Termites? Spot treatment might not work

Dear Angie: Does spot treatment for drywood termites work? I have drywood termite damage to some interior trim, and evidence of live termites (termite excrement, tiny sawdust pellets and wings) is in one room of a large home but in no other rooms. I'd prefer not to have to tent the entire home (and risk breaking tiles on the roof), but just spot-treat if it's effective. Is it? — Martin K., Tampa, Fla.

Dear Martin: Spot treatments can be effective, but there are several factors needed for them to work.

First, the termite problem needs to be isolated. There needs to be a clear sign of termite activity, and the area must be easily accessible. Of course, it also won't work if you aren't using the proper product; specifically, a termiticide made for spot treatments.

Visual evidence and accessibility are crucial in how effective spot treatment will be. If you can inject the termiticide in the galleries — the "tunnels" that termites form to travel inside wood — or on the termites, it should be effective. That, however, is the trouble with spot-treating for termites.

Because you can't see inside wood or walls, you can't be assured that the termites will come into contact with the treatment. There also could be several individual colonies inside the structure that you won't be able to reach. If you don't eradicate all the termites, they'll continue to mate and multiply.

Tent fumigation is the only guaranteed remedy because the fumigant penetrates all wood in the structure. Unfortunately, termite professionals often get called to tent a structure after a homeowner has spent time and money trying spot treatments.

I recommend that you have a thorough inspection by a reputable, certified termite inspector. Check consumer reviews and look for information about your specific need to see how companies have performed. Get three estimates for the treatment and follow the advice of the company you decide to hire.

If the problem is isolated, you might be fine with the spot treatment. If tenting the structure is needed, talk to the company and share your concerns about damage to the roof. If it's done carefully, there should little or no damage, and the cost for any repairs should be minimal, especially when compared with the damage termites can do.

This story was originally published July 14, 2012 at 12:00 AM with the headline "Termites? Spot treatment might not work."