Putting another log on the fire has real meaning for anyone who has a wood-burning stove in our coastal area. With a high percentage of folks still heating their homes with wood, some homeowners are concerned that every time they bring firewood into the house, they are also bringing in some unexpected hitchhikers. The question is: Will these insects make our home their home and should we be spraying the firewood with something to kill the bugs?
Luckily, most insects living in firewood pose no danger to humans, our homes, or our furniture. There are a variety of insects that spend their winters under the bark of trees in a woodpile. When firewood is brought inside the house and it warms, these insects crawl out of the wood. Pillbugs, centipedes, millipedes, and ground beetles are commonly found in firewood. They will not harm you or your house and need only be picked up and removed. Insects in firewood are either feeding directly on the wood, nesting in the wood, or are over-wintering under the bark.
The best way to prevent insects from emerging from firewood in the house is to leave the firewood outside until it is to be burned, bringing at most, a few day+s supply into the house at one time. Insects in firewood stored outdoors generally require several days to warm up inside your home before they become active.
Spraying firewood with an insecticide is of very little benefit and potentially dangerous. WSU entomologists strongly advise against treating firewood. Insecticides will not penetrate deeply enough into firewood to control the insects. In addition, storing and burning insecticide-treated firewood indoors could be a health hazard if the insecticide is vaporized into the living area of the house.
Do not stack wood up against the house or garage. This can result in moisture or insect problems in the building. A minimum of three feet between the firewood and building should be maintained. This also allows better air circulation, which promotes more rapid and thorough drying of the wood. Stacking the wood off the ground whenever possible also will reduce potential pest problems.
Two insects that may cause problems if you keep your firewood stacked against the outside walls of your house are carpenter ants and termites.
Wood that remains moist for an extended period is a likely candidate for infestation by carpenter ants. Carpenter ants do not feed on the wood, but they hollow out galleries in the wood for nesting. The galleries are smooth and go with the grain of the wood. Although an annoyance, the chances of these ants establishing a nest in your house are very slim. Stacking wood against the outside of your home may provide an avenue for these insects to enter your home.
Wood that is stacked directly on the ground may be fed upon by termites. Mud tunnels may be visible on the outside of the wood, or there may be mud-lined galleries within the log. The main termite nest containing the queen is in the soil, but the workers will tunnel into the firewood and feed upon it. Termites brought into your home in firewood cannot establish a new nest and will not damage your home or furniture. But as with carpenter ants, woodpiles stacked against the house can provide a way for termites to extend their feeding into your home.
Stacking firewood off the ground is the best method to prevent termites from feeding on your firewood. If you discover a termite infestation in firewood stacked next to your house you should have your home treated or inspected by a pest management professional.
The following guidelines may be helpful in reducing firewood pests:
1. Cut wood in mid- to late- fall. This may make the wood less attractive to attack by borers which emerge in the spring.
2. Bring firewood indoors only as needed, at most a couple of days supply at a time. Storing firewood in the home for long periods speeds insect development inside the wood, which allows them to emerge inside the home.