Disease Management

Maximum use of resistant varieties is the most effective control measure. Growing numbers of good peaches are highly tolerant of bacterial spot. Resistance in plums, nectarines, and apricots is not as common. Nurserymen are well aware of the degree of susceptibility of the varieties they sell and they can provide good information for specific areas. Since trees in poor vigor are more susceptible, orchard management programs should be designed to maintain good vigor. Major outbreaks of bacterial canker in young orchards are often attributed to poor cultural practices.

No completely successful spray programs exist for control of bacterial spot. Chemical sprays can help reduce the amount of fruit and leaf infection but must be applied before symptoms occur. In seasons when disease incidence is light, special programs do help. In those when infections are numerous, spray programs can reduce the number of infections, but not enough to prevent defoliation and fruit infection. Chemical applications suppress the development of disease but do not eliminate it. Because chemical control is uncertain, the use of resistant varieties appears to be the best control strategy.