Disease Update; Accumulated wetting hours and extended wetting events

Early this week we recorded another extended wetting event at our AREC: May 28-29, wet 12 hr at 63° with 0.04 in. rain. 

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 chose Apr 24 as our petal fall date for Winchester, so the start of wetting hour accumulation was from May 4. As of Monday morning May 29, accumulated wetting hours (ACW) toward the 250 wetting hour threshold for specific treatment against the SBFS fungal complex were: at 909 ft elevation, 204 hr; at 932 ft (the AREC NEWA station), 167 hr; and at the 983 ft elevation, 139 hr ACW. In the past week some wetting hour accumulation occurred from both rainfall and dew. 

For central Virginia, we have selected Apr 20 as the petal fall date, and accumulation of wetting hours from Apr 30 is recorded by three weather stations at different elevations at Tyro. As of May 29, a sensor placed at 1465 ft. elevation had accumulated only 75 wetting hours from Apr 30, while the one at 1165 ft. had accumulated 147 wetting hours, and the one placed at 941 ft elevation had accumulated 187 hr.

The NEWA station at Gadino Cellars (elev. 665 ft, in Washington, VA) has recorded 206 wetting hours since May 1.