Causal Agent:
Fungus (Collectotrichum higginsianum)
Characteristic Symptoms: | |
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Affects leaves, petioles and stem. |
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Lesions on leaves are circular to irregular, small, dry and pale gray. |
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Under favourable conditions, lesions coalesce forming irregular large spots. |
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Severe infection leads to yellowing of leaves and wilting. |
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Symptoms on petioles and stem include elongated, sunken, gray to brown lesions with black border. |
Conditions for Disease Development | |
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The pathogen can survive on plant debris, volunteer plants and related weeds. |
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Temperature range of 25-30°C, wet conditions and high relative humidity favor disease development.
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Management and Control: | |
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Maintain good field sanitation, remove infected plants/plant parts and dispose properly.
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Crop rotation with non-host crop for at least 3 years to reduce the amount of primary inoculum. |
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Remove volunteer and weedy crucifers that may serve as alternate hosts for the pathogen.
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Spray with copper-based fungicides (e.g. Cupravit®, Vitigran Blue®, Nordox 50®), Mancozeb (Dithane M-45®) or Chlorothalonil (Daconil 2787®) at the initial onset of the disease. |
References
Compendium of Brassica Diseases by APS (2007)
To view other diseases, click here.
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