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 have again chosen May 4 as our petal fall date for Winchester, so the start of wetting hour accumulation is from May 14. As of Monday, May 23, accumulated wetting hours (ACW) toward the 250 wetting hour threshold for specific treatment against the SBFS fungal complex were: at 909 ft elevation, 94 hr; at 952 ft elevation, 76 hr; and at the 983 ft elevation, 73 hr ACW.
To those farther south and east of the Blue Ridge, your normal petal fall date would have been a week or more ahead of ours at Winchester, so we have selected Apr 27 as the petal fall date for accumulation of wetting hours by weather stations at Tyro, VA. One of the purposes of having three weather stations at this location was to compare wetting hour accumulation at different elevations, but because many of the early wetting hours were a result of rainfall rather then dew, the early accumulation trend this year is a bit different than in previous years. As of May 23, a sensor placed at 1465 ft. elevation had accumulated 130 wetting hours from May 4, the one at 1165 ft. elevation had accumulated 107 wetting hours, and the one placed at 941 ft elevation had accumulated 133 hr.