Though spooky looking, most spiders are harmless and helpful house guests. They work to keep your home free of pesky insects and keep mostly to themselves. However, out of the thousands of arachnid species, a few are somewhat dangerous and should be removed from your living space. To learn to identify dangerous spiders, remove them safely, and keep your home spider-free, read after the jump.
Identifying Dangerous Spiders
Learn the common types of dangerous spiders. In North America, the most common types of dangerous house spiders are the black widow and the brown recluse, but learn the types of venomous spiders in your area and how to distinguish them from harmless house spiders.
Female black widows have shiny black coloring, with a distinctive red hourglass-shaped pattern on their underside. Males have a mixture of whitish dots on the upper abdomen, are typically about half the size of female spiders, and are not as dangerous as the female.
The brown recluse is a small sandy-brown spider with a violin-shaped body found primarily in the Midwest and South. They typically reside in tight, out-of-the-way spaces.
In Australia, the redback spider is a common and dangerous spider that ends up in people’s houses. Other spiders to watch out for might include the hobo spider and the wolf spider.
Study the webs. Fresh webs, as opposed to old dust-covered cobwebs, are signs of current spider activity. By learning a bit about the webs of the particular kinds of spiders you’re looking out for (or the lack thereof) you can prepare your plan of attack for undesirable spiders.
Black widow webs are usually irregularly shaped and somewhat thicker than other spider’s webs, and usually located within one foot of the ground. The webs of black widows are typically in dry corners and other safe areas, not out in the open and easy to find, and usually look somewhat erratic, with a tunneling feature where the spider hides during the day.
Brown recluse webs are loose and sticky, with an off-white color. You won’t see them strung between tree branches or in the corner of the house, but in “reclusive” spots like under boxes, in woodpiles, or other unused out of the way areas.
Large and intricate webs are the hallmark of the harmless orb-weaver spider, a helpful bug-catcher. Leave these spiders alone, or gently migrate them elsewhere.
Learn the spider’s behavior. Black widows are typically nocturnal spiders and the brown recluse rarely comes out of hiding. If you’ve got a large brownish hairy spider building a conspicuous web in the middle of the day, you probably don’t need to worry.
If you’re worried you’ve got a dangerous spider, check the webs in the middle of the day when the spider will be dormant. At this point, you can either lay out liquid or powder insecticide, or you can come back at night to kill them directly if you want to be sure.
Getting Rid of Spiders
Migrate harmless spiders and kill dangerous ones. Most spiders you encounter on a daily basis will be harmless. Move them outdoors where they can do more insect-catching good by trapping them in a jar or sweeping them onto a piece of paper and dumping them outside.
Get a large bowl or pan and sweep the spider into it with a broom. Use a magazine or newspaper large enough to cover the bowl to keep the spider from escaping prematurely, and then release it outside, far from your house if you wish.
If you want to kill the spider without smashing it, you can fill your bowl or pan with insecticide, killing the spider as you capture it. You could also spray the spider at this point with insecticide or hairspray. Only do this if the spider is harmful.
Lay out insecticide. Available in dry dusting and liquid spot varieties, you can lay this out when you find the webs during the day. This is an effective method that doesn’t require you to actively run around squashing spiders with a flashlight.
Dust applications like Drione Dust and Delta Dust are best for out of the way areas where only spiders will go, like under staircases or in attic spaces. Apply these insecticides with hand brushes in wall voids near the webs to make the locations uninhabitable for the spiders.
Liquid spot treatments like Demon WP and Cynoff EC can be used to spray under beds and in dark corners. These are usually sold in powder form, with specific instructions to mix with water and form the spray.
For a natural alternative, try diatomaceous earth, which consists of the powdered fossilized remains of diatoms. It is harmless to people and other pets, and is even used in some foods and cat litters, but dehydrates the exoskeletons of insects and arachnids.
After you’ve eradicated your spiders, it’s not a bad idea to treat the areas with insecticide as a preventative measure. Spiders tend to pick the same areas to colonize, so you might cut them off at the pass by spraying or laying some insecticide down.
Vacuum the spiders up. A good vacuum with a hose attachment means you can get rid of your spiders without ever having to get too close to them. Even if the spider is hiding in its tunnel, you can use the vacuum to suck out all the webbing and the spiders within it.
This is also an effective method for vacuuming up lots of house spider hatchlings that would be difficult to kill or migrate otherwise.
Once you’ve vacuumed spiders, remove the vacuum bag and seal it in a plastic garbage bag, and put it outside in the garbage.
Squash it. Sometimes you’ve just got to go old-school and use your shoe. If the spider is in its web, use a broom or stick to sweep the spider out into the open and use a shoe, rolled up newspaper, or book to smash the spider. It may be inelegant, but at least you’ll be sure you’ve got it. Black widows might have a tendency to head toward you if you miss, so be quick and keep your distance from dangerous spiders.
Keeping Your Home Spider-Free
Clean frequently. Since spiders like dark and undisturbed areas to build their webs, keeping a clean house is the best way to avoid infestation. Regularly sweep and mop your home, as well as vacuuming out small cracks and wall gaps. From the outside, power wash your windows to keep critters from congregating.
In the attic, basement, or anywhere you have lots of stuff and boxes stored, regularly move things around and vacuum to avoid creating spider habitats. Remove unnecessary clutter and stay tidy to eliminate the kinds of habitats spiders love. Consider spreading insecticide in those areas if you’re worried about cultivating habitats.
Outside, trim back shrubs and other foliage around your house, especially that nearest entrances. If you have firewood stacked anywhere near the house, consider moving it elsewhere. These are places spiders tend to congregate, and if they have easy access to the house, they’ll be able to make the jump quickly.
Check your doors and windows for cracks. Plug any gaps with weather stripping to make sure you’ve got a secure home and aren’t letting unwanted pests easy access to your house.
Consider spreading some insecticide into any cracks before you seal them. Use stick-on weather stripping or caulk to create the seal.
Use natural deterrents in your home and yard. Natural spider repellants are easy to make, use, and will ensure that your home stays spider free, so you won’t have to worry about killing them or moving them elsewhere. Add 3-5 drops of an essential oil like tea tree, peppermint, or lemon to a quart of water to clean your house with. These are harmless to people and pets, but create a undesirable scent for insects and spiders.
Plant eucalyptus and spread horse chestnuts. Many people believe that eucalyptus is a natural spider replant, and some studies have shown that saponin–a naturally-occuring chemical found in horse chestnuts–repels spiders.
Make a spider spray. Make a spider spray for spraying on the outside of windows and doors, and along fences and mailboxes. Mix and pour the following in a spray bottle:
1 cup vinegar
1 cup pepper
1 teaspoon oil
1 teaspoon liquid soap.
If you have repeated infestations of harmful spiders, contact an exterminator to solve your problem for you.
Don’t kill spiders if you don’t have to. They’re easy to move and good for your home.
If you get bitten by a venomous spider call the emergency room and get treated immediately.
Sources and Citations
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