A severe disease problem has been found in Florida in certain varieties of the "Diana-type" African violet. It was observed on both cuttings and potted plants in a commercial range throughout the year, but was most severe during the warm months. The symptoms: It first appears as a brown to black root and crown rot. Some isolated leaf spots were also noted. Leaf infection appeared to normally occur by progression of the rot through the petioles from infected crowns and roots. Infected petioles and leaves turned a greasy brown to black. Wilt and collapse of the plants was common. The cause: Laboratory insolations from diseased plants of Englert's cultivar D 108 revealed the disease organism Phytiphthora nicotianae var. parasitica. This organism has been reported as an important pathogen of African violets in Germany.
Source: • Greenhouse Notes PENNSYLVANIA STATE UNIVERSITY May 1975
Keywords: Disease problem crown rot brown to black root Erwinia chrysanthemi Erwinia Chrysanthemi