Occurrence of iFusarium/ispecies and associated T2-toxin in Kenyan wheat

摘要

Survey covering 120 wheat fields was conducted in three wheat-growing districts of Kenya during the 2008 cropping season to determine the incidence of Fusarium head blight (FHB) and T2-toxin contamination in grain. FHB incidence was determined as the number of blighted ears per 10m2. Information gathered included wheat production practices, rainfall and temperature data. Fungal pathogens were isolated from wheat stems, heads, straw, grains and soil and identified based on cultural and morphological characteristics. Wheat grain samples were analyzed for T2-toxin by competitive Enzyme Linked Immunosorbent Assay (ELISA). High FHB incidences of up to 88% were recorded. Fungal genera isolated included Fusarium, Epicoccum, Trichoderma, Alternaria and Penicilium. Wheat plant parts with high infection with Alternaria and Epicoccum had corresponding low levels of Fusarium spp. Whereas Fusarium spp. were the most common fungal pathogens in stems, heads and soil, Epicoccum was frequently isolated from straw and grains. Fusarium speciesisolated included F. poae, F. graminearum, F. stilboides, F. verticilloides, F. fusarioides, F. tricinctum and F. heterosporum with F. poae and F. graminearum accounting for approximately 40% of all Fusarium infections. T-2 toxin was detected in all the grain samples and varied from 3 to 22 ppb. The study showed that FHB and T2-toxin are prevalent in the study districts and the high diversity of Fusarium species implies a challenge in FHB management as well as a risk of chronic T2-toxin exposure to humans and livestock.