Biological and economic efficiency of fungicides application in the fight against sugar beet diseases in the south of the Non-Black Earth Zone of Russia

In a field experiment on leached heavy loamy chernozem in the southern Non-Chernozem zone of Russia, the efficiency of fungicides application on sugar beet crops of the Zemis variety to reduce the harmfulness of cercospora leaf spot (Cercospora beticola Sacc.) and phomosis (Neocamarosporium betae (Berl.) Ariyaw. & K. D. Hyde = Phoma beta A. B. Frank) was studied. The efficiency of the following preparations was assessed: Raek, EC, Kolosal Pro, EC and Tirada, SС. Beet plants were treated in late July – in the first ten days of August, the distribution and development of pathogens was recorded before harvesting root crops. Phytosanitary monitoring showed that a wide range of diseases are present in the sugar beet agrophytocenosis, but cercospora leaf spot and phomosis were dominant among them. It was found that the use of fungicides reliably changed the course of plant diseases. The greatest effect on cercospora leaf spot was observed in the variant using Kolosal Pro, EC (0.6 l/ha): the pathogen prevalence was 12% lower than the control variant, and its development was 88%. In relation to phomosis, the best phytosanitary effect was obtained when using Tirada, SС (3 l/ha): the prevalence of phomosis was 33% lower, and its development was 79% lower than the control. The highest sugar beet yield (58.3 t/ha) and the estimated sugar yield (up to 10 t/ha) were ensured by the application of the fungicide Kolosal Pro, EC.