Spiders offer benefits in and around a home by preying on other household pests. Nevertheless, you may prefer to keep your house free of the arachnids and their webs. This guide will review how to get rid of spiders and prevent them from entering your home, as well as how to identify the most dangerous spiders in North America.
When Are Spiders Dangerous?
Spiders can be beneficial in the yard or garden by keeping the insect population down, particularly ones that can spread disease, such as mosquitoes, flies, fleas and roaches. In addition, spiders are even known to kill and eat other spiders.
- Spiders breed throughout their life cycle and just one spider egg sac can contain anywhere from 100 to 3,000 eggs. If the egg sac hatches inside the house, you may wind up with a population of spiders making themselves at home.
- Unlike many insects and household pests, spiders cause no permanent structural damage, and most do not pose any sort of health threat. The majority of species in North America do not bite unless threatened. While infrequent, their spider bites can cause a skin reaction on some people.
- Of the thousands of arachnid species, there are only two that are both aggressive and dangerous to humans: the black widow spider and the brown recluse spider.
Safety: If you suspect you've received a black widow or brown recluse spider bite, seek medical attention immediately.
How to Spot Black Widow Spiders
Black widow spiders can be identified through the following traits.
- They’re common in warm climates.
- They can be found in basements, closets and attics.
- In Southern regions, they’re black with a red hourglass shape on the abdomen.
- In Northern regions, they’re black or dark brown with rows of spots (red, yellow or white) down the middle of the abdomen.
- They have a painful, highly toxic bite that attacks a victim's nervous system.
- Bite symptoms tend to be present within an hour and often include severe muscle cramps, abdominal pain, weakness and tremor. They also may include nausea, vomiting, faintness, dizziness, chest pain and trouble breathing.
- Seek medical attention after you’ve been bitten by a black widow. The following first aid steps can ease symptoms and prevent infection in the short term: Wash the bite wound with soap and water; elevate the area; and apply a cold washcloth or ice pack to the area.
How to Spot Brown Recluse Spiders
Brown recluse spiders can be identified by the following traits.
- They’re common in warm climates, especially the southern United States.
- They’re frequently found in closets, attics, under sinks, in wood piles, under picnic tables and outdoor sheds.
- They tend to be tan to dark brown with a violin pattern near the back of the head.
- They have a stinging, highly toxic bite that damages the victim's cells and tissues.
- Bite symptoms tend to be present within 8 hours and can include severe pain at the bite site, severe itching, nausea, vomiting, fever and muscle pain.
- Seek medical attention after you’ve been bitten by a brown recluse. The following first aid steps can ease symptoms and prevent infection in the short term: Wash the bite wound with soap and water; elevate the area; and apply a cold washcloth or ice pack to the area.
How to Get Rid of Spiders in the House
There are a number of effective, lethal methods of indoor spider control.
- Spider traps and sprays are generally preferred as foggers are ineffective at getting rid of spiders. Most spider-killing formulas are based on pyrethroids, chemicals made in large part from plants in the chrysanthemum family.
- Spider traps such as glue boards are non-toxic and cost-effective, but can be less effective against larger infestations. Place in corners, along walls and any locations where you've seen spiders.
- Spider sprays kill on contact and are easy to use, but leave a residue. Spray along baseboards, under furniture and in corners.
- Natural spider repellent is non-toxic and suitable for indoor or outdoor use, but can have a slightly higher cost and require reapplication more often.
Natural Spider Repellents
If you want to repel spiders from your home with natural substances, consider these substitutes for toxic pesticides.
- Diatomaceous Earth: Like insect pests, spiders can be killed with diatomaceous earth (DE), which lacerates their exteriors, leading to dehydration. Diatomaceous earth is best used in small, thin layers in hard-to-reach areas like between and at the backs of cabinets. Spreading it around the exterior of the home will also help prevent spiders from crawling inside.
- Peppermint oil: Mix 20 drops of peppermint essential oil (not peppermint extract) into a 32-ounce spray bottle filled with water. Spray the mixture in corners, near entrances and along the floorboards around the whole house. You can also shake peppermint oil directly onto cotton balls and stuff them into crevices where you suspect spider activity. Spiders don't tolerate the smell of peppermint and will avoid every area where it is applied. You can also use eucalyptus oil to the same effect.
- Vinegar: Mix equal parts white vinegar and water in a spray bottle and spray it directly onto any spiders you see. Vinegar contains acetic acid which burns the spider upon contact.
- Other natural substances that can be effective at repelling spiders are dry baking soda, lemon juice or solutions of water mixed with tobacco.
Safety: Do not apply diatomaceous earth to counters, open or drafty areas or anywhere food is prepared. Apply in thin layers and wipe up any visible residue immediately. Always read and follow label direction for safe use of any pesticide, especially if there are children or pets in your home.
Other Natural Spider Deterrents
If you want to keep nonvenomous spiders out of your house, consider these approaches.
- Keep cats or even frogs as pets, since they are known to hunt spiders.
- Use a vacuum cleaner if you need to kill one or just a few spiders efficiently. Spider physiology is not strong enough to withstand the suction of most vacuum cleaners; the force will throw them against the tube or inner chamber of the machine, killing them almost instantly.
- If you don't have a strong fear of spiders, it may be more humane to trap the spider in a jar or glass and set it free outside. When you spot a single spider, look at the markings. If it does not appear to be a poisonous spider, pop a cup or container over it, and then carefully slide a piece of paper or a note card under the mouth of the container. Keeping the paper in place with your hand, quickly flip over the container so the spider lands at the bottom and then walk it outside at least 10 feet from your house to let it go.
Safety: Never attempt to pick up brown recluses or black widows. Immediately kill the spider with an aerosol insecticide for spiders.
Spider Prevention Methods
In order to deter spiders, you must take preventative measures to support your selected treatment methods. This includes riding your home of other insect pests such as roaches or flies, which attract spiders in search of prey.
- First, clean vigilantly, as spiders avoid very clean homes due to the lack of hiding places.
- Be sure to sweep down or vacuum up spider webs and egg sacs whenever you see them.
- Keep food put away in tightly sealed storage containers. This will help eliminate ants, roaches and other pests, which will leave spiders with no food source.
- Pick up and put away clutter. Spiders like to hide in piles of old magazines, dirty clothes, junk and anything else that will provide them cover.
- Use pesticides or other pest control treatments based on any other insect problem you may have.
Take preventative measures outdoors to keep the spiders from coming in.
- Seal up your home to keep spiders from entering through cracks and crevices. Cover vents with fine mesh insect screens.
- Apply caulk around wires, cables, faucets and electrical components that run to the outside.
- Replace or fix torn window screens and caulk up gaps around windows.
- Keep outdoor lights off or switch to yellow sodium vapor lights to keep from attracting other pests that spiders might feed on.
- Remove vegetation within eight feet of the perimeter of your home. Shrubs, trees, and ivy provide shelter for spiders and harbor insects they use for food.
Getting rid of spiders can require a combination of indoor and outdoor spider control. Learning how to kill spiders is part of the process, but to keep them from returning, ensure that other insects can't invade your house. Preventing pests from entering your home is a good way to keep spiders from following to feed on them.
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