The laboratory toxicities of copper acetate,hymexazol,propamocarb and mancozeb against Pythiumaphanidermatum were tested by using mycelial growth rate method,and the EC50 values of these fungicides were 30.292 3,5.891 7,34.331 9μg/mL and 65.982 6μg/mL, respectively.The results showed that hymexazol had stronger toxicity to the Pythiumap hanidermatum.Field trials of the four fungicides against seedling damping-off of cueumber were also conducted.At the highest recommended use concentration of each fungicide,their control effects were 83.65%,80.14%,80.91% and 42.48% in turn,respectively.Based on the results of toxicity tests and field trials,copper acetate 35% WP,hymexazol 30% AS and propamocarb 72.2% AS could be recommende for controlling seedling damping-off of cueumber.%采用菌丝生长速率法测定了乙酸铜、噁霉灵、霜霉威、代森锰锌4种杀菌剂对瓜果腐霉病菌(Pythiumaphanidermatum)的毒力,各药剂的EC50值依次为:30.292 3、5.891 7、34.331 9、65.982 6μg/mL。可见噁霉灵30%水剂对瓜果腐霉病菌表现出较强的毒力。对4种杀菌剂还进行了田间黄瓜猝倒病的防治试验,其防效依次为83.65%、80.14%、80.91%、42.48%。根据室内毒力测定和田间药效试验结果,乙酸铜20%可湿性粉剂、噁霉灵30%水剂、霜霉威盐酸盐722克/升水剂对黄瓜猝倒病均具有较高的防效。
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