EPIPHYTIC PERSISTENCE OF XANTHOMONAS-CAMPESTRIS PV PRUNI ON PEACH AND PLUM

Epiphytic persistence of Xanthomonas campestris pv. pruni on peach (Prunus persica) and plum (P. domestica) trees was studied by sampling leaves, twigs, buds, flowers, and fruits of a susceptible cultivar of each species. The bacterium was found on all symptomless organs sampled during a 13-mo period during 1984-1985. Bacterial populations observed were variable among replicates and organs on all sampling dates, but populations were found consistently on some organs during winter and summer months alike. X. c. pruni can persist year-round on surfaces of peach and plum trees even in the absence of symptoms of bacterial spot.