I’m not saying it’s for everyone, and I can’t guarantee it’ll work for you. I can just tell you what’s worked for me.
I have a horror of what toxic chemicals do to groundwater, bees, birds, and planetary health. That said, I won’t get judgey if you decide to go that route. You do what you gotta do. But if you want to try less toxic methods, here is my experience, which is limited to wasps, yellow jackets, ordinary ants, and carpenter ants.
In general, I’m pretty tolerant of insects. A paper wasp nest over my deck was cause for low-level anxiety but not alarm, and it hung there all last summer, wasps shuttling overhead, without a single sting. Wasps are pollinators, and some species prey on other insects.
When wasps were nesting behind the shutters a few years earlier, a handyman friend agreed to fix my sagging gutters — but only if I got rid of the wasps. I found a recipe online for a natural insecticide consisting of white vinegar, vodka, liquid soap, and tea tree oil, which I combined in a spray bottle. When the wasps were bedded down for the night, I went out and (after apologizing profusely to them) sprayed the concoction across and behind the shutters. I also poured the liquid down behind the shutters from the top.
The next day, a few individuals, presumably having spent the night out in the field, returned to the deck, crawled behind the shutters, amf then emerged, looking confused. (I’m not sure what confusion looks like in a wasp, but the aimlessness of their bobbing flight might have represented disorientation.) They flew away, and the wasp situation was resolved. The gutters were fixed without incident.
The recipe came in handy again when I saw yellow jackets (the pretty black-and-yellow striped hornets that are said to be more aggressive than wasps) going in and out of a hole in my front lawn. They weren’t disturbing us, but at the time we were renting our house out on weekends, and I felt we owed our guests a hornet-free lawn, since they might walk across it and blunder over the nest.
I poured the solution down the hole one night. The next day, seeing no activity, I dug up the nest, and an overnight returner stung me. I repeated the treatment that evening, and the creatures were gone.
Three weeks ago, I was just finishing mowing the lawn when I ran the mower over a new yellow-jacket nest. Though I received four stings, they hadn’t bothered me until I was physically threatening the nest. We no longer rent out our house, so I just put a circle of wire fencing around the hole to mark it. There have been no further aggressions.
Spring often brings a trail of small ants into the kitchen. They are easily dealt. I place sprigs of fresh mint or tansy leaves from the garden, placed at strategic points along the anrs’ path. (Note: Tansy is not good for cats or small children.) Apparently, the strong odor of these plants confuses the ants’ sense of smell, which pilots their peregrinations. The ants may crawl over the leaves at first, but by the end of the day they are always gone.
Carpenter ants are more alarming, as they chew tunnels in wood for nesting and can ultimately undermine the structure of a home. They are also more difficult to get rid of. Their presence was made known by a plume of sawdust on the living-room windowsill each morning. I’d occasionally see a stray ant on the floor, but never a column of foraging ants, which sometimes tips homeowners off to an infestation.
A neighbor helped me trace the sawdust to a long, narrow crack in the woodwork over the picture window. I removed the molding from the top of the window and found the ants had also chewed a space along the edge of the plaster wallboard. When I sprayed my homemade insecticide through the cracks, ants emerged and ran in agitated circles.
I never did figure out what happened to these ants. They didn’t die on the floor or on the windowsill. I tried watching them to see where they went, but they just kept careening in circles. I went away for a couple of minutes, and when I returned, they were gone.
I also couldn’t figure out how the ants were getting out of their nest to find food. Despite scanning the outer wall of the house, I never found a line of ants venturing out to forage.
The morning after spraying, more sawdust had settled in the living room. In the garage, I found a not-so-toxic commercial product, Maggie’s Farm Home Bug Spray, containing oils of thyme, rosemary, and wintergreen. It provoked the emergence of more ants, this time barreling even faster across the window and floor, so I assume it is more powerful than my homemade solution. It also smells more pungent and not wholly unpleasant.
A bottle of diatomaceous earth (DE) showed up in the garage as well, and an old mustard dispenser, one of those squeeze bottles you used to find in diners. I filled it with DE, a powdery substance that kills insects by slicing and drying. I know, it sounds painful, and I don’t like to use it, but I was getting nervous about my house falling down. When professional exterminators are addressing carpenter ants, I learned, they drill holes and inject insecticide. So I drilled a series of holes in the wallboard and squeezed the DE through the holes.
After a few daily treatments of DE and spray, the sawdust no longer appeared. However, three or four weeks later, a few particles of sawdust drifted down. Spraying the cracks elicited a small number of ants, and I repeated the treatment over three days. Even pros make two or three visits, spaced several weeks apart, to complete an ant job.
Had I completely gotten rid of the ants? Or have they retreated to some other part of the house where they will drill in secret? Maybe I should call a pro, but I’m too stubborn. DIY rules!