Phage therapy for plant disease control.

Bacteria cause a number of economically important plant diseases. Bacterial outbreaks are generally problematic to control due to lack of effective bactericides and to resistance development. Bacteriophages have recently been evaluated for controlling a number of phytobacteria and are now commercially available for some diseases. Major challenges of agricultural use of phages arise from the inherent diversity of target bacteria, high probability of resistance development, and weak phage persistence in the plant environment. Approaches for resistance management--by applying phage mixtures and host-range mutant phages and, for increasing residual activity, by employing protective formulations, avoiding sunlight, and utilizing propagating bacterial strains--resulted in better efficacy and reliability. Deployment of phage therapy as part of an integrated disease management strategy, which includes the use of genetic control, cultural control, biological control, and chemical control, also has been investigated and will likely increase in the future.