Take-all
Take-all is a plant disease affecting the roots of grass and cereal plants in temperate climates caused by the fungus Gaeumannomyces graminis var. tritici. All varieties of wheat and barley are susceptible. It is an important disease in winter wheat in Western Europe particularly, and is favoured by conditions of intensive production and monoculture.
The disease
The disease survives in the soil on infected cereal and grass residues. The fungus infects the root tissue of young plants and can spread from plant to plant in the form of hyphae growing through the soil which is why the disease is often seen in patches. The fungus blocks the conductive tissue of the plants and reduces water uptake. Early signs of the disease include yellowing and stunting, tillering is reduced and plants mature prematurely and often exhibit bleached seed heads. The affected roots are blackened and the plants are easy to pull from the soil. These symptoms give rise to an alternative name for the disease, "whiteheads". Yield loss levels of 40 to 50% are often recorded in severe attacks.