Abstract:

Based on determining the surface tension of organosilicone solution and its expansion on the solid surface, the bioactivity of 5% WDG emamectin benzoate with organosilicone on Spodoptera exigua using the spraying methods was investigated to study synergistic activity of organosilicone to emamectin benzoate. The results showed that the organosilicone significantly reduced the surface tension of aqueous solution. Its surface tension was reduced to 26 mN/m, while the organosilicone concentration was 0.01%. The organosilicone significantly raised the expansion of liquid drop on the solid surface. The expanding diameter of 0.01% organosilicone at 10 μL was 34 mm. The laboratory bioassay results indicated that there were significant synergistic activity of organosilicone to emamectin benzoate on S. exigua while the additional amount of organosilicone were 1%-5%, and slow increasing rate of synergistic activity while the additional amount of organosilicone was higher than 5%. The results in a field experiment showed that the efficacy of 5% WDG emamectin benzoate with 5% organosilicone at 33 mg/L on S. exigua were 81.57% and 82.66% on the third day and on the seventh day after spraying insecticide, respectively, and significantly higher than these of 5% WDG emamectin benzoate at 33 mg/L, 24% SC metaflumizone at 96 mg/L, 5% SC chlorantraniliprole at 33 mg/L, 20% WDG flubendiamide at 40 mg/L and 15% EC indoxacarb at 43 mg/L.