INOCULATION IN THE FIELD FOR SCREENING TH E RESISTANCE OF SUGAR-BEET AGAINST LEAF-SPOT DISEASES

In 1993 and 1994 at Gottingen, out of strong diseased area of Germany, artificial inoculation of sugar beet with in vitro-material of Cercos pora beticola led to a strong and uniform infection. Disease severity increased similarly in both years due to secondary infections during t he vegetation period. The tested varieties differed in yield and quali ty according to susceptibility. Fungicide spraying had considerable ef fects on leaf spot disease and yield and quality. With fungicide spray ing, susceptible varieties obtained equal yield and quality as resiste nt ones, which are breeded for other countries.