What Is It?

What Is It? | Facts in Depth | For the Professional Diagnostician
Cucurbit Diseases | Phytophthora Blight

Phytophthora Blight
Identification

Foliage and Roots:

  • Damping off
  • Watery, soft root rot
  • Rapid wilting following heavy rains
  • Watersoaked, brown lesions on stem and vines
  • Watersoaked, chlorotic and brown lesions on leaves

CukePhytoph3 50 Quality PhytophPumpkinLeaves4 50 Quality PhytophPumpkinLeaves1 50 Quality
Foliar symptoms on cucumber plants (left) and pumpkin leaves (middle and right).

Fruit:

  • Watersoaked, slightly sunken and discolored areas on fruit
  • White-tan velvety growth on fruits

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Symptoms on cucumber fruit (left), pumpkin (middle), and winter squash (right).

Favorable Environmental Conditions

  • Warm soils (68-86° F)
  • Wet, waterlogged soils
  • Warm and rainy conditions

Often Confused With

  • Damping off
  • Anthracnose
  • Bacterial wilt
  • Fusarium wilt
  • Bacterial fruit blotch

Scouting Notes

  • Scout poorly-drained fields for this disease.
  • Look in low lying areas and areas prone to flooding.
  • Scout following heavy rains.

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Symptoms of wilting caused by Phytophthora blight in a zucchini field.