Although they look creepy, spiders are usually harmless animals and useful hosts around the house. They work to keep the house free from nuisance insects, and are almost always on their own. However, among the thousands of arachnid species that exist, a few are quite dangerous and should be eliminated from your living space. To learn how to recognize dangerous species, eliminate them safely, and keep your home free from spiders, read on below.
Steps
Method 1 of 3: Identify the Dangerous Spiders
Step 1. Learn about common dangerous spider species
In North America, the most common of the dangerous spiders in homes are the black widow and the brown hermit spider (or fiddle spider), but also learn what poisonous spiders are in your region and how to distinguish them from harmless house spiders.
- Black widow females have a glossy black color, with a characteristic hourglass-shaped red spot on the underside. Males have a mixture of whitish dots on the upper abdomen, are typically half the size of females and are not as dangerous as they are.
- The brown hermit spider is a small sand-brown spider with a violin-shaped body and is found mainly in the South and Midwest of the United States of America. They typically live in tight, out-of-the-way spaces.
- In Australia, the red-backed spider is widespread and dangerous, and is sometimes found in homes. Other species to stay away from are the wandering spider and the wolf spider.
Step 2. Recognize the cobwebs
Fresh cobwebs, unlike the old ones covered in dust, are a sign of the ongoing activity of a spider. With some knowledge about the webs of that particular type of spider you are looking for (or their absence), you can prepare your plan of attack against unwanted spiders.
- The webs of the black widow are usually irregular in shape and a little thicker than the webs of other spiders, and are usually found no more than 30 cm from the ground. The webs of black widows are typically found in dry corners and in other sheltered areas, not in open and easy to find places, and usually appear somewhat irregular, with a characteristic tunnel where the spider hides during the day.
- The webs of the brown hermit spider are sticky and loosely stretched, off-white in color. You will not see them in the branches of a tree or in the corners of the house, but rather in hidden corners, such as under boxes, in woodpiles, or in other little-used and out-of-the-way areas.
- Large and intricate webs are characteristic signs of the harmless Araneid spiders, useful insect hunters. Leave these spiders alone, or have them gently migrate somewhere else.
Step 3. Learn the spider's behavior
Black widows have nocturnal habits and the brown hermit spider hardly leaves its lair. If you find a large, brown, hairy spider weaving a remarkable web during the day, you probably don't need to worry about it.
If you are afraid of having a dangerous spider, check the web in broad daylight while the spider is dormant. At this point you can spread a liquid or powder insecticide, or if you want to be sure you can come back at night to kill it directly
Method 2 of 3: Get rid of the Spiders
Step 1. Make the harmless spiders migrate and kill the dangerous ones
Most of the spiders you will encounter on a daily basis will be harmless. Move them outdoors, where they can best go hunting for insects, trapping them in a jar or sweeping them on a piece of paper to throw them out.
- Get a large bowl or basin and walk the spider inside with a broom. Use a magazine or newspaper large enough to cover the container, to prevent the spider from escaping prematurely, and then free it outdoors, away from home if you want.
- If you want to kill the spider without crushing it, you can fill the bowl or basin with insecticide, killing the spider upon capture. You can also spray the spider in its place with insecticide or hair spray. Do this only if the spider is harmless.
Step 2. Spread some insecticide
Available in dry powders and wettable powders, you can spread it out when you find cobwebs throughout the day. This is an effective method and you won't need to go hunting for spiders with a flashlight.
- The use of powders, such as Baygon, is perfect in out-of-the-way areas reached only by spiders, such as the basement or in the attic. Apply these insecticides with a brush to dust in the voids of the walls near the canvas, in order to make the environment inhospitable for spiders.
- Wettable powder treatments, such as Triform, can be used to spray the space under the bed and in dark corners. These are usually sold in powder form, with specific instructions on how to be mixed with water to create the spray.
- For a natural alternative, try diatomite (or diatomaceous earth), which consists of a powder obtained from the fossilized remains of diatoms (microscopic algae). It is harmless to humans and pets and is even used in some feeds and cat litter boxes, but acts as a dehydrator for the exoskeleton of insects and arachnids.
- After you have eradicated the spiders, it wouldn't be a bad idea to treat the areas with an insecticide as a preventative measure. Spiders tend to colonize the same spaces, so you can stop them at the gate by spraying insecticide.
Step 3. Vacuum the spiders
Owning a good vacuum cleaner with a hose means getting rid of spiders without ever having to approach them. Even if the spider is hiding inside its lair, you can use the vacuum cleaner to suck all the web and the spider inside it.
- This is also a good method for sucking up many house spider pups that would otherwise be difficult to kill or move.
- After vacuuming the spiders, remove the vacuum cleaner bag, close it in a plastic bag and put it out in the trash.
Step 4. Squeeze it
Every now and then you will simply have to go back to the old ways and use a shoe. If the spider is in the web, use a broom or stick to move the spider outdoors and use a shoe, a rolled up newspaper or a book to crush it. It might sound unrefined, but at least you'll be sure you've made it.
Black widows tend to head towards you if you've missed them, so you need to be quick and keep your distance from dangerous spiders
Method 3 of 3: Keep Your House Free of Spiders
Step 1. Clean often
Since spiders prefer dark, undisturbed areas to weave their webs, keeping your home clean is the best way to avoid infestations. Sweep and wash the floors in your home often, and vacuum the dust from small cracks and voids in the walls. From the outside, pressure washes the windows to prevent pets from gathering.
- In the attic, in the cellar or in any other place where you store large quantities of boxes and various objects, move things regularly and vacuum to prevent the creation of habitats suitable for spiders. Eliminate the things left lying around that you no longer need and keep arranged to eliminate the kind of environments that spiders prefer. Consider spraying insecticide in these spaces if you are worried about fueling the development of potential habitats.
- Outside the home, prune shrubs and other types of greenery around the perimeter of the home, especially those that are closest to the entrances. If you have firewood stacked somewhere near your home, consider moving it elsewhere. There are places where spiders tend to congregate and, if they have easy access to the house, they will be able to jump into it quickly.
Step 2. Check the doors and windows for cracks
Seal any holes to make sure you have a secure home and don't leave easy access for unwanted pets.
Consider whether to spray insecticide inside the cracks before sealing them. Use adhesive gaskets or sealant to create the gasket
Step 3. Use natural deterrents at home and in the garden
Natural spider repellents are easy to make, use and ensure you have a spider-free home so you don't have to worry about killing them or letting them migrate.
- Add 3-5 drops of tea tree essential oil (tea tree plant), mint or lemon, to a quarter liter of water and use it to clean the house. The oils are harmless to people and pets, but they create an unpleasant odor for insects and spiders.
- Plant some eucalyptus trees and sprinkle some horse chestnut fruit. Many people consider eucalyptus a repellent for spiders and some studies have shown that saponin (a natural compound found in horse chestnut) is a repellent for spiders.
Step 4. Create a spider spray
You can create an outdoor spray yourself that you can spray on doors, windows, along fences and on the letterbox. Mix the following ingredients in a bottle equipped with a sprayer:
- 1 cup of vinegar
- 1 cup of pepper
- 1 teaspoon of oil
- 1 teaspoon of liquid soap.
Advice
- If you have had repeated infestations with dangerous spiders, contact an expert to fix the problem.
- Don't kill spiders if you don't need them. They move easily and are useful around the house.
