Abstract
BACKGROUND
Quantification of spray deposition on target crop is of vital importance to optimize the application techniques of pesticide. For traditional determination of spray deposition, a large amount of organic solvent is inevitably used to extract pesticides from the target crops. In the present work, water?soluble food dye of Allura Red was developed as a tracer to determine the spray deposition of pesticide on target crop of rice.
RESULTS
The addition of Allura Red does not obviously alter physicochemical properties of pesticide formulations (viscosity, density, and surface tension) and droplet spectra. Ultra performance liquid chromatography (UPLC) analytical method was developed and validated to determine the deposition amount of Allura Red on rice plant. Method accuracy and precision for Allura Red were found to be satisfactory with the recoveries ranging from 96.07% to 107.48%. For validation of the method, comparative deposition analyses were carried out with representative systematic and non?systematic pesticides (nitenpyram and chlorothalonil) under the same spraying scenarios using Potter spray tower. Allura Red and pesticides had comparable deposition under the same application conditions with the ratios from 0.98 to 1.21. Field trial performed by unmanned aerial vehicle (UAV) sprayer further indicated that the deposition rate for Allura Red and nitenpyram on the rice seedling were 13.04% and 11.07% with the corresponding %RSD (n = 5) of 16.39% and 18.79%, respectively.
CONCLUSION
Laboratory test and the field trial confirmed that the developed method of Allura Red as a tracer for spray deposition assessment is feasible and practicable.
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