Wednesday, April 14, 2010

Apple scab infection period

We recorded an apple scab infection period from 10 AM Apr 13- 8 AM Apr 14; wet 22 hours with 0.1 inches of rain. Few quince rust or cedar-apple rust spores have been discharged, so it is not likely that rust infection occurred although blossoms would still be very susceptible to quince rust infection. Hopefully, protectant fungicides applied last week would have lasted through this wetting event with only 0.1 inch of rain. If an orchard was not adequately protected, a fungicide with after-infection activity is advised.