Pest Control/Carpenter Ants
I have had some carpenter ants in my home for several years. I have the exterminator come whenever I start seeing them, but the exterminator never finds a nest. He sprays various areas outside of the house. I might see a few ants a week inside the house in various places, then I won't see any for a few weeks, then I see more. Is there a more effective way to eradicate them? I live in Long Island, NY. Also- about 10 years ago I had termites and my exterminator used the Sentricon system to eradicate them. I have an annual contract which costs me $350, and they come once or twice a year to check the receptacles in the soil around my property. They have never found a reinfestation or any signs of termites. If this was your house, would you keep paying for this protection?
I'm afraid the exterminator may be taking advantage of your "generosity". Carpenter ants are treated by some combination of exterior wall void treatment, perimeter sprays with Termidor and special baits. A SINGLE properly-done treatment should be enough, at least until nests are re-established. You don't need to locate the nest to control these ants. See the series of articles starting here http://www.livingwithbugs.com/carpenter_ants.html
for current methods.
The Sentricon baits are used to detect termite activity. There are DIY versions of these baits that would be far less expensive if you are willing to monitor the baits yourself. See http://www.livingwithbugs.com/termite.html
for a discussion of these baits.