Environmental Factors Influencing Growth and Sporulation of Cercospora Kikuchii

Abstract

Cercospora kikuchii grew in 10 different liquid or solid media. Most growth was obtained in V-8-juice broth, yeast-extract and potato-dextrose broth, and the least growth occurred in nutrient broth or sterile distilled water. The fungus sporulated abundantly on V-8-juice agar and carrotleaf-decoction agar, moderately on nutrient agar, yeast-extract agar and no conidia formed on water agar, cornmeal agar, malt-extract agar, malt agar or potato dextrose after 14 da at 28 C. At 13 C, the fungus sporulated in continuous light and in alternating light-dark periods (12 h/12 h) on V-8 juice agar, but in continuous darkness a 60% reduction in sporulation was noted. Higher temperatures (22 or 28 C) seemed to counteract this phenomenon, as no significant differences in conidial counts were obtained at 28 C in continuous darkness, alternating light and dark periods, or continuous light.