Olson H A, Benson D M
Department of Plant Pathology, North Carolina State University, Raleigh 27695.
Plant Dis. 2011 Aug;95(8):1013-1020. doi: 10.1094/PDIS-09-10-0619.
Isolates of Phytophthora in floriculture crops were collected from North Carolina commercial greenhouse facilities in 2007 and 2008, identified, and characterized for mating type and mefenoxam sensitivity. In all, 163 isolates from 13 host species at 11 locations were identified primarily as Phytophthora nicotianae (59%), P. drechsleri (23%), P. cryptogea (9%), and P. tropicalis (4%). Multiple Phytophthora spp. were found at five locations. DNA sequencing was more reliable for differentiating P. cryptogea and P. drechsleri. Only the A1 mating type of P. drechsleri was collected; however, both mating types of P. nicotianae, P. cryptogea, and P. tropicalis were found. Overall, 66% of Phytophthora isolates were resistant or intermediate in resistance to mefenoxam at 1 μg a.i./ml. Three groups of P. drechsleri isolates had effective concentration of mefenoxam providing 50% growth inhibition (EC) estimates over 700 μg a.i./ml. EC estimates for P. nicotianae ranged from 246 to 435 μg a.i./ml. Isolates of P. nicotianae exhibited phenotypic heterogeneity at several locations, suggesting multiple separate introductions to the facilities. In contrast, P. nicotianae and P. drechsleri isolates from two locations were phenotypically identical to a previous survey, suggesting that the facilities have Phytophthora spp. established onsite.
2007年和2008年从北卡罗来纳州的商业温室设施中采集了花卉作物中的疫霉菌分离株，进行了鉴定，并对交配型和甲霜灵敏感性进行了特征分析。总共从11个地点的13种寄主植物中分离出163株菌株，主要鉴定为烟草疫霉（59%）、德氏疫霉（23%）、隐地疫霉（9%）和热带疫霉（4%）。在5个地点发现了多种疫霉菌。DNA测序在区分隐地疫霉和德氏疫霉方面更可靠。仅采集到德氏疫霉的A1交配型；然而，发现了烟草疫霉、隐地疫霉和热带疫霉的两种交配型。总体而言，66%的疫霉菌分离株对1μg a.i./ml的甲霜灵具有抗性或中等抗性。三组德氏疫霉分离株的甲霜灵有效浓度提供50%生长抑制（EC）估计值超过700μg a.i./ml。烟草疫霉的EC估计值范围为246至435μg a.i./ml。烟草疫霉分离株在几个地点表现出表型异质性，表明该设施有多次单独引入。相比之下，来自两个地点的烟草疫霉和德氏疫霉分离株在表型上与之前的调查相同，表明该设施现场已存在疫霉菌。
