The only dangerous spiders we have in Iowa or Illinois are the brown recluse spider and the black widow spider. The brown recluse is not common. The black widow is common, but reports of it biting people are infrequent. Most spiders can live for several months without food. Therefore, controlling the insects upon which they feed is a very slow control technique.
Sanitation is the most practical method of spider control.
Clean away all webbing with a vacuum cleaner so that eggs and spiders are picked up and destroyed. Ordinary housecleaning with a cloth, dust mop, or broom is not effective. Keep premises free of unneeded, undis-turbed clothing, papers, and other litter. Many spiders may be excluded from the home by caulking or otherwise eliminating cracks and crevices around the foundation of the house and around windows and doors. Chemical control using a long-lasting residual spray containing Diazinon, malathion, or chlorpyrifos Dursban Pro and Dursban Granuels is effective when applied around the outside of the home and in undisturbed locations in the house where spiders are likely to be found.