Anthracnose
Pathogen: Colletotrichum coccodes
Symptoms
Water-soaked, pale yellow spots on leaves, which expand lengthwise until covering the entire leaf blade can be seen on the leaves; affected leaves shrivel and droop.
Disease development
The warmer and wet conditions in recent days favor the development of anthracnose. The pathogens survive on crop debris and spread occurs mainly with infected plant material and by mechanical means.
Disease management
Control may include removal of infected crop debris to reduce inoculum, crop rotation, fungicides (although effectiveness may be limited), biocontrol organisms (for example Trichoderma), and cultural measures (reduction of moisture in the crop). Some resistant or tolerant onion cultivars are being developed.
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