(Arachnida: Araneae)

General Information:
Spiders are the most feared of all pests around the home. For many, the fear of spiders may be linked to childhood stories or learned from friends and relatives. This fear is real and often well founded in the case of several species. For others, spiders are a nuisance with their unsightly webs up high in the corners of ceilings.

Spiders are not insects. They are different from insects in that they have eight legs instead of six; they have two body regions (head and cephalothorax) where insects have three (head, thorax and abdomen). Spiders feed with jaw-like structures called chelicerae (hollow fangs which can inject venom).

Spiders are often associated with moisture such as in dark crawl spaces. However, others live in warmer dry areas such as around floor vents or corners of rooms. The black widow and brown recluse spiders are the only dangerous species to humans within our region, even though all spiders utilize venom to subdue their prey.

Black widow
(Latrodectus mactans)
Black widows are generally found in secluded areas. This species is of concern to humans because of the effect of the venom released during a bite. Black widow spiders, like brown recluse spiders, build webs in secluded areas such as in firewood, under debris outside, water meter boxes, dark areas under and around homes. They are generally shy but will bite individuals when disturbed. Unlike the bite of the brown recluse, the black widow's bite is painful, like being stuck with a needle. Its venom contains neurotoxins that will affect an individual's nervous system. Some symptoms include muscular cramps, tremors, and irregular breathing that may result in convulsions and death with some victims. An anti-venom specific to black widows is available through most physicians. Therefor when dealing with spider bites take the spider with you to a physician.

Appearance: A female black widow spider is about 1/2 inch in length and is black in color. The abdomen is almost a perfect circle without any visible hair. On the underside of the abdomen is a red hourglass-shaped marking. Young spiders are usually orange or white.

Habitat: Outside the spiders can be found under stones or wood, in stumps, open structures (barns and sheds), brick veneer and barrels. Inside, they are found in undisturbed places such as out-of-the-way areas of garages and basements.

Spider control
A thorough inspection of the premises is the first step in controlling spiders. This process will help identify problem areas such as: 1) is the building spider proofed, i.e. windows screened, cracks, holes and pipe chases through walls sealed and voids (under cabinets, etc.) sealed if possible 2) is the building free of debris such as stacked papers, boxes, clothing and lumber 3) webs and egg sacs both inside and outside that need to be removed and disposed of. Monitors may be used to identify problem areas that may need more attention and to see how serious the problem is as in the case of brown spiders. Identification of the spider is important in determining proper treatment. Initial control can be very successful by space treatments with ULV (fogging) or dust pesticides in void areas such as crawl spaces and attics. Long-term control can only be achieved by working towards eliminating the insects the spiders are feeding on and by sealing harborage areas. This can be accomplished by having a professional treat the home on a regular basis with pesticides in conjunction with the homeowner sealing cracks and crevices.