Gruber B R, Davies L R R, Kruger E L, McManus P S
Department of Plant Pathology, University of Wisconsin, Madison 53706.
Department of Forest and Wildlife Ecology, University of Wisconsin, Madison 53706.
Plant Dis. 2009 May;93(5):512-518. doi: 10.1094/PDIS-93-5-0512.
In the Great Lakes region of the United States, cherry growers are poised to re-adopt copper-based fungicides to manage cherry leaf spot disease (CLS), caused by Blumeriella jaapii. However, application of copper is often associated with leaf bronzing. In growth chamber experiments, bronzing was observed on foliage of tart cherry (Prunus cerasus 'Montmorency') seedlings 1 week following application of a copper-based fungicide, only when leaves were also exposed to nightly dew. In potted, 1-year-old trees outdoors, light-saturated rates of net CO assimilation (A) and stomatal conductance (g) were not affected by treatment with copper sulfate, chlorothalonil, tebuconazole, or trifloxystrobin compared to a nonsprayed control. In 2005 and 2006, A and g were measured during late summer on leaves of mature trees in an orchard subjected to the following fungicide programs: synthetic fungicides only; synthetic fungicides integrated with copper-based fungicides; or not sprayed. Bronzing symptoms were observed on trees sprayed with copper. Regression analysis revealed that neither A nor g decreased as leaf surface area affected by bronzing increased (R = 0.004, P = 0.80 and R = 0.006, P = 0.74, respectively). Leaf bronzing associated with application of copper-based fungicides may therefore be inconsequential to foliar gas exchange in tart cherry during late summer.
在美国五大湖地区，樱桃种植者准备重新采用铜基杀菌剂来防治由雅皮氏球腔菌（Blumeriella jaapii）引起的樱桃叶斑病（CLS）。然而，施用铜制剂往往会导致叶片出现青铜色。在生长室试验中，仅当叶片在夜间接触露水时，酸樱桃（Prunus cerasus 'Montmorency'）幼苗在施用铜基杀菌剂1周后，叶片上才会出现青铜色。在室外盆栽的1年生树木中，与未喷洒的对照相比，用硫酸铜、百菌清、戊唑醇或肟菌酯处理后，净CO同化率（A）和气孔导度（g）的光饱和速率不受影响。在2005年和2006年夏末，对一个果园中成年树的叶片进行了以下杀菌剂处理方案后，测定了A和g：仅使用合成杀菌剂；合成杀菌剂与铜基杀菌剂混用；或不进行喷洒。在喷洒了铜制剂的树上观察到了青铜色症状。回归分析表明，随着受青铜色影响的叶表面积增加，A和g均未降低（R分别为0.004，P = 0.80和R = 0.006，P = （此处原文有误，应为0.74）0.74）。因此，在夏末，与施用铜基杀菌剂相关的叶片青铜色可能对酸樱桃的叶面气体交换影响不大。
