助剂对植保无人机喷施纳米农药理化性质和防治棉田蚜虫效果的影响

Effects of adjuvants on physicochemical properties of nanopesticide applied by plant protection unmanned aerial vehicles and control of aphids in cotton field

【目的】用植保无人机在棉田喷施纳米农药防治棉花蚜虫,探讨助剂对药液理化性质、抗蒸发性能、雾滴沉积分布及对纳米农药防治效果(防效)的影响。【方法】于室内利用动态光散射仪、自动界面张力仪、BP100张力计、接触角仪、超景深拍照系统等测定了添加3种助剂(优若派、杰效丰、Aero-mate 320)后8%(质量分数,下同)烯啶虫胺·呋虫胺纳米农药推荐使用剂量(1200 g·hm-2)减量20%的溶液的理化性质及抗蒸发性能,并结合植保无人机田间喷雾试验研究了助剂对雾滴在棉花冠层的沉积分布及农药对棉蚜防效的影响。【结果】在减少20%用量的纳米农药药液中添加体积分数为0.1%的优若派、0.1%的杰效丰和0.6%的Aero-mate 320助剂可以改善药液理化性质。其中:溶液的静态表面张力由36.43 mN·m^(-1)下降至31.82~34.99 mN·m^(-1);340 s后接触角减小到12.25°~14.85°,降低了22.97%~36.46%;润湿面积增加18.34%~33.57%;药液的蒸发抑制率达27.72%~73.40%;田间喷雾试验结果显示,棉花上部和下部冠层的雾滴直径中值由122.4μm和106.7μm分别增大至154.3μm和148.5μm;施药后7 d,纳米农药减量20%处理的防效为47.6%,而添加3种助剂的处理对蚜虫的防效分别提高至63.2%、65.0%和73.3%,与植保无人机喷施纳米农药常规用量防效(71.8%)和人工背负式喷雾器喷施相同成分常规农药的防效(74.9%)相当。【结论】在纳米农药减量20%用量的情况下,添加3种助剂有助于改善药液理化性质,增加润湿面积,减少雾滴蒸发和飘移,提高药剂对棉蚜的防效。

[Objective]The effects of adjuvants on the physicochemical properties,evaporation resistance,deposition and distribution of droplet,and control effect of nanopesticide against cotton aphid were studied through spray tests carried out by plant protection unmanned aerial vehicle(UAV)in cotton field.[Method]The dynamic light scatterometer,automatic interfacial tensiometer,BP100 tensiometer,contact angle meter and super depth of field photography system were used to evaluate influences of adding adjuvants(0.1%volume fraction of Youruopai,0.1%volume fraction of Jiexiaofeng,0.6%volume fraction of Aero-Mate 320)on the physicochemical properties and anti-evaporation of solutions with 20%reduced nanopesticide 8%(mass fraction,the same as below)dinieramine dinotefuran compared to the recommended dosage of 1200 g·hm-2,in the laboratory.The effect of droplets with adjuvant on the deposition and distribution in the canopy of cotton and its effect on the cotton aphid were explored.[Result]The physicochemical properties of the solutions were improved by adding Youruopai,Jiexiaofeng and Aero-Mate 320 adjuvants into the nanopesticide solutions with 20%reduced dosage.The static surface tension of solutions decreased from 36.43 mN·m^(-1) to 31.82-34.99 mN·m^(-1).The contact angles decreased to 12.25°-14.85°,which were decreased by about 22.97%-36.46%.The wetting areas increased by 18.34%-33.57%and the inhibition rates of spray evaporation reached 27.72%-73.40%.The results of field test showed that,the median diameters of the droplets in the upper and lower canopy of cotton were significantly increased from 122.4μm and 106.7μm to 154.3μm and 148.5μm,respectively.After 7 days of application,the control efficacy of treatment with 20%reduction of nanopesticide against aphids was 47.6%.However,the efficacies increased to 63.2%,65.0%and 73.3%,respectively,after three adjuvants were added in the above treatments.The efficiencies were comparable to that of conventional dosage sprayed by UAV(71.8%)and traditional pesticide sprayed by artificial knapsack sprayer(74.9%).[Conclusion]The results indicated that adding adjuvant could improve physicochemical properties,enhance wetting area,reduce evaporation and drift of droplets,and increase the efficiency of nanopesticide against A.gossypii.