Effect of glucose and biotin on the growth and sporulation ofFusariumspecies, especially pathogenic and nonpathogenic isolates ofFusarium oxysporum

Abstract

Fusarium spp. often initiate growth slowly on high glucose media in the absence of added biotin. Among the isolates of F. oxysporum studied, two types were apparent: low sporulating and high sporulating cultures on agar media. Saprobic isolates of F. oxyspo? rum found in sandy soils usually grew slower than the wilt pathogens from these soils. Within the group of isolates of F. oxysporum formae speciales which cause wilt in host plants, there were two distinct cultural types that were consistently isolated from all infested field soils and from infected plants in each field ob? served. These two types differed in their degree of sporulation and growth on high glucose agar medium without added biotin; they also could be distinguished based on whether or not they produced a substance easily detected by its odor.