Development of prothioconazole + tebuconazole 240 g/kg SC and its control effect on rice sheath blight and wheat sharp eyespot in the field

Prothiconazole, a new kind of broad spectrum triazolthione fungicide, was used to develop the suspension concentrate (SC) compounding with tebuconazole. The results of combined virulence determination, adjuvant system screening and physical and chemical properties detection showed that the ratio of prothioconazole to tebuconazole 2 : 1 had high combined virulence against Rhizoctonia solani and Rhizoctonia cerealis, the pathogen of rice sheath blight and wheat sharp eyespot, with the co-toxicity coefficients of 1.91 and 1.92, respectively. The reasonable formula of prothioconazole + tebuconazole 240 g/kg SC was prothioconazole 16.0%, tebuconazole 8.0%, Featdis SCP 4.0%, EFW 3.0%, xanthangum 0.2%, aluminum-magnesium silicate 1.0%, elycol 4.0%, and water up to 100%. After the product was stored at (54 ± 2) ℃ for 14 d, its characters were as follows: suspension rate 95.2%, pH value 6.9, average particle size 0.71 µm, water extraction rate 2.3%, and long-lasting forming ability less than 25 mL. After being stored at (0 ± 2) ℃ for 7 d, its characters were as follows: suspension rate 94.8%, pH value 7.1, average particle size 0.87 µm, long-lasting forming ability less than 25 mL, and viscosity between 200 mPa·s and 600 mPa·s. The field tests indicated that prothioconazole + tebuconazole 240 g/kg SC had good control effect on rice sheath blight and wheat sharp eyespot, and the control effect reached 89.01% and 86.26% at 210 g a.i/hm² and 150 g a.i/hm², respectively.