In vivo efficacy of natural essential oil of Syzygium aromaticum L. bud for protecting the Pisum sativum L. seeds

Abstract

The mycological investigations on sixty samples of stored garden pea food seeds revealed presence of twelve and ten species of fungi by blotter and agar plate techniques respectively. The fungal species were associated with genera viz., Alternaria, Aspergillus, Botrytis, Chaetomium, Cladosporium, Curvularia, Fusarium, Penicillium and Rhizopus. The fungal species viz., Cladosporium herbarum (Pers.) Link and Penicillium italicum Wehmer did not show its appearance in agar plate method. It showed dominance of Aspergillus flavus, Aspergillus niger, Aspergillus ochraceous, Aspergillus terreus in blotter method in comparison to agar plating. Aspergillus tmarii, P. italicum and Rhizopus stolonifer did not grow on sterilized seeds in Blotter method. Pathogenicity tests of dominant fungi caused biodeterioration in garden pea seeds. The antifungal testing of essential oils revealed Syzygium aromaticum L. bud oil to be fungitoxic at 500 ppm (0.025 mL). The minimum inhibitory concentration of the S. aromaticum oil was found to be 300 ppm against four fungi viz., A. flavus, A.niger, A. ochraceous and A. terreus. At this concentration the oil was found to be fungicidal and thermostable. The oilactivity was not affected by physical factors and showed broad spectrum. In vivo study depicted that clove oil was moreeffective in comparison to EDCT. It controlled a maximum of 4 fungi while the clove oil showed no growth of fungi evenafter 6 months storage.