Late blight infection at the base of the stem initiated by infected seed This symptom looks similar to blackleg see page 87 In humid weather no white mycelium develops on plants infected with blackleg
Late blight symptoms on stems are irregular dark brown to black lesions Under humid conditions fungal mycelium and spores develop on infected areas
Stem lesions expand rapidly in humid weather and can cover most of the stem
Infected stems are brittle and break easily
Seed ball infected with late blight
The right half of the field was killed by late blight
Note the regrowth of healthy shoots after the
infected plants died
The tender growing point is an easy target for late blight because
moisture persists there after a heavy dew rain or irrigation
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T.G. Lynn
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