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Poster: Biology & Disease Mgmt: Postharvest Pathology & Mycotoxins


Controlling bacterial soft rot in tomato fruit that have been inoculated through lenticels located around the stem attachment.
J. BARTZ (1), D. Spiceland (1), M. Elkahky (3), J. Brecht (4) (1) University of Florida, U.S.A.; (2) University of Florida, U.S.A.; (3) Faculty of Agriculture, Mansoura University, Egypt; (4) Horticultural Sci.; University of Florida, U.S.A.

Tomato fruit harvested from wet plants or exposed to rainfall prior to packing have a high potential for postharvest decays. In laboratory tests, bacterial soft rot (Pectobacterium carotovorum) development during storage of fruit inoculated in the stem depression was delayed by air-drying, wiping dry, or chlorine washes with efficacy linked with the interval between inoculation and treatment as well as type of treatment. Fruit that were exposed to water alone did not develop decay during storage. Incidence of bacterial soft rot was rare (0 to 13%) among inoculated fruit that were washed with chlorinated water, or wiped dry within 10 sec after dip inoculation, whereas lesions developed among > 50% of fruit washed or wiped dry at 60 min post inoculation. Incidence among non-treated controls was 100% within the 5-day storage. In three separate experiments, bacterial soft rot was reduced by an average of 52, 60, and 20% when fruit were air-dried (30 min) at 1, 4 or 18 h after inoculation, respectively. Corresponding values for washing in chlorinated water (200 ppm, pH 6.5) for 1 min averaged 48, 40 and 2%, respectively. Although evidence does not indicate that the pathogen is introduced into stem scar infection courts by contact such as occurs with wound inoculation, interventions must be initiated within an hour or less after stem scar exposure to inoculum in order to minimize the decay potential.