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POSTERS: Crop loss assessment

Assessment of the Relationship Between Bacteria Leaf Spot Severity and Crop Yield of Fresh Market and Processing Tomato
Carlos Saint-Preux - The Ohio State University. Melanie Lewis Ivey- Ohio State University, Sally Miller- The Ohio State University, Department of Plant Pathology

Tomato bacterial leaf spot (BLS) can reduce fruit quality and yield and existing management strategies are not effective. Furthermore, no economic threshold level has been established for the disease. Field trials were conducted to assess the relationship between disease severity on yield and the economic impact of BLS on the fresh market (FM) and processing tomato industries. Processing and FM tomatoes were evaluated independently. Each trial included a non-inoculated plot treated with an industry standard chemical spray program; plots inoculated with a high or low concentration of Xanthomonas gardneri(FM) or X. perforans(processing) and no chemical treatments and; a non-inoculated, non-treated control plot. For both trials, disease severity was lowest in the plots managed using a standard chemical spray program with no inoculum and highest in the plots with a high level of inoculum but no chemical treatment (p<0.0001). For FM tomato, marketable yield was significantly lower in the plots that were inoculated with a high concentration of X. gardneri(p<0.0001). No difference was observed in marketable yield among the processing tomato treatments (p=0.761). Production costs per ton of FM tomato were 2.1 times higher for plots with a high level inoculum compared to plots that were chemically treated but not inoculated (p<0.0001). There was no difference in production costs per ton of processing tomato (p=0.761). A negative correlation (p<0.0001; r= -0.621) was observed between marketable yield and disease severity in the FM tomato trial only.