• Chelle Hartzer

Time's Fun When You're Having Flies (AKA: Tying up competition)

Spiders are one of my favorites. There is such amazing diversity in spiders in appearance, food preferences, habitats, biologies, and more. From a pest management viewpoint, I get that people don’t want spiders inside. I get plenty of calls for what to “do” about spiders and what the best “treatment” for spiders is. The first question I typically ask is “why do you need to?”.


A spider isn’t going to kill you. Seriously, there hasn’t been a death associated with any spider species since the 1980s. If anyone has a reputable reference for something more recent, please send that to me! Most spiders are harmless to humans and the few that could (I stress COULD) cause more serious reactions are very rare and with adequate medical attention, rarely cause severe or long-lasting reactions. A lot of people will start to argue with me here because their brother’s girlfriend’s best friend’s cousin got bit by a spider and lost their leg and almost died. What they don’t mention is that this person was suffering from advanced diabetes, had a massive staph infection, and there was some kind of “mark” that they attributed to a spider. Do not get me started on “a spider bit me!”, that’s a whole separate soap-box rant.

So you have a spider in your basement in a back corner, or there’s a little jumping spider hanging out on one of the houseplants. They are providing free pest control for you. That little cellar spider is eating the tiny pillbugs and immature cockroaches that have gotten in. The jumping spider is taking care of the houseflies and fungus gnats that are there because the houseplant was overwatered. The spiders outdoors are even more beneficial. The news media picked up a story a couple of years ago and the headline was “Spiders can eat every human on earth in one year!”. The reality is that spiders consume massive amounts of insects and other arthropods and the weight of that prey could conceivable equal the weight of all humans. All that prey they consume is a good thing. That means less mosquitoes, fewer cockroaches, and a reduction in crickets and other generally annoying pests. But to be real, I get it, customers are calling you because they don’t want spiders around.


So where do we start? We start with why the spiders are there. Spiders, like all animals, need food. If there is no food source, they will go looking for a food source elsewhere. When spider “issues” occur, the spiders are often the symptom, not the problem. There is an overabundance of insects and other prey items and the spiders are happily providing their pest control services. A facility in Baltimore, MD was reported to have over four acres of spider webbing inside and well over 30,000 spiders collected. That’s just what they collected, not a full count! The issue here was not the spiders. It was a wastewater treatment site and the fly population was incredibly high. While most spider species aren’t truly social, some species will live in close contact with others when they have plenty of resources. Australia has seen a couple of instances of massive spider occurrences, often after floods or other weather events. The spider webs are so close together and so thick, it looks like snow. Removing or at least reducing the food source will reduce the number of spiders in the area.

While many folks want a spray or an aerosol or some treatment to get rid of the spiders, that’s a band-aid. Spray and kill a spider, and you have done just that: killed one spider. That hasn’t dealt with the root causes that enable the spider (and all her little spider friends) to want to be there in the first place. Here are a few things you can do:

· Habitat removal – knock down the webs. Spiders put a lot of time and effort into their webs and need them to catch their food. If you keep destroying them, they will go somewhere else that is better for them.

· Food removal – especially for spiders that don’t build webs for food. Spiders like ground spiders, jumping spiders, and tarantulas are actively hunting for prey. Removing the conditions that are allowing for an abundance of insects around a structure means the spiders go elsewhere for their lunch.

· Exclusion – spiders are especially beneficial outdoors, keep them there. Seal up structures, especially around doors and windows and just keep the spiders out.


Spiders are amazing and beneficial. Some make beautifully intricate webs, others have incredible color patterns, and many have cool behaviors (like mimicking ants so they can eat them without being detected). I get that customers may not feel the same way. There are plenty of ways to minimize spiders both inside and outside to make them happy.

If you are having challenges with spiders or any other pests, contact me to see how I can help you!



Lagniappe: If you can’t look at a video of a dancing peacock spider and smile, well… feel free to go read someone else’s blog on cute puppies.

Urban pest consulting

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