Mycosphaerella henningsii

Mycosphaerella henningsii is a fungal plant pathogen that causes Brown leaf spot (BLS) in cassava).Part It is one of the worst fungal diseases of cassava. BLS disease appears as small brown spots with dark borders on the upper leaf surface. The brown spots form between leaf veins so their size and shape are limited by the veins. The centre of the brown spots may fall out leaving a hole in the leaf. During a bad attack the infected leaves become yellow and dry, and may die early. The disease can greatly reduce yields. The fungus lives in diseased cassava leaves on the plant or those on the ground. It spreads to new leaves and plants by wind or rain splash....read more on Wikipedia.