How to Manage Pests

UC Pest Management Guidelines

Apricot

Jacket Rot

Pathogens: Botrytis cinerea, Sclerotinia sclerotiorum, Monilinia laxa, and Monilinia fructicola

(Reviewed 10/14, updated 10/14)

In this Guideline:


SYMPTOMS AND SIGNS

Jacket rot occurs during the jacket stage when remnants of the flower parts are still attached to the fruit. The disease causes a brown discoloration on the fruit under the jacket (shuck). The young fruit withers and falls off the tree within a few weeks.

COMMENTS ON THE DISEASE

Development of jacket rot is favored by wet weather during the bloom and jacket stage.

MANAGEMENT

One fungicide application at full bloom is generally effective. Fungicides applied during the jacket stage are generally ineffective. Treat at full bloom or shortly thereafter but before petal fall. The final bloom spray for blossom brown rot often provides control of jacket rot if the appropriate fungicides (Rovral+oil, Topsin M, Pristine, Vanguard) are chosen.

Common name Amount per acre REI‡ PHI‡
(Example trade name)   (hours) (days)

UPDATED: 10/14
Calculate impact of pesticide on air quality
When choosing a pesticide, consider its usefulness in an IPM program by reviewing the pesticide's properties, efficacy, application timing, and information relating to resistance management, honey bees, and environmental impact. Not all registered pesticides are listed. Always read the label of the product being used.
 
Caution: Never apply sulfur to apricot trees or captan to apricot fruit.
 
A. DIFENOCONAZOLE / CYPRODINIL
  (Inspire Super) 16–20 fl oz 12 2
  MODE-OF-ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3), Anilinopyrimidine (9)
  COMMENTS: For brown rot blossom blight, apply at early bloom and again at full bloom. For brown rot on fruit apply as needed, but not more than twice during preharvest with a minimum of 7 days between treatments.
 
B. PYRACLOSTROBIN / FLUXAPYRAXAD
  (Merivon) 4–6.7 fl oz 12 0
  MODE-OF-ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11) and Succinate dehydrogenase inhibitors (7)
  COMMENTS: To reduce the potential for the development of resistance, do not make more than two consecutive applications or more than four applications or 20.1 fl oz per season of Merivon or other quinone outside inhibitor (11) or succinate dehydrogenase inhibitor (7) fungicides.
 
C. THIOPHANATE METHYL
  (Topsin-M 70WP) 1.5 lb 48 (2 days) 1
  MODE-OF-ACTION GROUP NAME (NUMBER1): Methyl benzimidazole carbamate (1)
  COMMENTS: Apply thiophanate methyl in combination with another fungicide of different chemistry. For tank mixes, observe all directions for use on all labels, and employ the most restrictive limits and precautions. Never exceed the maximum a.i. on any label when tank mixing products that contain the same a.i.
 
D. PENTHIOPYRAD
  (Fontelis) 14–20 fl oz 12 0
  MODE-OF-ACTION GROUP NAME (NUMBER1): Succinate dehydrogenase inhibitors (7)
  COMMENTS: Resistance warning: do not make more than two consecutive applications, and no more than 61 fl oz/acre per year of Fontelis or other succinate dehydrogenase inhibitor fungicide.
 
E. PYRACLOSTROBIN / BOSCALID
  (Pristine) 10.5–14.5 oz 12 0
  MODE-OF-ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11) and Succinate dehydrogenase inhibitors (7)
  COMMENTS: To reduce the potential for the development of resistance, do not apply more than two consecutive applications or more than four applications per season of Pristine or other quinone outside inhibitor (11) or succinate dehydrogenase inhibitor (7) fungicides.
 
F. PYRIMETHANIL
  (Scala SC) 9–18 fl oz 12 2
  MODE-OF-ACTION GROUP NAME (NUMBER1): Anilinopyrimidine (9)
  COMMENTS: Resistant populations have been identified in Californian stone fruit orchards. Do not apply more than two consecutive applications or more than four applications per season of pyrimethanil or other anilinopyrimidine Group 9 fungicides.
 
G. CYPRODINIL
  (Vangard WG) 5 oz 12 2
  MODE-OF-ACTION GROUP NAME (NUMBER1): Anilinopyrimidine (9)
  COMMENTS: Resistant populations have been identified in California stone fruit orchards. Do not apply more than two consecutive applications or more than four applications per season of cyprodonil or other anilinopyrimidine Group 9 fungicides.
 
H. IPRODIONE
  (Rovral 4) 1–2 pt 24 NA
  MODE-OF-ACTION GROUP NAME (NUMBER1): Dicarboximide (2)
  COMMENTS: Addition of a narrow range oil (Superior, Supreme) at 1 to 2% increases the effectiveness of this material. Do not use after petal fall.
 
I. FENHEXAMID
  (Elevate 50WDG) 1–1.5 lb 12 0
  MODE-OF-ACTION GROUP NAME (NUMBER1): Hydroxyanilide (17)
  COMMENTS: Do not apply more than 6 lb/acre per season and avoid making more than two consecutive applications with this material.
 
J. DICLORAN
  (Botran 75-W) 2 lb 12 10
  MODE-OF-ACTION GROUP NAME (NUMBER1): Aromatic hydrocarbon (14)
 
K. CHLOROTHALONIL
  (Echo 720) 3.125–4.125 pt 12 NA
  (Bravo Ultrex) 2.8–3.8 lb 12 NA
  (Bravo Weather Stik) 3.125–4.125 pt 12 NA
  MODE-OF-ACTION GROUP NAME (NUMBER1): Multi-site contact (M5)
  COMMENTS: May cause an allergic skin reaction in some people. Do not use with or closely following oil sprays. Do not apply after jacket (shuck) split. Do not apply more than 20.5 pint Bravo Weather Stik/acre per season. Do not apply more than 18.8 lb Bravo Ultrex/acre per season.
 
L. CAPTAN
  (Captan 50WP) 3–5 lb 24 0
  MODE-OF-ACTION GROUP NAME (NUMBER1): Multi-site contact (M4)
  COMMENTS: Do not apply in combination with, immediately before, or closely following oil sprays. Do not apply after 75% petal fall.
 
Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
NA Not applicable.
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. For fungicides with mode-of-action group numbers 1, 4, 7, 9, 11, or 17, make no more than one application 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.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Apricot
UC ANR Publication 3433

Diseases

J. E. Adaskaveg, Plant Pathology, UC Riverside
W. D. Gubler, Plant Pathology, UC Davis
W. W. Coates, UC Cooperative Extension, San Benito County
J. J. Stapleton, UC IPM Program, Kearney Agricultural Center, Parlier
J. L. Caprile, UC Cooperative Extension, Contra Costa County
B. A. Holtz, UC Cooperative Extension, Madera County
K. M. Kelley Anderson, UC Cooperative Extension, Stanislaus County

Acknowledgment for contributions to Diseases:
B. L. Teviotdale, Kearney Agricultural Center, Parlier

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