Drift of Glyphosate Sprays Applied with Aerial and Ground Equipment

Abstract

The potential losses from spray applications of glyphosate [N-(phosphonomethyl)glycine] with and without the inclusion of a polymer thickening agent were evaluated in field tests, applied under identified weather conditions with a boom-nozzle ground sprayer, helicopter, and fixed-wing aircraft. The downwind transport and diffusion of the spray loss was assessed by means of Mylar fallout sheets, high volume air samplers, and 4-leaf wheat(Triticum aestivumL. ‘Anza’) plants. Lowest drift losses occurred, under 0.01 g/ha on fallout sheets at 100 m, with deflector fan nozzles (KGF) operating at a low pressure (7 kPa) on the ground sprayer. Drift losses from a helicopter equipped with micro-jet nozzles were only slightly higher, less than 0.03 g/ha on fallout sheets at 100 m. Drift losses from 8003 nozzles mounted on a ground sprayer and D-6 jet nozzles directed back on fixed wing aircraft produced much higher drift deposits, from 0.2 to 1.0 g/ha on fallout sheets at 100 m. The highest levels of drift losses were obtained with D-4 jet nozzles directed down on a helicopter, 5 g/ha on fallout sheets at 100 m. Some evidence of reduced airborne drift was apparent where the polymer thickening agent was used with aircraft and ground equipment. The test results indicate that significant reduction in drift losses were obtained with proper application equipment; however, the use of a polymer thickening agent reduced drift only slightly for certain applications.

Efeitos da deriva de clomazone, aplicado isoladamente ou em mistura com ametryn, sobre características produtivas de laranjeira 'Hamlin'

“…Depreende-se, assim, que o herbicida deve atingir de modo eficaz a planta daninha a ser controlada, uma vez que a ocorrência de deriva, além de reduzir a eficiência da aplicação (Gelmini, 1988), coloca em risco culturas vizinhas suscetíveis. Gotas pequenas podem ser transportadas em condições variáveis de vento e luminosidade, particularmente em condições de inversão térmica, atingindo assim áreas agrícolas adjacentes, sendo possível verificar sintomas de injúrias causados por deriva de herbicidas a quilôme-tros de distância do local de aplicação (Yates et al, 1978).…”

Effects of Herbicide Glyphosate and Glyphosate-Based Formulations on Aquatic Ecosystems

“…Other studies suggested that drift rates would be greater. For instance, residues have been measured 400 m downwind from applications sites (Yates et al, 1978;Payne & Thompson, 1992). Considering offsite movement of glyphosate from treated soils through drift and run-off, Giesy et al (2000) estimated an acute scenario considering worst-case exposure conditions.…”

Pesticide drift deposition in hedgerows from multiple spray swaths

“…The main conclusion from these measurements was that most of the pesticide is deposited within the nearest 5 m. 1,[7][8][9] The few studies that have compared cumulative deposition from one and ten runs show that integration of contributions from ten swaths increases spray drift with a factor of 3-10 for horizontal deposition measures. [10][11][12] The accumulated deposition at a specific position downwind was calculated from the measured deposition from a single swath at varying distances from the sprayer. A previous study that measured pesticide deposition in hedgerows found that between 2 and 20% of the dosage applied in the swath closest to the hedgerow drifted into the hedgerow.…”