Spiders are scary to some, but beneficial

By Toby Day - 09/15/2007

I like spiders. However, I don’t know if there is another creature the size of an M&M that instills more fear in humans. My wife’s fear of the eight-legged beast usually turns to anger when she is tiptoeing on the couch, pointing at it and yelling at me to kill it. What she hates most is that I usually play with the spider a while before slaying it (not my choice) with the most formidable weapon in the house — a tissue.

I start to see more spider samples come into my office this time of year because spiders are trying to find a new environment to survive the winter. People who bring me spiders for identification are usually convinced the one they found in their basement is poisonous. However, most are not.

There are only two spiders that are poisonous in Montana — the black widow and the hobo spider (also known as the aggressive house spider). Fear is rampant around Butte and the surrounding area about hobo spiders. Yes, the bite of a hobo spider may cause the tissue around the bite to die, but they are not deadly.

The best way to keep spiders out of your home is to exclude them and reduce their environment. Replace moldings around doors and windows and plug the holes in your foundation. Keep your house clean under furniture and in the corners, reducing a favorable environment. Removing debris from the outside of your house, such as woodpiles, will reduce spider havens and food sources.

And, remember this. Most spiders are beneficial; they prey on insects, not on you. Entomology specialists believe that control measures should only be used in situations where the spiders are intolerable and pose a threat to individuals or pets (which is rarely the case and usually involves the black widow). Use a vacuum or a broom to move or crush the spider (or a tissue, if you’re so inclined).

Don’t try to spray them with insecticides, they rarely work on spiders.

Toby Day is the Butte-Silver Bow Extension Agent specializing in horticulture and 4-H. He may be reached at the Butte-Silver Bow Extension office at 305 W. Mercury No. 302 in Butte, by phone at 723-0217, or by e-mail at tday@montana.edu.