Agriculture: Almond Pest Management Guidelines

Fungicide Resistance Management—Conventional Growers

SUGGESTED DISEASE MANAGEMENT PROGRAMS BY FRAC1GROUP NUMBERS—CONVENTIONAL GROWERS

Note: Not all indicated timings may be necessary for disease control (see Effective Treatment Timings for Key Diseases table). If treatments are needed based on host phenology, weather monitoring, inoculum models, or environmental-disease forecasting 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 last season.
  2. Select one of the suggested fungicide group numbers. Numbers separated by slashes are pre-mixtures, whereas numbers separated by pluses are tank mixtures. If several diseases need to be managed, select a group number that is effective against all diseases. Refer to the fungicide efficacy table for fungicides belonging to each FRAC group number. Group numbers are listed in numerical order within the suggested disease management program.
  3. Rotate group numbers for each application within a season and, if possible, use each group number only once per season, except for multi-site mode-of-action materials (e.g., M2).
Bloom Spring Summer
Disease Dormant Pink bud Full bloom Petal fall 2 weeks 5 weeks May June/July
alternaria 2 3, 3/7, 3/9, 3/11, 3/33, 7, 7/11, 11, 19 3, 3/7, 3/9, 3/11, 3/33,
7, 7/11, 11, 19
anthracnose 3, 3/7, 3/9, 3/11, 3/33, 7 3, 3/7, 3/9, 3/11, 3/33, 7, 7/11, 11 3, 3/9, 3/7, 3/11, 3/33, 11,
M3, M4, M5
3, 3/9, 3/11, 3/7, 3/33,
7, 7/11, 11, M3, M4, M5
3, 3/7, 3/9, 3/11, 3/33,
7, 7/11, 11,
M3, M4, M5
3, 3/7, 3/9, 3/11, 3/33, 7, 7/11, 11, M4 3, 3/7, 3/9, 3/11, 3/33,
7, 7/11, 11,
M4
bacterial spot M1, M1+M3 M1,
M1+M3
M1,
M1+M3
M1,
M1+M3
M1,
M1+M3
M1
brown rot 12, 2 +oil,
3, 3/7, 3/9, 3/11, 3/33, 9
12, 2 +oil, 3, 3/7, 3/9, 3/11, 3/33, 7, 7/11, 9, 11, 19 12, 2 +oil, 3/11, 3/33
7, 7/11, 9, 19
hull rot5 3, 3/7, 3/9, 3/11, 7/11,
11, 19
3, 3/7, 3/9, 3/11, 7/11
11, 19
jacket rot 12, 2 +oil,
3/7, 3/9, 3/11,
7, 7/11, 9, 19
12, 2 +oil, 3/7, 3/9, 3/11, 7, 7/11, 9, 19
leaf blight 12, 2, 3, 3/7, 3/9, 3/11, 3/33, 11 12, 2, 3, 3/7, 3/9, 3/11, 3/33, 11, M3, M4, M5 3, 3/7, 3/9, 3/11, 3/33, 11, M3, M4, M5
rust 3, 3/7,
3/11,3/331, 7, 7/11, 11, 19
M3
3, 3/7, 3/11,
3/33, 7, 7/11,
11, 19
3, 3/7, 3/11,
3/33, 7, 7/11,
11, 19
scab4 M1+oil,
M23,
M5+oil
12, 3/7, 3/9, 3/11, 3/33,
7, 7/112, 112
M3, M4, M5
12, 3/7, 3/9, 3/11, 3/33,
7, 7/112, 112
M3, M4, M5
3, 3/7, 3/9, 3/11, 3/33, 7, 7/112, 112
M23, M3, M4
M23, M4
shot hole M1 2, 3, 3/7, 3/9, 3/11, 7, 9, 11 2, 3, 3/7, 3/9, 3/11,7, 7/11,
9, 11, 19
2, 3, 3/7, 3/9, 3/11, 7, 7/11
9, 11, 19
7, 7/11, 11, 19, M3, M4, M5 7, 7/11,11,
19, M3, M4, M5
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. Note: FC 33 is currently P 07.
2 Strains of Monilinia fructicola and M. laxa resistant to Topsin-M, and T-Methyl are present in some California almond orchards. Resistant strains of the jacket rot fungus, Botrytis cinerea, and powdery mildew fungi have been reported in California on crops other than almond and stone fruits and may have the potential to develop in almond with overuse of fungicides with similar chemistry.
3 Use liquid lime sulfur in dormant applications and wettable sulfur at and after pre-bloom.
4 Apply petal fall treatments based on twig-infection sporulation model.
5 Effective hull rot management is dependent on integrated strategies including dust control, reduced irrigation, and limiting nitrogen fertilization prior to and during hull split, as well as ensuring adequate air circulation (appropriate pruning or hedging practices) in the orchard.

Effective hull rot management is dependent on integrated strategies including dust control, reduced irrigation, and limiting nitrogen fertilization prior to and during hull split, as well as ensuring adequate air circulation (appropriate pruning or hedging practices) in the orchard.

Acknowledgment: Adaskaveg et al., 2022. Fungicides, Bactericides, Biocontrols, and Natural Products for Deciduous Tree Fruit and Nut, Citrus, Strawberry, and Vine Crops. (PDF)

Text Updated: 03/22