Department of Plant and Environmental Sciences, Clemson University, Coastal Research and Education Center, Charleston, SC 29414.
Plant Dis. 2020 Nov;104(11):2832-2842. doi: 10.1094/PDIS-04-20-0728-RE. Epub 2020 Sep 18.
Species of cause root and stem rot in cucurbits, but no formal surveys have been conducted in the United States to identify which species are responsible. The cucurbit hosts bottle gourd, cucumber, Hubbard squash, and watermelon were transplanted in May, July, September, and November into sentinel plots in four and five different fields in 2017 and 2018, respectively, in South Carolina. Eight of the nine fields were replanted in March 2019. Isolates (600) were collected and identified by sequencing DNA of the mitochondrial cytochrome oxidase I region. The four most common species were (45.6% of all isolates), (20.0%), (15.3%), and (12.8%). and were predominantly isolated in May, July, and September, whereas were predominantly isolated in November and March. Isolates of , , and were more virulent than isolates of and at 25°C. Representative isolates were screened in vitro for sensitivity to three fungicides: mefenoxam, propamocarb, and oxathiapiprolin. All isolates were sensitive to mefenoxam and propamocarb, but these same isolates were insensitive to oxathiapiprolin, except those classified taxonomically in clade I.
引起葫芦科作物根和茎腐烂的物种，但在美国尚未进行正式调查以确定是哪些物种造成的。2017 年和 2018 年，南卡罗来纳州的四个和五个不同田地的哨兵田分别于 5 月、7 月、9 月和 11 月移植了葫芦科宿主瓠瓜、黄瓜、葫芦和西瓜。其中 8 个田块于 2019 年 3 月重新种植。通过对线粒体细胞色素氧化酶 I 区的 DNA 进行测序，收集并鉴定了 600 个分离物。最常见的四个物种是 （所有分离物的 45.6%）、 （20.0%）、 （15.3%）和 （12.8%）。和 主要在 5 月、7 月和 9 月分离，而 主要在 11 月和 3 月分离。在 25°C 时，与 和 相比， 和 的分离物的毒力更强。代表性分离物在体外对三种杀菌剂：甲霜灵、丙硫菌唑和唑虫酰胺进行了敏感性筛选。所有分离物对甲霜灵和丙硫菌唑敏感，但这些相同的分离物对唑虫酰胺不敏感，除了那些在分类学上属于 分支 I 的分离物。
