Sigatoka Symptoms on Lettuce

• Organs attacked :

• Symptoms :
  • Initially, small, moist, brown spots surrounded by a pale green to yellow halo developing more on older leaves (Figures 1 to 5).
  • Subsequently, the spots spread and form brown lesions sometimes circumscribed by the veins.
  • The center of the spots lightens as they necrotize, gradually taking on a gray to whitish hue, and show concentric patterns. A yellow halo is sometimes visible. Fabrics dry out, split and degrade.
  • Such spots are observable on the midrib (Figure 6).
  • Severely affected leaves turn yellow, and may become entirely necrotic (figure 7).

• Signs : Presence on the lesions of a greyish to buff down consisting of conidiophores and hyaline, cylindrical conidia, with 1 to 18 septa.
• Possible confusion : rare
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• Affected production areas :

• Cercospora sp. signalé sur laitue : Cercospora longissim a Cugini from Traverso (1903)