Biotoxicity of some plant essential oils against the termite Nasutitermes corniger (Isoptera: Termitidae)

• Essential oils of seven medicinal and aromatic plants were assessed by GC–MS.
• Insecticide activity of the essential oils was tested on termite Nasutitermes corniger.
• All essential oils were toxic to termites.
• Essential oils from Pogostemon cablin and Lippia sidoides were the most promising for the control of N. corniger.

The termite Nasutitermes corniger is an important structural pest in the Neotropics. Here we investigated the insecticidal activity of plant essential oils from Corymbia citriodora, Croton sonderianus, Cymbopogon martini, Lippia alba, L. gracilis, L. sidoides and Pogostemon cablin on N. corniger. The chemical composition of the essential oils was analyzed with gas chromatography coupled to mass spectrometry (GC–MS). Toxicity bioassays were performed by a topical application of the essential oils on the termites. Mortality was evaluated at 4, 24 and 48 h after the bioassays were conducted. The essential oils featured the following major compounds: citronellal and citronellol (C. citriodora); geraniol (C. martini); bicyclogermacrene and α-pinene (C. sonderianus); carvone and limonene (L. alba); carvacrol and methyl thymol (L. gracilis); thymol, ρ-cymene and methyl thymol ether (L. sidoides); and patchoulol, α-bulnesene and α-guaiene (P. cablin). The lowest LD50 and LD90 (μg of oil/mg of N. corniger) were observed for P. cablin (0.37 and 0.85, respectively) and L. sidoides (0.38 and 1.98, respectively), while C. sonderianus was least toxic (9.48 and 38.43, respectively). All essential oils were more toxic to the workers than to the soldiers. The oils from P. cablin and L. sidoides were up to 25 times more toxic than the oil from C. sonderianus. These results show that the essential oils from P. cablin and L. sidoides may be promising for further studies aiming the control of termites in the field.