Submitted to: Compendium on Alfalfa Diseases
Publication Type: Book / Chapter
Publication Acceptance Date: December 5, 2012
Publication Date: October 17, 2014
Citation: Samac, D.A. 2014. Cylindrocladium root and crown rot. In: Samac, D. A., Rhodes, L. H., and Lamp, W. O., editors. Compendium of Alfalfa Diseases and Pests. 3rd edition. St. Paul, MN: APS Press. p. 56. Technical Abstract: Several species of Cylindrocladium have been shown to cause damping-off, seedling blight, and a black crown and root rot of mature plants. In Hawaii, seedling disease was caused by Calonectria ilicicola (anamorph: Cylindrocladium parasiticum) and Cylindrocladium clavatum. A third species, C. scoparium (teleomorph: Calonectria kyotensis) was found associated with diseased plants at a low frequency. These fungi cause disease on a wide range of native and introduced plants in Hawaii. In Japan, Calonectria crotalariae was reported causing crown rot. In another study, C. kyotensis was observed on diseased alfalfa stems. In Florida, C. crotalariae was responsible for sporadic epidemics resulting in complete stand loss. Black sclerotia and orange-red perithecia of C. crotalariae were observed on the bases of diseased stems. In culture, C. parasiticum and C. clavatum produce conidia that cause seedling blight. The disease has not been reported since the 1980s. Fields infested with the pathogens should be avoided for alfalfa cultivation.