Eyespot disease of cereal

Abstract

Eyespot (Pseudocercosporella herpotrichoides ), a serious disease of winter wheat and barley, has increased in importance in the 1980s because I) pathogen populations have become resistant to the fungicides which were used to control it; 2) changes in cropping practices, such as earlier sowing dates, have favoured the development of severe epidemics. In 1987, ADAS national surveys suggested that, of the diseases surveyed, eyespot was the most serious disease problem on winter wheat, with losses estimated at c.£30M despite the widespread application of fungicides against eyespot (cost c. £23M). These figures are underestimates since they include neither the losses caused by eyespot-induced lodging, nor the costs of fungicide application. Furthermore, it is likely that eyespot has been an important factor in reducing the quality of milling wheat and malting barley crops so that they have to be sold for animal feed. Since the formula used by ADAS to estimate losses for winter wheat was derived both varieties and eyespot populations have changed, so experiments are needed to re-evaluate it. A national estimate of losses from eyespot-induced lodging is needed and a formula needs to be derived for winter barley