Impact of local pre-harvest management practices in maize on the occurrence of Fusarium species and associated mycotoxins in two agro-ecosystems in Tanzania

Abstract

Knowledge on the presence of mycotoxins in Africa is fragmentary, although it can be assumed that both concentrations and prevalence in food commodities is high. The present study focuses on the presence of Fusarium species and their associated mycotoxins in maize from two geographically distant agro ecological systems in Tanzania. In a two-year survey, both Fusarium species and concomitant mycotoxins were surveyed in the Northern highlands (Hanang district) and the Eastern lowlands (Kilosa district). Parallel with this, a questionnaire on agricultural practices in both agro-ecosystems was included in this study. This allowed us to put the presence of the toxigenic Fusarium species and their mycotoxins within a relevant agricultural framework. Fusarium verticillioides, Fusarium graminearum and Fusarium poae were the predominant species in both locations although the population in the Eastern lowlands was slightly more complex comprising also Fusarium culmorum, Fusarium avenaceum and Fusarium sporotrichioides. The predominant presence of F. verticillioides resulted in a high prevalence of fumonisins in both regions. The importance of F. graminearum in the population was reflected by the presence of deoxynivalenol in the mycotoxin analysis. Although the agricultural practices differed significantly amongst both locations, only few significant correlations were detected between mycotoxin presence and crop rotation, storage conditions, and insect control measures.