Hot Topics: Getting Rid of Carpenter Ants
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Original Post: carpenter ants
I noticed a lot of carpenter ants moving around my deck last year (it's Trex), and then saw them around an area of the siding on the house so I think they were in there. I sprayed some Ortho Home Defense in that area and later saw there were a bunch of dead ones. Surprisingly after that, I don't think I saw an ant on the deck the rest of the summer. Do they really just move on if they are disrupted like that?
Anyway, they were back again yesterday in a different location from last year as I noticed a few inside the house and then saw a bunch of them around the door out to the deck. Again, I sprayed the Home Defense inside along the baseboards and outside along the wall and even under the deck. There were a couple dead ones inside later on, but I haven't seen anymore.
I want to do a more thorough job this year with the bugs. I do see the occasional spider in the house (probably more often than I should) so I was wondering if there is a better spray or something else I should be using to keep the ants away (and spiders, too, if possible) or is that Home Defense adequate? Is my best bet to spray the entire perimeter of the house with something every so often?
PJmax Group Moderator
They won't touch Trex, but they will go after the framing. If you are seeing them where the deck joins the house, it sounds like you have a water penetration problem. They like to follow water and they will....right into your house.
Carpenter ant colonies expand until they get large and then a "satellite" colony breaks off. New queen(s) take a cross section of workers with them and overnight there will be a new colony in or around your house. A likely scenario is a mature colony is in a tree nearby and broke off a satellite colonly. If you choose to use fipronil, then I would spray the bottom three to four feet of tree trunks that are close to your house, if any.
Fipronil isn't great for spiders, but I'd focus on the ants first as the good spider sprays will be repellent. If you are seeing live ant activity, then now would be a good time to start. Two to three times a year of fipronil should be adequate. You can work in spider sprays in between. The fipronil will help with the spiders so it may be enough, but if someone was hiring me, I wouldn't use it for spiders.
I looked up the difference between repellent and non-repellent sprays so I can see why the non-repellent is so effective. How much time in between can you go before using a different type? You're right—the spiders aren't a huge problem. There are actually stink bugs that seem to be more of a problem that I forgot to mention.