Kerns J P, Soika M D, Tredway L P
Department of Plant Pathology, North Carolina State University, Raleigh 27695.
Plant Dis. 2009 Dec;93(12):1275-1280. doi: 10.1094/PDIS-93-12-1275.
Pythium root dysfunction (PRD), caused by Pythium volutum, has been observed on golf course putting greens established with creeping bentgrass in the southeastern United States since 2002. To evaluate preventative strategies for management of this disease, a 3-year field experiment was conducted in Pinehurst, NC on a 'G-2' creeping bentgrass putting green. Fungicide treatments were applied twice in the fall (September and October) and three times in the spring (March, April, and May) in each of the 3 years. Applications of pyraclostrobin provided superior preventative control compared with the other fungicides tested. Azoxystrobin and cyazofamid provided moderate control of PRD in two of three seasons. Experiments were conducted to determine whether the disease suppression provided by pyraclostrobin was due to fungicidal activity or physiological effects on the host. In vitro sensitivity to pyraclostrobin, azoxystrobin, fluoxastrobin, cyazofamid, mefenoxam, propamocarb, and fluopicolide was determined for 11 P. volutum isolates and 1 P. aphanidermatum isolate. Isolates of P. volutum were most sensitive to pyraclostrobin (50% effective concentration [EC] value = 0.005), cyazofamid (EC = 0.004), and fluoxastrobin (EC= 0.010), followed by azoxystrobin (EC = 0.052), and mefenoxam (EC = 0.139). P. volutum isolates were not sensitive to fluopicolide or propamocarb. Applications of pyraclostrobin did not increase the foliar growth rate or visual quality of creeping bentgrass in growth-chamber experiments. This work demonstrates that fall and spring applications of pyraclostrobin, azoxystrobin, and cyazofamid suppress the expression of PRD symptoms during summer and that field efficacy is related to the sensitivity of P. volutum to these fungicides.
自2002年以来，在美国东南部用匍匐翦股颖建植的高尔夫球场果岭上，已观察到由繁茂腐霉引起的腐霉根功能障碍（PRD）。为了评估这种病害的防治策略，在北卡罗来纳州的松hurst对一个“G-2”匍匐翦股颖果岭进行了为期3年的田间试验。在这3年中的每一年，秋季（9月和10月）施用杀菌剂2次，春季（3月、4月和5月）施用3次。与其他测试杀菌剂相比，吡唑醚菌酯的施用提供了更好的预防控制效果。嘧菌酯和氰霜唑在三个季节中的两个季节对PRD提供了中等程度的控制。进行了试验以确定吡唑醚菌酯提供的病害抑制是由于杀菌活性还是对寄主的生理作用。测定了11个繁茂腐霉分离株和1个瓜果腐霉分离株对吡唑醚菌酯、嘧菌酯、氟嘧菌酯、氰霜唑、甲霜灵、霜霉威和氟啶酰菌胺的体外敏感性。繁茂腐霉分离株对吡唑醚菌酯（50%有效浓度[EC]值=0.005）、氰霜唑（EC = 0.004）和氟嘧菌酯（EC = 0.010）最敏感，其次是嘧菌酯（EC = 0.052）和甲霜灵（EC = 0.139）。繁茂腐霉分离株对氟啶酰菌胺或霜霉威不敏感。在生长室试验中，吡唑醚菌酯的施用并未提高匍匐翦股颖的叶片生长速率或视觉质量。这项工作表明，秋季和春季施用吡唑醚菌酯、嘧菌酯和氰霜唑可抑制夏季PRD症状的表达，且田间防效与繁茂腐霉对这些杀菌剂的敏感性有关。
