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UC Pest Management Guidelines

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Peach fruit.

Nectarine

Fungicide Resistance Management

(Reviewed 6/10, updated 5/12)

In this Guideline:

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 fungicide groups. Numbers separated by slashes are pre-mixtures, 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 fungicide efficacy table for fungicides belonging to each FRAC group. Group numbers are listed in numerical order within the suggested disease management program.
  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 or natural products/biological controls (e.g., M2, NP/BC).
Suggested Disease Management Programs By Fungicide Frac1 Groups
Disease Dormant Bloom 3-6 weeks
postbloom		 Preharvest
20–40% 80–100% 3 weeks 1 week
Brown rot ---- 13
2 (+oil)
3
3/11
9
9/11 		13
2 (+oil)
34
3/11
7/11
9
9/11
17 		3
3/11
7/11
9/11
17 		3
3/11
7/11
9/11
17 		34
3/11
7/11
9/11
17
Powdery
mildew 		----/M22 13
2+oil
3 		13
3
7/11 		3
7/11
11
M22
NP/BC5 		---- ----
Leaf curl M1, M3
M5, M7

M3
M5 		---- ---- ---- ----
Rust M22 ---- ---- 13
3
7/11
11
M22 		3
7/11
11
M22 		----
Scab ---- 13
3
3/11
7/11
9/11
M3
M4
M7 		13
3
3/11
7/11
9/11
M4
M5
M7 		13
3
3/11
7/11
9/11
11
M22
M4, M7 		---- ----
Shot hole M1
M3
M5
M7 		2
M3
M4
M5
M7 		2
7/11
M3
M4
M5 		7/11
11
M4 		---- ----
1Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of actions (for more information, see http://www.frac.info/). 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.
2Efficacy of liquid lime sulfur in dormant applications has not been determined for powdery mildew. Use liquid lime sulfur in dormant applications and wettable sulfur at and after pre-bloom.
3 Strains of Monilinia fructicola resistant to Benlate (label withdrawn), Topsin-M, and T-Methyl are present in some California peach/nectarine 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 peach/nectarine with overuse of fungicides with similar chemistry. Subpopulations of both Monilinia spp. have been shown to be resistant to AP (FRAC 9) fungicides on prune in CA.
4Among the group 3 fungicides, only Elite/Tebuzol/Orius and Quash have some activity against Botrytis cinerea.
5NP/BC = Natural Products/Biological Controls such as copper, sulfur, potassium bicarbonate (Kaligreen), Streptomyces lydicus (Actinovate AG), Bacillus pumilus (Sonata), and Bacillus subtilis (Serenade)

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Nectarine
UC ANR Publication 3451
General Information
W. J. Bentley (Crop Team Leader), UC IPM Program, Kearney Agricultural Center, Parlier
K. R. Day, UC Cooperative Extension, Tulare County
R. A. Duncan, UC Cooperative Extension Stanislaus County
S. Johnson, Pomology, Kearney Agricultural Center, Parlier
J. A. Roncoroni, UC Cooperative Extension, Napa County

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