Effects of Adjuvants on Spraying Characteristics and Control Efficacy in Unmanned Aerial Application

Abstract

Pesticide application by unmanned agricultural aerial vehicles (UAVs) has rapidly developed in China and other Asian counties. Currently, tank-mix spray adjuvants are usually added into pesticide solutions to reduce spray drift and facilitate droplet deposition and control efficacy. The currently used tank-mix adjuvants are all derived from conventional ground sprays, and their mechanisms of action in aerial applications are still unclear. In order to clarify the spraying characteristics and control efficacy of those adjuvants in aerial sprays, the performances of various types of tank-mix adjuvants were compared by analyzing droplet spectrum, drift potential index (DIX) in a wind tunnel, field deposition and control efficacy on wheat rust and aphids. The atomization results showed that the addition of adjuvants could change the droplet spectrum of liquid, and the results suggest that droplet size is an effective indicator of spray drift potential. In the field application, the meteorological conditions are complex and uncontrollable, and the effects of adjuvants on droplet deposition and distribution were not significant. Compared with the control solution, there was no significant difference in the deposition amount of each adjuvant solution, and the CVs of deposition were higher than 30%. Adding adjuvants to the spray solution can significantly improve the control efficacy of pesticides on wheat aphids and rust and also prolong the duration of the pesticide. Our results suggest that tank-mix adjuvants should be added when UAVs are used for aerial application. This study can be used as a reference to the research and development or selection of adjuvants in aerial sprays of UAVs.

Effect of aerial application of adjuvants on pepper defoliant droplet deposition and efficacy of defoliation sprayed by unmanned aerial vehicles

“…The results of this study were similar to previous studies. In addition, adding adjuvants during pesticide spraying can change the physicochemical properties, promote the absorption of target plants or insects, and the retention of the liquid (Wang et al, 2022 ), thereby improving the utilization rate of pesticides.…”

Diatomaceous earth foliar spraying along with adjuvants in pistachio orchards associated with the common pistachio psylla, <i>Agonoscena pistaciae</i>

“…Wang et al showed that some adjuvants like organosilicon and polymeric components can increase the effect of pesticides foliar spraying. 23) Diatomaceous earth causes insects to dry out and die by absorbing the oils and fats from the cuticle of their exoskeleton. Diatomaceous earth has sharp edges that are abrasive, speeding up the process.…”

Bio-Inspired Robots and Structures toward Fostering the Modernization of Agriculture

“…It is not suitable for small farms and cannot be applied on farms with a mountainous terrain [ 125 ]. Moreover, large UAVs in pesticide application exhibit adjuvant-specific drift rates of 30–74% [ 126 ]. The higher the drift, the lower the precision and the higher the volume of pesticide wasted.…”

“…In the absence of conclusive data comparable to robot bees, the use of swarm robotic systems in pesticide application would remain limited. The view was further reinforced by the fact that mobility and adaptability are impacted by unexpected changes in atmospheric conditions and obstacles, common in farms situated in the mountainous regions of South Korea, Japan, and China [ 126 ]. Swarm robotics might exhibit an undesirable phase transition between two macroscopic states [ 132 ].…”