OCCURRENCE AND TOXIGENICITY OF FUSARIUM-PROLIFERATUM FROM PREHARVEST MAIZE EAR ROT, AND ASSOCIATED MYCOTOXINS, IN ITALY

Forty-two samples of preharvest maize ear rot, collected in 1992-1993 from different maize fields throughout Italy, were examined for the re lative incidence of Fusarium proliferatum and its toxigenicity. F. pro liferatum (34%), together with F. moniliforme (54%), were the predomin ant species in infected ear kernels. Less frequently isolated were F. equiseti(8%) and F. graminearum (2%), and to a much lesser extent, F. chlamydosporum, F. culmorum. F. oxysporum, F. semitectum, F. solani, F . sporotrichioides, and F. subglutinans. When cultured on autoclaved m aize kernels for 4 wk in the dark at 25 C, mycotoxin production by str ains of F. proliferatum was as follows: all of the 26 assayed strains (100%) produced fumonisin B-1 (up to 2,250 mg/kg); 22 strains (85%) al so produced beauvericin (up to 200 mg/kg); and 12(46%) produced fumoni sin B-1, beauvericin, and moniliformin (up to 5,300 mg/kg). Cultural e xtracts of almost all F. proliferatum strains revealed a high level of toxicity towards Artemia salina larvae. Selected infected maize ears, mostly colonized by F. proliferatum, were found to be contaminated by fumonisin B-1 (up to 250 mg/kg), beauvericin (up to 40 mg/kg), and mo niliformin (200 mg/kg). This is the first investigation of the relativ e incidence of toxigenic F. proliferatum strains as causal agents of m aize ear rot, as well as of the natural occurrence of mycotoxins in pr eharvest F. proliferatum-colonized maize ears. The results strongly su ggest a more significant role of F. proliferatum in maize ear rot and in the associated mycotoxicoses. Moreover, these results show that a p otential exists for the production of beauvericin, fumonisin B-1, and moniliformin in maize grown in Italy.