Fungal microflora causing maize ear rots in Uganda and associated aflatoxins

Abstract

Freshly harvested dry maize ears were sampled from farmers in 2002A and 2002B seasons in ten major maize growing districts of Uganda and kernels plated onto malt extract or malt salt agar for mould growth and were also analysed for moisture and aflatoxin content. Fusarium, Aspergillus, Penicillium, Phomopsis, Acremonium, Stenocarpella and Rhizopus were the genera identified. Fusarium verticillioides and Aspergillus flavus were the most common mould species identified and were isolated from both symptomatic and asymptomatic maize samples in both seasons. Overall, mean aflatoxin levels of both asymptomatic and symptomatic samples were lower than the FDA/WHO 20 ppb regulatory limit. Samples from Masindi district had the highest mean aflatoxin levels (13 ppb) followed by those from Mayuge (11.8 ppb) while those from Kapchworwa had the least mean levels (0.7 ppb). Samples collected during 2002A season had generally higher moisture content, mould incidence and aflatoxin levels than the 2002B samples. Although the findings from the study were only able to show aflatoxins, there is a strong likelihood of other mycotoxins occurring in maize grain in higher proportions. There is therefore the need to quantify these toxins to form a basis for the next course of action. © 2006 Asian Network for Scientific Information.