Marssonina Blotch of Apple

ଲକ୍ଷଣ

Late in the summer dark spots (5-10 mm) begin to appear on the upper surface of mature leaves. The symptoms are visible invariably after the rains in spring and in the early summer months. The leaves of older apple plants are more susceptible to the blotch than younger ones. The spots are usually grayish, brown with a tinge of purple at the tips. The disease symptoms appear in form of dark green circular patches on upper surface of leaf giving rise to 5-10 mm brown leaf spots which become dark brown in due course. At maturity, it also develops on lower surface of the leaves. The fungus also attacks the fruit by causing circular dark brown spots of varying sizes (3-5 mm in diameter) on commercial cultivars. Small asexual fruiting bodies are often visible on the surface. When more lesions are forming, they coalesce, while the surrounding parts turn yellow. Severe infestation like this result in defoliation. The fungus can also infect fruit, though not very common.