BIOTOXICITY OF TROPICAL PLANT ESSENTIAL OILS AGAINST SUBTERRANEAN TERMITES <em>COPTOTERMES</em> <em>CURVIGNATHUS</em>

Abstract

This study was established to evaluate the efficiency of essential oils from tropical plants such as Cinnamomum zeylanicum, Cinnamomum rhyncophyllum and Litsea elliptica in preserving susceptible timber against a subterranean termite named Coptotermes curvignathus. Two different tests mainly the toxicity and repellent tests were conducted in five concentrations (0.5%, 1.0%, 2.0%, 3.0% and 4.0%) to observe the repellency, feeding response and mortality of the termites. A no-choice test was conducted in the laboratory to investigate the effectiveness of essential oils in protecting Hevea brasiliensis. Based on the findings, C. zeylanicum essential oil showed high antifeedant (56.2%–96.2%) and repellent (41.0%–62.0%) activities. The oil was also very effective in no-choice test with a lower percentage of wood use (3.5%–5.9%), a higher percentage of C. curvignathus mortality (90.2%–100%) and a higher visual assessment (8.9–9.2). The performance was followed by C. rhyncophyllum, while L. elliptica essential oil had the highest repellent activity at each level of concentration. The results suggested that these essential oils had beneficial activities of economic value for the development of new or latest termite control product.