a potential mate. They use their antennae to “smell” these pheromones that are produced by other individuals to attract them. This has been exploited by humans to help manage certain insect pests by either creating lures for detection or control.
Peach Tree Borer- Fruit tree pest
A pest that attacks Cherry, Plum, Peach, Apricot and other stone fruits.
The best way to detect these pests is to look for the physical signs. These are located often just below the soil grade on the root flare. It can also be slightly higher up on the trunk but this is less common. It appears as an amber to maroon colored, jelly-like mass where the larvae has tunneled into the wood. From April through September, the larvae are often found in that mass or in the soil near the root flare. Other times, 1/4″ holes can be seen, sometimes in series above the root flare where the larvae have tunneled into the tree.
Identification can be easily confused with the amber-colored and often harder ooze on the trunks and limbs caused by Cytospora Canker. This is an entirely different problem resulting from a disease not a pest.
Peach Tree Borer adults fly from Mid-June through September laying eggs throughout their flight period. Females lay eggs on the lower trunk which hatch in about ten days. Eggs hatch into larvae that feed the rest of the warm season on the inner bark of larger roots and the lower trunk. They overwinter in the soil near the trunk and return to tunneling and feeding in the early spring. They continue feeding until they pupate under the soil in May through June. They emerge as adult moths looking more like wasps than moths.
Larvae cause damage by tunneling in the root flare and larger roots. Larvae grow to about 1/4″ diameter before pupating. Occasionally, smaller (6″ DBH or less) trees can be killed in a single season by girdling of the lower trunk from a heavy infestation.
Avoiding the pest through cultural practices is ideal. This includes planting at the proper height (root flare at or just above grade- see http://www.ext.colostate.edu/mg/gardennotes/636.html for more details) and avoiding excess moisture at the root flare. These two practices reduce the likelihood that an individual borer will take hold within the host and increase the overall health of the tree.
If trees show signs of previous infestations, the best management is through a preventative treatment application in early spring and again in mid-summer. Once the larvae are in the trunk, they cannot be controlled with pesticides very easily. A common protective treatment is a permethrin spray.
Not much can be done once larvae have entered the tree. However, carefully inserting a wire into the hole can kill the larvae by piercing it.
Moth Balls can be placed under the soil where borers are known to be and have been effective in killing the larvae under the bark. See CSU Fact Sheet #5.566 for more information on what type and how to apply moth balls.