EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
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SESSION 5: DISEASE CONTROL AND FORECASTING MODELS<br />
P116 - The potential risk <strong>of</strong> grain colonisation by<br />
fumonisin-producing Fusarium spp. and fumonisin<br />
synthesis in commercial maize in South Africa<br />
B. Janse van Rensburg 1 , N. W. McLaren 2 , B. C. Flett 1,3<br />
1 Agricultural Research Council-Grain Crops Institute, Private Bag X1251, Potchefstroom, 2520, South<br />
Africa; 2 Department <strong>of</strong> Plant Sciences, University <strong>of</strong> the Free State, P.O. Box 339, Bloemfontein, 9300,<br />
South Africa; 3 Unit for Environmental Science and Management, Faculty <strong>of</strong> Natural Sciences, North-<br />
West University, Private Bag X6001, Potchefstroom, 2520, South Africa<br />
E-mail: FlettB@arc.agric.za<br />
Fumonisins are carcinogenic mycotoxins that are produced primarily by Fusarium<br />
verticillioides and F. proliferatum on maize, globally. The natural occurrence <strong>of</strong><br />
fumonisin producing Fusarium spp. and fumonisin contamination <strong>of</strong> maize grain<br />
were quantified in selected maize cultivars from the major production areas <strong>of</strong><br />
South Africa. Samples were analysed using quantitative (q) real-time PCR to<br />
determine the respective biomasses <strong>of</strong> fumonisin-producing Fusarium spp.<br />
Fumonisin concentrations were quantified by means <strong>of</strong> High Performance Liquid<br />
Chromatography (HPLC). Results indicated high natural infection by fumonisinproducing<br />
Fusarium spp. and fumonisin concentrations in warmer production<br />
areas such as Northern Cape, North West and Free State Provinces. High<br />
fumonisin producing fungal biomass and concomitant fumonisin concentrations<br />
(above 2 ppm in certain localities) quantified in this study, could negatively impact<br />
grain quality and food safety and security due to the potentially harmful effects <strong>of</strong><br />
this mycotoxin on humans and animals. These data, together with meteorological<br />
data were used to develop a preliminary model based on the non-linear, 3dimentional<br />
Lorentzian equation (Sigmaplot 10.0). Fusarium colonisation <strong>of</strong> grain<br />
and fumonisin concentrations were related to prevailing weather conditions during<br />
early post-flowering and dough stage <strong>of</strong> grain development, respectively. Both<br />
colonisation and fumonisin production were significantly inversely correlated with<br />
mean maximum temperature (r=-0.77 and r=-0.60, respectively) with an optimum<br />
temperature <strong>of</strong> 30.5°C and minimum relative humidity (r=-0.83 and r=-0.79,<br />
respectively) with an optimum <strong>of</strong> 49.5 % during these critical growth periods.<br />
Keywords: Fusarium, fumonisins, epidemiology, incidence<br />
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