STM Article Repository

The objective of this research was to determine the effects of VEG’LYS® commercial formulation on the growth of fungal, oomycete and bacterial plant pathogens under laboratory conditions. Microbial growth was measured on potato dextrose agar containing 0.01, 0.05, 0.001, 0.0015, 0.0025, 0.003 and 0.005% VEG’LYS®. VEG’LYS® inhibited the growth of all plant pathogens tested, including Fusarium graminearum, Botrytis cinerea, Rhizoctonia solani AG-8, the oomycete Pythium ultimum and the bacteria Pseudomonas syringae and Ralstonia solanacearum. Fungi and oomycetes responded in a species-dependent manner, but their growth generally was inhibited at a concentration of 0.01% VEG’LYS (IC100). For bacterial pathogens, the IC100 ranged from 0.005%-0.05%. Bacterial endophytes, including Burkholderia, Curtobacterium and Rahnella, showed IC100 values of 0.0015%-0.0025%, also with genera- or species-dependent responses. The endophytes generally were most sensitive to VEG’LYS relative to the other microbes; however, the growth of two endophyte isolates was stimulated by the product, and a number produced spontaneous variants able to grow on concentrations exceeding the original IC100. These findings suggested that certain endophytes had the potential to adapt to the antimicrobial effects of VEG’LYS. In greenhouse studies, growth of wheat seedling roots was impaired by 0.02% and 0.05% VEG’LYS applied as a soil drench, and the treatment did not reverse root damage caused by the soilborne pathogen R. solani AG-8. Applications of this product in agricultural venues likely will require optimization.