Agriculture: Grape Pest Management Guidelines

Fungicide Resistance Management

Note: Not all indicated timings may be necessary for disease control (see Treatment Timing Table). If treatments are needed based on weather monitoring or environmental monitoring models, suggested fungicide groups are listed for each timing.

How to use this table:

  1. Identify the disease(s) that need(s) to be managed. Know the disease history of the orchard especially from the previous season.
  2. Select one of the suggested FRAC1 mode-of-action group numbers. Numbers separated by slashes are premixtures, whereas numbers grouped by pluses are tank mixtures. If several diseases need to be managed, select a group that is effective against all diseases. Refer to General Properties of Fungicides to determine which fungicides belong to each FRAC group. Group numbers are listed in numerical order within the suggested disease management program below.
  3. Rotate groups for each application within a season and, if possible, use each group only once per season, except for multi-site mode-of-action materials (e.g., M2) or natural products or biological controls (NP/BC).
Grapevines: Suggested Disease Management Programs By Fungicide FRAC1 Groups
Disease Dormant Bud break Full bloom Pre-close Veraison Preharvest
Botryosphaeria canker NP6 (lime sulfur)3 ---- ---- ---- ---- ----
Botrytis ---- ---- 3/7, 3/9
7/112 ,
9/12, 9, 17
19, M4
3/7, 3/9
7/112
9/12, 9, 17
19
3/7, 3/9
7/112
9/12, 9, 17
19
3/7, 3/9
7/11
9/12, 9, 17
19
Downy mildew NP, 4, 40, 43 4,40,43 ---- ---- ----
Esca NP6 (lime sulfur)3 ---- ---- ---- ---- ----
Eutypa NP6 (B-Lock),
1
---- ---- ---- ---- ----
Powdery mildew4,5 NP6 (lime sulfur) Oil M2 Oil 3/7, 3/9
7/11
13
17+11
19
U8
3, 3/7, 3/9
11, 7/11
13, U8
BC6
NP6
M4
3, 3/7, 3/9
11
13, 19
M4
U8
----
Phomopsis cane and leafspot ---- 2
11
M4/M3
---- ---- ---- ----
Summer bunch rot (sour rot) ---- ---- ---- 3/9, 7/11
9, 9/12
Oil, M1
3/9, 7/11
9, 9/12
M1
3,9, 7/117
97, 9/12
M17
1 Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of actions. Group numbers are listed in numerical order within the suggested disease management program. Fungicides with a different group number are suitable to alternate in a resistance management program. Refer to the fungicide efficacy table for fungicides belonging to each FRAC group.
2 Apply only if rain is forecasted. When using one class do not follow with the same class.
3 Use 10 gallons lime sulfur per acre in at least 100 gallons water. Use liquid lime sulfur in dormant applications and wettable sulfur at and after prebloom.
4 Apply bud break and full bloom treatments every year.
5 Apply as needed (a disease risk assessment model is available to help determine need for spray).
6 NP/BC = Natural Products/Biological Controls such as B-Lock, Sonata, Serenade, Kaligreen, Cinnacure, etc.
7 Apply when insect and bird damage present or when rainfall is forecasted.

Adaskaveg, J. E., B. A. Holtz, T. J. Michailides, and W. D. Gubler. 2017. Efficacy and Timing of Fungicides, Bactericides, and Biologicals for Deciduous Tree Fruit, Nut, Strawberry, and Vine Crops (PDF)

Text Updated: 06/17