Pest Identification And Information

WHARF BORER

Wharf borers are found in very moist wood. Larvae form extensive galleries in piling, wharves, decaying support timbers of buildings, wet flooring, wet boxes, wood lying on damp ground such as in crawlspaces or cellars, and wood buried under the soil. The presence of this insect often indicates unsatisfactory plumbing and rotting timbers. This insect may promote the extension of rot into wood, resulting in damage. Serious damage by wharf borers is debatable as the wood is already moist and decayed to a certain extent before feeding occurs. Adult beetles can emerge from wood in large numbers, creating a nuisance by their presence.

Identification

Adult wharf borers are narrow, depressed, about 1/2 inch long, and brownish to reddish-yellow on top. The tips of the wings, eyes, sides of the thorax, legs and undersides are blackish. The body is covered with a dense, yellow pubescence, with the wing covers pointed at the tips. Each wing has four lengthwise raised lines.

Antennae are about half the body length. Mature larvae are about an inch long, cream-colored and covered with brown hairs. They have brown mouthparts that are almost black at the tips. Larvae bear a wart-like swelling on the upper side of the last two segments of the thorax and the first two abdominal segments.

Life Cycle and Habits

Adult beetles usually are observed in May and June in large numbers when emerging from wood. Beetles mate in rotten wood kept moist and deposit eggs, which hatch into larvae. Pupation and adulthood follow. The life cycle from egg to adult is usually completed in one year, but in cooler climates, several years may be required to reach adulthood. Larvae may occur in cellars or basements and overwinter, protected in the damp wood. Introduced from Europe, this insect has been found in wharf timbers between flooding and the high water level, especially which were in badly decayed, well-riddled wood. A severe infestation occurred in greenhouse benches in Ohio. Annual swarming of adult beetles, especially into new structures, can disrupt business operations and annoy homeowners and apartment tenants.

Control Measures

If practical, correct the moisture problems and clean up or remove structurally unsound wood. Replacement timbers should be pressure-treated with an appropriate wood preservative. Should furniture and other movable wood articles be infested, control can be achieved with dry heat at 180 degrees F for 30 minutes. Use caution as superheating can result in wood warping or even damage to the finish.

Insecticides

In situations where replacing structural timbers is not needed, labeled pesticides should be sprayed, painted or injected into the infested wood under pressure to be most effective. These wood destroying borers can be treated with Borates. Borates are environmentally sound, odorless, non-flammable, low mammalian toxicity, not absorbed through skin contact, washes off easily with soap and water, readily absorbed into wood and can be used in homes with children and pets. The borates: disodium octaborate tetrahydrate (Bora-Care) 40% and (TIM-BOR) 98% are labeled. TIM-BOR is for pest control operator use only. It is usually best to employ the services of a licensed pest control operator or applicator since homeowners seldom have the training, experience or equipment to do the job thoroughly.

When emerging adults are creating a nuisance, use repeated applications of pyrethrins for quick kill. Collect dead and dying beetles with a broom and dustpan or vacuum cleaner and discard in a sanitary landfill.

Some use electrocuting devices with blacklight units to attract and kill these nuisance beetles with moderate success (beetles are typically attracted to lights). Others have drilled holes in the slab three feet apart and six inches from the wall to inject soil insecticides for a more long-lasting control. Always follow label directions and safety precautions.