Dispersal and management of Xanthomonas campestris pv. vesicatoria during thinning of direct-seeded tomato.

The spread of Xanthomonas campestris pv. vesicatoria during thinning of direct-seeded tomato was studied in two field experiments at Homestead, Florida. In a warm, humid season (spring 1988), the incidence of bacterial spot was less when plants were thinned in the afternoon when foliage was dry (44%) vs. those thinned in the morning when plants were laden with dew (87%). In a cool, dry season (fall 1988), disease incidence was reduced from 55% to 0% by waiting until afternoon when plants were dry before thinning. Ethanol and 10% povidone-iodine, applied as prophylactic hand washes, reduced disease incidence after thinning by 65% and 81 % respectively, in spring 1988 (...)