By the HMNDP Editorial Team. Last reviewed: June 2026.
Best insecticide for spiders: the short answer
The best insecticide for spiders is a pyrethroid barrier spray (bifenthrin or deltamethrin) applied around your home’s exterior, paired with a silica-gel or deltamethrin dust in cracks and voids. For a store run today, Ortho Home Defense Insect Killer (bifenthrin, about $10 to $18 at Home Depot) is the strongest consumer pick. Sprays alone underperform on spiders, so add web removal.
Here is the part most listicles skip: spiders are hard to kill with residual sprays. They do not groom themselves the way ants or roaches do, and they walk on the tips of long legs, so they pick up very little insecticide from a treated surface. Killing spiders reliably means combining a contact spray, a crack-and-void dust, physical web removal, and cutting off the insects spiders eat.
What insecticide for spiders can I buy at Home Depot or Lowe’s?
Consumer stores carry effective spider insecticides without a pro license. The strongest options are bifenthrin and deltamethrin liquids for perimeter barriers, silica-gel dust for voids, and glue traps for monitoring. Expect $8 to $30 per product in 2026. These are what a homeowner can actually put in a cart today, not the pro-only SKUs.
| Product | Type / active ingredient | Best for | Approx. 2026 price |
|---|---|---|---|
| Ortho Home Defense Insect Killer | Liquid, bifenthrin 0.05% | Perimeter barrier, indoor baseboards | $10 to $18 (1.1 gal) |
| Spectracide Bug Stop / Triazicide | Liquid/aerosol, lambda-cyhalothrin or gamma-cyhalothrin | Outdoor barrier, yard | $8 to $16 |
| Wondercide Indoor Pest Control | Spray, cedarwood + sesame oil | Indoor use near pets and kids | $18 to $28 |
| TERRO Spider Killer Aerosol | Aerosol, deltamethrin | Direct-contact kills, corners, eaves | $8 to $12 |
| TERRO Spider & Insect Traps | Glue board (no insecticide) | Monitoring, capturing wandering spiders | $6 to $10 (4-pack) |
If you want one product to start, Ortho Home Defense gives the longest residual (the label claims up to 12 months on non-porous surfaces) and works indoors and out. Wondercide is the pick if young children or pets rule out synthetic pyrethroids.
Professional-grade insecticides for spiders
Professional-grade spider insecticides are sold online through pest-control suppliers rather than big-box stores. They use concentrated pyrethroids or dual-active formulas, cost more per bottle, and cover far more square footage per dollar. Common picks include Onslaught FastCap, Demand CS, Temprid FX, and Suspend Polyzone. They are legal for homeowner use in most states when applied per label.
| Product | Active ingredient(s) | Why pros use it |
|---|---|---|
| Onslaught FastCap | Esfenvalerate + prallethrin + piperonyl butoxide | Fast knockdown plus residual; strong on spiders specifically |
| Demand CS | Lambda-cyhalothrin (microencapsulated) | Long residual, low odor, sticks to legs better than raw liquid |
| Temprid FX | Imidacloprid + beta-cyfluthrin | Dual mode of action for tough or resistant populations |
| Suspend Polyzone | Deltamethrin | Up to 90-day residual, holds up to rain and sun |
Microencapsulated formulas (Demand CS, and the “CS” or “polymer” versions of others) matter for spiders. The tiny capsules cling to the fine hairs on spider legs, so the insect picks up more active ingredient from a surface it barely touches. That partly answers the grooming problem, though it does not fully solve it.
Insecticide formulation types for spiders
Spider insecticides come in four formats, and each solves a different problem. Liquid concentrates make barriers, dusts treat voids and cracks, aerosols deliver direct-contact kills, and glue traps monitor and capture. No single format handles every situation, which is why effective spider control mixes at least two.
- Liquid concentrates: Mixed with water in a pump or hose-end sprayer. Best for perimeter and foundation barriers. Longest residual value per dollar.
- Dusts and powders: Silica gel (CimeXa) or deltamethrin (Delta Dust) puffed into voids. Stay active for months in dry, undisturbed spaces.
- Aerosols and sprays: Ready to use, ideal for spraying a spider or web directly. Short residual, fast knockdown.
- Traps and glue boards: No insecticide. They catch wandering spiders (males roaming for mates) and tell you where activity is.
Dusts for spider control: where they beat sprays
Dusts are the most underrated spider insecticide because they treat the harborage spiders hide in, not just the surfaces they cross. CimeXa (silica gel) and Delta Dust (deltamethrin) are the two to know. Silica gel kills by scratching and drying out the spider’s waxy cuticle, a physical mechanism that resistance cannot defeat, and it stays active for up to 10 years indoors when dry.
Apply dust into wall voids, around plumbing and wiring penetrations, in attic corners, under sinks, behind baseboards, and inside cracks along the foundation sill. Delta Dust is water-resistant, so it holds up in damp crawlspaces and weep holes where silica gel would clump. Use a bulb duster and apply a light film; a heavy pile repels insects rather than treating them.
Best insecticide for spiders outdoors: the barrier treatment
The best outdoor spider insecticide is a bifenthrin or lambda-cyhalothrin liquid concentrate applied as a residual barrier around the home’s perimeter and foundation. Spray a continuous band roughly 2 to 3 feet up the exterior wall and 2 to 3 feet out onto the ground. Treat eaves, door and window frames, and the underside of overhangs where webs form.
Barrier sprays intercept spiders and their prey as they approach the house. Reapply every 60 to 90 days during the warm season, and after heavy rain if the label is not rain-fast. The same logic applies to broader yard pest management; our guide to the best insecticide spray compares perimeter formulas in more detail.
Reduce the prey supply too. Exterior lights draw the moths, gnats, and flies that spiders eat, so switch to yellow “bug” bulbs or motion-only fixtures. Trim shrubs and mulch back from the foundation; dense plantings and thick mulch in flower beds against the wall give spiders cover and moisture.
Best insecticide for spiders indoors: safer around pets and kids
The best indoor spider insecticide is a low-odor pyrethroid applied to baseboards, corners, and closets, or a botanical spray (cedarwood-based Wondercide) where pets and children are present. Reserve dusts for voids people and animals cannot reach. Indoors, physical control (vacuuming webs and egg sacs) often outperforms spraying because you remove the spider directly.
For most homes, treat the indoor perimeter where floor meets wall, plus under furniture, behind appliances, and inside closets and the garage. Vacuum first to strip existing webs, then spray. A spider that rebuilds a web on a treated baseboard still touches the surface with only its leg tips, so pairing the spray with vacuuming is what clears an infestation.
Do insecticide sprays actually kill spiders? The entomology gap
Residual insecticide sprays kill spiders less efficiently than they kill ants, roaches, or fleas. The reason is biology: spiders do not groom or clean their bodies the way many insects do, and they walk on the tips of long legs, so they absorb very little active ingredient from a treated surface as they pass over it. A spray that wipes out ants may barely faze a spider.
This is the single fact most product listicles gloss over, and it changes your whole strategy. Direct-contact spraying (hitting the spider itself) works well. Residual barriers work partly. So the reliable formula is: barrier spray to catch prey and slow traffic, dust in voids for long-term contact, aerosol for spiders you can see, and mechanical control (below) to remove the ones chemistry misses.
Non-chemical control that makes the insecticide work
Mechanical control is not optional for spiders; it is what makes the insecticide effective. Because sprays under-deliver on spiders, physically removing webs, egg sacs, clutter, and prey does more per hour than any single product. Do these alongside treatment, not instead of it.
- Sweep and vacuum webs weekly. Removing webs and egg sacs (one sac can hold hundreds of eggs) cuts the next generation directly. Empty the vacuum outside.
- Seal cracks and gaps. Caulk around windows, doors, utility penetrations, and the foundation sill. Install door sweeps. This blocks entry the spray cannot.
- Reduce clutter. Boxes, firewood, and stored items in garages and basements are prime harborage. Store off the floor in sealed bins.
- Cut the food supply. Fewer insects means fewer spiders. Manage flies and moths, fix moisture, and dial down exterior lighting.
Traps and glue boards as a supplement
Glue boards do not replace insecticide, but they earn their place as monitors and catchers. Placed flat against walls, in corners, under furniture, and along baseboards, they trap wandering spiders (often males hunting for mates) and show you where activity concentrates. TERRO and Catchmaster boards run $6 to $12 for a multi-pack.
Use traps to decide where to spray or dust next. A board that fills up near the water heater tells you the void behind it needs dust. Traps are also the safest tool around toddlers and pets since they carry no active ingredient.
A note on beneficial spiders
Most spiders are beneficial and eat the pests you actually want gone: mosquitoes, flies, moths, and even other spiders. A handful of cellar or orb-weaver spiders in a garage or garden is doing free pest control. Total eradication is neither realistic nor useful, so target harborage and problem areas rather than blanket-spraying everything.
Dangerous species: recluse, widow, and hobo
A few US spiders warrant targeted control near living spaces. Brown recluse (south-central US), black widow (widespread), and hobo spiders (Pacific Northwest) can deliver medically significant bites. For these, dust wall voids and undisturbed storage aggressively, use glue boards heavily, and consider professional help for a confirmed recluse infestation, which often hides in wall cavities.
| Species | Where common | Best control approach |
|---|---|---|
| Brown recluse | South-central US (MO, KS, TX, AR) | Void dusting + heavy glue-board grids; pro help if established |
| Black widow | Most of the US, esp. South and West | Direct-contact spray on webs, dust in dark voids, wear gloves |
| Hobo spider | Pacific Northwest | Perimeter barrier + glue boards along ground level |
Is spider insecticide safe around pets and children?
Pyrethroid spider insecticides are safe when dry and applied per label, but they are toxic to cats and fish while wet. Keep pets and children off treated surfaces until fully dry, typically 2 to 4 hours for indoor liquids. Dusts should go only where people and animals cannot reach. Botanical sprays like Wondercide allow shorter re-entry.
| Product type | Re-entry after application | Notes |
|---|---|---|
| Pyrethroid liquid (Ortho, Spectracide) | Keep off until dry, ~2 to 4 hours | Toxic to cats and fish while wet |
| Pyrethroid aerosol (TERRO) | Ventilate, ~30 to 60 min | Spot use only, not broadcast |
| Silica-gel dust (CimeXa) | Void application; no contact needed | Wear a mask when applying |
| Botanical (Wondercide) | Once dry, often under 1 hour | Lower toxicity profile, shorter residual |
Always read the specific product label; re-entry intervals and pet cautions are legally binding and vary by formula and state. A healthy lawn and yard also reduce pest pressure overall, which is why our guides to the best fertilizer for grass and a greener lawn tie into whole-yard pest management.
Frequently Asked Questions
What is the best insecticide for spiders?
The best insecticide for spiders is a pyrethroid barrier spray (bifenthrin or deltamethrin) paired with a silica-gel or deltamethrin dust in cracks and voids. Ortho Home Defense (bifenthrin) is the strongest consumer pick; Onslaught FastCap and Suspend Polyzone lead the pro grade. Because spiders resist residual sprays, always add direct-contact treatment and web removal.
What insecticide for spiders can I buy at Home Depot?
At Home Depot you can buy Ortho Home Defense Insect Killer (bifenthrin, about $10 to $18), Spectracide Triazicide (lambda-cyhalothrin), TERRO Spider Killer aerosol (deltamethrin), and TERRO glue traps. For a lower-toxicity option near pets and kids, Wondercide cedar spray runs $18 to $28. Ortho Home Defense offers the longest indoor and outdoor residual of these.
What is the best insecticide for spiders outdoors?
Outdoors, a bifenthrin or lambda-cyhalothrin liquid concentrate applied as a perimeter barrier works best. Spray a band 2 to 3 feet up the wall and 2 to 3 feet out on the ground, plus eaves and window frames. Reapply every 60 to 90 days in warm months. Switch exterior lights to yellow bulbs to cut the prey spiders feed on.
What is the best insecticide for spiders indoors?
Indoors, use a low-odor pyrethroid (Ortho Home Defense) on baseboards, corners, and closets, or a cedarwood botanical (Wondercide) where pets and children are present. Puff silica-gel dust into voids you cannot reach. Vacuum webs and egg sacs first, since physically removing spiders indoors often works better than spraying alone.
Do insecticide sprays actually kill spiders effectively?
Not as well as they kill ants or roaches. Spiders do not groom themselves and walk on the tips of long legs, so they absorb little active ingredient from treated surfaces. Direct-contact spraying kills them; residual barriers help partly. The reliable approach combines a barrier spray, void dust, direct-contact aerosol, and mechanical web and prey removal.
What is a good DIY insecticide for spiders?
A good DIY combination is Ortho Home Defense (bifenthrin) for the perimeter, CimeXa silica-gel dust for cracks and voids, and TERRO glue boards for monitoring and capturing wanderers. Total cost is roughly $35 to $50. Pair it with weekly web removal and crack sealing, which does more for spider control than any single product.
How often should I spray insecticide to keep spiders away?
Reapply exterior barrier sprays every 60 to 90 days during the warm season, and again after heavy rain if the product is not rain-fast. Indoor treatments last longer on undisturbed surfaces; re-treat every 3 months or when you see new webs. Dusts in dry voids can remain active for months to years without reapplication.
Is spider insecticide safe to use around pets and children?
Yes, when applied per label and allowed to dry. Pyrethroid liquids are toxic to cats and fish while wet, so keep pets and children off treated surfaces until dry, usually 2 to 4 hours indoors. Apply dusts only in inaccessible voids. Botanical sprays like Wondercide have shorter re-entry, often under an hour. Always follow the specific label.