The female black widow spider is about 1/2 inch in length, glossy black in color, with a globe-like abdomen. The abdomen has two triangular red spots on its underside arranged in such a way that they look like an hourglass. The male is much smaller than the female; males are 1/4 inch in length with a longer, narrower abdomen and slightly longer legs.
Black widow spiders are shy and prefer to build their webs in dry, protected locations where their prey is likely to travel. They are commonly found in wood piles, barns, sheds and crawl spaces. The web is an irregular construction that serves to ensnare victims long enough for the spider to tangle it in more silk before giving it a lethal bite. The female often eats the male after mating, thus giving the spider its rather morbid name. The female lays its eggs in a silken case which it protects in the nest . Several cases may be constructed during a spider’s lifetime, each containing an average of 255 eggs. The young spiders remain in the case until the second molt. They live in the vicinity of the nest for two to three weeks before producing long threads of silk that help them float away like kites. Female spiderlings go through six to eight molts before maturing, which takes from 112 to 140 days. Black widows have poison glands and will bite if handled roughly or disturbed. They usually avoid trouble whenever possible. There have been deaths caused by black widow bites, but in most cases the bite is no more severe than a wasp sting.
Very few residual pesticides will effectively control spiders for any length of time. We have two products that have been proven effective for long-term control. One is a liquid concentrate, which can be sprayed on spider harborages for a treatment that will last for months. The other is a dust that can be applied in attics and wall voids and, because it is water-proof, it can also be used in areas of high moisture.
If you have any questions about these products, please visit your nearest Pestop location.