Abstract

Termiticide potential of six plant derived essential oils and their thirteen major active chemical constituents were investigated for their termiticidal activities against the termites, Heterotermes sulcatus Mathews 1977 (Isoptera: Rhinotermitidae) using no-choice bioassay method. Responses varied with different plant essential oils and their major chemical constituents at a fixed oil concentration. Among the essential oils tested, strong termiticidal activity was observed with the essential oils of Pittosporum undulatum, Lippia sidoides and Lippia gracilis. Oil was obtained by hydrodistillation for 4 h. Each crude essential oil was subjected to separation over SiO₂ soaked with AgNO₃ (15%) column chromatography eluted with n-pentane, n-pentane: CH₂Cl₂ and CH₂Cl₂ . The obtained fractions were analyzed by gas chromatography/flame ionization detector (GC/FID). The major constituent’s plant essential oils were identified by GC/MS. The constituents thus identified were tested individually for their termiticidal activities against H. sulcatus. Limonene, carvacrol and thymol resulted in 100% termite mortality, after relatively short-time of exposure. However, for the practical use of these components in the field, while agent termiticide, the safety of these compounds in humans and non-target organisms must still be evaluated.

Key words: Subterranean termites, terpenes, alternative control.