Trichoderma bio-inoculants to enhance grass seed yield in fields affected by take-all disease

Abstract

Take-all, a serious soil-borne disease of wheat also occurs on several herbage grasses (perennial ryegrass, prairie grass and timothy) and grass weed species (ripgut brome and smooth brome). The disease can affect seed yields both quantitatively and qualitatively. Glasshouse and field experiments were conducted using selected Trichoderma bio-inoculant formulations on prairie grass (Bromus willdenowii) and perennial ryegrass (Lolium perenne) in soils infested with Gaeumannomyces graminis var. tritici (Ggt). In a glasshouse experiment Ggt sugnificantly reduced prairie grass seed yield by 16% by reducing the number of seeds per plant. In the presence of Ggt, Trichoderma atroviride isolates LU132, LU140 and LU584 added to the soil in a prill formulation increased paririe grass seed yield by 13-16%, compared to Ggt control by increasing seed number per plant. In the field, two different bio-inoculant formulations were used, prills drilled into a second year perennial ryegrass seed crop, and seed coating for a new crop. In general, root quality observations revealed lower infection and disease severity in soils containing Trichoderma which led to an 20% seed yield increase for the prill formulation and 4% increase for the seed treatment. These increased seed-yields were associated with a higher number of reproductive tillers and a small reduction in seed dressing losses. Seed-coating with Trichoderma bio-inoculants as a prophylactic practice to improve grass seed yields will be discussed.