Diplocarbon Rosae (Black Spot) Royalty-Free Stock Photo

Black spot is a fungal disease that affects nearly all rose cultivars worldwide. It is a frequent problem for roses grown outdoors and reduces the quality and life span of the plants. However, the poor performance of roses in Florida can also be associated with various factors such as inadequate fertilization and water deficiency during the warm season, as well as the use of root stocks and scions not well-adapted to Florida's conditions.M. rosae produces black spots of about two to 12 mm in diameter usually in the upper surface of the leaves. Often, those spots may have irregular, radiate, feathery borders. In older lesions, black spore-bearing structures, called acervuli, can be observed as well as white, slimy masses of conidia. Yellowing around the lesions on infected leaves can occur, and severe defoliation occurs in the most susceptible cultivars. While leaves are the most susceptible part of the plant, stipules and pedicels can also be infected. Spots can also be found also in peduncles, fruits, and sepals. Symptoms of black spot are usually confused with those of Cercospora leaf spot.