Cherry -- Bacterial Canker
See Also: Cherry, Flowering - Bacterial Canker
Cause: Pseudomonas syringae pv. syringae, a bacterium. This disease can be the limiting factor against establishing a cherry orchard in the Pacific Northwest. Two common genetic traits increase the bacteria’s ability to cause disease. Most produce a powerful plant toxin, syringomycin, that destroys plant tissues as bacteria multiply in a wound. Bacteria also produce a protein that acts as an ice nucleus, increasing frost wounds that bacteria easily colonize and expand. These factors include wounds, frost damage, early dormant season pruning, heading cuts, incorrect soil pH, and poor nutrition. Important avenues of infection leading to tree death include natural leaf scars in the fall and heading cuts made in the spring after planting a new orchard. Infection by other pathogens including Cytospora, Verticillium, and Nectria can lead to more bacterial canker. Ring nematodes have also been associated with increased susceptibility to bacteria canker in both cherry and peach. Sources of bacteria include old cankers, healthy buds, systemic infections within trees (with or without cankers), as epiphytes on leaf surfaces, weeds, grasses, and even soil. Wind, rain, insects, infected bud wood, and infected nursery stock can spread bacteria. Pruning through cankered and then through susceptible, healthy tissue does not spread the disease.
References:
Kennelly, M. M., Cazorla, F. M., de Vicente, A., Ramos, C. and Sundin, G. W. 2007. Pseudomonas syringae Diseases of Fruit Trees: Progress Toward Understanding and Control. Plant Disease 91:4-17.
Spotts, R. A., Wallis, K. M., Serdani, M., and Azarenko, A. N. 2010. Bacterial canker of sweet cherry in Oregon—Infection of horticultural and natural wounds, and resistance of cultivar and rootstock combinations. Plant Dis. 94:345-350.
Content edited by: Jay W. Pscheidt on 1/1/2011 12:00:00 AM
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