Phase Doppler quantification of agricultural spray compared with traditional sampling materials

Abstract

The quantification of spray mass has historically been accomplished by means of fluorescent dyes and various string and ground samplers to capture the dye-laden spray. However, these methods are typically not used in close proximity to orchard sprayers and are prone to many sources of error. The objective of this study was to assess the ability of an in-field phase Doppler (pD) interferometer to quantify spray mass against two common string samplers. Measurements were taken at 0.5 m increments to 4.5 m vertically and 1.0 m increments to 5.0 m downwind from the spray. Converted flux measurements from the strings were compared with those obtained using the pD interferometer. The current pD technology was found to be incapable of collecting equivalent flux data to that obtained from the strings. However, the pD equipment did provide useful data on droplet velocity and size.

Methods for quantifying rain-splash dispersal of Neonectria ditissima conidia in apple canopies

“…PTSA (1,3,6,8-pyrenetetrasulfonic acid) is a water soluble, nontoxic, fluorescing dye used for tracing spray application (Fritz et al, 2011;Hoffmann et al, 2014;Roten et al, 2017). It is highly soluble, easily recoverable, stable in solution and not easily degraded in sunlight (Hoffmann et al, 2014).…”

“…These were sealed with foil (inhibiting light exposure) and refrigerated (4°C) until measurements were taken using a CLARIOstar plate reader (BMG Labtech, Ortenburg, Germany). An excitation wavelength of 375 nm and an emission wavelength of 405 nm was used (Hoffmann et al, 2014;Roten et al, 2017), and concentrations were calculated from the fluorescence using a 4-parameter fit and blank-corrected data (Armbruster and Pry, 2008). Blank controls for samples from rainwater traps were 170 mL of distilled water, and blank controls for lens tissue were 10% isopropyl alcohol (Armbruster and Pry, 2008).…”