云南魔芋新病害—疫病病原菌的鉴定

ttttt目的ttttt明确烟草疫霉对魔芋的致病性，为其引起的魔芋疫病的防治提供理论基础。ttttttttttttt方法ttttt对分离鉴定的5株烟草疫霉菌，在温室和实验室条件下利用植物活体和离体接种法进行致病性鉴定。ttttttttttttt结果ttttt5株疫霉菌对魔芋均表现出相似的强致病性，发病率达到100%。实验室致病性鉴定表明：疫霉菌株Ps1对叶片(病情指数98.33)和根部(病情指数94.07)致病力显著高于球茎(病情指数78.33)和茎秆(病情指数71.11)；在辣椒果实、马铃薯叶片、大豆和烟草茎基部分别接种Ps1菌株，不同寄主均出现明显病斑，其中疫霉菌对马铃薯的致病性(病情指数60.67)最强，对大豆的致病性最弱(病情指数32.59)。ttttttttttttt结论ttttt疫霉菌不仅对魔芋的不同部位有较强的致病性，还可侵染其他植物。tttt

First report of stem rot or konjac caused by Phytophthora nicotianae in China

tttttPurposetttttIn order to provide the theoretical foundation for prevention and control of konjac blight causing by Phytophthora nicotianae, the pathogenicity of Phytophthora should be determined.ttttttttttttttttttMethodtttttFive Phytophthora strains were tested using inoculation in vitro and in vivo method in laboratory and greenhouse conditions.ttttttttttttttttttResultstttttFive strains had the similar pathogenicity to konjac, and the disease incidence reach 100%. The pathogenicity of P. nicotianae to leaves (disease index 98.33) and root (disease index 94.07) were significantly higher than seeds bulbs (disease index 78.33) and stem (disease index 71.11) in the laboratory. Besides, red pepper, soybean root, potato leaf and tobacco stem base were inoculated with Ps1 strains respectively, clear spots were found in different hosts, and P. nicotianae was the strongest pathogenic to potato (disease index 60.67) and the weakest pathogenic to soybean (disease index 32.59).ttttttttttttttttttConclusionstttttThe P. nicotianae can not only infect konjac, but also infect other host.ttttttttt