In recent years, foam panels have gained a reputation as a cost-effective, energy-efficient building material. Now, at least two major panel manufacturers appear to be on the verge of eliminating one of the perceived drawbacks of foam – by making it unattractive to carpenter ants and termites. Both Winter Panel Corp. (RR 5, Box 168B, Brattleboro, VT 05301; 802/254-3435) and AFM Corp. (6140 Lake Linden Dr., Box 246, Excelsior, MN 55331; 800/255-0176) say they are preparing to introduce full lines of "bug-safe" panels this spring. The treatment processes are different, but the key ingredients used by both are borate compounds. The two firms use different types of foam. Winter Panel produces primarily polyisocyanurate panels, while AFM is an umbrella group for 21 manufacturers that use expanded