Enhanced dosage delivery of pesticide under unmanned aerial vehicle condition for peanut plant protection: tank-mix adjuvants and formulation improvement.

Abstract

Suspension concentrate (SC) is one of the most widely used formulations for agricultural plant protection. With the rapid development of unmanned aerial vehicle (UAV) plant protection, the problems of spray drift, droplet rebound and poor wettability in the application of SC from UAVs have attracted wide attention. Although some tank-mix adjuvants have been used to enhance dosage delivery for UAV, their effects and mechanisms are not fully clear, and few formulations are specifically designed for UAV. The type and concentration of tank-mix adjuvant affect the dosage delivery of SC. MO501 can significantly reduce DV<100μm , and inhibit droplet rebound on peanut leaves at concentrations ≥0.5%. Silwet 408 can achieve complete wetting and superspreading after adding ≥0.2% concentrations, but only ≥0.5% can inhibit rebound. XL-70 shows excellent regulation ability even at low concentration, and 0.2% concentration can simultaneously suppress impact and promote spreading. Besides, the formulation oil dispersion (OD) can significantly reduce the driftable fine fraction and inhibit rebound at dilution ratios of ≤250-fold, thus enhancing dosage delivery. SC is prone to rebound on hydrophobic leaf surfaces and shows poor wetting and spreading properties. Appropriate types and concentrations of tank-mix adjuvants and formulation improvement are two effective strategies for improving the dosage delivery of pesticides, whereas the addition of inappropriate adjuvants may cause potential risks instead. These findings provide guidance for the rational selection of tank-mix adjuvants and potential applications of OD for UAV plant protection. © 2023 Society of Chemical Industry.