The Biocontrol of Plant Pathogenic Fungi by Selected Lactic Acid Bacteria: From Laboratory to Field Study

Abstract

Plant diseases caused by pathogenic fungi generate large losses in crops and pose a threat to human and animal health. Since the European Green Deal put a strong emphasis on the need to reduce the use of chemical plant protection, interest in biological control has been growing. The present study aimed to investigate the efficacy of lactic acid bacteria (LAB) isolated from silages in the control of pathogenic fungi through in vitro, mini-plot, and field experiments. The tested LAB showed antifungal activity in vitro towards strains from the Fusarium, Alternaria, Rhizoctonia, Colletotrichum, and Sclerotinia genera; however, only five strains reached an activity ≥ 400 AU/mL towards all pathogenic fungi. The selected strains demonstrated high efficacy in reducing disease symptoms in plants in the mini-plot and field experiments. In the mini-plot experiment, stem smut of rye and wheat common bunt were reduced in the range 34.5–94.7% and 24.8–99.6%, respectively. In the field experiments, the efficacy of LAB in the control of rye and wheat disease differed and reached over 90% in some trials. The effectiveness of LAB in the control of seedling blight did not exceed 70%. A significant increase in yield (from 42.86 to 195.65%) was observed mainly in wheat cultivation. The increase in rye yield was observed only in chosen trials. No phytotoxicity was observed. The results indicate the potential possibilities of using LAB as a biocontrol agent.