ABSTRACT

Two experiments were conducted in which aerial applications of bifenthrin were made using a conventional spray boom and a boom fitted with Chimavir winglets. Two additional experiments were conducted to measure deposition of aerial applications of bifenthrin in cotton planted in 30" and 40" row spacings. The deposition of bifenthrin was determined by collecting leaves and main stem sections at three zones within the canopy. Deposition on the upper and lower leaf surfaces were determined at two canopy locations by washing leaves with a dual side leaf washer. All bifenthrin residues were quantified by gas chromatography. The boom with winglets deposited more bifenthrin on leaves in the upper canopy; whereas, the conventional boom deposited more bifenthrin on the upper canopy main stem. More bifenthrin was deposited on the upper leaf surface. However, there was no difference between booms in the amount of bifenthrin deposited on upper and lower leaf surfaces. Analysis of results of experiments comparing deposition in the 30" row and 40" row cotton canopies showed no significant interaction between row spacings, canopy levels, and plant tissue. Overall mean depositions of bifenthrin in the 40" row (112.2 ng/cm²) and 30" row (93.7 ng/cm²) were significantly different. There was no difference between row spacings in the amount of bifenthrin deposited on the upper and lower leaf surfaces.