Yes, Alpine WSG does kill spiders. Spiders are listed as a target pest on the product label, and its active ingredient, dinotefuran, works on spiders through direct contact and residual exposure. That said, spiders present a unique challenge for any insecticide because of their biology, and getting good results requires understanding how Alpine WSG actually works against them.
How Alpine WSG Works on Spiders
Alpine WSG contains 40% dinotefuran, a neonicotinoid insecticide. It disrupts the nervous system of insects and arachnids by overstimulating nerve cells, leading to paralysis and death. One of the key advantages for spider control is that dinotefuran is non-repellent. Spiders can’t detect it on treated surfaces, so they walk across it without avoiding the area. Repellent insecticides, by contrast, often push spiders to untreated zones rather than killing them.
The challenge with spiders is that they walk on the tips of their legs, minimizing the body surface area that contacts treated surfaces. They also don’t groom themselves the way insects do, so they pick up less product overall. This means spiders generally need more direct or prolonged contact with treated surfaces compared to ants or roaches. Alpine WSG’s non-repellent formula helps here because spiders will rest on treated surfaces without hesitation, increasing their exposure time.
Where and How to Apply It
Alpine WSG is a water-soluble granule that you mix with water and apply as a liquid spray. For general spider control, mix 0.5 ounces (one packet) per gallon of water. A lighter rate of 0.33 ounces per gallon works for maintenance applications once you’ve knocked down an existing population.
Focus your application on the spots where spiders travel and hide:
- Cracks and crevices along baseboards, window frames, door frames, and where walls meet ceilings
- Behind and under furniture that sits against walls, especially in basements and garages
- Around exterior entry points like weep holes, utility penetrations, vents, and eaves
- Storage areas such as closets, attics, and crawl spaces where spiders build webs undisturbed
For outdoor perimeter treatments, spray a band along the foundation and up the exterior wall about one to two feet. This catches spiders before they enter your home. Alpine WSG dries clear and doesn’t leave visible residue on most surfaces, which makes it practical for indoor use on finished surfaces.
How Long the Residual Lasts
Indoors, Alpine WSG provides residual killing power for roughly 30 days on undisturbed surfaces. Outdoors, UV exposure and rain break it down faster, so you can expect closer to two to three weeks of effective residual in exposed areas. Sheltered spots under eaves or porches hold up longer.
Because spiders reproduce and new ones wander in from outside, a single application rarely solves a spider problem permanently. Most people see the best results by reapplying every 30 days during peak spider season (late summer through fall in most regions) and spacing treatments out to every 60 to 90 days during quieter months.
Why Spiders Are Harder to Control Than Insects
Even with a good product like Alpine WSG, spiders are inherently more difficult to control than crawling insects. They don’t eat bait, so you can’t target them through their food. They spend long stretches motionless in their webs, meaning they may not contact treated surfaces for days. And because they prey on other bugs, a spider population often reflects an underlying insect problem. If your home has plenty of flies, gnats, or other small insects, spiders will keep showing up to feed on them.
This is actually where Alpine WSG offers a secondary benefit. Because it kills a broad range of insects including ants, flies, cockroaches, and beetles, it reduces the food supply that draws spiders indoors in the first place. Treating for the prey insects simultaneously makes spider control more effective over time.
Safety Considerations Indoors
Alpine WSG carries a “Caution” signal word, the lowest toxicity category for pesticides. Keep children and pets off treated surfaces until the spray has fully dried, which typically takes 30 minutes to two hours depending on ventilation and humidity. Cover fish tanks before spraying anywhere near them, as dinotefuran is toxic to aquatic organisms.
Do not spray it on mattresses, clothing, or directly on people or pets. When mixing and applying, wear long sleeves, long pants, socks, shoes, and waterproof gloves. Wash your hands thoroughly after handling. In commercial settings like healthcare facilities or schools, the label prohibits application in patient rooms while occupied and in classrooms while in use.
Getting Better Results Against Spiders
A few practical steps improve how well Alpine WSG works for spider control. First, knock down existing webs before you spray. Spiders sitting in a web above your spray zone won’t contact the product. Removing the web forces them to rebuild at surface level where they’ll pick up the residue. Second, reduce clutter in storage areas. Cardboard boxes, stacked items, and undisturbed corners give spiders harborage that’s nearly impossible to treat thoroughly.
Third, apply it with enough volume to get good coverage on the surfaces spiders actually walk on. A light mist on a baseboard won’t do much if spiders are traveling along ceiling corners. Use a sprayer with an adjustable nozzle so you can direct the spray into crevices and upper corners where spiders prefer to set up. Finally, seal obvious entry points around doors, windows, and utility lines. No amount of insecticide replaces the value of keeping spiders from getting inside in the first place.