|
|
  |
|---|
Recently we’ve had lots of people asking questions about spiders. For that reason (and perhaps also because I’m writing this near Halloween), it seems appropriate to talk about spiders. Gardeners know that spiders eat many bad bugs in the garden. We tolerate them, maybe even welcome them outside. We have all stopped at one time or another to admire a perfect, dew-spangled cobweb.
It’s when we notice spiders indoors that most people start to object. Let’s get one thing clear from the start. Your house, like mine, has a resident spider population. They live in attics, basements or crawl spaces; behind and under furniture; bookcases or appliances; and in cracks between boards. Corners and baseboards are favorite locations.
It’s best if you can be philosophical about resident spiders. A few spiders are rarely noticeable and help control other insects like flies, mosquitoes, clothes moths and cupboard pests. Some of the larger species mature and become more active from late August to early October. That’s when your the house may appear to have been invaded. Actually, although outdoor spiders do sometimes come in, most soon die of thirst or fall prey to resident species.
Spiders that are noticed--like the ones that get trapped in the tub or run up a wall--can be captured and released outside, vacuumed up or swatted flat. Usually spider activity declines by mid-October. Unless you are continually introducing new spiders on firewood, your household spiders will retire into obscurity for another year.
Spiders produce sheets or strands (cobwebs) of silk webbing and small, white specks of excrement, which may drop on underlying items. If these get bad enough to be annoying, it’s time to do a little spider management. People with allergies to spider venom, a fear of insects or severe health problems may want to take a less tolerant approach.
Horror movies and just plain misinformation about spiders often cause people to fear them. Also, some spiders move quickly, giving the impression they are "after" us. Others hang around at eye level, where we blunder into their webs. With some accurate knowledge about spiders, it may be possible to reduce the fear.
Spiders are predators, but humans are far too big to be prey--even for the most ambitious spider! Many spiders have small mouthparts and are not capable of biting through human skin. Spiders that can bite only do so when provoked, as a defensive reaction. Often bites occur when the spider is pinched or trapped in clothing.
Spiders inject a small amount of venom into their prey, so they are all "poisonous." A few spiders are known to be dangerously venomous to humans. The others able to bite people produce reactions varying from none to that of a mosquito bite or wasp sting, unless the individual has an allergy to that particular venom. Consult a physician, if pain or discomfort follows a spider bite.
The black widow is common east of the mountains, but it is highly unlikely you will ever see one in the Puget Sound region. The brown recluse spider is not known to be established anywhere west of the Rockies. Occasional reports of bites by brown recluse spiders have never been verified with an actual spider specimen.
The aggressive house spider, however, is frequently found in Western Washington. It bites when cornered or threatened and can cause a severe reaction in persons allergic to the venom. The allergic reaction is very similar to that of the brown recluse.
Though it is unrealistic to expect that they can be totally eliminated, you can manipulate the environment to reduce spider numbers. I haven’t room to go into it here, but I would be happy to send you information about management techniques. Send a self-addressed, stamped envelope to Snohomish County WSU Extension, 600 128th Street SE, Everett WA 98208 and ask for the free spider fact sheet. It is also available on line, along with some useful links, in our Library.
Hortsense: Managing plant problems with Integrated Pest Management
