Moorman G W, Walker A-S, May S
Department of Plant Pathology, The Pennsylvania State University, University Park 16802.
INRA, UR 1290 BIOGER-CPP, BP01, 78850 Thiverval-Grignon, France.
Plant Dis. 2012 Jan;96(1):147. doi: 10.1094/PDIS-08-11-0721.
Greenhouse-grown Heuchera plants, treated with fenhexamid (Decree, SePRO, Carmel, IN; FRAC group 17 hydroxyanilide), with active gray mold were submitted to the Penn State Plant Disease Clinic in December 2010 from a commercial operation in north-central Pennsylvania. Genetic and phenotypic analyses identified the isolate as Botrytis cinerea Pers. (teleomorph Botryotinia fuckeliana (de Bary) Whetzel), HydR3 phenotype (2) and not B. pseudocinerea (previously Botrytis group I) (4), naturally resistant to fenhexamid (phenotype HydR1) (1). While 0.2 μg of fenhexamid per ml or less is required to slow mycelial growth and germ tube elongation of sensitive isolates by 50% (EC), the radial growth EC of the Heuchera isolate was approximately 2,000 μg of fenhexamid per ml in culture. Five cucumber seedlings receiving 25 μl of 0.1 M dextrose containing the label rate of Decree (1,800 μg/ml) on the growing tip were inoculated with colonized agar in the drop. Five check plants received 25 μl of 0.1 M dextrose. B. cinerea from silica gel storage since 1988 was also tested. This experiment was repeated three times. The 1988 isolate killed all fungicide-free but no fenhexamid-treated plants. The Heuchera isolate killed all fungicide-free and fenhexamid-treated plants within 4 days. To our knowledge, this is the first report of B. cinerea from a greenhouse in North America with fenhexamid resistance. Resistance occurs in U.S. fields (3). The Heuchera isolate's HydR3 resistance phenotype (2) has been detected in Germany, Japan, and France and has mutations affecting the 3-keto reductase protein, encoded by the erg27 gene, the specific target of fenhexamid and involved in Botrytis sterol biosynthesis. The Decree label states that it is to be used only twice on a crop before switching to a different mode of action. Greenhouses have resident Botrytis populations that are likely to be exposed to any fungicide applied in the structure. Growers should consider using fenhexamid only twice in a particular greenhouse, rather than on a particular crop, before switching to a different mode of action. References: (1) P. Leroux et al. Crop Prot. 18:687, 1999.(2) P. Leroux et al. Pest Manag. Sci. 58:876, 2002. (3) Z. Ma and T. J. Michailides. Plant Dis. 89:1083, 2005. (4) A.-S. Walker et al. Phytopathology 101:1433, 2011.
2010年12月，来自宾夕法尼亚州中北部一家商业种植场、感染了活性灰霉病且用咯菌腈（商品名：Decree，SePRO公司，印第安纳州卡梅尔市；FRAC分类第17组，羟基苯胺类）处理过的温室培育矾根属植物，被送到了宾夕法尼亚州立大学植物病害诊所。遗传和表型分析确定该分离株为灰葡萄孢菌Pers.（有性型为富克尔葡萄核盘菌（德巴里）韦策尔），HydR3表型（2），而非拟灰葡萄孢菌（以前的葡萄孢菌第I组）（4），对咯菌腈天然抗性（HydR1表型）（1）。虽然每毫升0.2微克或更低浓度的咯菌腈就能使敏感分离株的菌丝生长和芽管伸长减缓50%（有效浓度），但在培养中，矾根属分离株的径向生长有效浓度约为每毫升2000微克咯菌腈。5株黄瓜幼苗在生长点接受25微升含Decree标签标注剂量（1800微克/毫升）的0.1M葡萄糖溶液，并在液滴中接种定殖在琼脂上的病菌。5株对照植株接受25微升0.1M葡萄糖溶液。还对自1988年以来保存在硅胶中的灰葡萄孢菌进行了测试。该实验重复了3次。1988年的分离株杀死了所有未用杀菌剂处理的植株，但未杀死用咯菌腈处理过的植株。矾根属分离株在4天内杀死了所有未用杀菌剂处理和用咯菌腈处理过的植株。据我们所知，这是北美温室中出现对咯菌腈具有抗性的灰葡萄孢菌的首次报道。在美国田间也出现了抗性（3）。矾根属分离株的HydR3抗性表型（2）已在德国、日本和法国被检测到，并且其突变影响了由erg27基因编码的3-酮还原酶蛋白，erg27基因是咯菌腈的特定作用靶标，参与葡萄孢菌的甾醇生物合成。Decree标签说明在转换为不同作用方式之前，它在一种作物上只能使用两次。温室中有常驻的葡萄孢菌种群，很可能接触到施用于温室结构中的任何杀菌剂。种植者在转换为不同作用方式之前，应考虑在特定温室中仅使用两次咯菌腈，而不是在特定作物上使用。参考文献：（1）P.勒鲁等，《作物保护》18:687，1999年。（2）P.勒鲁等，《害虫管理科学》58:876，2002年。（3）马泽和T.J.米哈利季斯，《植物病害》89:1083，2005年。（4）A.-S.沃克等，《植物病理学》101:1433，2011年。
