Northwest berry Foundation

Management Detail

Red Stele

in Strawberries

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Latin name: Phytophthora fragariae var. fragariae


This disease can show up at two distinct times during the growing season. The first is during bloom and is called blossom blight. The second is associated with the fruit and is called fruit rot. Blossom blight is characterized by petals and pedicels turning brown. The entire blossom may die. Fruit rot may occur on any portion of the fruit. It frequently develops at the calyx end and in tissues contiguous with rotting fruit or diseased flowers. Affected tissue turns light to medium brown. Lesions in green or white fruit develop slowly. The fruit may be misshapen as it enlarges. Fruit rot expands rapidly near harvest. In advanced stages, the fungus produces a gray mold over the fruit surface. Rot may not develop until after fruit is harvested.



  • Watch for areas of weak, stunted growth. Leaves may be wilted. Some plants may be dead.
  • Dig up affected plants to examine the roots to determine cause of problem.
  • Scrape the tips of the main roots to see the reddish color of the core. This symptom disappears by June.
  • Diagnostic of the disease is a red core in the main roots. (In black root rot main roots are black on the outside while the core is a normal whitish color)
  • Very few feeder roots will be present.

Cultural Controls:

  • Don't move soil from sites with red stele to clean sites. Wash equipment before moving.
  • Saturated soil is needed for disease spores to spread. Plant in well draining locations and/or on raised beds.
  • Improve drainage by subsoiling and/or tiling.
  • Plant resistant cultivars.


For information about chemical controls, check with our Pesticide Guide.


photo from University of Ohio

Damage done by red steele - photo from University of Ohio

from University of Ohio


Red steele damage to roots - photographer unknown


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