8种生物药剂对水稻稻曲病菌的室内毒力测定与田间药效试验

Laboratory Toxicity Tested and Field Control Effect of Eight Kinds of Biological Fungicides against Rice False Smut Ustilaginoidea virens

【目的】稻曲病是水稻重要的真菌病害之一,筛选出高效的防治生物药剂和最佳防治时间,为在生产上推广优化的防治模式提供依据。【方法】采用室内毒力测定和田间试验相结合的方法研究了8种生物药剂对稻曲病菌的毒力和药效,并以防效较好的2种生物药剂进行施药适期试验,比较不同时期施用生物药剂对控害效果的影响。【结果】室内毒力测定结果表明,蛇床子素、乙蒜素、紋曲宁、氨基寡糖素、多抗霉素、中生菌素、井冈霉素和宁南·嘧肽的EC50值分别为2. 00、2. 12、19. 15、30. 80、43. 28、51.60、372. 78和734. 16 mg/L,其中蛇床子素和乙蒜素对稻曲病菌的毒力最强。田间药效试验结果表明,2. 5%紋曲宁和15. 0%多抗霉素可湿性粉剂防效较好,病穗防效和病指防效都在80. 0%以上。不同时期施药结果发现,水稻破口前6～9 d内施药控制效果较好,至水稻黄熟期调查时,水稻病穗率和病情指数均较低。【结论】研究发现在水稻破口前6～9 d内喷施2. 5%紋曲宁或15.0%多抗霉素可湿性粉剂对水稻稻曲病有较好的防治。

【Objective】Rice false smut is one of the important fungal diseases for rice.【Method】The toxicity and efficacy of 8 biological fungicides were studied by the combination of the laboratory toxicity and field control.In order to screen the best application time for bio-fungicides,two kinds of bio-fungicides with good efficacy were for application in this experiment.【Result】The laboratory toxicity tests showed that the EC 50 values of Cnidium lactone,Ethylicin,Wenquning,Oligosaccharins,Polyoxin,Zhongshengmycin,Jinggangmycin and Ningnanmycin·Cytosintetidemycin were 2.00,2.12,19.15,30.80,43.28,51.60,372.78 and 734.16 mg/L,respectively.Among the tested 8 kinds of bio-fungicides,Cnidium lactone and Ethylicin had the strongest toxicity to Ustilaginoidea virens.The results of field trials revealed that 2.5%Wenquning and 15.0%Polyoxin WP had notable control effect,and the control efficiency was more than 80.0%.The results of the best application time showed that the control effect was better in 6 to 9 days before the rupturing stage of rice,and the disease spike rate and disease index were lower when investigated in the rice ripening stage.【Conclusion】It was found that 2.5%Wenquning and 15.0%Polyoxin WP had notable control effect in 6 to 9 days before the rupturing stage of rice.