Agriculture: Cherry Pest Management Guidelines

Ripe Fruit Rot

  • Ripe fruit rot: Botrytis cinerea, Monilinia fructicola, Monilinia laxa, Rhizopus spp.
  • Symptoms and Signs

    Fruit rot caused by Monilinia or Botrytis species results in dark brown, firm, circular spots that spread rapidly over fruit. Tan spore masses may grow on the rotted areas. The fruit become more susceptible as they ripen. Diseased fruits usually do not remain on the tree until the next season, but are present as inoculum sources for the current season's crop.

    Rhizopus rot is a postharvest storage problem. The decaying fruit tissue is watery and soft; the fungus is identified by masses of white mycelium with tiny black sporangia that form most abundantly on fruit near the edge of containers.

    Comments on the Disease

    Monilinia and Botrytis species can infect uninjured ripening fruit. Moisture, either rain or dew, and injury or fruit cracking increases the probability of preharvest infection and consequent rot. Rhizopus invades ripe fruit that has been injured or cracked, causing the fruit to rot after harvest.

    Management

    Injured, split fruits cannot be protected from rots caused by Monilinia and Botrytis by preharvest sprays, but uninjured fruit can. The best fungicide to use for control depends on whether Botrytis is present alone, Monilinia alone, or both are present. Since it is not practical to try to distinguish the species present, the best treatment materials tend to be those that effectively control both species.

    Protect ripe fruit from Rhizopus either with a preharvest treatment (for fruit that will be sold right after harvest) or a postharvest treatment (for fruit that will be shipped). After harvest, Rhizopus can be controlled if the fruit is stored below temperatures of 40°F. Apply a preharvest treatment 1 to 14 days before harvest. A postharvest spray can be made during stem cutting and sizing operations.

    Common name Amount per acre REI‡ PHI‡
    (Example trade name) (hours) (days)
    Not all registered pesticides are listed. The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least likely to cause resistance are at the top of the table. When choosing a pesticide, consider information relating to the pesticide's properties and application timing, honey bees, and environmental impact. Always read the label of the product being used.
     
    PREHARVEST: Monilinia and Botrytis (Fungicides below are effective against both species)
     
    A. 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 or make more than 2 consecutive applications with this product.
     
    B. TEBUCONAZOLE/TRIFLOXYSTROBIN
      (Adament 50WP) 4–8 oz 120 (5 days) 1
      MODE-OF-ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3) and Quinone outside inhibitor (11)
     
    C. TEBUCONAZOLE
      (Elite 45WP) 4–8 oz 120 (5 days) 0
      MODE-OF-ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
     
    D. PYRACLOSTROBIN/BOSCALID
      (Pristine) 10.5–14.5 oz 12 0
      MODE-OF-ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11) and Succinate dehydrogenase inhibitor (7)
      COMMENTS: To reduce the potential for the development of resistance, do not make more than two applications per season of Group 7 or 11 fungicides.
     
    E. THIOPHANATE METHYL
      (Topsin-M 70WP) 1.5 lb (0.33 – 0.5 lb/100 gal water) 12 1
      MODE-OF-ACTION GROUP NAME (NUMBER1): Methyl benzimidazole (1)
      COMMENTS: Recommended rate is 1.5 lb/A. Use only once a year. Do not use in orchards where resistance has been observed. Use only in combination or in an alternating application program with a fungicide with a different Group number. Resistant populations to benzimidazole fungicides may result in low performance or a failed fungicide treatment.
     
    F. CAPTAN
      (Various) 50WP Label rates 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.
     

    POSTHARVEST: Rhizopus only

     
    A. DICLORAN
      (Botran 75W) 2 lb 12 10
      MODE-OF-ACTION GROUP NAME (NUMBER1): Aromatic hydrocarbon (14)
      COMMENTS: Apply 10 days before harvest. Only for use on sweet cherries.
     

    POSTHARVEST: Monilinia, Botrytis, and Rhizopus

     
    A. FLUDIOXONIL
      (Scholar) 8–16 oz/50,000 lb of fruit NA NA
      MODE-OF-ACTION GROUP NAME (NUMBER1): Phenylpyrrole (12)
      COMMENTS: Treat 25,000 lb fruit in a high volume (dilute) application with agitation to keep Scholar in solution. Labeled for one postharvest application.
     
    B. TEBUCONAZOLE
      (Elite 45WP) Label rates NA NA
      MODE-OF-ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
      COMMENTS: For use on sweet cherries. Special Local Needs registration for Elite. Labeled for one postharvest application.
    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.
    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. 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.
    NA Not applicable.
    Text Updated: 09/15
    Treatment Table Updated: 09/15