Most spiders found in U.S. homes are harmless and actually beneficial — they eat other pests. But two species require immediate attention: the black widow and the brown recluse. Here’s how to identify them and protect your home from all spider activity. 

 

Black widow (Latrodectus species): Shiny black with a distinctive red hourglass marking on the underside of the abdomen. Found in dark, secluded areas: woodpiles, garages, sheds, outdoor furniture, and undisturbed storage areas. Their bite can cause severe neurological symptoms — seek medical attention immediately if bitten. 

 

Brown recluse (Loxosceles reclusa): Tan to brown with a violin-shaped marking on its back. Found primarily in south central states. Prefers undisturbed areas: inside storage boxes, closets, between sheets in spare rooms. Bites cause a necrotic wound that can expand over days — seek medical treatment promptly. 

 

 

General spider prevention: 

 

Reduce clutter in garages, basements, and storage areas — spiders nest in undisturbed spaces· 

 

Seal gaps in window screens, door frames, and foundation· 

 

Turn off exterior lights or switch to yellow “bug lights” — light attracts flying insects, which attract spiders· 

 

Vacuum regularly, including corners and under furniture where webs are built· 

 

Move firewood, boxes, and debris away from the house.

 

Control measures: 

 

Sticky glue traps placed in corners and along baseboards are effective at monitoring and reducing spider populations inside. Residual insecticide sprays applied along baseboards and in crevices kill spiders on contact and provide ongoing barrier protection. If you’re finding black widows or brown recluses consistently, the approach needs to be expanded: address the overall insect population in your home (which is the food source drawing spiders in) and consider professional perimeter treatment.