10种杀菌剂对水稻稻叶褐条斑病菌的室内毒力

Toxicity evaluation of 10 fungicides against rice brown streak leaf spot[Nigrospora oryzae(Berk.et Br.)Petch]

为了解化学药剂对水稻稻叶褐条斑病病菌的抑制作用,采用菌丝生长速率法,测定了10种杀菌剂对稻黑孢霉菌[Nigrospora oryzae（Berk.et Br.）Petch]的敏感性。结果表明：各药剂对稻黑孢霉菌的毒力差异显著。10%苯醚甲环唑水分散粒剂、25%吡唑醚菌酯乳油、50%咯菌腈可湿性粉剂对稻黑孢霉菌毒力居前列,EC50分别为0.507 2、0.639 8、0.995 9mg/L,其次是50%咪鲜胺锰盐可湿性粉剂、30%苯甲·丙环唑乳油、12.5%氟环唑悬浮剂、25%氟环·醚菌酯悬浮剂,EC50在1.380 3-2.118 2mg/L,毒力较弱的是40%稻瘟灵可湿性粉剂和70%甲基硫菌灵可湿性粉剂,EC50分别为16.317 8、17.425 7mg/L,毒力最小的是75%百菌清可湿性粉剂,EC50达41.595 7mg/L。综合各供试药剂的斜率和EC50、EC90,稻黑孢霉菌对测定的苯醚甲环唑、咯菌腈、咪鲜胺锰盐以及苯甲·丙环唑等药剂最为敏感,这些药剂可作防治稻叶褐条斑病的候选药剂。

To understand the inhibitive effects of the chemical fungicides on the pathogen of rice brown streak leaf spot,toxicity evaluation of 10 fungicides on Nigrospora oryzae was conducted with mycelium growth rate method.The result showed that the toxicities of these agents were significantly different.Among them,the toxicities of10% difenoconazole WG,25%pyraclostrobin EC and50%fludioxonil WP were the highest,with the EC50 values of 0.507 2,0.639 8 and 0.995 9 mg/L,respectively.And next was the toxicity of 50% prochloraz manganese chloride complex WP,30%difenoconazole·propiconazole EC,12.5%epoxiconazole SC and25%epoxiconazole·kresoxim-methyl SC,with the EC50 values ranged from1.380 3 to 2.118 2 mg/L.40%Isoprothiolane WP and70%thiophanate-methyl WP had low toxicity,with the EC50 values of 16.317 8 and 17.425 7 mg/L,respectively.While 75%chlorothalonil WP had the lowest toxicity,with the EC50 values of 41.595 7 mg/L.The results indicated that N.oryzae is sensitive to the agents such as difenoconazole,fludioxonil,prochloraz-manganese chloride complex and difenoconazole·propiconazole,which could be the candidates for control of rice brown streak leaf spot.