Bacterium malvacearum, the causative agent of ‘black-arm’, or angular leaf-spot disease of the cotton plant, has been described in certain recent papers as capable of producing a systemic ...

Angular leaf spot of rudbeckia Q: My black-eyed Susans get black spots on their leaves every year. Is there anything I can do to prevent that from happening? A: Rudbeckia species, commonly called ...

However, “Goldstrum” is particularly prone to angular leaf spot, a bacterial disease that ... It is sometimes called cutleaf coneflower, and its yellow petals bend downward from a greenish ...