1. UC IPM
  2. Weather, models and degree days
  3. Grape Powdery Mildew Risk Assessment Index
Weather, models & degree-days

RAI report for Del Rey

The grape powdery mildew risk assessment index (RAI) is useful for determining disease pressure and how often you need to spray to protect the vines. For information on how to use the RAI, see the pest management guideline.

Bud Break Date:

Grape Variety: Thompson Seedless

On This Page

Time Period: February 1, 2025 to May 7, 2025.

Date RAI Disease pressure Pathogen status Hours
70° ≤ Temp ≤ 85° 		Hours
Temp > 95° 		Notes
05/07/2025
60 high reproduces every 5 days 4.1 0.00
05/06/2025 70 high reproduces every 5 days 6.4 0.00
05/05/2025 50 moderate reproduces every 15 days 12.3 0.00
05/04/2025 30 moderate reproduces every 15 days 3.0 0.00
05/03/2025 40 moderate reproduces every 15 days 2.7 0.00
05/02/2025
50 moderate reproduces every 15 days 4.4 0.00
05/01/2025 60 high reproduces every 5 days 4.4 0.00
04/30/2025 70 high reproduces every 5 days 5.1 0.00
04/29/2025 80 high reproduces every 5 days 10.7 0.00
04/28/2025 60 high reproduces every 5 days 5.6 0.00
04/27/2025 70 high reproduces every 5 days 0.0 0.00
04/26/2025 80 high reproduces every 5 days 0.0 0.00
04/25/2025 90 high reproduces every 5 days 0.0 0.00
04/24/2025 100 high reproduces every 5 days 6.5 0.00
04/23/2025 100 high reproduces every 5 days 9.9 0.00
04/22/2025 80 high reproduces every 5 days 4.2 0.00
04/21/2025 90 high reproduces every 5 days 5.0 0.00
04/20/2025 100 high reproduces every 5 days 10.2 0.00
04/19/2025 90 high reproduces every 5 days 10.6 0.00
04/18/2025 70 high reproduces every 5 days 4.3 0.00
04/17/2025 80 high reproduces every 5 days 0.9 0.00
04/16/2025 90 high reproduces every 5 days 3.6 0.00
04/15/2025 100 high reproduces every 5 days 9.8 0.00
04/14/2025 90 high reproduces every 5 days 5.0 0.00
04/13/2025 100 high reproduces every 5 days 8.9 0.00
04/12/2025 100 high reproduces every 5 days 9.0 0.00
04/11/2025 100 high reproduces every 5 days 10.6 0.00
04/10/2025 90 high reproduces every 5 days 5.1 0.00
04/09/2025 100 high reproduces every 5 days 9.8 0.00
04/08/2025 80 high reproduces every 5 days 7.2 0.00
04/07/2025 60 high reproduces every 5 days 7.9 0.00
04/06/2025 40 N/A Not Present 8.2 0.00
04/05/2025 20 N/A Not Present 6.9 0.00
04/04/2025 0 N/A Not Present 1.4 0.00
04/03/2025 0 N/A Not Present 0.0 0.00
04/02/2025
0 N/A Not Present 0.0 0.00
04/01/2025 0 N/A Not Present 0.0 0.00
03/31/2025 0 N/A Not Present 0.0 0.00
03/30/2025 0 N/A Not Present 0.0 0.00
03/29/2025 0 N/A Not Present 0.0 0.00
03/28/2025 0 N/A Not Present 4.0 0.00
03/27/2025 20 N/A Not Present 9.3 0.00
03/26/2025 0 N/A Not Present 5.1 0.00
03/25/2025 20 N/A Not Present 8.6 0.00
03/24/2025 0 N/A Not Present 5.0 0.00
03/23/2025 0 N/A Not Present 0.0 0.00
03/22/2025 0 N/A Not Present 0.0 0.00
03/21/2025 0 N/A Not Present 0.0 0.00
03/20/2025 0 N/A Not Present 0.0 0.00
03/19/2025 0 N/A Not Present 0.0 0.00
03/18/2025 0 N/A Not Present 0.0 0.00
03/17/2025 0 N/A Not Present 0.0 0.00
03/16/2025 0 N/A Not Present 0.0 0.00
03/15/2025 0 N/A Not Present 0.0 0.00
03/14/2025 0 N/A Not Present 0.0 0.00
03/13/2025 0 N/A Not Present 0.0 0.00
03/12/2025 0 N/A Not Present 0.0 0.00
03/11/2025 0 N/A Not Present 0.0 0.00
03/10/2025 0 N/A Not Present 2.9 0.00
03/09/2025 0 N/A Not Present 5.3 0.00
03/08/2025 0 N/A Not Present 0.0 0.00
03/07/2025 0 N/A Not Present 0.0 0.00
03/06/2025 0 N/A Not Present 0.0 0.00
03/05/2025 0 N/A Not Present 0.0 0.00
03/04/2025 0 N/A Not Present 0.0 0.00
03/03/2025 0 N/A Not Present 0.0 0.00
03/02/2025
0 N/A Not Present 0.0 0.00
03/01/2025 0 N/A Not Present 5.4 0.00
02/28/2025 0 N/A Not Present 5.2 0.00
02/27/2025 0 N/A Not Present 4.8 0.00
02/26/2025 0 N/A Not Present 3.7 0.00
02/25/2025 0 N/A Not Present 0.0 0.00
02/24/2025 20 N/A Not Present 6.3 0.00
02/23/2025 0 N/A Not Present 5.5 0.00
02/22/2025 0 N/A Not Present 3.7 0.00
02/21/2025 0 N/A Not Present 1.1 0.00
02/20/2025 0 N/A Not Present 0.0 0.00
02/19/2025 0 N/A Not Present 0.0 0.00
02/18/2025 0 N/A Not Present 0.0 0.00
02/17/2025 0 N/A Not Present 0.0 0.00
02/16/2025 0 N/A Not Present 0.0 0.00
02/15/2025 0 N/A Not Present 0.0 0.00
02/14/2025 0 N/A Not Present 0.0 0.00
02/13/2025 0 N/A Not Present 0.0 0.00
02/12/2025 0 N/A Not Present 0.0 0.00
02/11/2025 0 N/A Not Present 0.0 0.00
02/10/2025 0 N/A Not Present 0.0 0.00
02/09/2025 0 N/A Not Present 0.0 0.00
02/08/2025 0 N/A Not Present 0.0 0.00
02/07/2025 0 N/A Not Present 0.0 0.00
02/06/2025 0 N/A Not Present 0.0 0.00
02/05/2025 0 N/A Not Present 0.0 0.00
02/04/2025 0 N/A Not Present 0.0 0.00
02/03/2025 0 N/A Not Present 0.0 0.00
02/02/2025
0 N/A Not Present 4.2 0.00
02/01/2025 0 N/A Not Present 0.0 0.00