关键词: 高效氯氟氰菊酯, 固体纳米分散体, 乳油, 微囊悬浮剂, 田间药效

Abstract: In order to clarify the physicochemical properties and field efficacy of lambda-cyhalothrin solid nanodispersions against Lepidoptera pests, commercial pesticide formulation semulsifiable concentrates and micro-capsule suspending agents were used as the control formulations, the morphology, dispersibility, contact angles and retention volumes were measured, the dispersion and interfacial properties were characterized and analyzed, and field efficacy test was also carried out to study its quick effect and persistent effect. The results showed that the mean particle size and polydispersion index (20.63 nm and 0.36) were all lower than those of emulsifiable concentrates (460.60 nm and 0.455) and micro-capsule suspensions (1 077.00 nm and 0.505), the rice contact angle was 9° (left) and 6° (right) smaller than emulsifiable concentrates. The contact angle of cabbage leaf was 46° (left) and 41° (right) smaller than micro-capsule suspending agents, and the retention amount of solid nano-dispersion on cabbage leaf was larger than that of micro-capsule suspending agent as 4.83 mg/cm2. Nanocrystallization reduced the particle size, improved dispersion characteristics, reduced contact angle and increased retention volume. The results of field efficacy showed that the solid nanodispersion of lambda-cyhalothrin had good rapid and persistent effects. When the dosage of solid nano-dispersion was 43.2% of the recommended dosage of emulsifiable concentrate (18.75 g a.i./hm2), the control effect of white head and protection effect upon seedling of the rice stem borer were 85.64% and 90.18%, respectively. The control effect was significantly better than that of emulsifiable concentrate, showing excellent quick effect. When the dosage of the solid nano-dispersion was equal to the recommended dosage (11.25 g a.i./hm2) of the commercial microcapsule suspension, the control effect to the cabbage caterpillar after applying pesticide 1 d, 3 d, 7 d and 14 d were 83.55%, 90.00%, 93.48% and 88.00%, respectively, which showed a good persistence. The results indicated that the solid nano-dispersion of lambda-cyhalothrin could effectively enhance the bioactivity of pesticide, because of its small size effect, surface effect, dispersive property, target spreading attachment and penetration force, quick effect and long persistence. It could also reduce the dosage and frequency of application. Therefore, it is a new type of safe and environment friendly pesticide formulation.

Key words: lambda-cyhalothrin, solid nanodispersion, emulsifiable concentrate, microcapsule suspending agent, field efficacy