Activity of vetiver extracts and essential oil against Meloidogyne incognita

Abstract

© The Society of Nematologists 2018. Vetiver, a nonhost grass for certain nematodes, was studied for the production of compounds active against the southern root-knot nematode, Meloidogyne incognita. In laboratory assays studying the effects on second-stage juvenile (J2) activity and viability, crude vetiver root and shoot extracts were nematotoxic, resulting in 40% to 70% J2 mortality, and were also repellent to J2. Vetiver oil did not exhibit activity against J2 in these assays. Gas chroma-tography-mass spectrometry analyses of three crude vetiver root ethanol extracts and a commercial vetiver oil determined that two of the major components in each sample were the sesquiterpene acid 3, 3, 8, 8-tetramethyltricyclo[5.1.0.0(2, 4)]oct-5-ene-5-propanoic acid and the sesquiterpene alcohol 6-isopropenyl-4, 8a-dimeth yl-1, 2, 3, 5, 6, 7, 8, 8a-octahydronaphthalen-2-ol. The acid was present in higher amounts in the extracts than in the oil. These studies demonstrating nematotoxicity and repellency of vetiver-derived compounds to M. incognita suggest that plant chemistry plays a role in the nonhost status of vetiver to root-knot nematodes, and that the chemical constituents of vetiver may be useful for suppressing nematode populations in the soil.