Take-All spreads from infested wheat residue and is most severe where consecutive wheat crops have been grown. Infection and development favored by soil temperatures of 50 to 68 F; neutral to alkaline soil pH; wet, poorly drained soils; and N, P and K deficiencies. Initial infection occurs as root growth through the soil intercepts infested plant residue, and can occur throughout the season. Localized plant- to-plant spread often occurs where roots of healthy plants intercept or cross roots of neighboring diseased plants. Root infections eventual progress to the crown and lower stems. turning them a shiny black to dark brown in appearance. Severely infected wheat plants also appear stunted and uneven in height. Tillers die prematurely, resulting in white heads bearing few or no kernels. Heavy use of nitrate-based fertilizers also favor take-all. Bromegrasses (Bromus species) and wheatgrasses (Agropyron species) including quackgrass (A. repens) are alternate hosts.