Washington State University

Plant Clinic FAQs - Spiders

Frequently Asked Questions About Spiders

Where can I find information about common spiders of Washington?
Hobo SpiderNumerous guidebooks provide general information about spiders. One Washington State University Internet source of information about Pacific Northwest spiders can be found at EB 1548: Spiders.



We've moved into a new house and there seem to be spiders everywhere. What can we do to get rid of them?
According to Rod Crawford, Curator of Arachnids at the UW Burke Museum, most of the spiders you find in your house are not the same species as those found in your yard and garden. These house spiders are adept at living with conditions found in the home, such as poor food and water supply, and most spend their entire life in and around the structure where they were born. Few pose a serious concern to humans. For more information on house spiders, please refer to the "Spider Myth" website associated with the UW Burke Museum.

Mechanical removal (vacuuming spider when observed or catching them on sticky traps) is often an effective management option for reducing spider populations in your home. Repeat as necessary.

To prevent spiders from accidentally entering the home from the outside, seal up the spider entry points of the house (e.g. around doors, windows, and pipes).

If you choose to use a fogger insecticide (commonly called "bug bombs"), follow label directions carefully and make sure that the product is labeled for home use to kill spiders. For information on foggers, click on Bug Bombs: Overkill Can Be Dangerous - Pesticide Safety.

I believe I have identified the spider I caught in my house this week as a hobo spider (Tegenaria agrestis) according the picture I found at
EB 1548: Spiders. Could I send you a picture and have you confirm this identification?
Hobo SpiderIn order to positively identify a hobo spider, we need to use a microscope to examine several key diagnostic features. A picture of your spider might help us to provide a tentative identification of the type of spider. Click on hobo spiders for additional information about identifying (or misidentifying) spiders.

Hobo spider bites have been associated with necrotic wounds in certain people. Thus, care should be taken around these spiders.

I have a spider I would like identified, how should I preserve it before submitting it to the WSU Puyallup Plant and Insect Diagnostic Laboratory?

The best way to preserve spiders is to place them in a vial containing 70% ethanol. Mailing such a sample through the mail, however, is illegal since alcohol is both liquid and flammable so these samples would need to be submitted in person to the clinic. See insect sampling instructions for further sample submission information.

I live in Eastern Washington and have just found a brown recluse spider in my house. What should I do about this spider in my house? I am worried because I have small children that crawl around on the floor.

Research has shown that the western United States has no local populations of the brown recluse spider (Loxosceles reclusa) so the spider you found is probably not a brown recluse. A spider specialist at University of California in Riverside, Rick Vetter, has devoted a lot of effort to dispelling brown recluse myths in the West. For more information on this work, refer to Spiders and other Arachnids at UC Riverside.

We do have other spiders in Washington that can bite. Fortunately, many spiders tend not to thrive in the dry environment of our homes. The most effective prevention technique against spiders is sealing up entry points into the home- alas easier said than done. Vacuuming regularly, especially in cracks and under furniture, will also help to reduce the number of spiders in your home. Some people have had success with glue-impregnated sticky traps placed in area of high spider traffic, but out of the way of children and pets.

I see a lot of spiders in my yard. How do I best eliminate them?
DON'T!! Spiders, due to their predacious nature, are beneficial; trapping and eating flies, and other insects. Conserve your local spiders.

I found a shiny black spider near my home in Washington with what appears to be red "hourglass" marking. Could it be a black widow spider?
Black Widow SpiderYes, black widow spider populations are found in Washington with most found in Eastern Washington. However, there are several local populations in Western Washington, for example, on several of the San Juan Islands.

Many of "black widow-like spiders" we see are other members of the "comb-footed" spider family (Theridiidae) and are considered harmless.

I live in Texas and I found several large spiders floating in my swimming pool. Why can't I submit these spiders to your laboratory?
The Puyallup Plant and Insect Diagnostic Laboratory is only equipped to handle the identification of certain spiders in the Pacific Northwest. We have no one on staff specializing in the identification of spiders. You would be better served by contacting your local Cooperative Extension program.

My neighbor just told me that the deadliest spider in the world has recently been introduced to our county and can be brought into home when you buy bananas. Evidently people are bit on the fingers as they peel the banana and expose the spider and their finger rot off. The story sounds fairly far-fetched to me and I wonder if there is a place I could go to find the truth about spider stories like this.
Rod Crawford, Curator of Arachnids at the UW Burke Museum has a wonderful website "Spider Myths", which explains the truth behind many of the myths and misconceptions surrounding spiders. This website is also full of spider-friendly comments and advice.

Puyallup Research and Extension Center, 2606 West Pioneer, Puyallup WA 98371-4900, 253-445-4500, Contact Us