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

Elk Rapids Grape Leaf Black Rot Report (Report issued 3/19/2024 5:27 )

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: 3/5 to 3/19/2024.


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 Elk Rapids 3/5 Midnight-1AM 3/5 9-10AM Wet: 10
Span: 10
37.7 0.57 No risk until pre-bloom period 0%
2 Elk Rapids 3/8 4-5PM 3/10 2-3PM Wet: 36
Span: 47
33 0.53 No risk until pre-bloom period 0%