Powdery Mildew

What Is It? | Facts in Depth | For the Professional Diagnostician

Ashlina Chin & Sally A. Miller

Powdery mildew is one of the most common diseases of tomatoes grown in greenhouses and high tunnels.  The disease occurs primarily on foliage, resulting in reduced photosynthetic activity.  Symptoms differ depending on which pathogen species is present but in general, a flat white cottony mycelium covers all infected leaves and stems of the plant, which leads to premature leaf drop and a reduction in fruit size and yield.  Removal and sanitation of infected plants has proven to be an effective management strategy for powdery mildew.

Available Fact Sheets (pdf)

English: Powdery Mildew

Scientific Names

Leveillula taurica
Oidium neolycopersici
Erysiphe orontii

Important High Tunnel Host Crops

  • Tomatoes
  • Pepper
  • Eggplant

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