Non biocide treatments for the protection of short rotation teak wood against subterranean termites

Martha, Resa; Candelier, Kévin; Thévenon, Marie-France; George, Béatrice; Rahayu, Istie; Darmawan, Wayan; Gérardin, Philippe

Non biocide treatments for the protection of short rotation teak wood against subterranean termites

2024

Short rotation teak wood is susceptible to biodeterioration, particularly to termite attack. The objective of this work was to investigate the effect of chemical and thermal treatment on resistance of sapwood, transition wood, and heartwood of short rotation teak against Asian and European subterranean termites. In a second time, the “non biocidal” aspect of different treatments was evaluated using “choice” and “non-choice” screening termite tests. Furfurylation (FA), thermal treatment (HT), and combination of chemical and thermal treatment using glycerol-maleic anhydride (GMA) were performed on sapwood, heartwood, and their transition fractions (50:50, sapwood:heartwood). On one side, the wood samples were exposed to Asian subterranean termite (Macrotermes gilvus) under field test, in Indonesia. On the other side, the wood samples were also tested against the attack of European subterranean termite (Reticulitermes flavipes) under non-choice and choice screening test, in laboratory. From field tests, the results show that heartwood exhibited a lower mass loss compared to sapwood due to its extractive content. FA and GMA at 220 °C treatments performed in better termite resistance after field test according to their mass losses. Results from the choice and no-choice tests show that chemical and thermal modifications improved termite resistance due to their low mass loss. No surviving termites were observed after the non-choice test on chemically and thermally modified wood. The high termite survival rate in the choice test confirmed the hypothesis that chemical and thermal modification treatments were non-biocidal to termites compared to borax control samples. The FA and GMA treatment could be considered as eco-friendly modification methods to protect the short rotation teak wood and wood in general against subterranean termites.

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