Take-all of wheat is caused by the soil-borne fungus Gaeumannomyces graminis var. tritici (Ggt), and is a widespread and destructive disease in temperate climates around the world where losses may be as high as 50%. Several practices are used to limit the disease on susceptible crops, including tillage, rotation, choice of variety, N fertilizer, and chemical and biological seed treatments. In relation to biological control, it is necessary to better understand the effects of different treatments on microbial dynamics in the rhizosphere and on roots.