Experiments on Controlling Alternaria alternata with Antagonistic Bacteria AM6 Metabolite

For developing new biological pesticides, the field experiments on controlling Alternaria alternata by applying antagonistic bacteria (Streptomyces globispotus) AM6 metabolized antagonistic substance at different concentrations and times were conducted.The results showed that the tobacco leaves sprayed with agent containing AM6 antagonistic substance had good control effects on Alternaria alternata, the control effects increased with the increase of antagonistic substance concentration.The control effect of the antagonistic substance applied twice at the dilution 100 was up to 80.3%.The control effects reached 46.9%, 64.9% and 69.3%, applied 1, 2, 3 times at the dilution 400, respectively.Meantime, no harmful effect on tobacco plants was found.