Effect of aerial spray adjuvant applying on the efficiency of small unmanned aerial vehicle for wheat aphids control

Small unmanned aerial vehicles(UAVs)have been widely used in different aspects of modern farming management,including pest and disease control in China in recent years.In this study,the spray performance of a small plant protection UAV at low volume spray was evaluated by adjusting the pesticide dosage and adding aerial spraying adjuvants.Droplet deposition,droplet density,coverage,control effect and pesticide residue from field trials were assessed.In addition,the residue and control effect of UAV spray were compared to manual knapsack at high volume spray.The results showed that,the adjuvant applying improved the efficiency of UAV spray.Also,the adjuvant applying reduced the dosage of imidacloprid by 20%.However,there was no significant difference on initial residue between UAV spray and knapsack spray.Thus,plant protection UAV spraying pesticide by adding appropriate adjuvant showed the ability of improving the pesticide effectiveness by improving the control efficiency,reducing the pesticide dosage and residue.

Drift potential of UAV with adjuvants in aerial applications

The reduction of pesticide aerial spraying drift is still one of the major challenges in modern agriculture.The aim of this study was to evaluate the drift potential of different types of unmanned aerial vehicle(UAV)and adjuvant products for reducing spray drift in aerial applications.Three types of UAV(3WQF120-12 and 3CD-15 fuel oil powered single-rotor UAV and HY-B-15L battery powered single-rotor UAV)were selected in this study with regular application parameters to compare each spray drift,and 3WQF120-12 fuel oil powered UAV was selected to quantify spray drift of 6 adjuvants dissolved in water under field conditions.Solutions were marked with brillant sulfoflavin dye(BSF)at 0.1%.Petri dishes and rotary impactors were used to collect airborne and sediment drift,respectively.Drift deposits were evaluated by spectrophotometry in order to quantify deposits.The results showed that when the flight height was 1.5-2.0 m above the crop at the flight speed of 4-5 m/s and the average wind speed of 1.63-1.73 m/s,3WQF120-12 fuel oil powered UAV had lower drift potential than the other two types;DV0.5 and percentage of droplets with diameter≤75μm had very significant effects on spray drift percentage(p=0.01);the risk of drift in agricultural spraying could be significantly decreased not only by reducing the percentage of fine droplets but also by changing droplet spectra.Compared to water,Silwet DRS-60,ASFA+B,T1602,Break-thru Vibrant,QF-LY and Tmax could reduce by 65%,62%,59%,46%,42%,and 19%spray drift,respectively.when water without adjuvants were sprayed,90%of drift droplets were located within a range of 10.1 m of the target area while with 0.8%Silwet DRS-60 adjuvant in water,the distance was shortened to 6.4 m.