Geary Brad, Johnson Dennis A, Hamm Philip B, Cummings Thomas F
Department of Plant Pathology, Washington State University, Pullman 99164-6430.
Department of Botany and Plant Pathology, Hermiston Agricultural Research and Extension Center, Oregon State University, Hermiston 97838.
Plant Dis. 1999 Jun;83(6):512-515. doi: 10.1094/PDIS.1999.83.6.512.
Chlorothalonil was applied to commercial potato fields of cvs. Russet Norkotah and Russert Burbank in replicated trials through either a center-pivot irrigation system or a spray-boom-attached-to-the-pivot system. Water rates were 26,192 and 675 liters/ha for the center pivot and attached boom, respectively. Three crop canopy levels were sampled within 2 h and again after 6 days following fungicide applications made at 7-day intervals. Efficacy of the two application methods was tested by inoculation of individual excised leaves with an isolate of strain US-1 or US-8 of Phytophthora infestans and by chemical residue analysis. Severity of late blight did not differ between the two fungicide application methods 2 h after application but, after 6 days, disease severity was significantly less on leaves where chlorothalonil was applied by the attached boom. Fungicide residues were three times higher on leaves where chlorothalonil was applied by the attached boom than with the center-pivot system. Significantly more disease occurred on fungicide-treated and non-treated leaves inoculated with the US-8 than the US-1 strain. Severity of late blight on inoculated leaves was inversely related to the amount of chlorothalonil residue on leaves.
在重复试验中，通过中心支轴灌溉系统或安装在支轴上的喷杆系统，将百菌清施用于商业种植的“褐皮诺科塔”和“褐皮伯班克”品种的马铃薯田。中心支轴和附着喷杆的灌水量分别为26192升/公顷和675升/公顷。每隔7天施用一次杀菌剂，在施药后2小时内以及6天后，对三个作物冠层水平进行采样。通过用致病疫霉US-1或US-8菌株的分离物接种单个离体叶片并进行化学残留分析，测试了两种施药方法的效果。施药后2小时，两种杀菌剂施药方法之间晚疫病的严重程度没有差异，但6天后，通过附着喷杆施用百菌清的叶片上的病害严重程度明显较低。通过附着喷杆施用百菌清的叶片上的杀菌剂残留量是通过中心支轴系统施用的三倍。接种US-8菌株的杀菌剂处理和未处理叶片上发生的病害明显多于接种US-1菌株的叶片。接种叶片上晚疫病的严重程度与叶片上百菌清残留量呈负相关。
