The Effect Of Pesticide Liquid Volume And Aircraft Control Additives On Low-altitude Low(Ultra-low) Volume Spray Application

In recent years,crop diseases and insect pests control has been widely applied due to its strong timeliness,short window period,high labor intensity,high efficiency of plant protection unmanned aerial vehicle application,low labor intensity and high safety of operators.However,due to the influence of factors such as small pesticide liquid volume applied by unmanned aerial vehicle,uneven droplet,easy evaporation,etc.,there are generally problems such as low effective deposition rate of pesticide droplet,insufficient coverage of target droplet,unstable prevention effect,etc.In this paper,indoor simulation and field experiments were used to systematically investigate the effects of fly-away additives on the surface tension,wetting property,water evaporation inhibition effect,droplet atomization particle size and uniformity of common commercial pesticide solutions.On this basis,the effects of pesticide liquid volume and aircraft control additives on low-altitude low(ultra-low)volume spray application effect were studied.The main research results are as follows:1 Effect of the pesticide liquid volume on droplet coverage density and control efficiency of low altitude and low(ultra-low)volume sprayExperiments on controlling main diseases and insect pests of wheat,corn and rice with different pesticide liquid volume were carried out indoors and in the field respectively.The results showed that there was a positive correlation between fog drop density and control effect and the pesticide liquid volume used per mu.Under indoor simulation conditions,the droplet density of 1400 ML/667m2 pesticide liquid volume reached above 74/cm2,and the control effects on wheat powdery mildew and corn leaf spot were 69.54%and 55.53%respectively,which were significantly higher than those of other low pesticide liquid volume treatments.The droplet density increased as the pesticide liquid volume continued to increase,but the control effects did not increase or did not increase significantly.The experimental results of controlling wheat scab by polar flying P20 and P30 unmanned aerial vehicles show that the droplet density and control effect are significantly higher when the pesticide liquid volume is 1200 mL/667m2 than other low pesticide liquid volume treatments.When DJI MG-1S uav was applied,the droplet density was 51/cm2 when the pesticide liquid volume was 1200 mL/667m2,and the control effect on Chilo suppressalis was 74.38%.when the pesticide liquid volume was continuously increased to 1500 mL/667m2 the droplet density and control effect did not increase significantly.2 Effect of aircraft control additives on droplet coverage density and control efficiency of low altitude and low(ultra-low)volume sprayThe control tests of self-developed additives(independently developed by the project team)or Maifei additives(Beijing Guangyuan Yinong Chemical Co.,Ltd.)on major diseases and insect pests of wheat,corn and rice were carried out indoors and in the field respectively.The results show that the fog drop coverage density and control effect after adding the aircraft control additives are significantly better than those of the treatment group without adding the aircraft control additives.Under the indoor simulation conditions,after adding self-research additive and Maifei additive,the droplet density of controlling wheat powdery mildew was 133/cm2 and 139/cm2 respectively,and the control effect is 90.85%and 90.07%respectively.The droplet density of controlling corn leaf spot was 96/cm2 and 101/cm2,respectively,and the control effect was 63.17%and 67.00%,respectively,which were significantly higher than that of the treatment group without additives.Field experiments on controlling wheat scab with polar fly P20 and P30 models showed that self-research additive could increase the adhesion of fog droplets on the target,the density of fog droplets increased by more than 44/cm2 compared with the control group without additive,and the control effect was significantly higher than that of the control group without additive.When DJI MG-1S uav was applied,the droplet density was 58/cm2 and 63/cm2 respectively after adding self-research additive and Maifei additive.The control effect on Chilo suppressalis was 81.70%and 88.67%respectively,which were significantly higher than that of the treatment group without additive.3 Effects of aircraft control additives on surface tension,wettability,water evaporation inhibition,atomization and stability of commercial pesticide solutionsThe aircraft control additive can change the surface tension of the liquid medicine,improve the wetting performance of the liquid medicine,reduce the evaporation rate and improve the atomization performance of the liquid medicine.With the addition of self-research or Maifei additives,the wetting and permeation time of 14 commercial pesticides tested was greatly shortened and the wetting performance was improved.VAD(volume weighted average particle size)of 14 commercial pesticides showed a decreasing trend.The vast majority of commercial pesticides tested RS(sample dispersion coefficient)decreased,surface tension decreased,water evaporation inhibition rate increased significantly,liquid medicine was stable,and no oil slick and precipitation occurred within 1 hour.