Wasp spray generally kills spiders. People often use it for spider control because its specialized nozzle allows for a jet stream application from a safe distance, and the chemicals are fast-acting. Although designed primarily for stinging insects, the potent ingredients are effective against a wide range of arthropods. The speed and distance capabilities make it a tempting choice, but the formulation is not intended for general pest control.
How Wasp Spray Works
Wasp spray relies on a high concentration of neurotoxins, primarily synthetic pyrethroids such as permethrin, cypermethrin, or tetramethrin. These compounds are chemical analogs of the natural insecticide pyrethrin and work by disrupting the target organism’s nervous system. Pyrethroids specifically interfere with the voltage-gated sodium channels in nerve cells responsible for transmitting signals.
This interference prevents nerve cells from closing properly, leading to continuous and erratic nerve impulses. The result is hyperexcitability, which rapidly causes muscle tremors, paralysis, and the characteristic “knockdown effect.” Many formulations include a synergist like piperonyl butoxide (PBO), which enhances the pyrethroid’s potency by inhibiting the organism’s ability to metabolize the chemical. The spray is delivered via a high-pressure aerosol system, ensuring the chemical mixture coats the target quickly, often from a distance of 12 to 20 feet.
Why Arachnids Are Affected
Spiders are arachnids, not insects, but their nervous system structure is highly susceptible to pyrethroid neurotoxins. Like insects, spiders rely on similar voltage-gated sodium channels for neural function, making them vulnerable to chemical disruption. When exposed, spiders exhibit immediate signs of intoxication, including rapid paralysis and lack of coordination.
Many spiders are often more sensitive to these chemicals than insects. Even sublethal doses of pyrethroids can significantly impact a spider’s behavior, causing ataxia (uncoordinated movement) and reducing their ability to hunt. The fast-acting effect is a direct consequence of the chemical’s ability to quickly penetrate the spider’s exoskeleton and overwhelm its nervous system.
Risks of Using Wasp Spray for Spiders
Using wasp spray for general spider control, especially indoors, introduces several significant hazards because the product is designed for outdoor application against large pests. The high-volume, long-range spray pattern is engineered to saturate a nest from a distance. This means a single application releases a substantial amount of chemical and propellant into the environment.
The highly concentrated pyrethroids and propellants create risks of airborne toxicity and surface contamination when used in confined spaces. Inhaling the aerosolized chemicals can lead to respiratory irritation, headaches, and nausea in humans and pets. The active ingredients also leave a residual toxicity on surfaces like floors, counters, and pet bedding, causing exposure long after the initial application.
Many wasp sprays use flammable propellants to achieve their long-distance jet stream. This flammability poses a fire risk if the spray contacts a pilot light, heat source, or electrical spark, especially in indoor settings like basements or garages. The product’s label explicitly warns that it is a pesticide and should not be used in a manner inconsistent with its labeling, which typically restricts use to outdoors or for treating nests.
Safer Methods for Spider Control
For a safer approach to managing spiders, exclusion and non-toxic methods are preferred over using potent chemical sprays indoors. Physical removal is an effective, non-chemical solution, often accomplished by simply vacuuming up the spider and its web. Sealing entry points is a proactive measure involving caulk to close gaps around windows, doors, and utility lines, preventing spiders from entering the structure.
Targeted sprays using lower-concentration, natural ingredients can also be effective. Spiders are repelled by strong scents, making diluted solutions of essential oils like peppermint, lavender, or tea tree oil a simple alternative for spraying along baseboards and entryways. Diatomaceous earth, a fine powder made from fossilized shells, can be applied to crevices and voids; it kills spiders by lacerating their exoskeleton and causing dehydration.