Antifungal activity and chemical composition of Citrus reticulata Blanco essential oil against phytopathogens from North East India

The essential oil (EO) isolated by hydro-distillation from the peel of fully matured ripen fruits of Citrus reticulata Blanco were analyzed by GC and GC–MS. Thirty seven different components were identified constituting approximately ≥99% of the oil. The major components were limonene (46.7%), geranial (19.0%), neral (14.5%), geranyl acetate (3.9%), geraniol (3.5%), β-caryophyllene (2.6%), nerol (2.3%), neryl acetate (1.1%) etc. The antifungal activity of the oil was tested by poisoned food (PF) technique and the volatile activity (VA) assay against five plant pathogenic fungi viz Alternaria alternata ( Aa), Rhizoctonia solani ( Rs), Curvularia lunata ( Cl), Fusarium oxysporum ( Fo) and Helminthosporium oryzae ( Ho). The oil showed better activity in VA assay. The Minimum inhibitory concentration (MIC) for Aa, Rs and Cl was 0.2 ml/100 ml whereas >0.2 ml/100 ml for Fo and Ho in PF technique. Fungal sporulation was also completely inhibited at 2 ml/100 ml of the oil except for Cl and Ho, which was only 0.5% (±0.5) and 0.25% (±0.25) respectively as compared to control.