First Blossom Blight Symptoms Visible in Winchester at AREC Trial (Infections 23-25 April)

(I) In our research trial at AREC we detected today first fire blight symptoms on 17 May on ‘Fuji’ flower clusters and shoots. We inoculated whole ‘Fuji’ trees with fire blight bacterium Erwinia amylovora on 23, 24, and 25 April (late April heat wave) at 80% bloom. It is almost certain that droplets of white fire blight bacterial ooze on the flower stem/s (peduncle) were first visible about 5 to 10 days before 17 May. At that time, 5 to 10 days ago, the blighted flowers and leaf necrosis were not visible yet. Visible symptoms from 17 May expressed due to the warm weather we received in the last 10 days (Figures 1 – 2 below). Click on the figure/s to enlarge the image. If natural fire blight infections took place on 23, 24 and 25 April, as models indicated, with warm weather fire blight clusters and strikes should be visible orchards that were not covered with streptomycin at that time.

(II) I have not yet seen symptoms of apple scab at AREC, as we did not have an untreated check trees this year. If, by any unfortunate chance scab symptoms on leaves are visible at any location known to you, please notify me. It would be good to know and get pictures.