Abstract

CRAGNOLINI, C.I. et al. Presence of Phomopsis viticola (Saccardo) Saccardo, causal agent of excoriosis, in vineyards of Córdoba, Argentina. Agriscientia [online]. 2009, vol.26, n.2, pp.35-41. ISSN 1668-298X.

Leaves with chlorotic spots and necrotic centers have been observed in Vitis vinifera and V. labrusca in vineyards of Córdoba, Argentina, since 2001. Plants exhibit veins, petioles, rachises, and internodes with necrotic spots that coalesce to form cracks in the cortical tissue. Grape berries can shrivel and fall off. Winter canes became whitish with black spots; pycnidia appear in canes and in dry organs, exuding whitish-cream cirri with alpha and beta conidia. The aim of this work was to confirm the presence of Phomopsis viticola (excoriosis) and quantify its incidence. Isolates obtained from petioles, shoots, tendrils, berries and canes produced light-coloured mycelium with pycnidia and alpha (7.5m±1.5 x 2.8m±2) and beta (19m±1 x 1.2m±0.5) conidia or only alpha conidia, typical of P. viticola. Identification was confirmed by molecular sequencing. In shoots of the varieties Malbec and Pinot noir inoculated with 3 10⁴ conidia/mL, leaves exhibited lesions and pycnidia after eight days, and berries showed yellow cirri 15-18 days after inoculation. P. viticola (Sacc.) Sacc. was reisolated from the cirri and the colonies produced typical pycnidia and conidia 10-20 days later. Excoriosis was present in 80% of grapevines evaluated with higher incidence in mature grapevines of Pinot noir and Isabella cultivars.

Keywords : Excoriosis; Necrosis of grapevine; Phomopsis cane blight and leaf spot; Phomopsis viticola; Vitis vinifera; Vitis labrusca.

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