Drop Size Spectra and Deposit from Aerial Spraying With and Without a Polymeric Adjuvant

In a study reported in the literature, an aqueous solution of a polymer, Sta-Put®, was shown to increase the drop sizes of the spray cloud when atomized using hydraulic nozzles in an airstream (speed, 192 km/h) under laboratory conditions. The objective of the present study was to examine if Sta-Put can influence the drop size spectra of the spray cloud under field conditions when applied through rotary atomizers using a fixed-wing aircraft flying at a speed of 160 km/h. Tank mixes were sprayed aerially with and without Sta-Put. Size spectra of drops were measured at the target site on Kromekote® cards. Deposits were assessed on balsam fir-shaped aluminum branch tips, natural fir needles, and glass plates.