Activity of vetiver extracts and essential oil against Meloidogyne incognita

Authors: JINDAPUNNAPAT, KANSIREE - Kasetsart University; Reetz, Nathan; Macdonald, Margaret; BHAGAVATHY, GANGA - University Of Maryland; CHINNASRI, BUNCHA - Kasetsart University; SOONTHORNCHAREONNON, NOPPAMAS - Mahidol University; SASNARUKKIT, ANONGNUCH - Kasetsart University; Chauhan, Kamlesh; Chitwood, David; Meyer, Susan

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2017
Publication Date: 9/3/2018
Citation: Jindapunnapat, K., Reetz, N.D., Macdonald, M.H., Bhagavathy, G., Chinnasri, B., Soonthornchareonnon, N., Sasnarukkit, A., Chauhan, K.R., Chitwood, D.J., Meyer, S.L. 2018. Activity of vetiver extracts and essential oil against Meloidogyne incognita. Journal of Nematology. 50(2):147-162.

Interpretive Summary: Root-knot nematodes (RKN) are microscopic worms that attack plants, causing billions of dollars of crop losses worldwide. One problem with reducing these crop losses is that growers lack safe chemicals for reducing RKN populations. Because vetiver grass—a source of numerous products, including essential oil, fragrances, food, and medicinal compounds— is not a host to RKN, it was studied for production of natural compounds active against RKN.”, it was studied for production of natural compounds active against RKN. In laboratory tests, crude root and shoot extracts from vetiver grass repelled the nematodes and caused death of 40% to 70% of nematode juveniles. Chemical analyses of three crude vetiver grass root extracts and commercial vetiver oil revealed that two of the major components in each sample were a sesquiterpene acid and a sesquiterpene alcohol. These results are significant because they demonstrate that plant chemistry plays a role in the nonhost status of vetiver grass to nematodes, and that natural compounds produced by vetiver grass may be useful for suppressing nematode populations in the soil. This research will be used by researchers developing safe methods for suppressing nematode numbers in agricultural soils.

Technical Abstract: Vetiver, a nonhost grass for certain nematodes, was studied for production of compounds active against the root-knot nematode Meloidogyne incognita. In laboratory assays studying 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 was not active against J2. Gas chromatography-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 derivative 3,3,8,8-etramethyltricyclo[5.1.0.0(2,4)]oct-5-ene-5-propanoic acid, and the sesquiterpene alcohol 6-isopropenyl-4,8a-dimethyl-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 nematodes, and that chemical constituents of vetiver may be useful for suppressing nematode populations in the soil.