Fifteen isolates of Diplodia and Diplodia-like fungi were grown on various synthetic media for study of the effects of pH, temperature, light, and vitamins on growth, sporulation, and stability of morphological characters currently used in identification. The pH of the culture medium within ranges for good growth had little effect on stabilizing the characteristics used in classification. Light, either continuous or cyclic, favored growth and maturity more than did continuous dark, although some isolates did grow under the latter condition. Two isolates required biotin for sporulation. All others tested grew and sporulated on minimal medium without biotin or other added vitamins. Potato-dextrose-agar is considered a satisfactory medium for growing these fungi for identification purposes.