Application of plant extracts for controlling fungal infestation of grains and seeds during storage

The antifungal potential of five plant extracts was tested in vitro against one relevant field fungus and six relevant storage fungi and in situ against the initial mycoflora of wheat grains after harvest. Pure clove extract caused a complete growth suppression of all target moulds in vitro. The antifungal potential of the other extracts was in the following order with decreasing activity: allspice, oregano, savory, cinnamon extract. In the in situ assays, only clove extract was able to inhibit completely the growth of the initial mycoflora on the wheat grains in concentrations of 50 and 100 %. Furthermore, the phytotoxic effects of the extracts on the wheat germ were determined in situ. Concentrations of clove extract needed to suppress fungal growth on the grains showed a high phytotoxic effect on the germ. When germination of such grains was investigated under practical conditions in soil, no obvious reduction of the germination rate was observed. These results provide a basis for the treatment of wheat grains with a natural antifungal product to control fungal growth during storage.