Botrytis cinerea infection in Vitis vinifera cultivars under cycle inversion

Abstract

ABSTRACT Grapes for winemaking are harvested in months of high precipitation and temperatures that favor fungal infection. The cycle inversion technique promotes fall-winter harvesting with slower maturation and improved quality. However, the incidence of latent Botrytis cinerea Pers. in the berries and the susceptibility of cultivars under this pruning system have yet to be studied. We evaluated the incidence of latent B. cinerea in grape berries under cycle inversion at pre-ripening and the susceptibility of different cultivars to B. cinerea infection at maturity. The experiment was conducted in a commercial vineyard in São Roque, São Paulo. The red grape cultivars evaluated were Cabernet Franc, Malbec, Syrah, and Marselan, and the white grapes were Viognier and Sauvignon Blanc. The incidence of latent B. cinerea in the berries ranged from 1 % to 33 % in the different cultivars and harvest seasons evaluated. Artificially inoculated B. cinerea (10 5 conidia m L –1 ) did not cause disease in detached, unwounded ripe berries. However, berries from all cultivars showed symptoms of gray mold and signs of the pathogen when artificially inoculated with the same concentration of conidia plus the nutritional contribution of grape juice in a 1:1 ratio.

Keywords

• latent infection
• plant health
• viticulture
• winter wines