Carpenter ants must die

Last year at this time, my wife found carpenter ants in the corner of the garage. We got a quote from an exterminator, but the only option they’d consider required a one year contract with monthly “treatments.” Net outlay would be $300 for the initial treatment plus another $450 for one year of followups.

I had several problems with this:

  1. It seemed like a lot of toxic shit was going to be sprayed each month, even when the ants were dormant, as they are half the year. (I can only assume that a licensed exterminator has access to a much deadlier arsenal of unpronouncable chemicals.)
  2. There was no guarantee that they’d actually get rid of the ants, only that we could call them and they’d come by and spray again.
  3. At the time, they also had a bulletin board whose comments were mostly disgruntled customers unable to get followup visits. (Don’t bother checking, it’s gone… I’m really surprised they had it there in the first place.)
  4. Our garage is unfinished, meaning there’s plastic sheeting covering the insulation. The contract required me to remove all this so they could spray behind it, then I’d have to put it back. That’s a lot of work on my part and I’d have to pay them money on top of that.
  5. They weren’t willing just to do a one-time treatment for the $300.

So for $21, I bought a pound of boric acid and some pre-mixed spray at Home Depot, removed the plastic and insulation, and coated the walls where we saw a definite nest. I followed up the remaining permiter with the boric acid. That seemed to fix the problem…

Until this evening. As I was pulling in the driveway this evening, I noticed my wife was hauling stuff out of the garage. She’s visibly upset, and eventually I figure out it has something to do with the ants streaming along one of the garage walls.

I spoke with a guy at Home Depot at great length and came away feeling that the only way to rid my home of carpenter ants was to spray around the perimeter very thoroughly, squirt boric acid behind the outlets, then, the following week, go after nearby food sources like tree stumps.

They recommended a $35 bottle of Ortho-Klor, which has bifenthrin. According to, this rates a “yellow,” which I assume is worse than Boric Acid (a “green”) but not as bad as chlorothalonil, an organochloride. The labels on all of the products you’ll find in the store are very scary, and I have strong reservations about using them. However, at this time, it’s too late to put up a sign: “The aphids are better next door.” Ants can’t read.

After the garage was cleaned out, I pulled off the plastic, donned my long-sleeve shirt, respirator, goggles and started mixing more ant toxin. I have to say again, that I really have concerns with using this stuff. It’s not just the “toxic to fish and wildlife,” but also it being absorbed by skin. And the math… the recommended mixture is 1 tablespoon to one gallon, unless you’re going after termites, then it’s 6 tablespoons to a gallon. (So a one-quart bottle will do about… 64 gallons! My God, that’s like two bathtubs.) The labels claims it kills ants for anywhere from four months to five years. five years?!

I spent most of the evening spraying in corners and especially saturating areas where I saw ants. I tried to keep it very close to the house so the kids would be less likely to play in it, but I can’t help but feel the earth is scorched. (Can you tell I’m really worried about the toxicity of this?) After the stuff dries, I’ll put the insulation and plastic back on, then slowly restock my garage. I guess this is incentive to get rid of all the junk I’ve acquired, eh?

Strangely, our other two “pests” don’t bother me.

  • Spiders — Western Washington is called “Spider Heaven,” and my house supports this claim. But you know, I don’t mind! Not only do they generally stay out of my way, but they also eat other bugs. (But they don’t eat wood.) When they get big and juicy enough for my spouse or kids to make a stink about them, I’ll try to scoop them up and let them go outside.
  • Slugs — there are more varieties than you care to know about. The yellow, banana slugs are native to the area and quite beneficial. We leave them alone. The others eat gardens. Although they’re a little gooey, they don’t move quickly and jump out at you, nor do they bore into your walls.

17 thoughts on “Carpenter ants must die”

  1. I’m glad to be out of San Diego. The place is a giant anthill. We’ve had a few ants here, but nothing like in San Diego. Even if you kept your kitchen spotless, you’d often wake up and have an army of ants hanging out on your kitchen counter.

    An easy way to get rid of visible ants is with ammonia-based window wash, like Windex. It basically freeze-dries them immediately. It also allows you to get rid of their chemical trail.

    We used borax liberally. But I wasn’t impressed by it.


  2. I am in Costa Mesa, which like SD is a giant ant hill. I had a professional exterminator come out about once every 4-6 months who charged me about $120 a visit and does the whole house, yard and garage for ants, spiders and other pests. I have no idea what he sprayed and I don’t want to know. On days he did this I had do a lot of prep work the night before making sure all cooking implements, toothbrushes and the like are all safely hidden away or covered. I also made sure no one would be in the house for more than 12 hours and we would go out to dinner those nights.

    When I had a baby I cut back, but it got really bad, so I started doing it about once/year when wife/baby left town for a week to visit grandparents, figuring the toxin levels would probably be back to background levels when they got back.

  3. The fun thing about carpenter ants is that they’ll take different routes to the nest each time so you can’t track ’em (unless you have a bunch of spare x10 cameras, and who doesnt have 5 or 6 laying around the house at any given time?).

    When we first moved into our house, or tallest maple had a rotted out trunk infested with carpenter ants. They seem to make absolutely perfect circles in the wood for their tunnels. I sprayed everything on that thing. Saddam came by and offered some chemicles and they didn’t help.

    Eventually I called a few tree doctors and they all said the same thing – the tree will grow up over the rotted trunk, become top heavy then fall over. At least it was going to fall in the neighbor’s yard.

    So, we had it removed and replanted there. The next summer, still some ants, but not as bad. It wasn’t until I was fixing some cracks in the concrete garage floor that I found the nest (or the nest they moved to). Poking a knife the crack to clean out the dirt and stuff before using the concrete sealant a metric buttload of ants come pouring out. I sprayed some chemicles in the crack and then sealed it up.

    I then laughed maniacally for the next 4 hours thinking of them trying to figure out how to escape.

    Anyway, check any cracks in the concrete in the garage – good nest spots.

    Oh, I had good luck with the boric acid only in ‘poofing’ it down holes. It travels nicely and you get a sick satisfaction of watching the ants scramble out covered in white to tell you that you did a good job. I never had any luck with it as a barrier.

    Also, if you see an ant, don’t just step on em and make em go squash. Try to take off a leg or mandible…let them know you’re someone to be messed with. If you do accidentally kill one, leave it hanging by your front door dangling by some floss – they’ll eventually get the message (I assume).

    If all else fails, go to Bolivia and smuggle yourself back an anteater. Just give it a lot of valium and tell US immigration that it’s your kids’ snuffleupagus doll. Works every time…

    1. Antkiller is hillarious!
      Where’s your book!?
      I’ll go buy it right now!

  4. We had the ants the first year we moved in. $300 for the exterminator. It worked for that year, though. For that year. $300 for the next year, too. I can’t afford $300 a year for these nasty little buggers. Last summer they came out to play from the overhang on our porch. I used what I had — a whole bottle of Dawn. I figured, “Hey, they’re ANTS. That means a trail.” It worked last summer. They moved. Found ’em again today. Guess the screen in those attic airholes had come loose and they’d crawled in. Out came the Dawn. I figure I killed about 500 of them today. I’ll just keep harassing them until they leave.

    One bright spot — I noticed these evening, when it had gotten cooler, that three or four big, fat red birds (robins, maybe) were chowing down on the ones that my hose had knocked to the ground. And the spiders (love those big hairy house spiders we get here in Western WA!) had captured another two dozen and were making short work of them.

  5. Except for when I inadvertantly walk into a web, spiders generally don’t bother me since they’re up high, don’t move particularly fast, and eat other bugs.

    Another thing that seemed to help with the ants — though it’s still early in the year — is clearing the yard of dead plant debris and tree branches.

  6. Hi Lauri,
    After I treated them with the bifenthrin, I hadn’t seen a recurrence until mid-May. There are a few “more than normal” crawling around the front, in a different place. I don’t know how much longevity the bifenthrin has, but I plan to respray around the house in a couple of weeks.

    A container of bifenthrin runs about $35 from Home Depot, add another $10 for disposable gloves & mask & bib — it’s seems to work reasonably well. It’s also diluted a lot, so you should be able to get a year’s treatments out of it easily.

    The professional exterminator was only interested in a monthly plan.


  7. Jim,

    I just read your article on carpenter ants, that you posted back in August of 2003. Did the Ortho-Klor (bifenthrin) work for you? Did you get rid of your carpenter ants.

    I live in NE Kansas and discovered them in a rotting out trunk of the elm tree that sits next to my house. I purchased some Ortho-Klohr today that I plan on using, so I would like to know if this help rid you of your problem, or did you have to use anything else along with it, or did you finally have to get professional help in removing them. After reading other letters it looks like I will probably lose my tree. I have done some very extensive research on this subject and am aware of what to look for, I would just like to know from someone who has actually treated for them if they ever have totally gotten rid of them.

    Thanks for your help

  8. After reading all the info. on the web about carpenter ants, I was rather discouraged. It seems that we may be dealing with these for a long time. Our neighbor is in the pest control business. He seemed to think that “locating the nest” was hopeless since it would require pulling off siding, trim, etc. He said that there many obscure places where the nests could be. He advised that we should spray around the perimeter once per month until Sept. and then again beginning next March. I think our nest has been around for a number of years, evidenced by the fact that we averaged around 6-7 winged reproductive ants per day for about two weeks. I guess we will attempt the Home Depot special, “Ortho bifenthrin” and try not to think about what’s in it.

  9. Lived in Seattle and now in Costa Mesa — the ants are way worse in Costa Mesa; there is no dormant season from what I can tell.

  10. Someone who will scoop up spiders is definitely on my “happy list”. I’m an arachnaphobic.

    Carpenter ants stink, by the way. What was God thinking when he made them so freaking LARGE?

  11. Discovered 3 huge carpenter ants checking out my house in 3 separate locations. I then found a nearby very tall, hickory tree in the yard that is just LOADED with ants and a hole that is ‘weeping’ that goes down inside the trunk. From your article and the other comments, I suspect that at least one nest is located inside this tree trunk. I will be making a trip to Home Depot tomorrow. I am single and retired and cannot afford monthly pest charges. I hope this works. Thanks for your article!

  12. Christopher

    I too am in Western WA, and I share the same battle. I have been using “Terro Liquid Ant Bait” from with great success. I placed the traps both outside and in, and the ants just love these things. We’ve dubbed them “Little Piggies,” because of all the action surrounding the traps once their placed.

    I’m currently engaged in a fierce battle with these minions of doom, and I am beginning to see victory once again. The ant horde is currently taking casualties and I am confident that their colony shall be smited. I have seen them carring their fallen away from the trap/food pathes. This is my third battle this season, and I am currently 2-0(one infestation in the kitchen and one outside on the lawn) in my previous campaigns. My last battle was 2 months ago and this new infestation just started. I belive that these ants are coming from my neighbors yard. I am beginning to suspect that my neighbors are ant sympathizers and that they are in fact harboring these vile creatures.

    Ummm… I’m rambling…

    With the sweet nectar traps, there’s no fear of a chemical fall-out.

    You can find these traps at Wal-Mart or Fred Meyer. Terro’s site has a store locater as well. And, you can even order from their online store. I did not see the “out-door” traps listed on their site though.

    Keep up the good fight.

  13. Time has moved on to August 2006
    I am hoping someone will resusitate this carpenter ant topic

    I have a Maple with the tell-tale BB-like holes. I saturated the tree with bifenthrin last week. Past 2 evenings I have stalked the ants with a spotlight covered with the 2″ red plastic packing tape – reportedly they don’t see red light.

    I saw only one ant which I eventually lost in a crack but both nights there was a large bee similar to carpenter bee that almost looked like it feel asleep

    I have read about bifentrin, boric acid diatamaceous earth baits – would appreciate any updated remedies for this pest.

  14. Hi,
    I sincerely hope I am not wasting your time, but I have a problem with Red Mite Spider in my hedgerows in my garden.
    I have been informed that it can be cured by using the chemical to which you refer to as, “Bifenthrin”, but I have met a dead end to any enquiries I have made concerning this chemical. I would ask if you know where or how this chemical, “Bifenthrin” can be obtained, thanking you in anticipation, Ernie.

  15. permethrin is great for killing insects. It even worked great on hornets I’ve had for ten years….terrible, climbing under my siding and setting up nests. The Hi-Yield brand 38 plus is longer lasting. It keeps on working for 12-16 weeks.

    If you are against pesticides, you might try apples. I’ve tried before in my garage and it seemed to work. Cut up slices of apples where you see the ants. They take pieces back to the nest and the acid kills the ants in the nest as well. This could take some time to get rid of all of the ants. I wonder if this works like boric acid? Nice thing with apples is that they take it back to the nest since they can carry pieces.

  16. I’ve been pre-treating the garage and the house perimeter with bifenthrin/permethrin in July — just before I’ve historically seen their activity. Seems to work pretty well.

    The apple idea is interesting – almost a sacrificial offering 😉

Comments are closed.