红花玉兰根腐病化学防治药剂的室内筛选及毒力测定

Laboratory Screening and Virulence Determination of Chemical Agents for Controlling Root Rot of Magnolia wufengensis

为筛选红花玉兰根腐病最佳抑菌化学药剂,在实验室条件下,选择代森锰锌质量分数80%可湿性粉剂、多菌灵质量分数50%可湿性粉剂、氰氨化钙、根腐消体积分数58%水剂、福美双质量分数50%可湿性粉剂和恶霉灵原药6种常见化学药剂,每种药剂设置5个稀释倍数,开展抑菌试验、计算有效中质量浓度(EC50),研究供试化学药剂对红花玉兰病原菌Fusarium solani(1123-3菌株、1129-4菌株)、Fusarium spp.(1223-8菌株、1108-3菌株)菌落生长、产孢量的抑制效果。结果表明:代森锰锌、多菌灵、根腐消、福美双和恶霉灵5种化学药剂对红花玉兰根腐病病原菌有明显抑制作用。稀释600倍液,即质量浓度为1.667 g·L^-1的氰氨化钙对4种病原菌有抑制作用,尤其对1123-3菌株有显著抑制作用。根腐消对试验菌株1123-3菌株、1223-8菌株和1108-3菌株抑制效果最好,EC50分别为0.384、0.583、0.394 mg·L^-1;多菌灵对1129-4抑制效果最好,EC50为0.002 mg·L^-1。

In order to screen the best bacteriostatic chemical agents for pathogen causing Magnolia wufengensis root rot,screening tests were conducted in laboratory.Six common chemical agents were selected including 80%mancozeb,50%carbendazim,calcium cyanamide,58%genfuxiao,and 50%thiram and hymexazol.Under laboratory conditions,the inhibition effect of the tested chemical agents on bacterial colony growth and spore production quantity was studied by using the bacteriostasis test and calculating EC50.The results showed that 80%mancozeb,50%carbendazim,58%genfuxiao,and 50%thiram and hymexazol had significant inhibitory effect on the pathogenic bacteria of root rot of M.wufengensis,while calcium cyanamide(1.667 g·L^-1)had inhibitory effect on the pathogenic bacteria,especially 1123-3(Fusarium solani).58%genfuxiao had the best inhibitory effect on 1123-3,1223-8(Fusarium spp.)and 1108-3(Fusarium spp.),with EC50 of 0.384,0.583 and 0.394 mg·L^-1,respectively.The 50%carbendazim had the best inhibitory effect on 1129-4(Fusarium solani),while EC50 was 0.002 mg·L^-1.