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UC Pest Management Guidelines


Ripening fruit is most susceptible to ripe fruit rot.

Apricot

Ripe Fruit Rot

Pathogens: Monilinia fructicola, Monilinia laxa

(Reviewed 11/07, updated 11/07)

In this Guideline:


SYMPTOMS AND SIGNS

Dark brown, firm, circular spots spread rapidly over fruit, and tan spore masses form in the centers of spots. Ripening fruit is most susceptible. Diseased fruits may remain on the tree until the next season.

COMMENTS ON THE DISEASE

Fruit rot is not as important as blossom blight in California apricots. Warm rains near harvest can lead to fruit rot infection in a few hours. At 67°F, fruit rot symptoms will appear within 48 hours of rain.

MANAGEMENT

The need for preharvest treatment depends upon the weather; the threat of rain or heavy dews in the last 2 to 3 weeks before harvest may signal the need for protection.

Take a fruit damage sample at harvest to assess the effectiveness of the current year's IPM program and to determine the needs of next year's program (see FRUIT SAMPLING AT HARVEST). Record results (sample form115 KB, PDF).

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

  Calculate impact of pesticide on air quality
When choosing a pesticide, consider the general properties of the fungicide as well as information relating to environmental impact.
 
Caution: Never apply sulfur to apricot trees or captan to apricot fruit.
 
PREHARVEST
A. PROPICONAZOLE
  (Bumper, Orbit) 4 fl oz 24 0
  MODE OF ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
 
B. FENBUCONAZOLE
  (Indar) 75WSP 2 oz 12 0
  MODE OF ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
  COMMENTS: Apply 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.
 
C. PYRACLOSTROBIN/BOSCALID
  (Pristine) 10.5–14.5 oz 12 0
  MODE OF ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11) and Carboxamide (7)
 
D. THIOPHANATE METHYL
  (Topsin M) 70WP 0.5 lb/100 gal water up to 1.5 lb/acre 12 1
  MODE OF ACTION GROUP NAME (NUMBER1): Methyl benzimidazole (1)
  COMMENTS: Apply only once per year. If thiophanate methyl was used earlier for brown rot or powdery mildew control, do not use it for control of ripe fruit rot. Check with your processor before using this material. Strains of Monilinia fructicola resistant to thiophanate methyl have been found in California apricot orchards. If resistance has occurred in your orchard, do not use this fungicide.
 
E. MYCLOBUTANIL
  (Rally) 40WSP 2.5–6 oz 24 0
  MODE OF ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
  COMMENTS: Do not apply more than 2.75 lb/acre/season.
 
F. 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/season.
 
G. CYPRODINIL
  (Vangard) 75WG 10 oz 12 2
  MODE OF ACTION GROUP NAME (NUMBER1): Anilinopyrimidine (9)
  COMMENTS: Efficacy is reduced under conditions of high temperatures (high 90s and above) and high humidity.
 
POSTHARVEST
A. FLUDIOXONIL
  (Scholar) 50WP 8–16 oz/7–100 gal water 0 0
  MODE OF ACTION GROUP NAME (NUMBER1): Phenylpyrrole (12)
  COMMENTS: Treats 200,000 lb fruit using a spray-application system. Do not make more than one postharvest application to the fruit.
 
 
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. For fungicides with mode of action Group numbers 1, 4, 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.

IMPORTANT LINKS

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

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