Red-Shouldered Bostrichid
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Hosts
Hickory, pecan, persimmon, black locust, oak, redbud, mulberry, elm, Osage-orange, apple, ash, peach, honey-locust, pear, poison sumac, poison ivy, eucalyptus. Hickory, pecan, and persimmon are favored hosts, but the range is diverse, occasionally including conifers and some vines (Beal and others 1952, Fisher 1950)
Range
Eastern half of the United States from Florida north to New York, west to Texas and Kansas and in southeastern Canada (Fisher 1950).
Description
Adult
Brownish black to dark reddish brown beetle with basal half of elytra reddish to brownish yellow, 3.3 to 7.0 mm long and 1.5 to 2.5 mm wide (Beal and others 1952, Fisher 1950, Gill 1924). Wing covers taper to oblique angle at posterior end, edges armed with three conspicuous teeth on each side. Antennae, palpi, and tarsi brownish yellow.
Larva
Yellowish white, wrinkled, C-shaped, 5 to 6 mm long. Small globular head with mouthparts extending forward. Thorax, and especially prothorax, greatly enlarged with three pairs of conspicuous legs.
Pupa
Pale yellow (Lugger 1899).
Biology
Adults emerge during summer and fly in search of suitable host trees, where they bore through the bark and into the sapwood (Gill 1924, Lugger 1899). Adult tunnels are constructed across the grain just under the bark surface in sapwood. Tunnels may girdle limbs and trunks of small diameter. Eggs are deposited at intervals along the sides of tunnels. Larvae feed mostly in sapwood and to some extent in heartwood, tunneling parallel to the grain. They spend winter in galleries, mostly as mature larvae, but sometimes as pupae or adults. Adults often bore into healthy twigs for food and shelter and commonly spend the fall, winter, and spring in galleries within twigs and branches. A generation can develop in 1 year under optimum conditions, but longer periods are sometimes required.
Injury and Damage
Stressed, dying, and recently dead trees are most susceptible to attack (Beal and others 1952, Gill 1924, Moznette and others 1931). Branches that fail to bud in spring and flagged branches having withered and brown leaves, along with girdled and fallen branches, are good indicators of infestation. Inspection of such branches reveals one round entrance hole 2 to 3 mm in diameter adjacent to one or more buds or leaf scars. Branches are easily broken at these sites because they have been partially to completely girdled beneath the bark. Emerging beetles leave many 2- to 3-mm round exit holes that give the appearance of shotholes (Gill 1924). Dissection of infested branches reveals numerous parallel galleries filled with very fine, powderlike frass. The round frass-packed galleries are most characteristic when viewed in cross section. Infested trees cut for use as wood products can be quickly destroyed if not processed promptly. These insects may cause some twig dieback and possibly hasten the death of trees already stressed or dying from other causes, but the threat to healthy trees is minimal.
Control
Natural control includes four species of hymenopterous parasites--Bephratoides n. sp., Ecphylus flavus Marsh, Glyptodoryctes caryae (Ashmead), Wroughtonia ferruginea (Brues), and an unidentified dipteron (Beal and others 1952, Burks 1979, Marsh 1979). Because borers present little threat to healthy well-kept trees, good cultural practices should be followed to maintain tree vigor (Moznette and others 1931). Sources of infestation can be eliminated by promptly removing and destroying all dead and dying twigs, branches, and prunings. Any dying or dead trees to be used for wood products should be processed promptly with assurance that boards do not contain wane edges with bark that encourage beetle attack.
References
Solomon, J.D. 1995. Guide to insect borers of North American broadleaf trees and shrubs. Argic. Handbk. 706. Washington, DC: U.S. Department of Agriculture, Forest Service. 735 p.
