Longevity of Xanthomonas campestris pv. phaseoli in Naturally Infested Dry Bean (Phaseolus vulgaris) Debris. Eladio Arnaud- Santana and Estela Pena-Matos, Arroyo Loro Experiment Station, San Juan de la Maguana, Dominican Republic; and Dermot P. Coyne and Anne K. Vidaver, Department of Horticulture and Department of Plant Pathology, University of Nebraska, Lincoln 68583. Plant Dis. 75:952-953. Accepted for publication 22 March 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-0952.
 

In two experiments, initiated in 1986 and 1987 in the Dominican Republic, Xanthomonas campestris pv. phaseoli, the causal organism of the common blight disease of dry beans (Phaseolus vulgaris), survived in surface debris composed of diseased leaves. In contrast, leaves in plastic mesh bags located at a depth of 15 cm were apparently decomposed and devoid of the pathogen in less than 30 days. After extraction of bacteria from debris using 12.5 mM potassium PO₄ buffer (pH 7.1) with 1 mM MgSO₄, dilutions were made and plated onto MXP medium. The pathogen survived for 5 mo in the diseased debris on the ground surface in both experiments but was not detected at 6 and 7 mo in experiment II. The pathogen was isolated from debris placed underground for 24 hr but was not detected after 30 days in either experiment. Presumptive X. c. phaseoli recovered from debris was pathogenic on cv. PC-50.