By Adam Bjerk
Spiders are supposed to be our arthropod allies - beneficial creatures. They feast on insects, other arthropods, and they sometimes cannibalize one another. Without spiders, our homes and gardens would be pretty much overrun by the pestilential hoard. I know that spiders don’t want to bite us, lay eggs in our brains, or empty their poison glands into our eyeballs while we’re sleeping. To spiders, we are just a substrate to walk over in search of food, sex, and shelter. And yet…when I see a spider in or around my home, our partnership becomes strained. Eight legs are just too many, and the ominous, hydraulic gait they produce transforms me from a relatively sophisticated, well-adjusted young man into an enraged, un-evolved hairless ground ape. Sometimes I calm down and let the spider go. Sometimes I find a blunt object. I’m working on my phobia.
The truth is that spider control is rarely necessary. The myths and fears surrounding these arachnids are completely unjustified. Spiders are shy, timid creatures that only bite when being threatened or flattened. Of the thousands of species in North America, very few sport fangs capable of piercing human skin. When they do happen, most spider bites result in mild agitation or nothing at all. That being said, there are a few spiders of medical importance. With some exceptions the two spiders capable of sending us to the hospital are widow spiders and brown recluse spiders (also known as violin spiders). But even if you’re not dealing with these rare, dangerous arachnids, the presence of any spider is intolerable to most, including myself. Whatever spider you’re dealing with, large or small, dangerous or harmless, outside or in the home, you’ll find how to get rid of them here. Below I outline spider control strategies that reflect an integrated pest control approach – meaning the use of a variety of techniques, non-chemical and chemical, to get rid of these beneficial-yet-sometimes-intolerable arachnids.
Reject your inner slob. Keep a clean home that is free of clutter. Clutter – newspapers, magazines, clothes piles, trash, etc. – provides ground-dwelling spiders and the insects they’re after with safe harborages. Keep basements and crawl spaces free of clutter and debris. A clean, well-maintained kitchen is also important. People who have a spider problem in the kitchen undoubtedly have other pest problems. The spiders are there not for your cornflakes, but for the roaches in the cornflakes.
Adjust your storing habits. Store seldom-used clothing and other items in plastic bags or plastic or rubber containers with tight-fitting lids rather than cardboard boxes, which often turn into spider hotels. Storage areas should be cleaned often to detect spider populations and other pests.
Get rid of excessive moisture to control spiders. Spiders – as well as the insects they prey on – require a regular water source to survive. Fixing and insulating pipes is an important step. Using a dehumidifier in crawl spaces, basements, and attics also helps to make your home inhospitable to spiders and other pests.
Avoid spider bites. If you’re dealing with a black widow or brown recluse spider infestation (or you’re just deathly afraid of all spiders), there are a few things you can do to avoid encounters that result in spider bites. First off, keep spiders off your bed by moving it away from the wall and keeping bedding off the floor. Next, be sure to keep shoes and clothing off the floor. As an added precaution, vigorously shake them out before dressing.
If you’re cleaning an area you know to be infested with widows or browns, wear a long-sleeved shirt and pants, as well as a hat and gloves. Pants should be taped into boots and gloves should be taped into shirtsleeves.
Spider bite first aid. Spiders are generally passive and must be severely stressed to bite. If you are bitten by a spider, the American Red Cross recommends the following first aid:
Address your other pest problems. If you have a large population of spiders indoors, that means they have a plentiful food source in your home – insects. To get rid of the spiders, you’ll also need to get rid of their prey.
There are many ways to make your property less hospitable to spiders and the insects they are after. Making these changes will decrease the amount of spiders in your yard, as well as reduce the likelihood that they’ll migrate indoors.
Get rid of rock and wood piles. Decorative rock piles and wood piles are a favorite dwelling place for ground spiders. Get them away from the house. If possible, keep wood piles off the ground and only bring into your home as much as you immediately need. Similarly, it is best to just get rid of other spider shelters adjacent to the home - bricks, building materials, compost piles, debris, trash, etc.
Remove excess vegetation for spider control. Let the sun in, keep the spiders out. Thick vegetation makes for great spider habitat. Keep vegetation around your home trim and away from the house. Clear away ivy, bushes, shrubs, and grasses – anything that fosters large spider populations near your home. Promptly clean up leaf litter and debris. Mow your lawn regularly, and trim tree branches that are too near or overhang your home. Plant trees and shrubs away from structures to allow for light.
Get rid of spider entry points. Exclusion – also known as pest-proofing – is an essential part of spider control and indeed all pest control. Here are some things you can do to keep spiders out of your home.
Get rid of spider harborages (hideouts). Once you’ve worked to spider-proof outside, head indoors and start again. First stop is the basement, crawl space, or lowest level. Fill in any cracks or crevices in the foundation and around windows. Find the same utilities you sealed around outside (pipes, plumbing, wires, etc.) and seal them inside. Work your way up from the basement. Spiders hide in cracks in trim, flooring, behind outlets, countertops – any dark secluded space. Of course it would be difficult, if not impossible, to seal all such areas inside the home. Focus your energies where you’ve seen the most spider activity and where your spider traps (mechanical control below) have killed the most spiders.
Use glue boards for spider control and monitoring. While sticky traps won’t work for web- building spiders, they are outstanding for the many ground-dwelling, hunting spider species, including funnel-web, wolf, and brown recluse spiders. With glue boards, more is better. Place them along walls, in corners, behind furniture, and in dark, protected areas, in outbuildings and garages, in window sills and near doors, as well as places you’ve seen spider activity.
Glue boards not only kill spiders in a spiteful, inhumane fashion, they also help you monitor spider activity as well as that of other pests. By routinely checking and replacing glue boards, you’ll be able to determine whether your spider control strategies are working. Full, disgusting traps help pinpoint areas with the most spider activity so you’ll be able to focus your efforts in the right places. The best sticky spider traps are those that are not raised and do not have a lip, but lie flat against surfaces.
Replace outdoor lights with “bug lights.” Lights near doors and porches attract hoards of insects, which in turn attract armies of spiders to eat them. Many of these spiders may migrate into your home. Replace your blue wave lights with yellow bug lights, LED lights, or sodium vapor lights, which do not attract insects or their predators. It also helps to draw shades around windows during darkness. Perhaps you’ll miss the horror show on your doorstep, but I doubt it.
Utilize a hose or pressure sprayer for outdoor spider removal. Entrenched between two lakes and much wilderness, my neighborhood is spider prone. We generally wash them off our homes a few times a year using a pressure sprayer or a simple hose attachment. It’s effective and chemical free.
Kill spiders with a vacuum. Break out the vacuum hose and all its spider-killing attachments as often as necessary to remove webs, egg sacs, and spiders. Focus on suspected sites, corners, window sills, along trim, closets, behind furniture, and any dark, protected areas. You may need to gather your courage and adorn a rosary before bringing your vacuum into your attic, basement, and similar spider hot spots. When finished, remove the vacuum bag (or contents) and seal it in a plastic bag and toss it in an outside trash can. You can rest easy knowing that the spiders that survived the violence of your domestic killing machine will no doubt liquefy and eat one another.
Diatomaceous Earth (DE). Diatomaceous earth is made of the fossilized remains of ancient algae called diatoms. It is a food-grade, pet and child friendly dust that can be used in the same fashion as other insecticidal dusts. When spiders (or any creature blessed with an exoskeleton) walk over a thin layer of DE, they leak fluids, dehydrate, and die. Apply DE as a perimeter barrier around your home. You can also dust wood and rock piles. Indoors, use DE in basements, crawl spaces, cracks and crevices, door and window thresholds – anywhere you’ve seen spider activity.
Natural spider repellents. Though you won’t find much research to back them up, there are a variety of popular natural spider repellents. Of these, the most widely-used are osage hedge balls, which can be found in the produce section of some grocery stores (you can ask your grocer to order some). You place them in corners of rooms and windows and apparently spiders don’t like this. Horse chestnuts and eucalyptus are other popular spider repellents that are used in the same manner.
There are many consumer products on the market that effectively kill spiders, and I will make some recommendations below. However, chemicals for spider control are often discouraged unless you’re dealing with the black widow or brown recluse spider. When it comes to chemical spider control, more important than what you use is how you use it. First of all, chemicals alone won’t solve your problem; if you don’t make the changes listed above, your property will still have the same spider population potential. Secondly, use chemicals in a focused manner, not indiscriminately all over the place. Lastly, always pay close attention to directions when dealing with pesticides. They are only deemed safe by the EPA when used according to the label.
For outdoor spider control. Barrier treatments, in conjunction with pest proofing, can effectivly protect your home from spiders. Before sealing off cracks and crevices in siding and foundation, apply something like Delta Dust Insecticide (deltamethrin) or Drione Dust (pyrethrins, pipernyl butoxide, and silica gel). Besides the cracks and crevices, you may want to treat under the eaves of the roof, under porches, along the base of the foundation, the lowest edge of siding, behind shutters, and around doors and windows. For these areas you’ll want a non-dust outdoor insecticide for spider control. Good options are Bayer Advanced Home Pest Control: Indoor and Outdoor Insect Killer (cyfluthrin) and Ortho Home Defense Perimeter & Indoor Insect Killer (bifenthrin).
For trees, vegetation, and lawn. Two respected yard spider control products are Spectricide Triazicide Insect Killer (lambda-cyhalothrin) and Ortho BugBGon Max Garden & Landscape Insect Killer Concentrate (esfenvalerate).
For indoor spider control. Insecticide dusts like Drione Dust, Delta Dust Insecticide, and EcoExempt D (plant based) are ideal for wall voids, basements, behind power outlets and light switches, cracks and crevices, and other spider retreats. For direct contact spider killing, use a non-residual aerosol like CB-80 Extra or 565 Plus XLO (your shoe can be just as effective). For a longer lasting residual treatment, try Cy-Kick Aerosol, D-Force HPX, Demon WP Insecticide, or Cynoff WP (or Cynoff EC). Many of the products listed above for outdoor use can also be used to spot treat indoors, so read labels.