Probst Claudia, Nelson Mark E, Grove Gary G, Twomey Megan C, Gent David H
Department of Plant Pathology, Washington State University, Irrigated Agriculture Research and Extension Center, Prosser 99350.
Department of Botany and Plant Pathology, Oregon State University, Corvallis 97331.
Plant Dis. 2016 Aug;100(8):1599-1605. doi: 10.1094/PDIS-10-15-1127-RE. Epub 2016 May 9.
Podosphaera macularis, the causal agent of hop powdery mildew, is a recurrent threat to hops in the Pacific Northwest because of the potential to reduce cone yield and quality. Early-season pruning is a common practice in hop production for horticultural reasons. Studies were conducted over a 3-year period in a commercial hop yard to quantify the effect of pruning method and timing on disease development, yield, and cone quality factors. A 4-week delay in pruning reduced the incidence of leaves with powdery mildew from 46 to 10% and cones from 9 to 1%, with the specific effect being season dependent. Pruning using chemical desiccants rather than by mechanical means had similar effects on disease levels on leaves. On cones, though, chemical pruning had a small but significant reduction in the incidence of powdery mildew compared with mechanical pruning. Cone yield, levels of bittering-acids, and color were not negatively affected in any individual year or cumulatively over three seasons when pruning treatments were applied repeatedly to the same plots during the study period. Delayed pruning may offer a low-cost means of reducing both the incidence of powdery mildew and early-season fungicide inputs in certain cultivars.
啤酒花白粉病的病原菌黄斑单囊壳菌，因其有可能降低球果产量和品质，对太平洋西北地区的啤酒花构成了反复威胁。出于园艺方面的原因，早期修剪是啤酒花生产中的常见做法。在一个商业啤酒花园中进行了为期3年的研究，以量化修剪方法和时间对病害发展、产量和球果品质因素的影响。修剪推迟4周，白粉病叶片发病率从46%降至10%，球果发病率从9%降至1%，具体效果因季节而异。使用化学干燥剂而非机械方式进行修剪，对叶片上的病害水平有类似影响。不过，在球果上，与机械修剪相比，化学修剪使白粉病发病率有小幅但显著的降低。在研究期间，当对同一地块反复进行修剪处理时，任何单一年度或三个季节累计的球果产量、苦味酸含量和颜色均未受到负面影响。推迟修剪可能为某些品种提供一种低成本的方法，既能降低白粉病发病率，又能减少早期杀菌剂的使用量。
