When using Boracare to treat for an active infestation of wood fungus it is applied at a 1:1 ratio for wood that is 4" thick or greater. Use a 3:1 dilution ratio for wood less than 4" in thickness. You can spot treat the areas that have active fungus and then use the 5:1 for future prevention in the non effected areas. You should be sure to address the moisture issue in the area before or during treatment of Boracare and apply a vapor barrier after the product has dried. Please see the product label for complete application instructions.
Yes, BoraCare may be used on wood that is currently and/or previously infested by termites. Please read the product label for complete use instructions.
The water that Boracare is mixed with will eventually evaporate, and it will dry. You could also wash the product off the tarp and reuse it.
Per Boracare's label you need to allow the first application to dry by waiting at least 20 minutes in between applications. For some applications, like when treating for Subterranean or Formosan termites, you may need to wait at least an hour between applications.
Boracare can create a crystal-like residue if heavily applied. You can wipe the residue away with water and soap.
Boracare is specifically designed to be applied to plywood and any other raw wood surface that hasn't been stained or finished with anything like paint or a sealant.
Boracare takes care of any active infestation of wood-destroying insects such as termites, carpenter ants, powderpost beetles, etc. It is possible for the wood to become infested again if it has been exposed to water, if the wood wasn't treated in any way, like if it wasn't stained, after the Boracare treatment dried or if not all exposed sides were treated.
Although, from the information you provided regarding the termite tunnels, if you're talking about mud tunnels then you are dealing with Subterranean termites. Boracare will still affect them if the eat the wood but the method of treatment to get rid of the colony will be to do a trench treatment around the Perimeter of your home with Termidor. Termidor can't be used indoors unless it's sprayed/foamed inside an enclosed wall void.
If you are sure, however, that you are dealing with Drywood termites, we recommend that you call Nisus (800) 264-0870 to troubleshoot with them as they are the makers of Boracare.