Many different kinds of spiders live in and around dwellings. Some, such as the cellar spider, construct webs to help entrap their prey. Others, like the wolf spider, are free roaming and make no webs. Most spiders are harmless and in fact beneficial because they prey upon flies and other pests. The majority of spiders have fangs too small or weak to puncture human skin. Those that are capable of biting humans generally will not do so, unless they themselves are harmed or threatened.
Their webs, fecal spotting, and discarded prey can also become an unsightly nuisance.
The following tips pertain to managing all spiders, followed by information specific to the black widow and brown recluse:
- Routine, thorough house cleaning is the best way to eliminate spiders and discourage their return. A vacuum cleaner or broom effectively removes spiders, webs, and egg sacs. Destruction of egg sacs is crucial since each can contain hundreds of young spiders.
- Spiders prefer quiet, undisturbed areas such as closets, garages, basements, and attics. Reducing clutter in these areas makes them less attractive to spiders.
- Large numbers of spiders often congregate around building exteriors. Moving firewood, stacked items, and debris away from the foundation helps reduce migration indoors. Shrubs, vines and tree limbs touching the house should also be trimmed back since these afford harborage and a convenient bridge to the structure.
- Install tight-fitting window screens and door sweeps to exclude spiders and other pests.
- Consider installing yellow or sodium vapor light bulbs at outside entrances. These lights are less attractive than conventional bulbs to night-flying insects, which in turn, attract spiders.
- To reduce spider entry from outdoors, insecticides can be applied as a ‘barrier spray’ around the perimeter of the building. Pay particular attention to door thresholds, garage and crawl space entrances, foundation vents, and the bottommost edge of siding. Products containing ingredients such as bifenthrin, cyfluthrin, deltamethrin or lambda cyhalothrin are effective, but may need to be applied periodically (e.g., monthly or bi-monthly) during warmer times of the year.