Mildew days and wetting hours

As an indicator of relative annual mildew pressure, we note the number of days above 53º without rain as potential "mildew days". From March 30, when powdery mildew spores were first were available on infected emerging buds, until June 1, we had 45 mildew days this year. Since 1993, the number of such days from tight cluster to six weeks after petal fall (about third cover) has ranged from 24 (in '96 and '03) to 49 in '99. This year ranks as the second most frequent mildew weather in 18 years.

Accumulated wetting hours (starting April 29, 10 days after petal fall, Apr 19) now stand at 185 hr. The wetting hour threshold for presence of sooty blotch and flyspeck fungi on unprotected fruit is 250 hr. Rappahannock county (Washington, VA) has logged 237 wetting hours, also as of June 7, using the Apr 19 petal fall and Apr 29 start accumulation date. Rappahannock's total will be updated every two weeks.