Symptoms cucumber

• Organs attacked :

• Symptoms :
  • All aerial organs can be affected.
  • Spots with moist lesions, rather circular, gradually browning and reddening before becoming necrotic (figures 1 to 4). Large sectors of the blade sometimes affected.
  • Presence of a translucent to yellowish halo around the lesions, the internal tissues being able to decompose and fall giving the limbus a riddled appearance. Sometimes significant defoliation.
  • Longitudinal cankerous lesions on stems and petioles, slightly depressed, beigeish in color (figure 5), sometimes with the presence of brown exudates.
  • Circular spots on fruits, dark to blackish in their center (figure 6), reaching the internal tissues.

• Signs : presence of numerous black pits, stromas (figure 7), and salmon pink gelatinous masses, acervuli producing numerous spores and materializing the asexual reproduction of Gloeosporium orbiculare . Note that these fructifications are sometimes arranged in concentric circles, that a white mycelial felting is sometimes visible on the lesions, and that they can be observed on all the affected organs.
• Possible confusion : cladosporiosis, corynesporiosis, alternariosis, septoria, bacteriosis.
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• Affected production areas :

•  Colletotrichum spp. reported on cucumber : Gloeosporium orbiculare