Identification of the Bacterial Leaf Spot Pathogen of Lettuce, Xanthomonas campestris pv. vitians, in Ohio, and Assessment of Cultivar Resistance and Seed Treatment.

摘要: In 1995, a bacterial leaf spot disease was observed on lettuce plants grown muck soils in north central Ohio. Characteristic symptoms were water-soaked circular, dark brown- or olivecolored spots, approximately 1 to 2 mm diameter, along the margin of leaves; V-shaped lesions beginning at margins and advancing veins; individual black spots scattered surface. Five strains isolated from infected leaves two cultivars, Darkland Go Green. These identified as Xanthomonas campestris pv. vitians based morphological, physiological, biochemical, pathogenicity tests, well fatty acid methyl ester (FAME) analyses. One five tested resistant streptomycin sulfate (100 μg/ml), none copper sulfate. Eight commercial cultivars evaluated for resistance X. vitians. Of these Redine highly resistant; Focus Crisp Green partially Slobolt, Tiara, Carmona susceptible; susceptible pathogen. Surface disinfection with 0.52% sodium hypochlorite 5 min nearly eliminated bacterium seed without affecting viability.