Effectiveness of sol-gel treatments coupled with copper and boron against subterranean termites

Abstract

Wood modification by sol-gel treatments shows many positive features, like antimicrobial properties. Wood was also successfully modified with alkoxysilanes enhancing its resistance against soil micro-organisms. Silver, copper, zinc compounds, boric acid or organic biocides such as alkylammonium compounds may be added to the sol-gel to enhance its biocidal properties. Nevertheless, if some of these active ingredients and compounds are not fixed into wood by chemical reactions, they can be easily leached out by water. To overcome this limitation, a system based on silica sol-gel material starting from alkoxysilanes has been functionalized with organic groups having copper linking function. Sol-gel was also coupled with boric acid. As preliminary tests against the brown rot agent Coniophora puteana (Schumacher ex Fries) gave good results, the sol-gel formulations were also tested for their efficacy against subterranean termites. A no-choice test was set up, in two different time scales. Results show that though the sol-gel treatments act in very different ways, all of them are efficacy against subterranean termites. The total mortality occurred in the longer test suggested that active ingredients may be added in lower quantity.