COMBATTING FORMS OF RESISTANCE OF DOWNY MILDEW - Plasmopara viticola

Grapevine downy mildew, Plasmopara viticola, is the most damaging disease of grapes globally. Although the management of this disease involves the application of fungicides during the growing season, the resistance developed often makes chemical treatments ineffective. Most studies refer to combating the pathogen during the plant's growing season, although it continues to evolve during the vegetative rest period of the grapevine crop, in the leaf debris in the soil. In this study, laboratory research methods were used, as well as field research methods on the experimental plot. Five experimental variants and a control were used. Following the experiments carried out, it was found that the most effective variant was the 4-cymoxanil + copper hydroxide variant (13.33% attack degree). The aim of the experiments was to combat overwintering resistance forms of P. viticola in order to reduce the number of treatments during the growing season.