DEVELOPMENT OF THE MAIN MYCOSIS ON PLANTS OF DIFFERENT GRAPEVINE VARIETIES OF DON AMPELOGRAPHIC COLLECTION

Information on the degree of resistance of grapevine plants of various varieties to the main phytopathogens (mildew, oidium) in the conditions of the Don ampelographic collec-tion is given. It was found that the meteoro-logical conditions of 2019 contributed to the depressive development of mildew and the epiphytotic development of oidium. The limit-ing factor for the development of mildew was the increased temperature in June, with maxi-mum values of 37.20C with low air humidity and a small amount of precipitation. Under the conditions of the ampelographic collec-tion, mildew sypmtoms were detected only on plants of unstable varieties: Dimackun, Neizvestnyj donskoj, Puhlyakovskij chernyj, Tavrosi, Cimladar, Cimlyanskij Sergienko, Cimlyanskij chernyj, Shampanchik – 2, Sham-panchik cimlyanskij. The meteorological con-ditions in July - moderate air temperature and high humidity in July, as well as the presence of foci of infection in the ampelocollections were favorable for oidium and contributed to the epiphytotic development of the pathogen, the first signs of which were detected in the phase of the beginning of berry growth. Dur-ing the growing season, despite the protective treatments against powdery mildew, the de-gree of pathogen infestation reached the max-imum values in 88% of the studied varieties. The smallest degree of oidium damage (3.3–3.6 points) was noted in the varieties Tavrosi, Kumshatsky beliy, Kumshatsky chernyj.