Most spiders are not harmful to humans and are beneficial in controlling other insects through consumption. Thus, experts often recommend tolerance and capture and removal rather than any aggressive seek and kill control efforts. However there are both chemical and non-chemical means of getting rid of spiders in your home.
Non-chemical Control of Spiders
Spiders tend to spin their webs in quiet, secluded areas. To discourage such nesting in and around your home:
- Keep firewood and logs away from the home. Clean up leaves and other organic debris from around the yard. Trim back any trees and shrubs that contact the home.
- Caulk or otherwise seal cracks and gaps in the home's structure, placing strong focus on foundations and around windows and doors.
- Doors and windows should also fit tightly in their frames, have no tears or holes in screening, and have sweeps installed at the bottom edge of doors.
- Reduce the insects that attract the spiders by replacing standard mercury vapor lights with high pressure sodium vapor or halogen lights. Although it is common to place lights on exterior walls near doors, it is better to place the light farther away, using pole lights when possible, with the light shining toward the door for safety.
- Spiders that are nesting on the exterior of the home can be removed with the spray from a high-pressure hose, an industrial vacuum, or long-handled broom. Be sure to remove egg sacs as well.
- Indoors, spiders can be discouraged from web-building through frequent vacuuming and sweeping of corners, closets, basements and other out-of-the-way places.
- When vacuuming, sweeping or otherwise removing webs, be sure that all egg sacs are captured as well to prevent a new generation from being born.
- A fly swatter or rolled-up newspaper can also be used to kill individual spiders. When doing so, it can be prudent to find and destroy its web to ensure against egg hatching as well.
- Reduce or eliminate piles of papers, boxes, bags, and other clutter to reduce potential harborage areas.
- Integrated Pest Management (IPM) efforts, including prevention, sanitation, and exclusion, that reduce insects will also help to reduce spiders both directly and indirectly—by reducing the "food" on which they prey.
- Check boxes, plants and firewood before bringing it into the home to ensure that spiders are not hitching a ride.
Chemical Control of Spiders
- A residual pesticide sprayed into under siding and into cracks and crevices where spiders harbor can have some temporary effect in keeping spiders from spin their webs on your home. Use only pesticides labeled for spiders, the spider to be controlled, and the area where application is intended. Reapply as specified on the label.
- Pyrethrin or pyrethroid space sprays can also have some effect. These will only kill spiders that are directly contacted and will have little residual effect, so application should be made to contact as many spiders and webs as possible. The space spray will also need to be repeated when spider eggs hatch, generally about 4 weeks.
- A light application of an aerosol or liquid insecticide that is labeled for spiders can be applied into cracks and gaps where spiders can provide some control .
- Pesticide dusts can provide control in secluded areas, such as voids where spiders harbor. Dust that contacts webs will stick and be consumed by spiders as they digest the web's silk to reproduce more.
These general control methods apply to most spiders, but, because some species can be dangerous and require immediate control measures, and others can be difficult to control, it is important to identify the spider to be controlled.
When a dangerous spider is identified, such as the black widow, brown recluse, or hobo spider, it is advisable to contact a pest management professional who has the knowledge, tools, and equipment to safely deal with the problem.