I agree that the t-foot is sticky enough to do a great job. If you don't have any at home now and want to promptly put up an available, non-messy barrier to ruin the carpenter ant's lunch plan, sticky masking tape can snag carpenter ants as they try to walk over it to check on their herd of aphids higher up the trunk. A couple of separated rings of 1" masking tape with the sticky side facing outward that are snuggly wrapped around a smooth bark area has proven here that various kinds of ants "can drop in any time you want, but you can never leave", to borrow the song lyrics. Just check each AM to see if any small lizards would be snagged and need to be gently set free. As the sticky glue begins to lose it's stickiness, just replace it with a fresh strip. Or when there are too many bugs on it.........It would be good to hose off the aphids thoroughly to "reboot" the tree before putting the strips.

Are you sure they are carpenter ants? Here's a link that is helpful. http://www.extension.umn.edu/distribution/housingandclothing/DK1015.html

You are dead wrong in your supposition, wynsworld. The people you will talk to when calling the information hotline are in the business of helping people like you use their products properly, safely, effectively, and legally. They are one hundred percent willing to tell a caller that they MUST NOT use their product in a certain way because it may: damage the plant, not do the job the user intends, harm the user, harm non-target animals, harm the environment, or be illegal. Ortho has nothing to gain from people who get themselves into trouble by misusing their products and a great deal to lose. That number is the very first place you should go to for good information. Look on the label and call the number listed. If you have never done so, you might be surprised. I've called them many times over the years, mostly to see to what they had to say about certain off label uses. I've never had a sales job pulled on me, but have been given a great deal of good information....mostly in the form of "NO, you cannot use our Ortho product for that use." But plenty of times to explain how to safely use it for something that might not be listed on the label. Chemical companies spend multimillions of dollars in research in order to produce their products and the labels that are considered federally legal documents. They want their customer to be successful and will help you to that end. On the other hand, if someone wants to do something dangerous or even non-effective with their product, they'll tell you immediately that you cannot. I suspect that they will be happy to bless your use of this pesticide for your purpose, and why not take advantage of their insight? They have an awfully lot at stake that you will be satisfied with their pesticide and live to tell the story. ;-)

Post a picture of your yard. I'm concerned about a big hollow tree potentially overhanging your home. IF a big tree is in the middle of my yard ready to fall on nothing I will leave it there and let it decline naturally. Its a neat look. IF that same tree was overhanging my house where there was a chance of it causing me to have to pay my insurance deductible and maybe kill my kids its chainsaw time. For what its worth, I gather carpenter ants / termites do best in declining trees. Imagine all the sap from a healthy maple covering them up when they try to enter.