Getting rid of Black Widow Spiders requires a combination of both chemical and non-chemical measures. Think of non-chemical measures as limiting or removing conditions that contribute to the infestation. These measures include vacuuming, sanitation, harborage removal, and exclusion, are largely preventative. The next step is to come in with the ammunition (chemical pesticides) that does the job of physically wiping out an infestation.
A quick inspection of the premises can help you zero in on areas where black widow spiders are hiding. Then you will know where to focus the majority of your efforts. Keep in mind that black widow spiders often build webs in and around boxes and piles of clutter.
Non-Chemical Measures for Black Widow Spiders
Sanitation: Black Widow Spiders are often attracted to a building, home, or other structure by favorable conditions and hiding places surrounding the exterior. The following sanitation practices are recommended:
- Piles of lumber, firewood, stones, boards, or other debris should be moved as far from the home or structure as possible, stored off the ground, and covered with plastic.
- Heavy vegetations such as ivy should be cut away from the foundation.
- Tall grasses should be regularly cut short.
- Improve storages in basements and garages by storing items off the floor and away from the wall; reducing clutter also limits available harborages.
Spider Removal: Existing black widow spiders, webs, and egg sacs can be removed by way of a vacuum when they are spotted during an inspection. After vacuuming black widow spiders, the vacuum bag should be removed immediately after finishing and sealed in a plastic bag before being discarded in an outdoor garbage receptacle.
Exclusion & Lighting: Any cracks or gaps in the building exterior or surrounding window and door frames should be sealed with caulk or fine wire mesh in order to prevent entry. Doors should be fitted with weather strips on the bottom and all vents should contain tight-fitting screens. Outdoor lighting should utilize bulbs that attract fewer flying insects, reducing food available to spiders.
Chemical Treatments for Black Widow Spiders
- Contact Sprays: A non-residual aerosol insecticide can be sprayed directly on black widow spiders to eliminate live spiders. This treatment is a quicker and easier alternative to vacuuming. PT 565 PLUS XLO and CB-80 Extra are ideal flushing and contact agents for black widow spiders and just about every other pest you could have a problem with.
- Dust Applications: A dust agent (we recommend Delta Dust Insecticide or Drione Dust) is an ideal treatment for out-of-the-way areas where infestations are especially heavy, such as attics, basements, crawl spaces, sill plate areas, and wall voids. For application to these and other areas, follow the directions found on the product label. Application to wall voids may require a Hand Duster.
- Spot Treatments: A liquid residual wettable powder (like Demon WP Insecticide) or microencapsulated (ME, CS) formulation can be sprayed in corners, behind and under furniture, behind stored items, and on or around other areas where black widow spiders are found using a One Gallon Sprayer. The insecticide residual will both kill existing spiders and prevent new spiders from building their webs.
- Exterior Treatments: Before sealing cracks in the exterior walls of the building, treat these openings with a residual dust (Delta Dust Insecticide or Drione Dust) to prevent spiders from entering in the future.
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