Six years ago I wrote a post about integrated pest management options and approaches for dealing with termites (which has a lot of great reference material on the insects themselves and approaches for managing them. [1]) The post went live not long after the first (and, I believe, the last) time I spread nematodes in the yard as an organic pesticide option, so (as it was one of the earliest posts on this blog) it seemed like time for an update on what has and hasn’t happened in the intervening years.
My spot-treating of the swarm locations did not work – because that’s not how termites work. The following five springs, we saw evidence of termite swarms, including inside our house, and I kept promising to do something about it. However, thanks to a perfect storm of analysis paralysis, wishful thinking / denial, the only friend-vetted organic pest control company in the area going out of business, and illness / exhaustion, I displayed an epic level of procrastination that tested the very limits of my husband’s patience. It was finally this spring that I took action, recognizing that if I didn’t, I might soon not have a house to live in… or a husband.
Long-Delayed Action
This post comes with a huge disclaimer that I have no evidence that the plan I’m about to describe worked – only a lack of evidence to the contrary. (But that’s how testing this hypothesis goes: I can’t prove there aren’t any termites in or around our house, only that there have been none of the signs that we’ve seen in previous years.)
Image credit: [2]
My primary goal, of course, was to rid our house of the termites, but I wanted to do that without synthetic chemical pesticides, if at all possible. As laid out in my previous post on the subject, my approach would follow the steps of prevention first, followed by organic pest treatments, with chemical solutions as a last resort. I then got to contacting service providers in my area (and outside my area for second opinions). From weatherization, [3] to concrete, [4] to electrification, [5] I am every contractor’s worst nightmare because I used to manage housing contractors for work. As a result, I am clear about my expectations upfront, as well as when they are not being met during the job.
In order to ensure I got what I was looking for from a pest management company, I was crystal clear in my initial outreach that my priority was organic treatment, spot treatment if possible, and something that would not harm the beneficial insects (such as spiders and house centipedes) in the house. I also mentioned that my garden is registered under two separate certification programs that involve avoiding pesticides, [6] that we have two geriatric cats with health issues, and that one of the humans living there is a public health professional. In the end, I am not surprised that only two of the seven companies even responded, but I will always take quality over quantity.
If you read the previous post, you will remember that I used beneficial nematodes to kill the termite colony I believed to be living in the front garden planter (the place I first noticed them, as alates, a.k.a. “swarmers,” emerged on a warm spring day). I can confirm that the planter is now inhabited by a colony of ants, which was, technically, a success. However, I expressed concern to these two contractors about the, now, annual emergence of alates in our living room. Interestingly, neither of them suggested any kind of indoor treatment because “the swarmers aren’t the ones doing the damage” – they’re basically just an indication that there is an active colony nearby. The swarmers simply swarm in order to go create new colonies elsewhere (and die if they don’t mate), while others in the existing colony do the job of eating the wood in the house. Treatments around the entire perimeter of the house are necessary because, while termites gather food inside the house, they still live in colonies outside (for the most part), so they must cross the barrier of the foundation to do that. They pick up the pesticide at the perimeter and carry it back to the colony.
Unsavory Options
The first company to call me back shall remain nameless because, while I got some good information about termite behavior, I still got a lot of mansplaining about the chemicals used in the process. Their approach is a common one, and it involves applying an insecticide called “Termidor” (brand name) around the perimeter of the house, drilling holes into adjacent hard surfaces (e.g. porch, walk, and driveway) for thorough application. The rep assured me that the chemical involved, fipronil (generic name), is “perfectly safe” and is the same chemical used in the flea medications we’ve put on our cats. [7] I didn’t say that flea medication is not “perfectly safe,” as there are restrictions on how it’s applied, even to cats. Nor did I say that the dosage for cats is a few drops, rather than however much would be needed to cover the entire perimeter of our house. He also assured me that his company had tried offering organic options before, but those alternatives didn’t work, and customers weren’t happy. (I did not get specifics on what those alternatives were.)
Image credit: [8]
Nevertheless, despite my politeness, he probably sensed my skepticism because he didn’t even show up for our scheduled home assessment (nor did he even call to tell me he wasn’t coming). I wasn’t upset, however, since I spent some time after our conversation looking into this “perfectly safe” chemical. Fipronil is a broad-spectrum insecticide (meaning that it would not be safe for the friendly insects nearby) that poses several known environmental and human health risks. The fipronil page from American Chemical Society (NOT American Chemistry Council – they are different!) highlights a Dutch scandal about widespread chicken egg contamination, as well as research into human endocrine disruption. [9] Meanwhile, Beyond Pesticides lists risks of fipronil exposure, including acute and chronic health effects, as well as categorizing it as a wildlife and bee poison. [10] In short, there was no way I was ever going to agree to fipronil.
A few days later, someone called me from Witt Pest Management, [11] a company I will name because the call went so well. Their rep recommended Sentricon, a treatment that involves bait stations – in fact, that is what the previous owner used around our home because I have found them while gardening. She explained that, given my concerns, the chemical used in the bait, hexaflumuron, is not as dangerous to the environment as fipronil, and the bait stations attract only termites: the termites have to enter the bait station and take the poison back to their colony. I was still opposed to the idea of using a chemical pesticide – for the record, hexaflumuron is highly toxic to aquatic animals, so bait stations should not be placed in areas where the bait might be washed out. [12] However, if we had to go the route of using some kind of chemical, this one seemed like a more realistic option in a pollinator garden as an absolute last resort. When I expressed gratitude that she had actually read and responded to the concerns I listed in my message, she seemed surprised that others hadn’t (since good customer service is about listening to the customers).
Palatable Alternatives
With Beyond Pesticides listing fipronil and hexaflumuron under “Chemicals to Avoid,” I took a look at the “least toxic chemical options as a last resort” section. Diatomaceous earth and silica aerogel are options for prevention to be applied during construction, but for existing homes, the recommendation is boric acid, which still carries some health risks, including reproductive and developmental impacts, based on lab studies with rats. [13] There are DIY termite control options available online, similar in structure to the Sentricon system, that contain boric acid instead of hexaflumuron. That, to me, felt like a better option to try before going to Sentricon and only after my first resort failed. (Consequently we did not have to go with Witt Pest Management, but if I were going to use a professional company, they would be my choice in the Pittsburgh area.)
Image credit: [14]
Although I had tried nematodes before, I made the mistake of only applying them where I saw the swarmers emerging, assuming I would get the rest of the colony through that avenue. I was wrong. In the years since my successful eradication of termites in my front garden box, I had removed a wooden fence and dead stumps from around the back of our house (both of which could have fed a colony located near there). It seemed like it was time to try nematodes again and follow the actual instructions: applying them all the way around the perimeter of the house (I now knew why that was essential) and keeping the ground wet for two weeks to ensure these microscopic creatures could successfully make their way to the termite colony (or colonies) around my house. [15]
Fortunately, I spread the nematodes around the house in late March, meaning that I could take advantage of spring rain instead of hauling the watering hose around every day for two weeks. According to the materials that accompanied my new friends, it would take four to six weeks for the nematodes to do their work in the colony, killing the termites from the inside. I marked the six-week point on my calendar but still held my breath for a while longer since we had a very cold spring, which might delay the swarmers in taking their nuptial flight. Now that we are into June and finally experiencing some truly hot weather, I feel cautiously optimistic in announcing that I have not seen any termites emerging in or around our house this year. (I have, however, seen plenty of house centipedes, so they’re thriving and snacking on something.) Of course, annual and correct, application of nematodes will be necessary moving forward, but I’d love to continue with that approach until I have reason to escalate.
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Have you done DIY organic pest treatments at home? I’d love to hear what you tried and what you learned in the comments below.
Thanks for reading!
[1] https://radicalmoderate.online/integrated-pest-management-termites/
[2] https://www.sentricon.com/en-us/why-sentricon/how-the-Sentricon-System-works.html
[3] https://radicalmoderate.online/weatherization-update-electricity-savings-part-1/
[4] https://radicalmoderate.online/concrete/
[5] https://radicalmoderate.online/electrical-service-upgrade/
[6] https://radicalmoderate.online/monarch-waystations/
[7] https://radicalmoderate.online/the-flea/
[8] https://www.innovativepest.com/boric-acid-for-termites/
[9] https://www.acs.org/molecule-of-the-week/archive/f/fipronil.html
[10] https://www.beyondpesticides.org/resources/managesafe/choose-a-pest?pestid=26&pestlocation=indoor
[12] https://www.beyondpesticides.org/assets/media/documents/pesticides/factsheets/Hexaflumuron.pdf
[13] https://www.beyondpesticides.org/resources/pesticide-gateway?pesticideid=12
[14] https://www.pctonline.com/news/ontario-township-to-use-nematodes-for-termite-control/
[15] https://www.arbico-organics.com/category/beneficial-nematodes
2 Comments
valorie214 · June 15, 2025 at 3:47 pm
Very interesting article! Can nematodes be used proactively? Also, are swarmers a one day incident? Does anything else resemble swarmers? A few years ago, I saw something in a swarm near our front door (and they returned the following spring) so we got an exterminator to treat. We never saw them at any other time or since. No one seemed to know what they were. Our current exterminator (for mice, shrews, carpenter bees, mosquito’s) claims everything is human, child, and garden safe. We keep kids off the grass for a day, but he sprays around my garden.
Alison · June 15, 2025 at 6:38 pm
Thanks, Valorie!
Termites (at least in my experience) generally swarm one or two days when the weather gets warm. What you saw might have been ants, but their bodies look different: ants are more hourglass-shaped, while termites are more cylindrical. I’d suggest Googling pictures of both so you can get a better sense of what you’re looking at.
As for what your current exterminator is spraying, get the name of the chemical from him and look it up yourself (specifically look at the exposure pathways and the health effects for humans, animals, and insects). The first guy I talked to said what he used was safe, but that was categorically false – especially for the pollinators I’m trying to protect around here.