Causal Agent:
Fungus (Corynespora cassicola)
| Characteristic Symptoms: | |
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Target spot begins on leaves as yellow leaf spots which later become angular. |
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Later spots become circular with light brown centers surrounded by dark brown margins. |
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Lesions coalesce to produce large necrotic areas. |
| Conditions for Disease Development | |
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Infection occurs under conditions of high humidity and temperatures from 25-35C. |
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Target spot disease is favored by high temperatures and long days with fluctuating day and night temperatures.
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| Management and Control: | |
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Use resistant varieties, if available.
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Maintain good field and greenhouse sanitation (e.g. prune heavily affected leaves). |
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Destroy infected debris after each cropping season.
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Disinfect greenhouse walls, floors, tables and farm implements after each cropping to reduce the amount of inoculum. |
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Apply fungicides such as pyraclostrobin+dimetomorph (e.g. Cabrio Team®) mancozeb (e.g. Attain M-80®, Achem Mancozeb 80 WP®, Micron 80 WO®, Vanzeb®, Aljay Mancozeb®, Shogun 800®, Emzeb 42 SC®) or maneb (e.g. Maneb®). |
References:
http://extension.uga.edu/publications/detail.cfm?number=B1179
http://ipm.ncsu.edu/vegetables/Pamphlets/cucumber/cucumber.html
Compendium of Cucurbit Diseases (2010) by The American Phytopathological Society
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