During the initial stage of infection, brownish circular spots with light-grey 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.
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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.
At later stages of the infection, leaves turn yellow and wilt or drop, exposing fruits to sunscald.
In some cases, the fungus may also cause lesions on the stems and even the fruits of the affected plants.