Abstract: In order to explore the possibility of essential oil from Citrus maxima used to control diseases of postharvest,essential oil was extracted from Citrus maxima peel through hydro-distillation.The antifungal activity of the essential oil against Botrytis cinerea was determined by the poison food technique and the volatile activity assay.The results showed that yield of the essential oil was about 0.32% (w/w) for 10 h extraction and density of the essential oil was 0.66 g/cm3.Eight different compositions in the essential oil were identified by using GC-MS.The major components in the essential oil detected were limonene,myrcene and nootkatone,respectively.Comparing with the poison food technique the essential oil and its two main constituents,limonene and myrcene,showed better antifungal activity against B. cinerea in volatile activity.Antifungal activity of limonene was significant higher than the essential oil andmyrcenedid at same concentration.It is necessary to explore the possibility of Citrus maxima peel essential oil used in practice of postharvest disease control because of its significant antifungal activity.

Key words: Citrus maxima peel, essential oil, chemical composition, antifungal activity, Botrytis cinerea