Antifungal activity of essential oils against wood degrading fungi and their applications as wood preservatives

Essential oils were screened for their antifungal activity against common wood inhabiting fungi. Subsequently, two pure essential oil extracts, eugenol and cinnamaldehyde, were evaluated for their efficacy on radiata pine wood durability. During the in vitro screening trial, variability in the tolerance of the tested fungi towards the selected essential oil was apparent. However, wood durability test on wood confirmed the antifungal activity of eugenol and cinnamaldehyde but highlighted the leaching (when exposed to wet conditions) of these compounds from treated wood. Blocks treated with 3% w/v eugenol without exposure to wet conditions had <1% weight loss when exposed to all three test fungi, Oligoporus placenta, Coniophora puteana and Antrodia Xantha. However, blocks which were exposed to water showed weight losses in the range of 13·4–23·1%. This study identified eugenol and cinnamaldehyde as potentially benign wood preservatives for treatment of timber not exposed to wet conditions.