Best Outdoor Spider Insecticides: Bifenthrin, Granules, Aerosols

The best insecticide for spiders outdoors is Talstar One, a bifenthrin concentrate you mix and spray along the foundation, eaves and frames. Miss Muffet's Revenge is the ready-to-use bifenthrin option, Amdro Quick Kill granules treat the ground for wolf spiders, and Black Flag's aerosol kills black widows on contact. Outdoors, every insecticide needs retreating.

Which Insecticides Work on Spiders?

Spiders are harder to kill with insecticides than most insects. They do not eat baits, they spend most of their time still in webs, and they touch only a small area of any treated surface. That leaves two ways an insecticide reaches them: a direct spray on the spider, or a residue on the surfaces it walks across.

Most products that work use pyrethroids, synthetic versions of compounds from chrysanthemum flowers. The University of Kentucky's brown recluse fact sheet lists products containing bifenthrin, cyfluthrin, deltamethrin or lambda-cyhalothrin as often effective against spiders, sprayed behind shutters, along the bottom edge of siding and along the foundation. Pyrethrins, the natural version, knock spiders down fast but break down quickly in sunlight, which is why aerosols often pair them with a longer-lasting pyrethroid.

The form matters as much as the chemical. Liquid sprays coat walls, eaves and frames where web builders anchor, while granules release the insecticide into soil and mulch where ground hunters such as wolf spiders travel. A house with webs under the eaves and wolf spiders coming in under the doors usually needs both.

For the full range of outdoor options, including cobweb dusters and bug-light bulbs, see our guide to the best outdoor spider repellents. The outdoor spider spray guides also cover ready-to-use sprays and homemade options.

Spider Insecticides by Active Ingredient

Read the label rather than the brand name. The same active ingredient can be labeled for different pests and surfaces depending on the product, and a label that lists spiders only for contact kill will not give you a lasting barrier against them.

How We Selected These Products

We compared outdoor insecticides on their active ingredients, whether their labels list spiders and black widows, how they are applied, how long they last and what buyers report. Our sources were the makers' listings, Amazon's review digests, the University of Kentucky's spider guidance and the National Pesticide Information Center; we did not test the products.

We favored residual products that list spiders, plus one contact aerosol for dangerous spiders. We left out a spray whose residual claim excludes spiders, plant-oil sprays (covered in our homemade guide), and large ready-to-use jugs without buyer feedback. The four picks cover the three outdoor jobs: a perimeter barrier, ground treatment and a direct hit on dangerous spiders.

Talstar One: Best Overall Insecticide for Spiders Outdoors

Talstar One is the concentrate here: 1 gallon of water-based bifenthrin that you dilute in a pump sprayer before use.

• The maker lists spiders, ants, roaches, fleas, ticks and mosquitoes among the pests it controls.
• It is labeled for perimeter sprays around foundations, doors, windows and exterior surfaces, and for cracks and crevices indoors.
• It dries clear with little odor, per the maker.
• Buyers find it effective on spiders, call it exceptional value and report that it lasts for months.

Choose it for treating a whole house, deck and shed in one session. Spray a band along the foundation and the bottom edge of the siding, then the eaves, door and window frames, porch ceilings and railings. Mix only at the label rate, wear gloves and eye protection, and check the label for any limits in your state.

OUR CHOICE

Envu Talstar One Insecticide 1 gal

BifenthrinConcentrate1 gallon

Best for: A whole-house perimeter at the lowest cost per square foot

• ✓Lists spiders among many pests
• ✓Exceptional value, per buyers
• ✓Lasts for months, per buyers
• −Needs mixing and a pump sprayer
• −Keep off blooming plants bees visit

Editor's Note

It treats a whole house, deck and shed in one session. Mix only at the label rate.

Check Price

Specifications (3)

Unit Count

128 Fluid Ounces

Target Species

ants, beetles, spiders, flies, ticks, and wasps

Material Features

Water-Based

Miss Muffet's Revenge: Best Ready-to-Use Bifenthrin Spray

Miss Muffet's Revenge is bifenthrin already diluted: a 64-ounce jug with an attached sprayer, so there is nothing to mix or measure.

• The maker says one application kills spiders and leaves a barrier inside and outside the home for up to 12 months.
• The sprayer reaches up to 10 feet, per the maker.
• Apply in calm weather with no rain expected for 24 hours, per the maker.
• Buyers find it effective and fast, but many say the attached sprayer does not work well, and opinions on how long it lasts are mixed.

Choose it if you want bifenthrin without mixing or buying a pump sprayer, for a single-story house or the entry areas of a larger one. The maker says it is formulated for all spiders except black widows and brown recluses. If the attached sprayer fails, contact the maker for a replacement rather than pouring the product into another container.

Wet & Forget Miss Muffet's Revenge 64 oz

BifenthrinAttached sprayer

Best for: Bifenthrin without mixing

• ✓Up to 12 months per application, per the maker
• ✓Sprayer reaches up to 10 feet
• ✓Effective and fast, per buyers
• −Not formulated for black widows or brown recluses
• −Attached sprayer often fails, per buyers

Editor's Note

It gives bifenthrin without a pump sprayer. Pair it with an aerosol for black widows.

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Specifications (3)

Active Ingredients

Bifenthrin

Liquid Volume

1.89 liters

Item Form

Spray

Amdro Quick Kill Ant and Spider Killer: Best Granules for Ground Spiders

Amdro Quick Kill comes as a 3-pound shaker bag of bifenthrin granules.

• The maker says one bag covers up to 3,000 square feet and works for up to 3 months.
• It is labeled for lawns, ornamentals, flower gardens and the home perimeter.
• No mixing or equipment is needed; you shake it from the bag.
• Buyers find it easy to use and report ants and spiders gone within a couple of days; overall effectiveness gets mixed reviews.

Choose it for wolf spiders and other ground hunters that wander in from the lawn and mulch beds. Spread a band along the foundation and water it in as the label directs. It does nothing for web builders under the eaves, so pair it with a spray for those.

BUDGET PICK

Amdro Quick Kill Ant & Spider Killer 3 lb

GranulesBifenthrin

Best for: Wolf spiders and other ground hunters

• ✓Covers up to 3,000 sq ft, per the maker
• ✓Up to 3 months, per the maker
• ✓Easy shaker bag, per buyers
• −Does nothing for web builders on walls
• −Mixed effectiveness, per buyers

Editor's Note

It treats the ground where wolf spiders hunt. Pair it with a spray for webs under the eaves.

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Specifications (2)

Item Form

Granules

Active Ingredients

0.1155 Bifenthrin

Black Flag Spider and Scorpion Killer: Best for Black Widows

Black Flag's aerosol is sold by the case, 12 cans of 16 ounces each, for direct hits on dangerous spiders rather than a barrier.

• It lists black widows, brown recluses, wolf spiders and scorpions, and the maker says it kills black widow spiders as they hatch.
• The maker says to spray spiders directly or spray webs and egg sacs, from up to 5 feet away.
• Buyers find it kills spiders and scorpions quickly, including inside egg sacs; some say it does not reach the full 5 feet.

Choose it for black widows under deck rails, in woodpiles, around crawl space vents and in sheds, where a direct hit matters more than a barrier. Wear gloves when you clean up the web afterward.

Black Flag Spider & Scorpion Killer 16 oz 12-Pack

Aerosol12 cans

Best for: Black widows, scorpions and egg sacs

• ✓Lists black widow, brown recluse and wolf spiders
• ✓Sprays webs and egg sacs
• ✓Kills quickly, per buyers
• −Does not always reach 5 feet, per buyers
• −A case of 12 is a large purchase

Editor's Note

It handles black widows where a direct hit matters. Wear gloves to clean up the web.

Check Price

Specifications (2)

Unit Count

12 Count

Item Form

Spray

Whichever you choose, when and where you apply it decides how well it works.

When and How to Spray for Spiders Outside

1. Time it before late summer: spiders and webs peak from late summer into fall, so treat before then and again as the label allows.
2. Pick a dry, calm day: no rain in the forecast and no wind to carry spray onto plants or neighbors.
3. Knock down webs first: sweep eaves and corners a day before so the residue lands on bare surfaces.
4. Spray a band, not the whole wall: the foundation edge, the bottom of the siding, door and window frames, eaves and light fixtures.
5. Keep off flowers, gardens and water: skip blooming plants, vegetable beds, ponds and birdbaths.
6. Keep people and pets off until dry: follow the label's re-entry directions.
7. Retreat at the label interval: sooner on surfaces exposed to rain and direct sun.

Common Questions About Outdoor Spider Insecticides

Which One Should You Buy?

Talstar One is the insecticide to buy for spiders outdoors. Its bifenthrin residue lasts for months by buyers' accounts, and one gallon of concentrate treats a whole house, deck and shed for far less than ready-to-use jugs.

Choose Miss Muffet's Revenge if you would rather not mix, Amdro Quick Kill granules for wolf spiders coming in from the lawn, and Black Flag for black widows and scorpions. Pair any of them with web removal and warmer outdoor bulbs, since insecticides alone do not keep spiders away for long.

Before you buy, check whether your problem is web builders under the eaves or hunters on the ground, since that decides between a spray and granules.