10种常用杀菌剂对水稻纹枯病菌的敏感性及其协同作用

Sensitivity of 10 common fungicides to Rhizoctonia solani and their synergistic effects

  • 摘要: 【目的】筛选出对水稻纹枯病菌具有较好协同作用的药剂组合,为田间防治水稻纹枯病和开发增效组合制剂提供理论依据。【方法】以水稻纹枯病菌为材料,采用菌丝生长速率法测定10种常用杀菌剂原药(包括嘧菌酯、啶氧菌酯和吡唑醚菌酯等8种甲氧基丙烯酸酯类杀菌剂,丙环唑和苯醚甲环唑2种三唑类杀菌剂)对水稻纹枯病菌的毒力,及丙环唑·肟菌酯组合对水稻纹枯病菌的协同作用;采用电导率法、可溶性蛋白试剂盒、超氧化物歧化酶(SOD)试剂盒和过氧化物酶(POD)试剂盒等评价杀菌剂组合对水稻纹枯病菌生理生化特性的影响。2019年8月进行田间试验,评价250 g/L丙环唑EC、50%肟菌酯WDG及组合(250 g/L丙环唑EC与50%肟菌酯WDG有效质量比1:5)对水稻纹枯病的田间防治效果。【结果】10种杀菌剂原药对水稻纹枯病菌均有较高的毒力,EC50为0.20~1.61 μg/mL,除唑菌酯和醚菌酯对纹枯病菌的毒力相对较弱外,其余8种杀菌剂对纹枯病菌菌丝生长均具有较好的抑制作用,EC50均小于1.00 μg/mL,以吡唑醚菌酯的毒力作用最强,EC50为0.20 μg/mL。丙环唑原药与肟菌酯原药按有效质量比1:10、1:5和5:1组合时对水稻纹枯病菌均具有较好的协同作用,其中以1:5组合时协同作用较明显,EC50为0.24 μg/mL,共毒系数(CTC)为393.41;用该组合处理水稻纹枯病菌后,能提高病菌细胞膜的通透性,明显抑制蛋白的合成,降低SOD和POD活性。田间喷施250 g/L丙环唑EC与50%肟菌酯WDG组合后21 d,对水稻纹枯病的田间防治效果达94.08%,高于单剂250 g/L丙环唑EC(88.79%)和50%肟菌酯WDG(92.72%)处理。【结论】丙环唑·肟菌酯对水稻纹枯病菌具有较好的协同作用,对水稻纹枯病具有较好的防治效果,且可极大减少药剂使用量,具有开发成水稻纹枯病增效组合制剂的潜力。

     

    Abstract: 【Objective】Screening the fungicide combinations that had a strong synergistic action on Rhizoctonia Solani and providing a new theoretical basis for filed control of synergistic action and developing synergism combinations against R.solani.【Method】R.solani was the material.The mycelial growth rate method was used to determine the virulence of ten fungisides(eight methoxyacrylate fungicides such as azoxystrobin, picoxystrobin and pyraclostrobin, and two kinds of triazole fungicides including propiconazole and difenoconazole) to R.solani.The synergistic effect of propiconazole·trifloxystrobin combination to R.solani was determined by mycelium growth rate method.The effects of the combination on the physiology and biochemistry of R.solani were evaluated by conductivity method, soluble protein kit, superoxide dismutase(SOD) kit and peroxidase(POD) kit.And the field experiment was conducted in August, 2019 to evaluate the field control effects of 250 g/L propiconazole EC, 50% trifloxystrobin WDG and combinations(effective mass ratio of 250 g/L propiconazole EC to 50% trifloxystrobin WDG was 1:5) on rice sheath blight disease.【Result】The results showed that the ten fungicides had high sensitivity to R.solani.The EC50 range was 0.20-1.61 μg/mL.Among them, the virulence of pyraoxystrobin and kresoxim-methyl was relatively weak.And the other eight fungicides had better inhibitory activity on the mycelial growth of R.solani, their EC50 were all less than 1.00 μg/mL.The virulence of pyraclostrobin was the strongest with EC50 of 0.20 μg/mL.Propiconazole and trifloxystrobin had better synergistic effects on R.solani when the effective mass ratios were 1:5, 1:10 and 5:1.Among them, the synergism was the most obvious when the effective mass ratio was 1:5.Its EC50 value was 0.24 μg/mL and cotoxicity coefficient(CTC) value was 393.41.Furthermore, the combination could increase the permeability of cell membrane, inhibit the synthesis of protein and decrease the activity of superoxide dismutase(SOD) and peroxidase(POD) after the treatment.After 21 d of field spraying the synergistic combination of 250 g/L propiconazole EC and 50% trifloxystrobin WDG, the control effect of rice sheath blight was 94.08%, which was higher than that of single application of propiconazole EC(88.79%) and 50% trifloxystrobin WDG(92.72%).【Conclusion】The results show that the combination of propiconazole·trifloxystrobin has a better synergistic effect on R.solani.It has good control effect on rice sheath blight, and can greatly reduce the dosage of fungiside, and has the potential to be developed into a combination preparation for rice sheath blight.

     

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