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Size: |
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Adults can be 1/16-1 inch (2-24 mm); one western species is 2 inches (52mm) long. Mature larvae are 1/4-3/8 inch (5-8mm) long. |
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Characteristics: |
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Most species are long and cylinder shaped, with rasp-like teeth and heads pointed downward, so not easy to see from above. Some species have flat bodies, no rasp-like teeth, and heads easy to see from above; antennal club has 3-4 segments, often enlarged to one side. Larvae are C-shaped with enlarged thorax; legs are hairy with 4 segments. |
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Color: |
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Adults are reddish brown to black. Larvae are nearly white. |
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Droppings: |
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Powdery frass which resembles fine meal; contains fine wood fragments, no pellets. |
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Where Found: |
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Around the world; about 60 species in the United States. |
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Comparison: |
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Bostrichids, or False Powderpost Beetles, differ from lyctids, which were first to be called Powderpost Beetles because of their powdery frass. Deathwatch beetles (anobids) have expanded club segments on antennae, no rasp-like teeth. Powderpost Beetles (lyctids) have flat bodies, head easy to see from above, and abrupt 2-segmented clubs on antennae. Bark and Ambrosia Beetles have elbowed, clubbed antennae. Pinhole Borers and Ambrosia Beetles have large, flat, 1-segmented clubs on antennae, and no rasp-like teeth. |
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Habitat: |
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Sapwood of both hardwood and softwood lumber and products that are less than 10 years old with a moisture content of 6-30% or more. |
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Food: |
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Larvae feed on wood cell contents which are mainly starch, with somew protein and sugar. These beetles cannot digest cellulose. |
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Biology: |
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Females bore into wood, making tunnels across the grain of the wood before laying eggs in wood pores. Larvae tightly pack mealy frass into tunnel behind them as they bore through wood. After molting several times, mature larva bores closer to the surface, makes a chamber, and pupates. Emerging adult bores to the surface and exits. Development from egg to adult usually takes 1 year. For some species that breed in partially seasoned wood, it may take up to 5+ years in fast drying wood. |
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Damage: |
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Structural damage to lumber and manufactured products. Black Polycaon (western U.S.) attacks hardwoods, including plywood. Leadcable Borer (Pacific Coast) bores through lead cable covering and plastic conduits. Redshouldered Shothole Borer (eastern U.S.) attacks hickory and persimmon. Bamboo Powderpost Beetle (Bamboo Borer) larva feeds on stored food, spices, and drugs. Oriental Wood Borer infests some hardwood imports from tropical Asia. |
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Invasion: |
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Adults are usually seen outside of wood spring through autumn. |
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Control: |
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Wood Destroying Organism control requires inspection of the structure by a registered company and state licensed inspector to find and identify conditions. A written report will be issued. This report must list findings and appropriate recommendations as per the rules and regulations established by the regulatory agencies in the various States. Consult with you local office for the requirements that effect your structure.
Look for round exit holes with a diameter of about 1/8-1/4 inch, accompanied by piles of powdery frass without pellets. Identify correct beetle family/species on the basis of type and age of wood, type of product damaged, exit hole size and shape, frass, and wood moisture content since these insects are rarely seen. Appropriate recommendations can be made once a proper inspection is performed. Fumigation of the entire structure may be recommended or treatment with other registered materials may be made locally. Replacement or reinforcement of infested or damaged wood members may be made. |
