本研究采用生长速率法,在室内条件下测定了20%甲基立枯磷乳油、24%噻呋酰胺悬浮剂、2.5%咯菌腈悬浮种衣剂、25%吡唑醚菌酯乳油4种新型杀菌剂对立枯丝核菌（Rhizoctonia solani）的毒力。结果表明,4种杀菌剂对立枯丝核菌都有一定的抑制作用,其中,20%甲基立枯磷乳油对立枯丝核菌的抑制作用最强,EC50值为6.9888×10^-9 mg/L;24%噻呋酰胺悬浮剂抑制作用次之,EC50为6.6995×10^-7 mg/L;2.5%咯菌腈悬浮种衣剂和25%吡唑醚菌酯乳油的抑制作用稍差,EC50分别为7.6599×10^-5 mg/L、1.0060×10^-4 mg/L。田间防治黑痣病药效试验表明,4种药剂对马铃薯安全,其中20%甲基立枯磷乳油的防治最好,其次为24%噻呋酰胺悬浮剂,2.5%咯菌腈悬浮种衣剂、25%吡唑醚菌酯乳油防治效果较低,这与室内测定结果一致,因此生产上可用20%甲基立枯磷乳油20 mL拌种100 kg、24%噻呋酰胺悬浮剂每667 m2沟施100 mL来防治马铃薯黑痣病。%Toxicity bioassay of four novel fungicides,including 20% tolclofos-methyl EC,24% thifluzamide SC,2.5% fludioxonil SC and 25% pyraclostrobin EC on Rhizoctonia solani was tested by using the method of growth rate.The results showed that all of the four fungicides could inhibit Rhizoctonia solani,of which 20% tolclofos-methyl EC had the biggest inhibition with 6.9888 ×10^-9 mg / L EC50,and the EC50 of 24% thifluzamide SC,2.5% fludioxonil SC and 25% pyraclostrobin EC was 6.6995 ×10^-7 mg / L,7.6599 ×10^-5mg / L and 1.0060 ×10^-4 mg / L,respectively.The results of the field trial indicated that the four fungicides were safe to potato and 20% tolclofos-methyl EC and 24% thifluzamide SC had better efficiency,which was in correspondence with the result of bioassay.Two approaches were suggested to control potato black scurf-one was seed dressing by 20% tolclofos-methyl EC with the dose of 20 mL / 100 kg and the other was furrow applying 24% thifluzamide SC with the dose of 100 mL / 667m^2.
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