Though the name might cause some confusion, peach tree borers create devastating infestations on plum trees. Since plum tree bugs can have a fast and significant effect on tree health, familiarize yourself with borers, what to look for on trees, and reliable control methods. Provide proper care to your plum trees to increase your chances of regaining health from a bug infestation.
Peach tree borers are white or cream in color in their larval stage, displaying a brownish head that may appear yellow or very dark, according to the University of Rhode Island Landscape Horticulture Program. Larvae begin at 1/16 inch in length and grow just beyond 1 inch. In their adult form, peach tree borers resemble wasps; with clear wings, males are blue- and yellow-striped while female bodies are blue with an orange stripe. The male wingspan measures 1 1/8 inches across while the female wingspan is 1 1/2 inches.
From July through October, adult peach tree borers mate and females lay up to 800 eggs on host plants, particularly on damaged trees. In the middle of July, eggs hatch and larvae push their way into the bark of the plum tree through any available openings, according to the University of Rhode Island Landscape Horticulture Program. Wounds from improper pruning present an ideal entrance for this plum tree bug.
Symptoms and Damage
Larvae feed on the tissue called the cambium that grows between the wood and the bark of the plum tree, according to the University of Rhode Island Landscape Horticulture Program. Larvae remain near the base of the tree close to the soil line and also feed on substantially sized roots. Look for areas with gummy substances oozing from bark or spots that appear saturated with liquid, according to the Colorado State University Extension. Damage often includes death of young trees and severe decline of more established trees.
To prevent the occurrence of a plum tree bug infestation, apply insecticides to the plum tree when adults are laying eggs during the middle of the growing season; effective control chemicals include insecticides with the active ingredient permethrin or carbaryl, according to the Colorado State University Extension. If insecticides are not available for home use, contact a licensed professional for a treatment program. A suggested application schedule includes a spray in the beginning of July followed by a second spray in August.
If your plum tree is already under attack by peach tree borers, first collect and destroy fallen plant parts from around the base of the tree, according to the Colorado State University Extension. A gas-releasing fumigant called paradichlorobenzene, referred to as PDB, kills plum tree bugs within the trunk. During the end of September through the end of spring, depending on borer activity in your region, apply a ring of PDB crystals around the trunk of the tree leaving approximately 2 inches between the ring and the tree base and cover the ring with a compact soil application to a height of 10 inches. Leave this ring for three weeks and then remove the soil. PDB injures trees on contact, so apply with extreme caution.