Fusarium populations in the household food gardens of a peri-urban community

Toxigenic Fusarium species, studied mainly for the damage they cause to commercial crops, have received scant research attention in the context of small-scale food production. In this regard home gardens are an important source of nutrition for resource-poor urban families in Africa. We have investigated the presence of Fusarium in household food gardens in a peri-urban setting in the Rustenburg district of South Africa. Standard techniques were employed for the isolation and morphological species identification of Fusarium species from various sources, namely, maize,, soil, air and naturally growing morogo vegetables,thepe and lerotho. Nine Fusarium species with mycotic and mycotoxigenic potential were specifically targeted for detection: F verticillioides, F proliferatum, F solani, F subglutinans and F oxysporum were predominantly isolated from maize, air, soil and morogo vegetables. All species were isolated in significantly higher numbers from localities in proximity to maize. Fusarium chlamydosporum, F semi-tectum and F equiseti were not retrieved where maize was absent, whereas F verticillioides and F proliferatum were predominantly isolated from maize cobs. These results have public-health implications. All nine Fusarium species retrieved from peri-urban food gardens produce toxins and, except for F poae, have been implicated in opportunistic infections in immune-suppressed individuals.