IDENTIFICATION:
Adult Old House Borers are beetles 5/8 to 1 inch long, slightly flattened, brownish-black with many gray hairs on the head and thorax, two prominent black bumps on the prothorax and long antennae. The thorax (segment behind the head) has a shiny ridge down the middle and a shiny raised knob on each side, appearing as a face with a pair of eyes. Wing covers are marked with whitish spots that form two irregular bands or spots near the middle. Larvae are up to 1-1/4 inches long and have tiny ocelli (black eye spots) on each side of the head. They are flesh-colored, wedge-shaped (wider at the head), and segmented with legs present. Pupae are flesh-colored and about the size of the beetle. Eggs are white to grayish-white.

LIFE CYCLE AND HABITS:
The biology of the beetle's life cycle is greatly influenced by temperature, relative humidity, and protein content of the wood. In Virginia, larvae require two to ten years to become fully grown and their feeding can cause extensive damage to infested wood. The adult stage is short, lasting eight to sixteen days, while the egg stage is about two weeks, the larval stage lasts several years, and the pupal stage is two weeks. Under ideal conditions in many southern states, adults may appear after three to five years, sometimes remaining in larval tunnels for as long as 10 months before emergence. In more northern states, where humidity is low (as in some attics), an additional two to five years may be required to complete the life cycle. Adults emerge June, July, and August with females attracted to dry, seasoned wood where eggs are laid re-infesting additional softwood. (Oils and resins in the heartwood portion of wood are undesirable.)

PREVENTION:
Damage depends on several factors. If the house is heated centrally, has no moisture problems from ventilation or poor drainage, and does not stay closed up and unoccupied for long periods of time, infestations do not worsen significantly, and re-infestations are unlikely after the first generation. It is sometimes common for a few boards in the house to be infested, resulting in very little economic damage in spite of a gnawing nuisance by a few larvae and occasional emergence by a beetle or two. However, in portions of the house with a high enough humidity to allow re-infestation, serious damage can result. Moisture contents below 10 percent cause very slow larval development and some die. Ideal development is at moisture contents of 15 to 25 percent. Larvae will even attack wood that has been air dried or kiln dried to about 25 percent moisture content. They do not infest firewood or any softwood not seasoned to some degree. The majority of infestations originate in wood containing larvae prior to construction. Larvae and adults have been found in lumberyards where structural and log-home timber were cut, dried, and stored. The extent of damage depends on the proportion of sapwood to heartwood. With heating inadequate to dry out the framing timbers and high moisture present, such as in unheated storage areas or recreational structures occupied intermittently, serious damage can occur. Avoid using farm-sawed lumber of freshly cut logs unless chemical treatment has been applied.

Larvae of the Old House Borer feed on seasoned softwoods and prefer the sapwood portions of pine, spruce, and fir. Sometimes, larvae are serious pests in modern log homes as well as conventional homes. Houses less than 10 years old are primarily attacked contrary to the name of “Old House” Borer. Full grown larvae can be heard boring in the wood, making a rhythmic ticking or rasping sound much like the sound of a mouse gnawing. In log houses, this sound may be heard from a distance of five to ten feet, day and night, at infrequent intervals. If the larvae work close to the surface, homeowners may find blistering of the wood, boring dust on surfaces below infested timbers, powdery borings in sapwood, oval emergence holes about 1/4 inch wide on the wood surface, larvae in tunnels, or beetles in the building.