ABSTRACT
The displacement and deposition pattern of aerially applied Pounce® Insecticide (permethrin) as conventional water and ultra low volume, non-volatile oil formulations have been compared in absolute and relative terms. Results are based on four trials conducted in California and four in Mississippi. Each trial consisted of ten (10) applications with each carrier, at the standard Pounce use rate (0.10 lb ai/A), made over a single spray line. This multiple application procedure was used to increase quantitative accuracy at sampling points up to one-half mile downwind of the spray line. Whole cotton plants, static collectors (mylar sheets) and high volume air sampling devices were used to measure deposited and airborne quantities of permethrin applied in oil and water base spray. Results indicate that there was no significant difference (P=70.05) in overall amounts of airborne permethrin collected by air samplers up to 2640 feet downwind of the spray line. Numerically, there was more airborne material collected initially (165 - 57/ feet) from oil sprays than water. However, from 577 - 2640 feet, there was more airborne material collected from water sprays than oil sprays. Analysis of whole plant and mylar sheets indicate there was no significant difference (P=0.05) in absolute deposition of permethrin applied in oil or water sprays. A consistent qualitative difference in deposition pattern was obtained in that the oil formulation was always displaced slightly but not significantly (P=0.05) farther downwind than was the water formulation, regardless of the absolute quantities of each recovered. Examination of these data in terms of current commercial practices, single passes over different spray lines, indicates that oil sprays would yield a more uniform deposit on the crop than would water based sprays.
|