Cause The bacterium, Pseudomonas syringae, is causing a new disease on broccoli. Though it hasn't been found in the Pacific Northwest, it has been described in California production.
Symptoms Large, angular lesions develop on leaves. At first, lesions are gray-green but then turn tan. Overhead irrigation is associated with numerous spots on each leaf.
Cultural control
- Minimize overhead irrigation if possible. If it must be used, time so that plants dry rapidly after irrigation.
Chemical control Studies are under way at University of California-Davis.
- Cueva at 0.5 to 2 gal/100 gal water on 7- to 10-day intervals. May be applied on the day of harvest. 4-hr reentry. O