Several wood-infesting insect pest species can be found in the northeast, including eastern subterranean termites, powderpost beetles, carpenter ants and old house borers. A lesser known wood-infesting insect species in the northeast is commonly known as the “wharf borer,” and this species is notable for suddenly appearing within homes in large numbers. These structural beetle pests can be recognized for their long slender bodies, which measure around half an inch in length, and for their long antennae, which is about half the length of their body. Wharf borer adults are often dull yellow or reddish-orange in color, and the tips of their wings are deep purple to black. Spotting wharf borers within a home does not necessarily indicate that an infestation is active within the home’s structural wood, but eliminating the insects should be made a priority in these cases.

Wharf borer infestations within wood can be maintained for many years or even decades without the pests emerging from the structural wood sources that they infest. These long lasting infestations are possible due to the wharf borer’s exclusive reliance on damp or waterlogged wood sources for sustenance, and remaining within wood protects these insects from predators. Most infestations see a large amount of nesting larvae and adults, further indicating that these insects prefer to remain within wood sources. Adults can be found emerging from structural wood sources within a home at any time of year, but in most cases, adults emerge in between the months of May and August. Infestations begin after females lay eggs on moist wood, and larvae immediately tunnel through interior wood sources upon hatching. Not only do wharf borer females choose moist wood sources for laying their eggs, but the feeding activity of wharf borers contributes to wood decay, causing further damage to already compromised structural wood sources. Infestations are commonly found in fence posts, utility poles, underground lumber, and damp structural wood located near moisture sources, particularly leaking pipes.

For reasons that researchers do not yet understand, wharf borers gravitate toward toilets, and structural wood within bathrooms is the most common infestation site within homes. These insects likely gravitate to toilets due to their attraction to water and moisture, but wharf borers even demonstrate a preference for infesting wooden utility poles and fences that have been soiled by dog urine. No insecticides have been approved for wharf borer extermination, but infestations can usually be eliminated and prevented by reducing sources of moisture that make contact with structural wood. Wood that has been infested with wharf borers usually needs to be replaced.

Have you ever heard of wharf borers?