Indian Journal of Nematology

The essential oil isolated from Mentha longifolia has not been evaluated for it's nematicidal activity and thus was evaluated against J2s of Meloidogyne graminicola and chemical composition using GC and GC-MS. The yield of essential oil was 1.17% on fresh weight basis. In GC-MS analysis, a totalsixteen compounds representing 84.53% of the oil were identified. The oil was found rich in oxygenated monoterpenes (64.91%), followed by sesquiterpenes hydrocarbons (1.62%). Piperitenone oxide (62.91%) was identified as major compound while Limonene (0.88%), Germacrene-D (0.75%), 1,8-Cineole (0.75%), Piperitenone (0.37%), Linaloolpropanoate (0.33%), and p-Mentha-1,8-diene-2-one (0.23%)were minor compounds in the oil. The essential oil and crude solvent extracts (acetone, methanol and hexane) were evaluated for nematicidal activity against rice root-knot nematode, Meloidogyne graminicola under in-vitro and in-vivo condition at different concentrations (15.62 to 1000 ppm). Results showed higher mortality, egg hatching inhibition and strongly suppressed nematode infestation, multiplication at higher concentration on rice roots and showed significant (P < 0.05) increase in rice biomass ascompared to control. In-vitro toxicity (LC₅₀) revealed that essential oil was toxic to juveniles (J₂s) of M. graminicola at lower dose (13.91 ppm) at 96 hours of exposure. These results indicated that oil and crude extracts has the potential for management of M. graminicola infecting rice.