Causal Agent: 

Fungus (Corynespora cassicola)

Characteristic Symptoms:

Target spot begins on leaves as yellow leaf spots which later become angular.

Later spots become circular with light brown centers surrounded by dark brown margins.

Lesions coalesce to produce large necrotic areas.

Conditions for Disease Development
Infection occurs under conditions of high humidity and temperatures from 25-35C.
Target spot disease is favored by high temperatures and long days with fluctuating day and night temperatures.
Management and Control:
Use resistant varieties, if available.
Maintain good field and greenhouse sanitation (e.g. prune heavily affected leaves).
Destroy infected debris after each cropping season.
Disinfect greenhouse walls, floors, tables and farm implements after each cropping to reduce the amount of inoculum.

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®).



Compendium of Cucurbit Diseases (2010) by The American Phytopathological Society

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