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Relation Between Resistance of Tomato Fruit to Infiltration by Erwinia carotovora subsp. carotovora and Bacterial Soft Rot. J. A. Bartz, Plant Pathology Department, University of Florida, Gainesville 32611. Plant Dis. 75:152-155. Accepted for publication 16 July 1990. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-0152.

Fruit of some tomato cultivars, including Sunny and Horizon, did not absorb water or cell suspensions of Erwinia carotovora subsp. carotovora as readily as did those of Florida MH-1, Walter, or Flora-Dade. These differences were consistent among fruit from successive harvests of the same crop or harvests of different crops in the same or different years. Large and mature green fruit absorbed more water or inoculum than did small, pink ones. The incidence of bacterial soft rot among infiltrated fruit increased with quantity of inoculum absorbed and was unrelated to disease development in wound-inoculated fruit. The resistance of some cultivars to bacterial soft rot as determined through wound-inoculation tests was overcome by the volume of inoculum absorbed when fruit were inoculated by infiltration. Some significant differences among cultivars for disease incidence persisted, however, even though incidence was adjusted to account for differences in inoculum absorbed. Therefore, some characteristic of tomato fruit besides porosity of the stem scar to water affected disease development. Fruit that resist infiltration by water are less likely to become inoculated with rot-inducing fungi or bacteria when handled in the water dumps and flumes at modern packinghouses.