The FHB challenge to irrigation wheat production in South Africa

Abstract

Irrigation wheat production in South Africa is seriously impaired by the regular occurrence of Fusarium head blight epidemics. The disease was noted for the first time in 1980 and has since caused damage whenever the seasonal climatic conditions were favourable. Higher levels of disease concurred with an increase in conservation tillage and maize production in a double cropping system with wheat. Farmers are challenged by a lack of rotation summer crops and high input costs, forcing them towards reduced tillage practices. At present the disease has not been successfully controlled with fungicides and most commercial cultivars show a low level of resistance. Removal of high levels of maize residue, before the cultivation of a wheat crop, has proved effective in reducing disease. Climatic conditions during flowering are extremely unpredictable, but excessive rainfall, lower night temperatures and subsequent higher humidity seem to be key factors in the development of high infection levels. Research currently focuses on cultivar and resistance evaluation, tillage practices, climatic triggers for disease and a fungal population study.