Leaf blight

(Exserohilum turcicum (Pass.) KJ Leonard & EG Suggs)

 Symptoms

• Symptoms are visible from the seedling stage to the crop maturity stage.
• Small, reddish or tan spots develop on seedlings, the spots later enlarge and coalesce resulting in wilting of young leaves.
• On mature plants, long, elliptical, reddish purple or yellowish lesions develop, first on lower leaves and later progress to the upper leaves and stem as well.
• In humid weather, numerous grayish black spores are produced in the lesions in concentric zones.

 

 Fig. 1: Reddish purple lessions on the leaf

Control measures

• Grow disease resistant cultivars, such as SPV 1411, ICSV 700, CSH 25 and CSH 22SS
• Spray Zinab or Mancozeb 0.2%, 3-4 sprays beginning at 40 days after emergence.