Cercospora leaf spot

 During the initial stage of infection, brownish circular spots with light-gray centers and reddish-brown margins appear on leaves. Later on, they develop into large circular tan spots, up to 1.5 cm in size, formed by dark concentric rings growing around a whitish center. A rough dark ring and a yellow halo gives the spots the characteristic 'frog-eye' appearance. As the spots become more numerous, they gradually coalesce to form large leaf lesions. The white center often dries and falls out, leaving a ‘shot-hole’ effect. At later stages of the infection, leaves turn yellow and wilt or drop, exposing fruits to sunscald. In severe cases, spots can also be observed on fruit stalk and calyx, often resulting in stem-end rot.

Damage symptoms:

• Circular spots with brown margins and grey centre appear on leaves


• The spots enlarge and coalesce with others


• The central portion of the spot becomes white and the leaves turn yellow and defoliate


• Sometimes central portion of spot drops off


• Spots also appear on stems and twigs as dark brown, irregular lesions with whitish centers


• In severe cases die-back of twigs occur

Survival and spread:

• Primary: Dormant mycelium in the infected crop debris, seeds and volunteer plants


• Secondary: Wind dispersed conidia