Effects of 2,4-D Formulation and Quinclorac on Spray Droplet Size and Deposition¹

Abstract

Studies were conducted on the campuses of Texas A&M University in College Station, TX, and New Mexico State in Las Cruces, NM, to determine the spray droplet size spectra produced by quinclorac and 2,4-D as the liquid, dry, and emulsion formulations during application with various nozzle sizes using a laser spectrometer. Quinclorac and 2,4-D formulations were also sprayed through three different nozzle sizes in a drift chamber and allowed to settle on glass slides placed downwind. The amounts of each herbicide deposited on the slides were quantified using high-performance liquid chromatography/photodiode array (HPLC/PDA) analysis to assess spray deposition of each formulation at different wind velocities. Data from the laser spectrometer suggested that formulations of 2,4-D affected droplet size, particularly when the 380 ml/min flat-fan nozzle was used. Quinclorac droplet sizes were similar to water regardless of nozzle size. Liquid and dry-formulated 2,4-D tended to be deposited downwind in greater quantities than the emulsion formulation when using the 380 and 760 ml/min spray nozzles with wind velocity of 15 km/h.

Effects of Multiple Applications of Simulated Quinclorac Drift Rates on Tomato

“…Quinclorac is widely used because it is efficacious toward many problem weeds in rice (Stauber et al 1991;Street and Mueller 1993;Zwick et al 1987) and can be applied throughout the growing season (Eastin 1989). Tomato plants are extremely sensitive to quinclorac (De Barreda et al 1993;Grossmann 1998), and growers feel that extensive use of this herbicide, coupled with a large potential risk of drift from aerial application (Barrentine and Street 1993;Sciumbato et al 2005), has resulted in repeated damage to their tomato crops (Bansal et al 1999).…”

“…Residue recovery correlated well with the reported chemical use in the vicinity. Studies also indicate that dry herbicide formulations have a greater potential for drift than emulsions (Sciumbato et al 2005). Quinclorac is a dry-formulated herbicide, thus drift potential may be greater than the previously mentioned herbicides.…”

Study on Spray Evaluation: The Key Role of Droplet Collectors

“…In practical agricultural settings, a meticulous evaluation of spray quality is instrumental in enhancing both the spray techniques and the overall pesticide application technology. Key detection indicators that serve as metrics for this evaluation include droplet coverage [2], droplet density [3] and deposition [4]. The size sprayed during the application varies, influencing their distribution uniformity [5].…”