How to Manage Pests

UC Pest Management Guidelines

Almond

2013 Fungicide Efficacy and Treatment Timing

(Reviewed 3/10 , updated 10/13 )

In this Guideline:


FUNGICIDE EFFICACY FOR ALMONDS DISEASES

Fungicide Resistance risk (FRAC)1 Brown rot Jacket rot Anthracnose Shot hole Scab3 Rust3 Leaf blight Alternaria leaf spot 3 PM-like5 Hull rot16
Bumper/Tilt4 high (3) ++++ +/- ++++ ++ ++ +++ ND ++ +++ ++
Indar high (3) ++++ +/- +++ ++ ++ NL ND + ND ----
Inspire Super4 high (3/9) ++++ ++++ ND +++ +++ +++ ND +++ ND +++
Luna Sensation medium (7/11)3,7 ++++ ++++ ++++ ++++ ++++ ++++ ND ++++ +++ +++
Pristine medium (7/11)3,7 ++++ ++++ ++++ ++++ ++++ +++ ND +++ +++ +++
Merivon* medium (7/11)3,7 ++++ ++++ ++++ ++++ ++++ +++ ND ++++ ++++ +++
Quash4 high (3) ++++ ++ ++++ +++ +++ ++++ ND ++++ +++ +++
Luna Experience medium (3/7)3 ++++ +++ ++++ +++ ++++ ++++ ND ++++ +++ +++
Quadris Top medium (3/11)3 ++++ +++ ++++ +++ ++++ ++++ ND +++ +++ +++
Quilt Xcel medium (3/11)3 ++++ +++ ++++ +++ ++++ ++++ ND +++ +++ +++
Rovral + oil8 low (2) ++++ ++++ ---- +++ +/- ++ ND +++9 ND ----
Scala3 high (9)3, 7 ++++ ++++ ND ++ ---- ND ND + ---- ----
Tebuzol (Elite**) high (3) ++++ +/- +++ ++ ++ +++ ND + ND ++
Topsin-M/T-Methyl/ Incognito2 high (1)2, 7 ++++ ++++ ---- ---- +++8 + +++6 ---- ++ ----
Vangard high (9)3, 7 ++++ ++++ ND ++ ---- ND ND +9 ---- ----
Fontelis high (7)4 ++++ ++++ ++ ++++ +++ +++ ND +++ ND ----
Abound4 high (11)3,7 +++ ---- ++++ +++ ++++ ++++ +++ +++10 +++ +++
Elevate high (17)7 +++ ++++ ---- + ND ND ND ND ND ----
Protexio* high (17)7 +++ ++++ ---- + ND ND ND ND ND ----
Gem4 high (11)3, 7 +++ ---- ++++ +++ ++++ ++++ +++ +++10 +++ +++
Laredo high (3) +++ ---- ++ ++ ---- + +++ ---- +++ ----
Rovral/Iprodione/Nevado low (2) +++ +++ ---- +++ ---- ---- ND ++9 ---- ----
Bravo/Chloro-thalonil/Echo/Equus11,12 low (M5) ++ NL +++ +++ +++15 ++++ NL NL ---- ----
Captan4,12 low (M4) ++ ++ +++ +++ ++ ---- +++6 + ---- ----
CaptEvate** low (M4/17) +++ +++ +++ +++ +++ ---- +++ + ---- ----
Ph-D medium (19) ++ +++ ---- ++ +++ +++ ND ++++ ND ++
Syllit* Medium (M7) + ---- ND +++ ++++ ND ND + ND ----
Rally13 high (3) +++ ---- ++ +/- ---- + +++ ---- +++ ----
Ziram low (M3) ++ + +++ +++ +++ ---- ++ + ---- ----
Copper14 low (M1) +/- +/- ---- + +15 ---- ---- ND ---- ----
Copper + oil14 low (M1) ND ND ---- + +++15 ---- ---- ND ---- ----
Lime sulfur12 low (M2) +/- NL ---- +/- ++15 ++ NL NL ---- ----
Sulfur4,12 low (M2) +/- +/- ---- ---- ++ ++ ---- ---- +++ ----
PlantShield***17 low ---- ---- ---- ---- ---- ---- ---- ---- ---- ----
 
Rating: ++++ = excellent and consistent, +++ = good and reliable, ++ = moderate and variable, + = limited and/or erratic, +/- = minimal and often ineffective, ---- = ineffective, NL = not on label, and ND = no data
* Registration pending in California
**Not registered, label withdrawn or inactive
*** Section 24C (special local needs) registration approved in California for silver leaf disease of almond.
1 Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of actions (for more information, see http://www.frac.info/). Fungicides with a different group number are suitable to alternate in a resistance management program. In California, make no more than one application of fungicides with mode of action Group numbers 1, 4, 9, 11, or 17 before rotating to a fungicide with a different mode of action Group number; for fungicides with other Group numbers, make no more than two consecutive applications before rotating to fungicide with a different mode of action Group number.
2 Strains of the brown rot fungi Monilinia laxa and M. fructicola resistant to Topsin-M and T-Methyl have been found in some California almond orchards. MBC-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 almonds with overuse of fungicides with similar chemistry. MBC-resistant strains of the scab fungus, Cladosporium carpophilum, have been found in California.
3 Field resistance of Alternaria sp. and Cladosporium carpophilum to QoI and SDHI fungicides has been detected in almond orchards. AP-resistant populations of Monilinia spp. have been found on other stone fruit crops in California.
4Of the materials listed, only sulfur, Abound, Gem, and some of the DMI fungicides (FRAC Group No. 3) are registered for use in late spring and early summer when treatment is recommended.
5PM-like refers to a powdery mildew-like disease on almond fruit that is managed with fungicides. Recent information suggests an Acremonium species is involved.
6Excellent control obtained when combinations of Topsin-M or T-Methyl and Captan are used.
7 To reduce the risk of resistance development start treatments with a fungicide with a multi-site mode of action; rotate or mix fungicides with different mode of action FRAC numbers for subsequent applications, use labeled rates (preferably the upper range), and limit the total number of applications/season.
8 Oils recommended include "light" summer oil, 1-2% volume/volume.
9 Not registered for use later than 5 weeks after petal fall.
10Efficacy reduced at high temperatures and relative humidity; experimental for Alternaria.
11 Bravo Ultrex, Bravo WeatherStik, Echo Ultimate, and Chlorothalonil are currently registered.
12 Do not use in combination with or shortly before or after oil treatment.
13 Efficacy is better in concentrate (80-100 gal/acre) than in dilute sprays.
14 The low rates necessary to avoid phytotoxicity in spring reduce the efficacy of copper.
15 "Burns out" scab twig lesions when applied at delayed dormant. (Chlorothalonil can be applied with dormant oil during tree dormancy).
16 Hull rot ratings are for the disease caused by Rhizopus stolonifer. Ratings for the disease caused by Monilinia spp. will be provided in the future.
17 Active ingredient, Trichoderma harzianum Rifai strain KRL-AG2, provides control of Silver leaf disease.

ALMOND: TREATMENT TIMING

Note: Not all indicated timings may be necessary for disease control.

Disease Dormant Bloom Spring1 Summer
Pink bud Full bloom Petal fall 2 weeks 5 weeks May June
Alternaria ---- ---- ---- ---- ---- ++ +++ +++
Anthracnose2 ---- ++ +++ +++ +++ +++ +++ ++
Brown rot ---- ++ +++ + ---- ---- ---- ----
Green fruit rot ---- ---- +++ ---- ---- ---- ---- ----
Hull rot7 ---- ---- ---- ---- ---- ---- ---- +++
Leaf blight ---- ---- +++ ++ + ---- ---- ----
Scab3 ++ --- --- ++ +++ +++ + ---
Shot hole4 +5 + ++ +++ +++ ++ ---- ----
Rust ---- ---- ---- ---- ---- +++ +++ +6
 
Rating: +++ = most effective, ++ = moderately effective, + = least effective, and ---- = ineffective
1 Two and five weeks after petal fall are general timings to represent early postbloom and the latest time that most fungicides can be applied. The exact timing is not critical but depends on the occurrence of rainfall.
2 If anthracnose was damaging in previous years and temperatures are moderate (63°F or higher) during bloom, make the first application at pink bud. Otherwise treatment can begin at or shortly after petal fall. In all cases, application should be repeated at 7- to 10-day intervals when rains occur during periods of moderate temperatures. Treatment should, if possible, precede any late spring and early summer rains. Rotate fungicides, using different fungicide classes, as a resistance management strategy.
3 Early treatments (during bloom) have minimal effect on scab; the 5-week treatment usually is most effective. Treatments after 5 weeks are useful in northern areas where late spring and early summer rains occur. Dormant treatment with liquid lime sulfur improves efficacy of spring control programs.
4 If pathogen spores were found during fall leaf monitoring, apply a shot hole fungicide during bloom, preferably at petal fall or when young leaves first appear. Re-apply when spores are found on new leaves or if heavy, persistent spring rains occur. If pathogen spores were not present the previous fall, shot hole control may be delayed until spores are seen on new leaves in spring.
5 Dormant copper treatment seldom reduces shot hole infection but may be useful in severely affected orchards and must be followed by a good spring program.
6 Treatment in June is important only if late spring and early summer rains occur.
7 Make application at 1-5% hull split to manage hull rot caused by Rhizopus stolonifer.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Almond
UC ANR Publication 3431

General Information

Acknowledgment: Adaskaveg et al., 2013. Efficacy and Timing of Fungicides, Bactericides, and Biologicals for Deciduous Tree Fruit, Nut, Strawberry, and Vine Crops (PDF).

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