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Causes of Postharvest Losses in a Florida Tomato Shipment. J. A. Bartz, Associate Professor, Department of Plant Pathology, University of Florida, Gainesville 32611. Plant Dis. 64:934-937. Copyright 1980 American Phytopathological Society. DOI: 10.1094/PD-64-934.

At least six different postharvest plant pathogens were isolated from lesions on tomatoes in a commercial shipment that was rejected at the receiving point because of excessive decay. Sixty percent of the fruit from a representative 30-lb box were diseased. The lesions were light to dark, slightly sunken, and water-soaked. Based on symptoms, 2% of the lesions were associated with wounds, 10% were beneath or beside the blossom scar, 59% were adjacent to the stem scar, and 29% were internal. Pectolytic or decay bacteria were isolated from 90% of 50 randomly selected lesions. Erwinia spp. comprised 66% of the isolates, Pseudomonas marginalis 17%, and P. aeruginosa 17%. Representative isolates of the two pseudomonads, though considerably less virulent on tomatoes than a known isolate of Erwinia carotovora var. carotovora, were capable of causing lesions that contained the macerated tissues, juices, and bacteria needed for secondary spread. The pseudomonads could function as primary rather than secondary organisms in naturally occurring outbreaks of bacterial decay in tomatoes.