Cylindrocladium Root and Crown Rot of Alfalfa in Hawaii. J. J. Ooka, Assistant Plant Pathologist, Department of Plant Pathology, University of Hawaii, Honolulu 96822. J. Y. Uchida, Research Associate, Department of Plant Pathology, University of Hawaii, Honolulu 96822. Plant Dis. 66:947-948. Accepted for publication 20 April 1982. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-947.

Calonectria crotalariae (anamorph: Cylindrocladium crotalariae) and Cylindrocladium clavatum were consistently isolated from crown and root lesions of young alfalfa (Medicago sativa) plants. Retarded growth, chlorosis, and death of plants were characteristic of this disease. Black, slightly sunken lesions 2–10 mm in their greatest dimension often girdled the stems, leading to a rapid collapse and death of plants. Seedling damping-off was also associated with infection. The disease was reproduced by artificial inoculations with conidia from both fungi.

Keyword(s): Cylindrocladium floridanum, C. scoparium, lucerne.