Efficacy of commonly used wood preservatives against subterranean termites in Akungba-Akoko, Ondo State, Nigeria

Abstract

The efficacy of three commonly used wood preservatives in Akungba-Akoko, against subterranean termites attack was investigated using three  lesser durable wood species. Samples were prepared according to ASTM D3345-17 for durability test. All samples were oven dried for 24 hours at  103±2 oC prior to preservative treatments. Treated wood samples were buried half way in the soil and exposed to subterranean termites for 12 weeks at a timber grave yard. Weekly visual rating of the stakes was performed, while a gravimetric weight loss assessment was carried out after the 12 weeks of exposure. Results revealed the presence of two termite species: Macrotermes subhyalinus Rambur and Microtermes spp. within the graveyard. Density of the wood species ranged from 542.28±42.40 Kg/m3 (P. macrocarpa) to 237.99±6.94 Kg/m3 (R. heudelotii). Kinematic viscosities (25 oC) of the liquid preservatives ranged from 1433.25±30.96 cSt (Timbguard™) to 3909.75±225.76 cSt (Solignum). Preservative absorption capacity ranged from 7.82±2.31 % (P. macrocarpa treated with spent engine oil) to 52.16±9.36 % (R. heudelotii treated with Timbguard™), while preservative retention ranged from 2.57±0.17 Kg/m3 (R. heudelotii treated with spent engine oil) to 14.42±1.13 Kg/m3 (A. boonei treated with Timbguard™). All the three preservatives were effective in protecting the three selected wood species with gravimetric weight loss values less than 10 %; establishing their efficacy in protecting wood material against subterranean termites.

Keywords: Wood preservatives, subterranean termites, Preservative efficacy, Wood protection