Effect of seed treatment with novel strains of Trichoderma spp. on establishment and yield of spring wheat

Fusarium head blight (FHB) is the most important disease of wheat in Canada. FHB reduces grain yield and quality and results in seed contamination with Fusarium spp. that is associated with reduced seed vigor and poor stand establishment in wheat. The effect of seed treatments with six strains representing three species Trichoderma, selected based on their superior antagonistic ability on mycelium growth of F. graminearum in dual culture assays, on wheat seed lots contaminated with Fusarium spp. (28-43%) was examined in field trials in 2008, 2009, and 2011. None of the six strains of Trichoderma spp. showed a significant seed treatment effect for all parameters measured each year, but over the three years, all six strains significantly reduced root rot severity and increased yield, three stains (Trich12, TrichC70 and TrichPine) increased emergence and four strains (Trich06, TrichC39, TrichC70, and TrichMM7) increased plant dry weight, compared with the untreated control. TrichC70 was the only strain that showed a significant improvement to all four parameters, increasing emergence by 10.9%, dry weight by 51.7%, and yield by 11.0% and reducing root rot severity by 51.7%. These effects were less but not significantly different from that of the registered fungicide Vitaflo-280 (carbathiin + thiram) used as the positive control in the field trials. The results indicate that Trichoderma stain TrichC70 may be used as an alternative to fungicide seed treatments to alleviate the detrimental effect of the seed-borne phase of FHB in wheat.