Causal Agent:
Fungi (Colletotrichum lindemuthianum)
| Characteristic Symptoms: | |
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Lesions are sunken and light to dark brown on both sides of the leaves but usually more severe on the underside. |
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On petioles and branches, lesions are sunken, brown-black and are commonly slender to oval-shaped. |
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Symptoms on pods appear as light to dark brown sunken lesions with slightly raised, well-defined black ring margin. |
| Conditions for Disease Development: | |
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Frequent rainfall, presence of free moisture and cool to moderate temperatures (18-26°C) are critical factors for disease development. |
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The pathogen survives between crops on infected plant residue or infected volunteer plants and can be carried on seed harvested from infected fruit. |
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Conidia/spores produced on foliage are disseminated by wind, rain splashes, tools/implements and field workers. |
| Management and Control: | |
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Use pathogen-free seed.
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Remove and dispose infected plants/plant parts as soon as symptoms are observed to minimize spread of disease. |
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Avoid overhead irrigation or prolonged moisture to minimize disease incidence and severity. |
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Staking increases air movement and may help reduce infection in the field. |
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Deep plowing of crop residue immediately after harvest can effectively reduce inoculum carryover. |
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Crop rotation with non-host crops for at least 1 year may help reduce inoculum in the soil. |
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Apply copper–based fungicides as early as symptoms are observed or when conditions are favorable for disease development. (e.g. Cupravit®, Super BlueⓇ, Vitigran blueⓇ, FunguranⓇ, KocideⓇ, Hydroxide superⓇ). |
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