Symptoms of Corynespora cassiicola on cucumber

• Organs attacked :

• Symptoms :
  • Small moist lesions delimited by the veins, visible on both sides of the lamina (figures 1 to 5).
  • These lesions extend and progressively become necrotic, taking on a beige to light brown color (figures 2 to 10). The limb at the periphery of the spots is more or less chlorotic (figure 5), and some of them show discreet concentric patterns. (figure 10)
  • Under favorable conditions, the spots coalesce and entire sectors of the lamina become necrotic and die.

• Signs : fruiting bodies of the fungus dot the lesions, sometimes giving them a slight dark gray to black tint (figure 11). They consist of simple conidiophores, more or less brown, bearing conidia isolated or in short chains, cylindrical, straight or curved, subhyaline to olive brown, and septate (5-18 septa).
• Possible confusion : downy mildew ( Pseudoperonospora cubensis )
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• Production areas affected :