VIEW ARTICLE

Variation Among Isolates of Cercospora beticola from Sugar Beet. E. G. Ruppel, Research Plant Pathologist, Plant Science Research Division, ARS, USDA, Crops Research Laboratory, Colorado State University, Fort Collins 80521; Phytopathology 62:134-136. Accepted for publication 10 August 1971. DOI: 10.1094/Phyto-62-134.

Significant differences in growth were found among 14 Colorado sugar beet isolates of Cercospora beticola on cornmeal, V-8 juice, and sugar beet leaf extract agar (SBLEA). Cultural appearances also differed; however, with one exception, no grouping of isolates was possible based on mutual characteristics on all media. Significant differences among isolates, as measured by disease severity on sugar beet seedlings, were obtained in only one of two pathogenicity tests. Differences in disease reaction among sugar beet lines were highly significant, but the isolates X lines interaction was not significant in either test. Correlation studies indicated that neither growth on SBLEA nor spore length was associated with disease severity. Results demonstrated the variability among isolates of C. beticola, but resistance in sugar beet to the fungus was effective against all the isolates from Colorado.