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How to Manage Pests

UC Pest Management Guidelines

| More pests | More crops | About guidelines |

Brown rot blossom infections.

Cherry

Brown Rot Blossom and Twig Blight

Pathogens: Monilinia fructicola, Monilinia laxa

(Reviewed 4/06, updated 4/06)

In this Guideline:

SYMPTOMS

Infection occurs through blossom parts and progresses into the twig, killing blossoms, spurs, and associated leaves. Small cankers on twigs form below infected spurs; gum may be present at the base of flowers and dead flowers remain on the tree. Gray-brown spore masses develop on diseased flowers under high humidity.

COMMENTS ON THE DISEASE

Infection is favored by rain or dew and moderate temperatures.

MANAGEMENT

One and sometimes two applications are necessary for control; applications are most effective when made sufficiently in advance of rain so that the spray has time to dry. Start treatment at the popcorn stage of bloom. To provide adequate continuing protection, spray every 14 days until bloom is completed. When continued heavy rainfall is occurring or other conditions are conducive to infection, shorten this interval to 10 days. Aerial applications are generally not as effective as properly applied ground sprays but may be necessary when the orchard floor is too wet.

Common name Amount/Acre P.H.I.+
(trade name)   (days)
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.
 
A. TEBUCONAZOLE
  (Elite) 45WP 4–8 oz 0
  MODE OF ACTION: A DMI (Group 3)1 triazole fungicide.
 
B. IPRODIONE
  (Rovral) 4 1–2 pt  
  MODE OF ACTION: A dicarboximide (Group 2)1 fungicide.
  COMMENTS: Addition of a narrow range oil (superior, supreme) at 1–2% increases the effectiveness of this material. Do not apply after petal fall.
 
C. PROPICONAZOLE
  (Break EC, Orbit) 4 fl oz  
  MODE OF ACTION: A DMI (Group 3)1 triazole fungicide.
  COMMENTS: Do not apply more than 8 fl oz/acre/crop.
 
D. FENBUCONAZOLE
  (Indar) 75WSP 2 oz 0
  MODE OF ACTION: A DMI (Group 3)1 triazole fungicide.
  COMMENTS: Apply in a minimum of 50 gal water/acre. A protectant fungicide. Begin applications before infections occur if conditions are conducive to disease development. Do not apply more than 1 lb of formulated product/acre/season.
 
E. THIOPHANATE METHYL
  (Topsin M) 70WP 0.5 lb/100 gal water
up to 1.5 lb/acre 		1
  MODE OF ACTION: A MBC (Group 1)1 thiophanate fungicide.
  COMMENTS: Use only once a year. Resistance to thiophanate methyl is common in populations of Monilinia fructicola and Botrytis cinerea in California cherry orchards. If resistance has occurred in the orchard, do not use this product. Use only in combination or in an alternating application program with a fungicide that has a different Group number.
 
F. PYRACLOSTROBIN/BOSCALID
  (Pristine) 10.5–14.5 oz  
  MODE OF ACTION: A Qol (Group 11)1 and carboxamide (Group 7)1 fungicide.
  COMMENTS: To reduce the potential for the development of resistance, do not make more than five applications/season of Group 7 or 11 fungicides.
 
G. AZOXYSTROBIN
  (Abound) 12.3–15.4 fl oz 0
  MODE OF ACTION: A Qol (Group 11)1 fungicide.
  COMMENTS: Do not apply more than two applications before alternating with a fungicide that has a different Group number. Do not apply more than 1 lb a.i./acre/season.
 
H. FENHEXAMID
  (Elevate) 50WDG 1–1.5 lb 0
  MODE OF ACTION: A hydroxyanilide (Group 17)1 fungicide.
  COMMENTS: Do not apply more than 6 lb/acre/season and avoid making more than 2 consecutive applications with this material.
 
I. MYCLOBUTANIL
  (Rally) 40WP 2.5–6 oz 0
  MODE OF ACTION: A DMI (Group 3)1 triazole fungicide.
  COMMENTS: Do not apply more than 3.2 lb product/acre/season. More effective when applied as a concentrate (80-100 gal/acre) than as a dilute spray.
 
J. TRIFLUMIZOLE
  (Procure) 50W 10–16 oz 1
  MODE OF ACTION: A DMI (Group 3)1 triazole fungicide.
 
K. FENARIMOL
  (Rubigan) EC 6–12 oz/200 gal water  
  MODE OF ACTION: A DMI (Group 3)1 pyrimidine fungicide.
  COMMENTS: Do not apply more than 48 oz before harvest.
 
L. CAPTAN
  (Various) 50WP 4 lb  
  MODE OF ACTION: A multi-site contact (Group M4)1 phthalimide fungicide.
  COMMENTS: Do not apply in combination with, immediately before, or closely following oil sprays.
 
M. CHLOROTHALONIL
  (Echo 720) 3.125–4.125 pt  
  (Bravo Ultrex) 2.8–3.8 lb  
  (Bravo Weather Stik) 3.125–4.125 pt  
  MODE OF ACTION: A multi-site contact (Group M5)1 chloronitrile fungicide.
  COMMENTS: May cause an allergic skin reaction in some people. Do not use with or closely following oil sprays. 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.
 
 
+  Preharvest interval. Do not apply within this many days of harvest.
1 Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of actions. Fungicides with a different group number are suitable to alternate in a resistance management program. For more information, see http://www.frac.info/.

More information on cherry fungicides

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Cherry
UC ANR Publication 3440
Diseases
J. E. Adaskaveg, Plant Pathology, UC Riverside
W. D. Gubler, Plant Pathology, UC Davis
Acknowledgment for contributions to the diseases section:
B. L. Teviotdale, Kearney Agricultural Center, Parlier

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