| White rot / mouldy nose/ Dry rot: Sclerotium cepivorum |
Symptom:
- Leaves - yellow and dieback
- Roots - rotten & base of the bulb covered with a watery or grey fungal growth
- Numerous small black spherical sclerotia are produced
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Grey fungal growth |
Watery fungal growth |
Sclerotia |
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Identification of pathogen:
Mode of spread and survival:
- Sclerotia persists in soil for eight years
- Pathogen has no direct sporulation stage and it is not air borne
- Sclerotia are transported from field to field by flood water
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Management:
- Long rotation of 8 to 10 yrs
- Good drainage
- Use of healthy planting materials
- Destruction of wild onion and leeks
- Seed dressings-benomyl/carbendazim
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Source of Images:
https://www.rhs.org.uk/advice/profile?pid=226
http://www.thegardenersalmanac.co.uk/Data/Onion%20White%20rot/White%20rot.JPG |
