Molecular Epidemiology ofXanthomonas perforansOutbreaks in Tomato Plants from Transplant to Field as Determined by Single-Nucleotide Polymorphism Analysis

Current management of Xanthomonas perforans on tomato plants mainly relies on the frequent application of pesticides. However, the lack of effective pesticides and the development of strain tolerance to certain bactericides limit the ability to control outbreaks in production fields. Better knowledge of probable sources of X. perforans inoculum during tomato production is required to refine management strategies. Tomato plants are typically established in the field using transplants. This study aimed to determine if strains from field epidemics were coming from transplant facilities or resulted from local field outbreaks. The overall goal was to identify potential sources of inoculum and subsequently develop strategies to reduce carryover from transplant production to the field. Our results indicate that tomato producers should shift disease management efforts to transplant facilities to reduce disease in the field. Improved transplant health should reduce the likelihood of bacterial spot outbreaks and subsequently reduce pesticide usage in the field.