The evolution of the degree of attack by grey rot (Botrytis cinerea) on four wine grape cultivars under conventional and organic control treatments, in the Murfatlar viticultural center

Between 2023 and 2024, in the vineyard of the Research and Development Station for Viticulture and Oenology Murfatlar, the susceptibility of four wine grape cultivars (Vitis vinifera) ('Columna', 'Pinot gris 13', 'Mamaia', and 'Feteascǎ neagră') to grey mold (Botrytis cinerea) was tested under two types of disease control: organic and conventional. In both disease control systems, four botrytis treatments were applied each year, using the same commercial products with the same active substances per hectare. The treatments, both organic and conventional, were applied during the phenological stages when the grapevine is most vulnerable to this pathogen: after flowering, during bunch closure, at the beginning of veraison and during veraison. Thus, a trifactorial experiment was achieved: vintage year x disease control system x grape cultivar. In the two years of study, the two types of disease control were also differentiated by appropriate field and fertilization technologies. The degree of attack by grey rot (Botrytis cinerea Pers.) was determined on 100 grape clusters per variant at harvest. For the less affected cultivars, 'Columna' (2.48%) and 'Mamaia' (3.49%), the degree of attack (DA %) was statistically lower under all control systems and compared to the other cultivars. These cultivars showed greater native resistance to grey rot compared to 'Feteascǎ neagră' (3.78%) and 'Pinot gris 13' (4.59%). These results are of interest for organic grey rot control practices, and consequently, the 'Columna' and 'Mamaia' cultivars can be recommended for organic cultivation.