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  • Michigan State University Extension
  • Michigan State University Ag Bio Research
  • Project GREEEN

Romeo Grape Leaf Black Rot Report (Report issued 5/7/2024 19:53 )

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 not reached. Using 5/1/2024 as a default date.
Time period assessed for wetting events: 5/1 to 5/7/2024. Events between 4/23 and 5/7/2024 shown.


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 Romeo 5/3 3-4AM 5/4 8-9AM Wet: 22
Span: 30
57.8 0.19 Yes 182%
2 Romeo 5/4 7-8PM 5/5 2-3PM Wet: 17
Span: 20
61.4 0.09 Yes 185%
3 Romeo 5/7 3-4PM Ongoing. Last hour with moisture: 5/7 4-5PM Wet: 2
Span: 2
62.2 0.04 None 19%