Pythium and Phytopythium spp. associated with soybean in Huang-Huai region, their relative aggressiveness on soybean and wheat, and their sensitivity to seed treatment fungicides
作者单位：Nanjing Agricultural University
会议名称：《多彩菌物美丽中国——中国菌物学会2019年学术年会》
会议日期：2019年
学科分类：09[农学] 0904[农学-植物保护] 090401[农学-植物病理学] 090402[农学-农业昆虫与害虫防治]
基 金：China Agriculture Research System(CARS-004-PS14) the Special Fund for Agro-scientific Research in the Public Interest of China(201303018)
关 键 词：Pythium Phytopythium soybean Huang-Huai region
摘 要：Pythium and Phytopythium spp. cause seed decay, damping-off, and root rot in soybean and wheat;their diversity and importance as pathogens in Huang-Huai region, one of the main soybean producing areas in China are unknown. We identified the Pythium and Phytopythium spp. present in Huang-Huai region soybean fields, determined their aggressiveness on wheat and soybean, and investigated their sensitivity to seed treatment fungicides. Here, 212 isolates representing the 32 Pythium and Phytopythium spp. were identified based on the internal transcribed space 2（ITS2） and cytochrome oxidase subunit 1（COI）, and their aggressiveness on soybean and wheat were determined with seed assay and seedling assay. Of 32 species evaluated, six Pythium spp. were pathogenic on both soybean and wheat. Averaged over all Pythium and Phytopythium isolates and species the effect of infection of wheat appeared to be more severe than infection of soybean. Pythium and Phytopythium *** Huang-Huai region are diverse and a significant cause of disease on soybean and wheat. The sensitivity of nine pathogenic Pythium and Phytopythium species to metalaxyl and mefenoxam was tested using poison-plate ***50 of all isolates tested were less than 10μg·mL-1, which indicates isolates tested were sensitive and had no resistance to the two fungicides. MIC（minimum inhibitory concentration） values to mefenoxam was significantly lower than to metalaxyl, which indicated Pythium and Phytopythium spp. tested were more sensitive to mefenoxam than to metalaxyl.