Spider Control

Spider Questions, Answered

Which spiders matter, which ones don't, and how we keep your home spider-free in the Bay Area.

Realistically, only one: the western black widow. It's the only native Bay Area spider with venom medically significant enough to require attention from an adult. Bites are rare and rarely fatal in healthy adults thanks to modern care, but they can be serious in children, elderly people, or anyone with underlying health issues. The much-less-common brown widow has been spreading in California in recent years; its venom is less potent than the black widow's. Everything else you're likely to find in or around your house — wolf spiders, house spiders, jumping spiders — is harmless to humans, even if it looks scary.
Nobrown recluse spiders aren't found in California. Brown recluses are native to the central and southern U.S. (think Missouri, Tennessee, Arkansas), and decades of scientific surveys have confirmed they don't have established populations in California. Most "brown recluse bites" diagnosed in California turn out to be something else entirely — usually a skin infection or another insect bite. If you find a small brown spider in the Bay Area, it's almost certainly a harmless species. When in doubt, send us a photo and we can identify it.
Mature female black widows are shiny jet-black, about ½" body length, with a distinctive red or orange hourglass shape on the underside of the abdomen. Their webs are messy and irregular (not the classic flat spiral) and are usually built in dark, sheltered spots — under outdoor furniture, in garage corners, around hose bibs, in woodpiles, and in low brush. Juveniles and males are smaller and don't have the classic hourglass, but adult females are what you're avoiding. If you suspect one, leave it alone and call us.
Two main reasons. First, spiders follow food — a lot of spiders usually means a lot of other insects, often unseen. The spiders are a symptom of an underlying pest problem. Second, fall is mating season for many Bay Area spider species; males wander indoors looking for females, which is why you'll often see big, fast-moving spiders cross a kitchen floor in September and October. Treating the underlying insect population (and the perimeter) usually quiets the spider activity within a few weeks.
They do — ecologically, spiders are great predators of mosquitoes, flies, ants, and other insects. The trade-off is when their population grows large enough that you're seeing webs in every corner, that means they have a steady food supply, which usually means you have other pest issues attracting them. Good spider control isn't just killing spiders — it's reducing the insects they feed on so spiders don't have a reason to set up shop. That's how a quarterly perimeter program quietly fixes both.
Three things, in order. (1) We physically sweep the eaves and exterior corners to knock down all existing webs and egg sacs — even if you killed the spider, an egg sac left behind can hatch hundreds more. (2) We apply a residual perimeter treatment in the spots spiders favor: eaves, soffits, foundation corners, garages, sheds. (3) We treat the underlying insects that draw spiders in. Most homeowners notice a sharp drop in webs and spider sightings within a week or two of the first visit.
Garages, basements, and crawl spaces are spider paradise: dark, undisturbed, often slightly humid, and full of other insects (and clutter that those insects hide in). They also offer easy entry from outside through gaps under garage doors and around vents. Clearing clutter, sealing gaps, and adding the garage perimeter to your regular pest treatment will dramatically cut the spider population in those rooms — and the storage boxes in them.
New spiders will always wander in from outside — that's normal, especially in Bay Area neighborhoods with mature landscaping. The difference with our recurring quarterly service is that we maintain a fresh residual barrier and sweep the eaves on every visit, so spiders never get a chance to build webs and establish. If you see new web activity between visits on a recurring plan, give us a call and we'll come back to re-treat at no additional charge.