Last night we had an extended wetting period following afternoon rains: 16 hr with 0.22 in. of rain at 75°. This wetting period was favorable for rots.
As of this morning, July 3, we had accumulated 258 wetting hours since May 18, surpassing the 250-hour threshold for specific treatment against the sooty blotch/flyspeck (SBFS) fungal complex at our usual AREC monitoring site at elevation 950 ft. This is the elevation from which we have reported cumulative wetting hours since 1994, and this is the latest we have reached that threshold since 1999. But we have recorded 352 CWH at a lower AREC site (elevation 910 ft).
The wetting hour threshold indicates the time at which we would expect the SBFS organisms to be present, but not yet visible on unprotected fruit but we expect symptoms in the more advanced area shortly. Remember to scout your lower orchard areas regularly for onset of SBFS appearance and adjust your fungicide program accordingly.
Disease management information directed mostly to the Frederick County Virginia tree fruit industry, updated as needed throughout the growing season. Keith Yoder, Virginia Tech Agricultural Research and Extension Center, Winchester, Virginia
About Me
- Keith Yoder
- Professor Emeritus of Plant Pathology, Virginia Tech Ag. Research and Extension Center, Winchester, VA
