Saville Amanda, Graham Kim, Grünwald Niklaus J, Myers Kevin, Fry William E, Ristaino Jean Beagle
Department of Plant Pathology, North Carolina State University, Raleigh 27695.
Horticultural Crops Research Laboratory, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Corvallis, OR.
Plant Dis. 2015 May;99(5):659-666. doi: 10.1094/PDIS-05-14-0452-RE.
Phytophthora infestans causes potato late blight, an important and costly disease of potato and tomato crops. Seven clonal lineages of P. infestans identified recently in the United States were tested for baseline sensitivity to six oomycete-targeted fungicides. A subset of the dominant lineages (n = 45) collected between 2004 and 2012 was tested in vitro on media amended with a range of concentrations of either azoxystrobin, cyazofamid, cymoxanil, fluopicolide, mandipropamid, or mefenoxam. Dose-response curves and values for the effective concentration at which 50% of growth was suppressed were calculated for each isolate. The US-8 and US-11 clonal lineages were insensitive to mefenoxam while the US-20, US-21, US-22, US-23, and US-24 clonal lineages were sensitive to mefenoxam. Insensitivity to azoxystrobin, cyazofamid, cymoxanil, fluopicolide, or mandipropamid was not detected within any lineage. Thus, current U.S. populations of P. infestans remained sensitive to mefenoxam during the displacement of the US-22 lineage by US-23 over the past 5 years.
致病疫霉引发马铃薯晚疫病，这是马铃薯和番茄作物的一种重要且造成巨大损失的病害。对美国近期鉴定出的致病疫霉的七个克隆谱系进行了六种卵菌纲靶向杀菌剂的基线敏感性测试。在2004年至2012年间收集的优势谱系的一个子集（n = 45）在添加了一系列浓度的嘧菌酯、氰霜唑、霜脲氰、氟吡菌胺、双炔酰菌胺或甲霜灵的培养基上进行体外测试。计算每个分离株的剂量反应曲线以及抑制50%生长的有效浓度值。US-8和US-11克隆谱系对甲霜灵不敏感，而US-20、US-21、US-22、US-23和US-24克隆谱系对甲霜灵敏感。在任何谱系中均未检测到对嘧菌酯、氰霜唑、霜脲氰、氟吡菌胺或双炔酰菌胺不敏感的情况。因此，在过去5年US-23取代US-22谱系的过程中，美国目前的致病疫霉种群对甲霜灵仍保持敏感。
