Abstract
A disease of sugar beets caused by Colletotrichum dematium was found in Hokkaido in August, 1981. Both root crop and seed crop were injured. In root crop, the symptom mainly appeared as fujiform lesions on petioles. The symptom of seed crop were necrotic spots on stalks, leaves and flowers and greater damage was resulted on the seed crop than on the root crop. The fungus was pathogenic on Chenopodiaceae. Beta vulgaris var. saccharifera, Beta vulgaris var. cicla, Beta vulgaris var. rapa and Spinacia olelacea. Optimum temperature for mycelial growth on PDA was between 20 and 27C. Based on morphological characters and host ranges, the present fungus was identified with C. dematium f. spinaciae. The occurrence of the present disease in fields was different in the degree depending on sugar beet cultivars and this varietal difference was highly correrated with the results of artificial inoculation. In Japan, Nakata et al. first reported the disease as called “Shinba kurogare” disease in 1922. Present fungus is considered the same to that which caused the disease reported by Nakata et al. However, due to the marked difference of symtoms from the previous report, the present authors propose the common name of this disease “Sugar beet Anthracnose”.
