Problem Identifier Unit Screen//v.w/ RR Template

Problem Identifier Unit Screen//v.w/ RR Template Flatheaded Borers

Problem
Leaves wilt and turn brown. Patches of bark on the trunk are sunken, discolored, and may be soaked with sap. There may be holes about 3/8 inch in diameter in the affected bark. Sawdust-filled tunnels in the wood may contain yellowish white, flat-headed grubs about ¾ inch long. In late spring to midsummer, bronze or copper-colored beetles ½ to ¾ inch long may be seen feeding on the foliage. Newly planted or weak trees are most severely affected.

Analysis
(Chrysobothris species)

In addition to damaging apples, these insects attack many other trees and shrubs. In late spring to midsummer, the females begin to lay eggs in crevices in the bark. The emerging larvae bore through the bark into the outer layer of wood, creating winding tunnels. These tunnels damage the nutrient and water-conducting vessels in the tree, causing twig and branch dieback and sometimes killing the tree. The mature larvae bore deep into the heartwood to pupate; adult beetles emerge the following spring. Newly transplanted, weakened, and diseased trees are most susceptible to borer infestation.

Solution
Apply an insecticide containing lindane according to label directions. Keep your tree healthy and vigorous by watering, fertilizing, and pruning it properly. For more cultural information, see Apple. Discourage borer infestation by wrapping the trunk soon after bloom with tree-wrapping paper or burlap. Prune out and destroy infested branches.

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