Scots pine (Pinus sylvestris L.) sapwood specimens modified with short- and long-chain amino-functional siloxane emulsions were exposed to subterranean termites (Reticulitermes flavipes Kollar). Laboratory choice and no-choice tests following the standard EN 117 (2013) were conducted for 8 weeks in order to evaluate the influence of these silicon-based compounds on the termite resistance of treated wood. The wood specimens were vacuum-pressure impregnated to reach 2, 5 and 8% weight percent gain (WPG). Subsequent to the treatment, half of specimens were leached according to the standard EN 84 (1997) before the termite test. Following exposure, the wood specimens were assessed for termite damage using a visual rating system (from 0 to 4). Mass losses were also recorded. The tests were validated because the feeding pressure was sufficient according to the standard. The results revealed that in case of the no-choice test, samples treated with the different siloxanes were classified as non durable (according to the standard EN 117 (2013)), despite the fact that there was a significant reduction of mass loss. In contrast, when exposed to a choice test with wood treated with short-chain siloxane without emulsifier, the termite workers exhibited significant avoidance to the treated wood samples. In all cases, termite chose untreated wood instead wood modified with short-chain siloxane. The mass losses, even in case of leached specimens, were found to be in agreement with this finding. Therefore, the results of this study verify that treatment with short-chain siloxane without emulsifier was successfully effective against termite attack when there is a choice of feeding.

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