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.