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

Chatham Grape Leaf Black Rot Report (Report issued 3/28/2024 10:44 )

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: 3/14 to 3/28/2024.
Hourly weather data missing for: 3/28/2024 8-9AM - 3/28/2024 9-10AM (2 hours); Total of 2 missing hours
Hourly weather data estimated for: 3/14/2024 Midnight-1AM - 3/28/2024 7-8AM (344 hours); Total of 344 estimated hours
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 Chatham 3/16 9-10PM 3/18 11PM - Midnight
Some estimated data used.
Wet: 24
Span: 27
24.3 0.65 No risk until pre-bloom period 0%
2 Chatham 3/18 9-10AM 3/18 11AM-Noon
Some estimated data used.
Wet: 3
Span: 3
23.9 0.06 No risk until pre-bloom period 0%
3 Chatham 3/19 Midnight-1AM 3/19 2-3AM
Some estimated data used.
Wet: 3
Span: 3
24.6 0.07 No risk until pre-bloom period 0%
4 Chatham 3/19 4-5PM 3/20 11PM - Midnight
Some estimated data used.
Wet: 7
Span: 8
28 0.13 No risk until pre-bloom period 0%
5 Chatham 3/20 8-9AM 3/20 3-4PM
Some estimated data used.
Wet: 2
Span: 8
17.6 0.03 No risk until pre-bloom period 0%
6 Chatham 3/22 11AM-Noon 3/22 Noon-1PM
Some estimated data used.
Wet: 2
Span: 2
32 0.04 No risk until pre-bloom period 0%
7 Chatham 3/22 9-10PM 3/23 8-9AM
Some estimated data used.
Wet: 6
Span: 12
18.5 0.08 No risk until pre-bloom period 0%
8 Chatham 3/24 11AM-Noon 3/27 1-2AM
Some estimated data used.
Wet: 53
Span: 63
34 1.81 No risk until pre-bloom period 0%
9 Chatham 3/28 Midnight-1AM 3/28 Midnight-1AM
Some estimated data used.
Wet: 1
Span: 1
26.1 0.01 No risk until pre-bloom period 0%