DISEASE-INDUCED LOSSES IN WINTER-WHEAT IN ENGLAND AND WALES 1985-1989

Annual surveys of winter wheat diseases in England and Wales provide information on the relative severity of the leaf and stem-base disease complex. Septoria tritici was the most damaging disease during the 5-year period 1985-1989 causing annual losses estimated to be 0.329 Mt compared with 0.251 Mt and 0.231 Mt for eyespot and mildew, the next most damaging winter wheat diseases. Annual losses during the period averaged 1.078 Mt excluding losses attributable to the fusarium diseases, for which no satisfactory yield loss relationships are available. Sowing date and length of break from cereals exert a strong influence on incidence of eyespot and losses attributable to the disease and, on the basis of these surveys, growing all winter wheat crops after a 1-year break would prevent national losses of approximately 100 kt annually.