Lettuce – Downy Mildew

Key Points:

  1. Downy mildew occurs worldwide
    and is a serious fungal disease of
    field and greenhouse lettuce

  2. Lettuce downy mildew is caused
    by the fungus Bremia lactucae and usually occurs in Spring and Autumn

  3. Primarily a foliar disease, lettuce downy mildew has a direct effect on
    yield and quality

  4. Although yield losses in the field at harvest may be substantial, further losses may occur during transit or storage
  5. Control measures include:
    • downy mildew resistant cultivars
    • cultural practices, such as:
      • A ‘lettuce-free’ period
      • Crop rotation
      • Destruction of weed hosts
      • Increasing space between plants
      • Early removal of crop debris
      • Irrigation management

Matters of Facts #47 Lettuce Downy Mildew August 2007
No. 47 download pdf 154kb

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