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  • MSU Extension
  • Michigan State University Ag Bio Research
  • Project Greeen

East Lansing (MSUHort) Grape Leaf Black Rot Report (Report issued 5/28/2015 11:49 )

Wetting periods start with rainfall (at least 0.01 inch) and continue until the start of at least eight hours without moisture (rainfall, leaf wetness, high relative humidity). Wetting periods are classified as "ongoing" until eight consecutive dry hours have passed. After that, the official end of the wetting period is recorded (the start of the 8 hour dry period).

Black rot model available after 4/15. Pre-bloom estimated as 5/29/2015 (800 DD Base 42 after 1/1).
No missing degree day data.
Time period assessed for wetting events: 5/14 to 5/28/2015.

Wet Period Station Start of wetting period End of wetting period Duration (Hrs.) Avg temp (F) Rainfall (in.) Grape Leaf Black Rot Progress toward infection
1 East Lansing (MSUHort) 5/15 2-3AM 5/15 11AM-Noon Wet: 10
Span: 10
53.2 0.27 No risk until pre-bloom period 44%
2 East Lansing (MSUHort) 5/16 8-9AM 5/17 8-9AM Wet: 18
Span: 25
66.4 0.01 No risk until pre-bloom period 219%
3 East Lansing (MSUHort) 5/17 9-10PM 5/18 7-8AM Wet: 11
Span: 11
70.1 0.29 No risk until pre-bloom period 150%
4 East Lansing (MSUHort) 5/18 6-7PM 5/18 6-7PM Wet: 1
Span: 1
79.5 0.01 No risk until pre-bloom period 14%
5 East Lansing (MSUHort) 5/25 1-2PM 5/27 2-3PM Wet: 27
Span: 50
67.7 0.7 No risk until pre-bloom period 339%