Spider Control

The web tells you more than the spider does. A cobweb tangle out in the open, with the spider hanging upside down in it, is an American house spider. A sheet web with a funnel retreat is a grass spider or a hobo spider. No web at all means a wolf spider, which hunts on the ground. Webbing that radiates from a single crevice is a southern house spider.

The brown recluse has six eyes, not eight. They sit in three pairs in a U-shaped line, and seeing them needs a good hand lens. The body runs 6 to 13 mm, the tan color is uniform, and the legs carry no bands and no conspicuous spines. A spider with eight eyes, banded legs, leg spines, a patterned abdomen, an open web, or a body over half an inch is not a recluse.

The violin marking is not reliable. Arachnologist Rick Vetter at UC Riverside is explicit that so many people read violin shapes into ordinary markings that it is not a usable characteristic for a non-expert. The eye count and the rule-out list above are what hold up, and in younger recluses the mark is fainter still.

Range is the strongest filter of all. Penn State Extension lists the brown recluse as established in 16 states, from Nebraska and Kansas south to Texas and east to southern Ohio and Georgia. Over several decades about 20,000 suspected spiders were turned in by Californians and none was a brown recluse. Outside the established range, a recluse report is almost always a misidentification.

The widow hourglass sits on the underside and it varies. UC IPM describes it as anything from two merged triangles to separated triangles, a triangle and a small bar, barely perceptible red, or absent entirely. You see it only when the spider hangs underside up in its web. Males and juveniles look nothing like the stereotype, and Penn State notes they lack fangs large enough to pierce human skin.

Shed skins and egg sacs confirm a recluse infestation without a sighting. University of Kentucky describes the molted skins as having a distinct outstretched appearance. Egg sacs are off-white, about a third of an inch across, and hold 40 to 50 eggs. Look along joists, sills and rafters, and under rolled insulation, in garages, attics, basements and crawl spaces.

A recluse web is a hiding place, not a trap. University of Arkansas Extension describes small, loose, white to off-white webs with irregular strands, built against a wall or ceiling in an undisturbed corner and used as a retreat. Suspended webs strung along walls, corners, ceilings and outdoor vegetation belong to other spiders. If the web is visible from across the room, it is not a recluse.

Flat sticky cards are the extension-recommended way to survey. Use cards without a raised perimeter edge, placed in corners, along baseboards and at wall-floor junctures, especially behind furniture and clutter, because recluses follow walls. Judge progress by the number of new spiders caught. No authoritative source publishes a catch-count severity scale, so treat the numbers as relative rather than as tiers.

A zero catch is itself meaningful. University of Kentucky makes the inference directly: a suspected bite becomes even more unlikely if a thorough inspection of the premises yields no sign of brown recluse spiders. Dozens of cards left out for several weeks with nothing on them is strong evidence against an infestation.

Widow spiders show up in web strength and egg sacs. UC IPM describes an irregular, tough-stranded, sticky cobweb mesh, usually within three feet of the ground, with the spider hanging underside up. Western black widow sacs are yellowish and teardrop shaped and hold about 300 eggs. The brown widow sac is unmistakable: silk protuberances all over the surface, like a very large pollen grain.

Where to look outdoors. UC IPM points to holes, cracks and crevices associated with structures, with brown widows favoring cluttered spots such as woodpiles, chain-link fences and plastic patio furniture. Penn State adds stones, stumps, vacant rodent holes and dark corners of barns and garages.

Spiders do not damage a house. No university extension or federal agency source documents structural damage from any US house spider. They do not chew wood, tunnel through materials, or nest inside building components. What they leave is webbing and egg sacs in eaves, garage corners, window frames and storage areas, which is an appearance and cleaning problem rather than a repair problem.

A spider population is a symptom of an insect population. Spiders settle where prey is, so the durable change is cutting the insects they feed on, reducing the exterior lighting that draws those insects in, clearing clutter and woodpiles stacked against the wall, and sealing gaps. UC IPM notes that regularly vacuuming or sweeping windows, room corners and storage areas removes the spiders and their webs together.

Cellar spiders and cobweb spiders are worth leaving alone. University of Kentucky notes they prey on other pests, including brown recluses and the insects recluses hunt, which makes them beneficial in the places people most want to clear out. Removing them can work against you.

What can a spider bite tell you?

Almost nothing about which spider did it. Dermatology and entomology sources agree that bite reactions are non-specific. The same welt can come from a mosquito, a flea, a mite, a spider, or a drug reaction. Texas A&M AgriLife states it is often very difficult to determine the cause of a bite with certainty without a specimen or an observation. Confirmation comes from finding the spider, its shed skins, or its egg sacs.

Do brown recluse bites usually turn necrotic?

No. Necrosis is the minority outcome. Penn State Extension and UC Riverside put roughly 90 percent of bites at no reaction or a small red papule that heals on its own, about 10 percent at a dermonecrotic lesion, and under 1 percent at a systemic reaction. The American Academy of Family Physicians reports the same order: bites typically resolve in a week or less, with an estimated 10 percent becoming necrotic after 24 to 48 hours.

Why are recluse bites so often diagnosed in error?

Because around 40 other conditions look like one. UC Riverside lists staph infection including MRSA, strep, shingles, Lyme disease, sporotrichosis, diabetic ulcer, pyoderma gangrenosum and focal vasculitis among them. Several are dangerous if treated as a spider bite. In California, more people are diagnosed with recluse bites in a month than recluse spiders have ever been collected in the state.

An infestation does not mean bites. Vetter and Barger collected 2,055 brown recluse spiders in six months from one occupied home in Lenexa, Kansas, at least 400 of them large enough to envenomate. The family of four had lived there for years and not one envenomation occurred.

What does a black widow bite do?

It acts on the nervous system rather than the skin. The local lesion is minimal, often two puncture marks. Poison Control puts muscle cramping at 15 to 60 minutes. The American Academy of Family Physicians describes symptoms arriving in waves and continuing for 48 to 72 hours while rarely being life threatening. Penn State records no US deaths from black widow bites since 1983, and notes that immature and male widows cannot pierce human skin.

Do hobo spiders or yellow sac spiders cause flesh-eating wounds?

No. The CDC and NIOSH venomous spiders page lists only the black widow and the brown recluse. Utah State Extension states that the CDC does not list hobo spiders among venomous species toxic to humans and that no significant scientific evidence suggests a necrotic bite. For yellow sac spiders, a review of 20 verified US and Australian bites found no necrosis at all.

What should you do after a spider bite?

CDC and NIOSH advise staying calm, identifying the spider only if that can be done safely, washing the bite with soap and water, applying a cold compress, elevating the area and seeking medical attention. Poison Control suggests cold water or a cloth filled with ice for 10 to 20 minutes. MedlinePlus lists applying a tourniquet under what not to do. Poison Control is free, confidential and open 24 hours at 1-800-222-1222.

This is general information, not medical advice. PestChief does not diagnose bites, and no one can name a pest from a mark on skin. If a bite concerns you, contact a healthcare professional or Poison Control.

1. Do not knock down webs you want identified: Leave one or two intact webs and photograph any spider you are worried about from a safe distance.
2. Declutter storage areas: Move boxes off the garage or basement floor and away from walls so shelter sites can be treated.
3. Wear gloves when handling stored items: Widow and recluse spiders bite defensively when pressed against skin, usually in boxes, gloves or shoes.
4. Clear the exterior perimeter: Move firewood away from the wall and trim vegetation touching the siding.

Which spiders should I actually worry about?

The great majority of spiders found in and around US homes are harmless to people and are useful predators of other insects. Two groups get special handling in pest control work: widow spiders and recluse spiders. Both are shy, both prefer undisturbed spaces, and both are worth professional attention when found indoors where people reach blindly.

University extension guidance is consistent on one practical point: correct identification matters, because harmless cellar spiders, wolf spiders and grass spiders are frequently mistaken for medically significant species.

How do professionals control spiders?

Spiders are not controlled the way ants are. They do not share food with a colony, so bait does nothing. Control comes from physical removal, habitat change and treating the specific voids and eaves where they rest.

Because spiders eat other insects, the most durable result comes from reducing that food supply. Cutting flying insect pressure at exterior lights and clearing web sites under eaves usually does more than any single product application.

• De-webbing eaves, porches, window frames and garage corners
• Crack and crevice treatment where spiders shelter, not broadcast spraying
• Sticky monitors in garages and basements to confirm which species are present
• Exclusion work on door sweeps, vents and window screens
• Advice on exterior lighting, mulch depth and storage that reduces prey insects

When do spiders come indoors?

Late summer and fall produce the most calls. Spiders mature, males wander looking for mates, and cooler nights push both spiders and their prey toward the warmth of a structure. A second, smaller wave happens in spring in mild climates.

Where are brown recluse and widow spiders found?

Brown recluse populations are concentrated in the central and southern states, so recluse concerns in the Northeast or Pacific Northwest are usually misidentifications. Widow spiders are widespread but especially common in the South and Southwest, where garages, block walls and irrigation boxes give them ideal harborage.

Does pest control get rid of spiders permanently?

No treatment makes a home permanently spider-free. Regular de-webbing, exclusion and reducing the insects spiders feed on keeps numbers low. Most homeowners with ongoing spider pressure use a recurring exterior service.

How do I know if I have a black widow?

Black widows are glossy black with a red hourglass on the underside of the abdomen and build irregular, strong webs low to the ground in sheltered spots like garages, crawlspaces and meter boxes.

Are brown recluse spiders in my area?

Established brown recluse populations occur mainly in the central and southern United States. Outside that range, suspected recluses are usually other tan spiders, so identification by a local professional or extension service is worth doing before acting.

Do spider sprays work on their own?

Contact sprays kill the spider you hit but leave the web sites and the insect prey that attract more. Removing webs and cutting prey insects around lights and doorways gives longer-lasting results.

Why are there suddenly so many spiders in fall?

Spiders that hatched in spring reach adult size by late summer, males wander to find mates, and falling night temperatures push spiders and their prey toward buildings. The population did not appear, it grew up.

How much does spider control cost?

Targeted spider visits commonly fall in the $150 to $300 range, and spiders are usually covered in general pest plans at roughly $40 to $80 monthly. These are national estimates from published sources, not a PestChief quote. The company that inspects your home sets its own price.

Does PestChief treat spiders?

No. PestChief does not spray, de-web or inspect. PestChief passes your ZIP code and your pest to one independent local pest control company that covers your address and handles spiders, and that company contacts you directly. The service is free to the homeowner.

• UC Statewide IPM Program, Home and Landscape pests
• Penn State Extension
• Texas A&M AgriLife Extension
• University of Kentucky Entomology ENTfact-631, Brown Recluse Spider
• University of Kentucky Entomology ENTfact-622, Spiders
• Penn State Extension, Brown Recluse Spiders
• Penn State Extension, Southern Black Widow Spider
• UC Riverside, How to Identify and Misidentify a Brown Recluse Spider
• UC Riverside, Myth of the Brown Recluse
• UC Riverside Department of Entomology, No, That Is Not a Brown Recluse Spider Bite
• UC Riverside, What Causes Necrotic Wounds Other Than Brown Recluse Bites
• University of Arkansas Cooperative Extension, Brown Recluse Spiders
• UC IPM, Widow Spiders and Their Relatives
• Utah State University Extension, Hobo Spiders
• CDC NIOSH, Venomous Spiders at Work
• Texas A&M AgriLife ENT-3006, Diagnosing Mysterious Bug Bites
• American Academy of Family Physicians, Arthropod Bites and Stings, 2022
• National Capital Poison Center, Black Widow Spiders
• MedlinePlus, Insect Bites and Stings