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Myrothecium Leaf Spots and Rots

Myrothecium leaf spots and rots Common name Myrothecium leaf spot and rots Causal agent Myrothecium roridum is a fungal disease caused by the genus myrothecium. It mainly affects bedding plants and perennials. Scientific name Myrothecium roridum Symptoms & Signs It causes small, dark brown lesions on the leaves that expand gradually, making a hole in the leaf. A few raised, black structures may also be seen on the lesions with a white tuft over them called sporodochia. The crown and petioles also show brown soft rot, a characteristic feature of myrothecium leaf spot and rot. Transmission The fungi produce spores in the sporodochia, which travels by means of water, air, and contact with the infected plant. Warm, wet conditions favor the growth of spores and the spread of the disease. Time of concern Early spring to late summer Common hosts Pansies Begonias Coneflower Verbenas