In addition to insects, we are also often asked to identify spiders and to provide recommendations on how to control them. I have already received several phone calls and office visits this year about spiders. Therefore, this may be a good time to share some information about spiders with you.
Most of the specimens we receive in the office for identification turn out to be wolf and jumping spiders. These spiders are actually beneficial, because they prey upon a wide variety of insect pests.
Almost all spiders produce venom, which they use to paralyze or kill their prey. As with any insect bite or sting, some people may be hypersensitive to this venom and may need to seek medical treatment if bitten. But for the most part, being bitten by common spiders should not cause more than temporary discomfort for the healthy adult.
The problem for most homeowners occurs when spiders invade houses in search of prey. Since most people are terrified of spiders, the spider inevitably comes out on the short end of this domestic encounter. Rarely is any kind of indoor chemical control treatment for spiders needed or warranted.
There are only two "poisonous" spiders naturally occurring in North Carolina, and people are urged to be cautious of both. By understanding a little bit of the biology and behavior of these two spiders and by employing a little common sense, most people can minimize encounters and possible bites from these arachnids.
Black widow spiders have a shiny black appearance and are usually 1/2 to 3/4 inch in size. A characteristic red "hourglass" marking is found on the underside of the abdomen. This red marking is not always distinct and, in some cases, is not always completely hourglass-shaped. Therefore, it is best to treat any large, black, shiny spider as a black widow. Virtually all adults have seen black widows and can identify them when they see them.
These spiders are rarely found inside homes but are usually found near human habitation or newly disturbed areas such as water meters and telephone boxes, benches, building materials, or outside storage areas. Painful encounters with black widows can be avoided simply by looking before you stick your hand somewhere or start moving objects that have been piled on the ground for any length of time.
Brown recluse spiders warrant far more attention, because they resemble many of the more common tan and brown spiders which invade homes. The recluse has a distinct dark "fiddle-shape" design on the upper surface of the body where the legs are attached. The bite of a brown recluse is particularly nasty since the toxin can cause localized tissue damage.
As the name indicates, these spiders are relatively shy and are usually found hunting in warm, dark or dimly lit areas and crevices such as in attics, garages, or basements. They may also hide inside clothes stored in barns, basements, or garages. Bites often occur when someone reaches for an object in these areas or puts on clothing left there and in which the spider has taken up residence.
Although they are found in North Carolina, the occurrence of this pest is pretty sparse. They have been officially documented in only five counties. This is probably because the victim does not actually feel the bite when it occurs but begins to notice the discomfort and symptoms some time later. Because of this, it is difficult to determine exactly where the spider may have been and even more difficult to locate it later.
If you encounter spiders in your home, especially either of the poisonous species, it is best to have the problem handled by a licensed pest control operator. These people have the equipment that is needed to do "crack and crevice" treatments. Simply setting off an insect bomb in your attic, basement, or garage is not likely to kill off all of the critters. Boxes which have remained undisturbed in these areas for any lengthy period of time should be opened and examined carefully and stored clothes should be shaken to dislodge any unwelcome visitors.
If either a black widow spider or brown recluse spider bites someone, immediate medical attention should be sought. If possible, the culprit spider should be captured so that a positive identification can be made. For more information about spiders or household pests, please contact Cooperative Extension by calling 671-3276.
— Everett Davis is the Robeson County Cooperative Extension Director.