戊唑醇对立枯丝核菌的抑制作用及在水稻上的应用

戊唑醇是一种高效、广谱、内吸性强的三唑类杀菌剂。研究表明,在离体条件下其对立枯丝核菌Rhizoctonia solani Kuhn菌丝生长具有很强的抑制作用,EC50值为0.509 μg/mL。无论在天然培养基(LBA)还是在半组合培养基(AEA)上,戊唑醇均会抑制菌核的产生,且菌核的产量随着药剂浓度的增加而降低;虽然其对菌核的萌发无影响,但对菌核萌发后菌丝的生长有强烈的抑制作用。温室试验结果表明,立枯丝核菌菌碟经戊唑醇处理后,其对分蘖期水稻植株的致病力随着药剂浓度的提高而下降;戊唑醇可很好地被水稻叶片和根系吸收,并输送到水稻的茎部;对水稻纹枯病具有保护和治疗作用,EC50值分别为58.03和62.53 μg/mL;对立枯丝核具有较长的持效期,800 μg/mL处理水稻7 d后再接种的防效为41.46%。田间药效试验表明,43%的戊唑醇悬浮剂在有效剂量116.10 g/hm2下两次喷药后15 d的防效达71.97%。该药剂在本试验剂量范围内对水稻安全。

Fungicidal Activity of Tebuconazole against Rhizoctonia solani and its Application to Rice

Tebuconazole is one of triazole fungicides with high efficacy,broad-spectrum and good systemic activity.Studies on the fungistasis of tebuconazole to Rhizoctonia solani Kühn causing rice sheath blight showed that tebuconazole strongly inhibited mycelium growth,with EC50 value 0.509 μg/mL.On both LBA and AEA media,the fungicide could inhibit the production of sclerotia,and the mass of sclerotia reduced as the compound concentration increased.It has no effect on sclerotium germination,but could strongly inhibit the mycelial growth.The pathogenicity of R.solani which was treated by tebuconazole on tillering rice plants decreased obviously as the concentration of the fungicide increased.Tebuconazole could be easily absorbed by the leaves and roots of rice,and translocated into the stem.Both protective and curative effects of tebuconazle against rice sheath blight caused by R.solani,with EC50 value 58.03 and 62.53 μg/mL,respectively.The fungicide has long persistence effect against R.solani on rice plants inoculated with the fungus 7 days after treatment at 800 μg/mL,and the efficacy was 41.16%.In the field trial test,tebuconazole was sprayed at a.i. 116.10 g /hm2 twice at the interval of 7 days,and showed 71.97% controlling effect against sheath blight after 15days. Tebuconazole was safe to the rice plants at the tested dosage.