Spider Control and Black Widow Removal in Los Angeles

Two widow spiders now share Southern California yards. The western black widow is native and, according to UC IPM, very common in populated areas across the state, usually outdoors around homes, outbuildings and rock walls. The brown widow is a newcomer: for decades it was known in the U.S. only from Florida, then turned up in large numbers in Southern California during the 2000s.

By 2016 UC IPM described the brown widow as well established from Santa Barbara to the San Bernardino area and south to Mexico, while it had not established north of the Los Angeles Basin, in the Central Valley or in the desert.

The two species split the property in a predictable way. Brown widows favor cluttered, man-made outdoor spots such as cheap plastic patio furniture, chain-link fences, woodpiles and plant pots, and a 2012 study cited by UC IPM found them outnumbering black widows in urban sites while being absent from natural chaparral and coastal sage scrub.

Black widows lean toward darker, drier shelter: garages near doors and vents, rodent burrows, holes in walls and the clutter that collects along side yards. A European look-alike, the noble false widow, was first found in Southern California in 2011, which adds to the confusion when people try to identify a dark spider from a photo.

Older housing gives spiders more ways in. UC IPM lists foundation cracks and gaps around windows and doors as the main entry routes, and those gaps widen with age. In the East Pasadena–East San Gabriel planning area, for example, county planners counted 83.6% of housing units as built before 1979. On homes like these we check weatherstripping, garage door seals and foundation vents along with the webs themselves. [2] [1] [6]

Many Los Angeles residents are told, by a neighbor, a website or sometimes a clinic, that a skin wound is a brown recluse bite. UC IPM is clear that there are no populations of the brown recluse in California.

Fewer than 20 verified brown recluse specimens have been collected in the state over several decades, and the ones found were hitchhikers in belongings moved from other states. In a 2000–2005 nationwide survey, nearly 600 spiders submitted from California yielded exactly one brown recluse, from a family that had moved from Missouri. CDC describes the brown recluse range as the midwestern and southern United States.

California does have native recluse relatives, but they are not a household issue in the LA Basin. The most common, the desert recluse, lives mainly in the Sonoran and Mojave deserts and dry foothills of the lower San Joaquin Valley, areas with few people.

A non-native Chilean recluse is established in a small part of Los Angeles County, where UC IPM reports it is usually found in commercial and municipal storage basements rather than homes. The violin marking people look for is unreliable, and UC IPM notes that more than 99% of spiders Californians bring in for identification are not recluses.

The wounds blamed on recluses usually have other causes. UC IPM lists bacterial infections such as MRSA and Group A strep, bites from fleas, bed bugs, mites, mosquitoes and ticks, and conditions such as shingles, diabetic ulcers and chemical burns; in one study, 29% of patients who arrived with a supposed spider bite had MRSA.

Those findings are why we recommend seeing a doctor for any spreading or worsening wound, and why we identify the spiders on your property instead of treating for a species that is not there. If you catch the spider, keep it in a sealed jar for us. [3] [1] [5]

UC IPM notes that black widow bites are quite rare even where the spiders are common, and nearly every medically important bite comes from an adult female. Bites usually happen when a hand meets a web: reaching under a patio chair, picking up firewood, pulling on a garden glove or shoe left in the garage.

The bite itself may feel like a pinprick or nothing at all. Within about an hour, symptoms can include pain that spreads from the bite to the chest, abdomen or whole body, rigid stomach muscles, muscle cramps, sweating, nausea, headache and restlessness. CDC also lists difficulty breathing and high blood pressure among possible effects.

Brown widow bites are much milder; in the study UC IPM cites, the main symptoms were pain at the moment of the bite and burning at the site, and brown widows tend to play dead rather than bite. False black widow bites resemble a yellowjacket sting. Yellow sac spider bites usually cause bee-sting-like pain and some redness. Those differences are one reason species identification is the first step of every PesPro spider visit.

For a suspected black widow bite, UC IPM advises staying calm and seeking medical attention promptly; CDC's first-aid steps are to wash the bite with soap and water, apply a cold, damp cloth or ice, elevate the area if possible, and get professional medical care right away. Do not try to remove the venom yourself. Trouble breathing, chest pain or severe, spreading pain needs emergency care. An antivenom exists, and doctors decide whether to use it. Bring the spider if it can be captured safely. [2] [5] [1]

UC IPM states plainly that insecticides alone provide no long-term spider control, and that both widow species re-infest areas that have been treated. Over-the-counter sprays work mainly on a spider you can see and hit directly; the widow retreating deep in a block-wall crack, or the one sitting 10 feet up under the eaves with its web hanging lower, is untouched. Spiderlings also disperse by ballooning on silk from fence posts and plants, so a neighbor's yard can restock yours.

Egg sacs are the bigger problem. A black widow sac holds about 300 eggs, and a single brown widow can produce 20 or more sacs over her life. In a 2016 study described by UC IPM, the common water-based products did not affect the eggs inside brown widow sacs at all; only petroleum-based formulations penetrated the silk. Spraying a patio set without removing its spiky sacs leaves the next generation in place.

PesPro's approach is built around those facts. We physically remove webs and egg sacs indoors and out, apply targeted treatments into the cracks, voids and crevices where widows retreat, add a perimeter treatment to slow new arrivals, seal the entry points we find, and treat the insects that are feeding the spiders. Some spider-control materials, such as the dusts UC IPM mentions for wall voids and attics, are restricted to licensed applicators. Because spiders keep arriving from outside, lasting control comes from repeat visits, which is why spiders are covered in our bi-monthly and quarterly general pest programs. [2] [1]

Spiders go where the food is. UC IPM points out that homes with more insects are more likely to have spiders, and that outdoor lighting draws the night-flying insects that web-building spiders feed on. Where you can, aim fixtures away from the house, windows and doors, or move the light to a post a short distance from the wall so insects gather there instead of at your entry. Good window and door screens keep out both the insects and the spiders hunting them.

Clutter is the second lever. Keep firewood stacked away from the house and wear gloves when moving it. Clear leaf litter, trash and dense plantings from the strip along the foundation, and trim shrubs back from walls. In the garage, store boxes off the floor and away from walls with the seams taped shut, and keep gardening gloves and work clothes in closed bags. UC IPM also recommends checking plastic toys and playhouses for openings where widows can settle.

Inside, regular vacuuming is one of the most effective tools available, because spiders and their egg sacs rarely survive the trip through the hose. Pay attention to window frames, ceiling corners, closets and storage rooms. Outside, a broom or a strong spray from the hose takes down webs on eaves and walls. Sealing foundation cracks and gaps around doors and windows closes the routes UC IPM identifies as the main ways spiders get in. We point out the specific gaps and light fixtures that matter during each inspection. [1] [2] [4]

Most encounters with widows in Southern California happen in a handful of predictable places: the underside of plastic patio chairs and picnic tables, the handles of trash cans, the rims of plant pots, toy bins and playhouses, and shoes or gloves left in the garage. UC IPM lists most of these as typical brown widow sites, and CDC's prevention advice is simple: shake out or inspect clothing, shoes and gear before use, and wear gloves when handling stacked or long-undisturbed materials.

On a PesPro visit, these are the spots we check first, because they are where small hands and curious pets reach. We remove webs and egg sacs from play areas and outdoor furniture by hand rather than relying on product, and we keep any treatment to cracks, crevices, wall voids and the perimeter rather than surfaces children touch. PesPro uses pet-safe and child-safe formulations following California Department of Pesticide Regulation guidelines, and your technician will tell you how long to keep pets off treated areas, typically until the application has dried.

It also helps to know which spiders can stay. UC IPM describes most spiders as beneficial predators of pest insects; an orb weaver in the rose bed is doing useful work. The goal around a family home is to keep widows away from the places people put their hands, and to keep cobweb spiders out of the living space, not to sterilize the yard. Spider control is quoted after we see the property, and quotes are free. [2] [5] [1]