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Monilinia fruiticola

Overview

  • American brown rot is an important fungal disease of cherries
  • Without control, and under wet conditions, partial to complete fruit loss can occur as a result of brown rot

Symptoms

  • Brown rot affects blossoms, spurs, shoots, and fruit but fruit infections are most destructive
  • As cherry fruit mature, they are more likely to become infected, developing light brown spots which eventually take over the whole fruit and give it a fuzzy brown appearance and eventually rotting the fruit

Disease cycle

  • Source of infection in cherry is primarily overwintering inoculum in fruit mummies, peduncles, and cankers
  • Wind-driven rain in the spring infects blossoms, depending on the duration of wetting and temperature
  • Fruit infection can occur through the cuticle, or more easily in natural openings and wounds; rain-cracked cherries are brown rot's best friend!
  • Level of inoculum drives infection severity, so once brown rot gets going and it is wet stand back! Or spray fungicide...

Management

  • Sanitation - remove non-harvested, mummified cherries if possible; keep orchard floor clean
  • Fungicides - beginning at bloom, 2 or 3 sprays (often overlooked) and then resuming as fruit ripens; timing and frequency depends on weather/wetting and condition of crop, but in most years several fungicide sprays are necessary during pre-harvest and harvest; be sure to rotate fungicides to prevent resistance development
  • Sweet cherries are generally more susceptible to brown rot than tart cherries; otherwise, there is very little difference in variety susceptibility

Special note on European brown rot (Monolinia laxa). European brown rot may be present in New England on tart cherry, however, it has not been confirmed. It is common in the midwest and has been reported in New York. The main difference between American and European brown rot is European is far more aggressive infecting blossoms and spurs, resulting in blight/dieback of blossoms and spurs. It's not pretty. It can be confused with bacterial canker. Two sprays, one at popcorn bud stage and then another 7 days later are recommended on all tart cherry. Resistance may be an issue.

cherry brown rot fruit
cherry brown rot fruit
cherry brown rot fruit close-up
cherry brown rot fruit close-up