Chestnut (Castanea spp.)-Bacterial Blight

Cause Pseudomonas sp., a bacterium. There are few descriptions of this disease. It has been reported in Japan and found in Oregon. The bacterium in Japan was named Pseudomonas syringae pv. castaneae.

Symptoms Young shoots and leaves at first show water-soaked spots. Affected tissues turn brown, and leaves may be distorted. Generally, dieback occurs only on 1-year old wood but may be found in older limbs. A sharp line between damaged and healthy tissue can be seen by late spring or early summer.

Cultural control

  • Prune out infected wood before budbreak in spring.

Chemical control Populations of bacteria resistant to copper products may compromise control efforts.

  • Badge X2 at 1 to 4 lb/A. Group M1 fungicide. 24-hr reentry. O

Reference Takanashi, K., and Shimizu, K. 1989. Pseudomonas syringae pv. castaneae pv. nov., causal agent of bacterial canker of chestnut (Castanea crenata Sieb. et Zucc.). Japanese Journal of Phytopathology, 55:397-403.