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UC Pest Management Guidelines


Jacket rot on young apricot fruit.

Nectarine

Jacket Rot

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

(Reviewed 6/10, updated 6/10)

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. 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 and frost during the bloom and jacket stage.

MANAGEMENT

One fungicide application at full bloom is generally effective. Fungicides applied during the jacket stage are generally much less effective. Treat at full bloom or shortly thereafter but before petal fall. The final bloom spray for blossom brown rot often provides jacket rot control if appropriate fungicides (e.g., iprodione, thiophanate-methyl, pyraclostrobin/boscalid, cyprodinil, etc.) are chosen.

Common name Amount/Acre R.E.I.+ P.H.I.+
(trade name)   (hours) (days)

  Calculate impact of pesticide on air quality
The following materials are listed in order of usefulness in an IPM program, taking into account efficacy. When choosing a pesticide, also consider information relating to environmental impact. Not all registered pesticides are listed. Always read label of product being used.
 
A. TEBUCONAZOLE/TRIFLOXYSTROBIN
  (Adament 50 WG ) 4–8 oz/acre 5 days 1
  MODE OF ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3) and Quinone outside inhibitor (11)
 
B. PROPICONAZOLE
  (Bumper, Tilt) 4 oz/acre Tilt: 12
Bumper: 24
0
  MODE OF ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
 
C. TEBUCONAZOLE
  (Elite, etc. 45WP) 4–8 oz/acre 12 0
  MODE OF ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
  COMMENTS: Do not apply more than 3 lb/acre/season.
 
D. FENBUCONAZOLE
  (Indar 75WSP) 2 oz/acre 12 0
  MODE OF ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
  COMMENTS: Do not apply more than 1 lb/acre/season.
 
E. IPRODIONE
  (Rovral 4) 1–2 pt 24 see comments
  MODE OF ACTION GROUP NAME (NUMBER1): Dicarboximide (2)
  COMMENTS: Addition of a narrow range oil (superior, supreme) at 1–2% increases the effectiveness of this material. Do not use after petal fall.
 
F. THIOPHANATE-METHYL
  (Topsin-M, etc. 70 WP) 1.5 lb 12 1
  MODE OF ACTION GROUP NAME (NUMBER1): Methyl benzimidazole (1)
  COMMENTS: A benzimidazole fungicide. Apply thiophanate methyl in combination with another fungicide of different chemistry.
 
G. PYRACLOSTROBIN/BOSCALID
  (Pristine) 10.5–14.5 oz 12 0
  MODE OF ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11) and Carboxamide (7)
  COMMENTS: A strobilurin and carboxyanilide fungicide. To reduce the potential for the development of resistance, do not make more than five applications/season of Pristine or other strobilurin or carboxyanilide fungicides.
 
H. CYPRODINIL
  (Vangard 75WG) 5–10 oz 12 2
  MODE OF ACTION GROUP NAME (NUMBER1): Anilinopyrimidine (9)
  COMMENTS: An anilinopyrimidine fungicide.
 
I. FENHEXAMID
  (Elevate 50WDG) 1–1.5 lb 12 0
  MODE OF ACTION GROUP NAME (NUMBER1): Hydroxyanilide (17)
  COMMENTS: A hydroxyanilide fungicide. Do not apply more than 6 lb/acre/season and avoid making more than 2 consecutive applications with this material.
 
J. DICHLORAN
  (Botran 75W) 1.33–5.33 lb 12 10
  MODE OF ACTION GROUP NAME (NUMBER1): Aromatic hydrocarbon (14)
  COMMENTS: An aromatic hydrocarbon fungicide.
 
K. CHLOROTHALONIL
  (Echo 720) 3.125–4.125 pt 12 see comments
  (Bravo Ultrex) 2.8–3.8 lb 12 0
  (Bravo Weather Stik) 3.125–4.125 pt 12 0
  MODE OF ACTION GROUP NAME (NUMBER1): Multi-site contact (M5)
  COMMENTS: An aromatic nitrile fungicide. May cause an allergic skin reaction in some people. Do not use with or closely following oil sprays. Do not apply Echo 720 after jacket (shuck) split. Do not apply more than 20.5 pt Bravo Weather Stik/acre/season. Do not apply more than 18.8 lb Bravo Ultrex/acre/season.
 
L. CAPTAN 50 WP 5 lb 24 see comments
  MODE OF ACTION GROUP NAME (NUMBER1): Multi-site contact (M4)
  COMMENTS: A phthalamide fungicide. Do not apply in combination with, immediately before, or closely following oil sprays. Do not apply after 75% petal fall.
 
+ Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) 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.
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 a fungicide with a different mode of action Group number.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Nectarine
UC ANR Publication 3451
Diseases
J. E. Adaskaveg, Plant Pathology, UC Riverside
R. A. Duncan, UC Cooperative Extension Stanislaus County
K. R. Day, UC Cooperative Extension, Tulare County
Acknowledgment for contributions to Diseases:
B. L. Teviotdale, Kearney Agricultural Center, Parlier
W. D. Gubler, Plant Pathology, UC Davis

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