Seasonal Changes - May 2023

Do you leave any firewood in your home during the summer?

A number of different insects can emerge and enter the home from firewood especially if the wood has been left sitting indoors for an extended period of time. Quite often many insects are woodboring and bark beetles and become especially abundant around lights and windows to which they are attracted. Certain flies and carpenter ants can also invade the home from firewood, however, since these and other insects may also originate from other situations in the home, proper identification of the insect in question is required to help determine their source. To find out what the insect may be the insects should be collected in a small plastic pill container or a similar tight container and brought into the Insect & Disease Laboratory for identification, along with a brief description of where they are occurring.

Most of the insects emerging from firewood are primarily a nuisance and pose no threat to the home. The species which pose the greatest threat of infestation are the carpenter ants and powder post beetles.

Powder post beetles are a particular group of insects which bore in dead wood which can become a problem in the home if conditions are right. Both the small brownish-black beetles and the whitish grubs bore throughout the wood and reduce the wood to a fine flour-like powder over a period of time. The presence of small pinholes in the bark of the wood (from pin-sized to pencil lead sized holes) and the presence of flour-like powder may indicate the presence of these insects. Less destructive bark beetles show similar signs but the bark beetles form the characteristic galleries along the surface of the wood beneath the bark whereas the powder post beetles do not but rather bore throughout the wood. All woods are subject to the attack of powder post beetles but hardwoods, especially birch, seem to be favored. Powder post beetles and carpenter ants need relatively high moisture levels to develop.