Susceptibility to downy mildew (Plasmopara viticola) of different Vitis varieties

• Susceptibility of different Vitis sp. to P. viticola under different conditions has been studied.
• Grapevine varieties showed different degrees of susceptibility to downy mildew.
• The results could provide new material to be used in grapevine integrated control strategies.
• The selection of old varieties may contribute towards the growth of organic viticulture.

The susceptibility of different varieties of Vitis vinifera and other Vitis species to downy mildew (caused by Plasmopara viticola) in field, greenhouse and laboratory tests was compared over a period of three years. Different degrees of susceptibility were detected. The most susceptible V. vinifera varieties were ‘Treixadura’ and ‘Albariño; ‘Cabernet Sauvignon’, ‘Mencía’ and ‘Chasselas Doré’ were the least susceptible. The non-vinifera varieties showed no symptoms of downy mildew in the field. Surprisingly, in laboratory and greenhouse tests, the rootstock 110-R was much more susceptible to infection than S04. No relationship was seen between susceptibility and berry colour, or the time of sprouting or fruit ripening. Neither was any correlation seen between susceptibility and the condition of being a traditional or introduced variety. Better knowledge of the susceptibility to downy mildew of different varieties would allow for growers and breeders to select those that are more resistant.