Buck J W, Wise K, Dong W
Department of Plant Pathology, University of Georgia, Griffin 30223.
Plant Dis. 2011 Mar;95(3):325-330. doi: 10.1094/PDIS-09-10-0646.
Greenhouse experiments were conducted to evaluate the effect of post-symptomatic fungicide applications on urediniospore production of leaf rust of wheat, Puccinia triticina, and daylily rust, P. hemerocallidis. Fungicides from five chemical classes were evaluated for their effect on urediniospore production at 24-h intervals post application for 96 h. The quinone outside inhibitor (QoI) fungicide (azoxystrobin) significantly reduced cumulative urediniospore production by P. triticina (40.1 and 11.3% of control) and P. hemerocallidis (37.9 and 35.6% of control) in both trials. The demethylation inhibitor, myclobutanil, significantly reduced urediniospore production by P. hemerocallidis 24 h post treatment in both trials and cumulative production in one trial. Myclobutanil did not affect urediniospore production by P. triticina. Four QoI fungicides significantly reduced urediniospore production by P. triticina at all collection times (24, 48, and 72 h) and cumulative production in both trials. No differences were observed between the QoI fungicides with P. triticina. The four QoI fungicides significantly reduced urediniospore production by P. hemerocallidis compared with the nonfungicide control, with significantly fewer urediniospores produced in the pyraclostrobin-treated lesions compared with azoxystrobin, fluoxastrobin, and trifloxystrobin. Differences in leaf morphology between daylily and wheat such as leaf thickness and waxiness may contribute to the differences observed between the two pathosystems. The significant reductions in urediniospore production by postsymptom applications of QoI fungicides, combined with their known fungistatic properties, suggest that these chemistries would be useful for reducing the spread of viable inoculum to noninfested plants.
进行了温室试验，以评估症状出现后施用杀菌剂对小麦叶锈病（小麦柄锈菌）和萱草锈病（萱草柄锈菌）夏孢子产生的影响。对来自五个化学类别的杀菌剂进行了评估，观察其在施药后24小时的间隔内，持续96小时对夏孢子产生的影响。醌外抑制剂（QoI）杀菌剂（嘧菌酯）在两项试验中均显著降低了小麦柄锈菌（分别为对照的40.1%和11.3%）和萱草柄锈菌（分别为对照的37.9%和35.6%）的累积夏孢子产量。脱甲基抑制剂腈菌唑在两项试验中均显著降低了处理后24小时萱草柄锈菌的夏孢子产量，并在一项试验中降低了累积产量。腈菌唑对小麦柄锈菌的夏孢子产量没有影响。四种QoI杀菌剂在所有采集时间（24、48和72小时）均显著降低了小麦柄锈菌的夏孢子产量以及两项试验中的累积产量。在小麦柄锈菌试验中，各QoI杀菌剂之间未观察到差异。与未使用杀菌剂的对照相比，四种QoI杀菌剂显著降低了萱草柄锈菌的夏孢子产量，与嘧菌酯、氟嘧菌酯和肟菌酯相比，吡唑醚菌酯处理的病斑产生的夏孢子显著减少。萱草和小麦叶片形态的差异，如叶片厚度和蜡质程度，可能导致了两种病害系统之间观察到的差异。症状出现后施用QoI杀菌剂可显著减少夏孢子产量，再结合其已知的抑菌特性，表明这些化学药剂可用于减少活的接种体向未感染植株的传播。
