It’s getting cold and the spiders are trying to find a warm spot to spend the winter. Most spiders are completely harmless, even beneficial, just creepy. One exception is the Hobo spider. Their bite causes a wound that can be slow to heal. The bite of the Hobo spider (tegenaria agrestis) has been mistakenly identified as being a bite from the Brown Recluse, but that spider does not live in Idaho.
Hobo spiders are brown, non-descript spiders. A quick look at the spider’s legs will tell you whether you need to look farther to make a positive ID. Does the spider have stripes on its legs? If so, no problem because the hobo spider’s legs have no rings, they are all one, light brown color. No rings? Look farther. Their abdomens have chevron shaped markings (think stripes on a military uniform). The male has boxing glove type sexual organs (palps) on the front of this body. The female has them too, but here palps aren’t swollen at the tip.
This spider is a funnel weaver and the web is non sticky. An insect trips the web and the hobo spider races out and quickly captures the invading insect. The hobo spider also has poor eyesight. Between the trapping instinct and the spider’s poor eyesight, this spider bites first and asks questions later. That is the reason this spider is sometimes called the “aggressive house spider” and why the word agrestis is in the spider’s name. Usually bites happen when the spider is trapped in clothing, bedding or in shoes. Fifty percent of these bites are considered ‘dry’, and one never even knows they’ve been bitten. If venom is injected, redness will develop and the bite can be mistaken for a mosquito bite for the first 24 hours. After that, a blister develops which breaks after about 24-36 hours and begins oozing. This deep, oozing wound can take months to heal. If the bite is in a fatty area of the body, it might take more than a year and in extreme cases skin grafts might be needed. Flu-like symptoms could also be present. Yikes!
Get rid of this spider! How? Pre-baited sticky traps are the most successful. Insecticides labeled to kill spiders usually aren’t effective against the hobo spider. In fact, insecticides may make your population of those insects worse because the chemical kills off the predatory spiders that eat the hobo. Pre-baited traps have been impregnated with a pheromone to attract the hobo spider and are placed around baseboards and behind furniture. They are very sticky and catch any spider or insect that wanders across them, not just the hobo spider. Put them where kids and pets can’t get to them because like I said, these things are really sticky. These traps can be found at D&B Supply.
Seal your doors and windows to keep out the cold as well as insects. Send the message that the hobo spider should hop the next train out of town with his little knapsack thrown over his back.