Brown Recluse Spider Control

Brown recluse spiders do have a dark, violin-shaped mark on the front of their bodies, but so do several other species that aren’t as venomous. What is key to identifying brown recluses is their eyes. If you can examine a squished, definitely-dead specimen, look for six eyes, in three pairs, arranged horizontally. Only a few species have this arrangement; most spiders have eight eyes.

Brown recluse spiders are found in a wide area from the Gulf of Mexico up through Texas, Oklahoma and Kansas, east to Indiana, Kentucky, Tennessee and Georgia, preferring the warmer southern parts of the country. Surprisingly, most homes and buildings in their range are probably infested with brown recluses. They’re secretive; their webs are usually inside the walls of a home or building. They keep to dark areas with reduced air circulation, e.g. in closets, behind drawers, under and behind furniture, around and under boxes, and beneath clothes or towels on the floor. Brown recluse spiders like it warm and dry, and are found more often in attics and upper floors, and the south and west sides of the house. Any place where there’s storage or clutter, there’s probably spiders.

Outside, brown recluses set up shop where they’re protected from wind, rain and bright light, and can remain mostly undisturbed. This could be under loose bark on trees; scrap, debris, firewood, or lumber piles; rock piles in caves or barns; or storage buildings and garages.

Detective Work: Tracking Brown Recluse Spiders

To scout out where the spiders are entering your rooms, grab a flashlight and look around between 9-10pm. This is when they’re starting to get active and emerge from their mostly-hidden webs. (The flashlight will help you see in corners, closets, under furniture, etc.) When you spot a spider, examine the wall and floor to find a possible hiding place or entrance point. If you have a partner, have them make notes of these places.

Put glue traps in corners, in closets and cabinets, and under furniture (with appropriate considerations for children and pets). The relative numbers of spiders you catch each week will be a good indicator of how well your control efforts are working.

Essential Housekeeping Measures to Discourage Brown Recluse Spiders

Brown recluse spiders very rarely bite humans; follow these measures to help keep it that way.

Never leave clothes, linens, or towels lying on the floor. Don’t let bed sheets, blankets, or bed skirts reach the floor. Pull beds and cribs away from the wall. Examine towels before using them, and shake out clothing and shoes before putting them on.

Brown recluse spiders hide in and under clutter, so eliminate it all, especially in closets, attics, garages, and under furniture.

Seal boxes and bags whenever possible to prevent the spiders from getting inside. In most homes, storage is inevitable, so keep several inches of space between stacks of boxes and between the boxes and walls.

Clean frequently. It’ll allow you to locate and kill spiders more often, and keep their insect prey populations down.

Tight-fitting trim and caulking of all cracks or gaps in walls will prevent the spiders from entering a room from their webs inside the walls and behind baseboards. (Be sure to seal up cracks and gaps on the outside of your house or structure, too.)

Getting Rid of Spiders, Inside and Out

This is an organized, thorough system to deal with spider populations: do these things, and you’ll greatly reduce your chances of having problems later on, too. Of course, these methods may not get rid of 100% of your spiders, but they should cut the populations down by a lot. While you’re at it, wear gloves.
1. Start outside: spiders that try to migrate into your house in the fall usually come from wood or junk piles, disused yard furniture or toys, trash bins, outdoor stairwells and under porch structures, window frames, brick piles, etc. Clean up (carefully! Gloves and long sleeves are our friends!) and cover piles of firewood.
2. And stay out! Fix tears in screens; install or repair weatherstripping around doors; fill any gaps around water pipes under sinks; and be zealous about sealing up cracks and openings in the foundation, such as wear utility lines enter the house.
3. All the hiding places: Now is a great time for spring or fall cleaning, regardless of what the calendar says. If you’ve got areas of stored boxes, magazine piles, or where belongings are sitting undisturbed for long periods of time, you’ve got spider hideouts. Clean them up (wear gloves). Vacuum behind and under bookshelves and furniture, along baseboards and corners, especially in areas likely to house spiders.
4. Bombs away! Indoor aerosol bombs or foggers will be a lot more effective if you’ve done the work to clean up spider hiding places first. They probably won’t provide residual control for any spiders coming in later, though; seal up cracks and openings as described in point #2, above, if you haven’t already. It’s crucial that you use a product that’s labeled for use on spiders, and is labeled for indoor use; follow label instructions and do not use more product than recommended. If your first round of fogging doesn’t work, look again for hiding places outside and inside your home, or call in the pros.
5. Boric acid works, but a bit more slowly. The upside is that it isn’t toxic to humans. Spiders pick it up on their bodies as they go about their business, then ingest it when they groom themselves.
6. If you spray outside: Reading the small print on the label might not be fun, but it is extremely important. Use only pesticides labeled to be effective against spiders and for use outside; spray around any crack or opening. Do not overspray.
7. Firewood: Don’t spray the firewood pile, unless you plan on throwing it all away afterwards. It is not safe to burn firewood after you’ve doused it with pesticides.
8. New construction or remodeling: If you’re building a house or adding a room, have the wall voids treated with boric acid.

Insecticidal Sprays, Bombs, and Powders for Brown Recluse Spiders

It seems to be common sense, but it bears repeating: read the instructions. And follow them. Using chemicals in a fashion contrary to the label can be ineffective at best, and harmful at worst.
There are a lot of insect control potions available at your friendly neighborhood hardware store or grocery store. Aerosol foggers or bombs are the most popular because they’re so easy to use, but when dealing with brown recluse spiders, they really don’t work that well. They only kill the spiders that come into direct contact with the spray; once the spray dries, the spiders are relatively unaffected. “Residual” effects on brown recluse spiders are negligible.
Insecticidal powders are where the gold is. The powder lasts a while; spiders ingest it when grooming, offering long-term control.
If getting the powder in the walls and behind the baseboards of your home seems overwhelming, save yourself the headaches and call in the pros. Professional pest control operators or exterminators will tackle the job for you, saving you a lot of work and worry. Look for ones with experience with spider problems in your area.