Evaluation of NE-1020 wine grape cultivars for resistance to early season downy mildew and phomopsis cane in Biglerville, PA, 2012

摘要

Commercial cultivars from the North East 1020 Wine Grape program were evaluated for resistance to downy mildew and Phomopsis cane and leaf spot at the Penn State Fruit Research & Extension Center, Biglerville, PA. Seventeen Vitis vinifera and Vitis interspecific hybrid Vidal vines were trained to VSP, while the other three interspecific hybrid vines in the treatment block were trained to a single top wire. Vines were spaced 6 x 9 ft. All cultivars were arranged in a randomized complete block design with six replications, 4 vines per plot. The vineyard received a maintenance insecticide program throughout the season using an air-blast sprayer (100 gal/A at 400 psi). All vines also received a maintenance fungicide program applied at 7-14 day intervalsto control seasonal grape diseases. After 7 spray applications of a complete fungicide maintenance program, the susceptibility of the different cultivars to downy mildew and Phomopsis shoot/cane were evaluated on 18 Jun when grape vines were susceptibleto infection. Disease incidence was rated on leaves, shoots/canes and fruit by visually determining the percent infected of 40 arbitrarily-selected leaves, shoots/canes and fruit clusters per plot. Data were analyzed using analysis of variance and meanseparation was determined by the Fisher’s Protected LSD test (P < 0.05) (SAS Institute Inc., Cary, NC).