Sooty blotch/flyspeck thresholds reached at Winchester and Tyro; extended wetting events

For purposes of predicting the development of the sooty blotch and flyspeck (SBFS) fungal complex, we record accumulated wetting hours from rainfall or dew, starting 10 days after petal fall. This year we began wetting hour accumulation at Winchester from May 14. As of Monday, June 6, accumulated wetting hours (ACW) toward the 250 wetting hour threshold for specific treatment against the SBFS fungal complex were: at 909 ft elevation, 257 hr (with the 250-hr threshold reached June 5); at 952 ft elevation, 194 hr; and at the 983 ft elevation, 185 hr ACW.

At Tyro, VA we started wetting hour accumulation May 4, and as of June 6, a sensor placed at the 941 ft elevation had accumulated 245 hr (with the 250-hr threshold reached June 6); the one at 1165 ft. elevation had accumulated 173 wetting hours, and the one 1465 ft. elevation had accumulated 200 wetting hours.

The sensors at the higher elevations at both Winchester and Tyro could reach the threshold ACW within the next week or two, and similar accumulations should be expected for the Carroll-Patrick, Roanoke-Botetourt and Rappahannock-Madison fruit production areas.

At Winchester we had two more extended wetting events at relatively warm temperatures favorable for SBFS and fruit rot development and secondary scab infection last week: June 2-3: 19 hr at 75-64°, with 0.3 in. rain,  and June 4-5: 16 hr at 75-67°.