Gadoury David M, Seem Robert C, Pearson Roger C, Wilcox Wayne F, Dunst Richard M
Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva, 14456.
Vineyard Research Laboratory, Cornell University, New York State Agricultural Experiment Station, Fredonia 14063.
Plant Dis. 2001 Feb;85(2):137-140. doi: 10.1094/PDIS.2001.85.2.137.
Vitis labruscana 'Concord' is a widely planted grape cultivar grown in the United States for processing into juice and other products. Concord fruit are sporadically but sometimes severely damaged by the grape powdery mildew pathogen, Uncinula necator. The effects of powdery mildew on vine growth, yield, and quality of Concord grapes at three levels of cropping intensity commonly found in commercial grape production were determined in vineyard studies. Top-wire cordon-trained Concord vines were balance pruned, pruned to retain 80 nodes, or minimally pruned. Replicated plots of the foregoing were then either protected from powdery mildew by regular fungicide applications, or were inoculated and left unsprayed. Over a 4-year period, the effects of foliar infection on vine growth, yield, and juice quality of unsprayed vines were compared with vines that received a conventional protection program of four fungicide applications. Failure to control powdery mildew resulted in a chronic reduction in wood maturity measured as the number of nodes on canes that developed periderm. The reduction in nodes did not reduce yield, possibly due to compensation in shoots produced from the remaining nodes. Powdery mildew did not affect bud survival or vigor, measured as the number of shoots produced per node on retained canes. The most significant effects of powdery mildew were on berry sugar levels and juice color and acidity, which on the unsprayed vines were sometimes reduced below minimally acceptable thresholds for processed grapes. Significant reductions due to powdery mildew in these parameters occurred in all three pruning treatments, but were most pronounced at higher cropping levels.
康科德葡萄（Vitis labruscana 'Concord'）是一种广泛种植的葡萄品种，在美国被用于加工成果汁和其他产品。康科德葡萄果实偶尔会受到葡萄白粉病病原菌——葡萄钩丝壳菌（Uncinula necator）的侵害，有时危害还较为严重。在葡萄园研究中，测定了白粉病对商业葡萄生产中常见的三种种植强度下康科德葡萄藤生长、产量和品质的影响。采用顶丝单臂水平整形方式的康科德葡萄藤分别进行了平衡修剪、保留80个芽眼的修剪或轻度修剪。上述处理的重复小区随后要么通过定期施用杀菌剂来预防白粉病，要么接种病菌且不进行喷洒。在4年的时间里，将未喷洒药剂的葡萄藤上叶片感染对白粉病对藤生长、产量和果汁品质的影响与接受四次杀菌剂常规保护方案的葡萄藤进行了比较。未能控制白粉病导致以形成周皮的茎上芽眼数量衡量的木材成熟度长期降低。芽眼数量的减少并未降低产量，这可能是由于剩余芽眼产生的新梢进行了补偿。白粉病并未影响芽的存活或活力，芽的活力以保留茎上每个芽眼产生的新梢数量来衡量。白粉病最显著的影响在于浆果糖分水平、果汁颜色和酸度，对于未喷洒药剂的葡萄藤，这些指标有时会降至加工葡萄最低可接受阈值以下。在所有三种修剪处理中，这些参数因白粉病导致的显著降低均有发生，但在较高种植强度下最为明显。
