Evaluation of Northern Grape Hybrid Cultivars for Their Susceptibility to Anthracnose Caused by Elsinoe ampelina

Abstract

Use of winter-hardy grape cultivars has enabled expansion of wine grape production in the province of Quebec, Canada, but some of the cultivars have been reported as susceptible to grape anthracnose, a serious disease. The disease causes grape leaves and berries to dry up and drop prematurely, resulting in poor or no yield and, in cold climates, reduced winter survival. On susceptible cultivars, anthracnose management is costly, making grape production unprofitable. Therefore, cold climate grape cultivars were evaluated for their susceptibility to leaf infection by E. ampelina. Plants were grown from dormant cuttings and on each plant the youngest three leaves were tagged and inoculated with a conidial suspension of E. ampelina (1 × 106 spores per ml). Immediately after inoculation, plants were maintained under high humidity conditions at 24 ± 2°C for 72 h. The number of lesions per leaf was determined 14 days after inoculation. Cluster analysis was used to group the cultivars based on their susceptibility. The cultivars were classified as: (i) resistant or slightly susceptible – DM 8521-1, ES 10-18-30, St-Pépin, Sabrevois, Vidal banc, Baltica, Frontenac gris, Ste-Croix, Somerset, Frontenac, Seyval blanc; (ii) susceptible – Muscat de Swenson, Geisenheim, La Crescent, Frontenac blanc, Louise Swanson, Delisle; and (iii) highly susceptible – Swenson White, Vandal Cliche, Traminette, and Marquette. Knowledge of the susceptibility of grape cultivars to anthracnose will help growers to make prudent cultivar choices when new vineyards are established. Accepted for publication 31 May 2011. Published 5 August 2011.