Q. I have been getting hundreds of little "centipedes" in our basement for the past couple of weeks. They are about an inch long, rather thin and black or very dark brown. They must not live long since there are 50 additional dead ones on the floor each day. They do not seem to be doing any damage but they are rather crunchy underfoot. What are they, and is there a good way to keep them out of the house?
A. Centipedes are sometimes called hundred legers, thus, the centi. These guys are flattened and elongated with many segments. Most have one pair of legs per segment. The first pair of legs is a set of poisonous jaws below the mouth. Their antennae have 14 or more segments. These ugly critters tend to be grayish-yellow, sometimes reddish-brown and may have three dark, long stripes down the back. Legs are encircled with alternating dark and white bands. They are about 1 inch long with 15 pairs of very long legs.
Centipedes need moist habitats. Thus, it is very important to address your moisture issues. They breed in dark cracks and crevices. The larvae have only four pairs of legs when they hatch out of the egg. The larvae continue to molt as it grows, taking about five or six molts to reach adolescence. The teens pass through four adolescent stages with 15 legs per stage. They use the last pair of hind legs to hold their victims while they paralyze them with the venom from their poisonous jaws. They feed on other insects and spiders, so they are not that bad to have around. They are, however, a warning that you have moisture issues and other insects inside the home. They are actually harmless, just ugly.
The best control is to address your moisture issues. Run a dehumidifier in your basement to reduce humidity. Run a fan to improve ventilation. Inspect your foundation for cracks and crevices for possible entries for all insect and rodent pests. Clean up around the foundation to eliminate breeding places like stacks of old wood, rocks, brick, compost, leaves, etc. Clean up at least 3 feet out from the foundation so that soil dries out. Make sure soil slopes away from the foundation to provide proper drainage away from the home.
Treat the foundation and about 20 feet around the perimeter with residual insecticide. Treat baseboards and basement walls with residual insecticide. Use sticky traps and sweep up live ones you see and discard them. Because not all chemicals are available in all areas today, contact your local Dept. of Agriculture Extension Agent for a list of approved chemicals in your area. If in doubt, contact a professional exterminator.
Moisture issues can also be symptoms of mold and mildew. In addition, they can mean that your home is attractive to wood-boring insects like termites. An annual professional inspection by a professional exterminator and recommended treatments are worth the cost for the protection of the investment in your home and to eliminate pest problems.