Don’t be spooked if spiders creep indoors this fall, experts say

SALT LAKE CITY — With the weekend forecast bringing colder weather, spiders are bound to make their way into homes any day now. A Utah State University extension in pest management wants to help prepare people for the creepy encounters.

As spiders near the end of their life cycles, they search for mates and a sheltered place to lay their egg sacks. Nick Volesky said it doesn’t need to be scary because most species of spiders in Utah are not a danger to humans, and are typically considered unaggressive or even docile.

In fact, spiders are highly beneficial to the environment and people. They prey on other pests and insects, and serve as an excellent source of food for the more preferable insects, birds, and wildlife in Utah.

Here are some common spiders you might encounter:

Cellar spiders:

• found in cool, dark, moist places like basements and crawlspaces, or under furniture, etc.
• brown, six eyes, long skinny legs
• often build cobwebs in corners, on walls, and ceilings, to capture prey
• female spider carries her eggs in her fangs
• not a medical concern to humans, beneficial

 

Wolf spiders:

• found in plants or dirt, under objects, in piles of objects, etc.
• brown or black, up to 2″ diameter, eight eyes in unique pattern
• not likely to build webs, actively hunt other insects and spiders
• Female spider carries egg sack under belly, and carries baby spiders (spiderlings) on her back
• not of medical concern to humans, beneficial

Hobo spiders:

• found in cracks and crevasses, gardens, dirt, plants, under rocks, ground level, pipes, tubs and sinks, etc.
• body up to 3/8 inches long, hairy legs add diameter, fast moving, variety of colors but no stripe pattern on legs
  • many funnel web spiders often look similar, particularly hobo and grass spiders
• builds funnel webs to catch prey
• Female deposits eggs in fall, male dies after mating
• do not cause necrotic lesions in humans, beneficial

Here are ways to keep spiders and other pests out of your home:

• Caulk, seal and screen all entry points into the building to exclude spiders.
• Change exterior lighting from standard lights to sodium vapor bulbs to reduce insects attracted to the building.
• Vacuum regularly to suck up spiders, webbing, and other insects which can serve as food for spiders.
• Minimize clutter to reduce areas for spiders to hide, reproduce, and lay eggs.
• Use sticky traps along baseboards to monitor and help control ground dwelling spiders.
• Interior/exterior insect sprays are generally ineffective at reducing spider populations long-term, but may provide some short-term knockdown and repellency.
• Insecticidal dusts can be used in low traffic areas such as boiler rooms, crawl spaces, and voids for longer residual control of spiders

If you have been bitten by a spider, Volesky said the only way to confirm what kind of spider bit you is to collect it and have it identified, which you can do through Utah State University Otherwise, a bite is rarely identifiable by symptoms.

The spider of medical concern in Utah is the black widow, but if you experience a reaction to a bite or symptoms mimic a severe bite, you may want to seek medical attention.