Efficacy of Biological Control and Cultivar Resistance on Fusarium Head Blight and T-2 Toxin Contamination in Wheat

Abstract

Laboratory and green house experiments were carried out to evaluate the efficacy of fungicides, biological agents and host resistance in managing FHB and the associated T-2 toxin. In vitro activity of fungicides and antagonists was de-termined by paired culture method. Effect of microbial agents on FHB severity and mycotoxin content was determined by co-inoculating F. graminearum and F. poae with Alternaria spp., Epicoccum spp. and Trichoderma spp. Fungicides Pearl® (500 g/L carbendazim), Cotaf® (50 g/L hexaconacole), Thiovit® (micronised sulphur 80% w/w) and Folicur® (430 g/L tebuconazole) were the standard checks. Host resistance was determined by inoculating F. poae and F. graminearum to four wheat cultivars and fifteen lines in pot experiments. Fungicides resulted in 100% inhibition of pathogen radial growth in in vitro while microbial agents suppressed pathogen growth by up to 53%. Thiovit® and Trichoderma were the most effective in reducing FHB severity in green house pot experiments. The wheat cultivars and lines varied in susceptibility with cultivar Njoro BW II showing least susceptibility while line R1104, cv. Mbuni and cv. KIBIS were most susceptible. All the wheat cultivars and lines accumulated T-2 toxin by up to 5 to 28 μg/kg. The re-sults indicated that neither fungicides nor antagonists can solely be relied on in managing FHB and toxin accumulation. Therefore, integration of biocontrol agents, fungicides and further breeding efforts to improve lines and cultivars with promising resistance to FHB and T2-toxin contamination is recommended