Effects of Formulated Glyphosate and Adjuvant Tank Mixes on Atomization from Aerial Application Flat Fan Nozzles
Abstract : This study was designed to determine if the present USDAARS spray-nozzle models, which were based on spray solutions of water plus non-ionic surfactant, could be used to estimate spray droplet-size data for different spray formulations through use of experimentally determined correction factors. Twelve spray-solution treatments were evaluated, ten of which contained a formulated glyphosate product and nine of these contained an additional tank-mix adjuvant. Droplet-size testing was conducted across multiple operational points (nozzle-orifice size, nozzle orientation spray pressure, and airspeed), in a high-speed wind tunnel, which corresponds to the response surface experimental model used to develop the present spray-nozzle models. The hypothesis that the different treatment solutions would respond linearly across a range of operational parameters and that a correction factor from relative to water plus non-ionic surfactant solution was proven false. When compared to water or the water plus non-ionic surfactant, the changes in atomization across the operation spectrum of the nozzle were not consistent and varied by formulation. Attempts to apply regression fits for a correction factor based on solution physical properties were not successful. With the formulated glyphosate tank mix used, none of the adjuvants tested, except the polymer, showed significant changes in droplet size under the high air shear regime. Whereas there is likely a need to develop formulated product-specific atomization models, the further addition of adjuvants do not significantly change the atomization characteristics and, as such, should not require a unique spray-nozzle model.
Measurement and Prediction of Atomization Parameters from Fixed-Wing Aircraft Spray Nozzles
A survey of spray nozzles used by the agricultural aviation industry identified nozzles and operating conditions that were most commonly used in applying agricultural chemicals in the U.S. Eleven hydraulic nozzles and their typical range of operating conditions were selected from the survey. These eleven nozzles were subjects of a research program to develop spray atomization models that would be easy for aerial applicators to use in adjusting operations to control spray drift from aerial agricultural sprays. Each nozzle was conducted through a series of trials in a spray nozzle test facility equipped with a laser spectrometer to develop a data set for atomization model development. Computer spreadsheet models were developed from the data set with operator selection of a specific spray nozzle and inputs of nozzle orifice size, spray discharge angle, spray pressure, and aircraft airspeed. The model outputs included droplet size parameters, drift potential parameters, and droplet spectra classification. Aircraft speed was the dominating factor influencing atomization from most of the spray nozzle models. Validation studies showed that the models gave useful estimates of the computed parameters for estimating compliance with product label and state regulatory agency requirements for spray drift mediation. The models are available on-line and in a user handbook as well as in the current technical presentation.
Experimental aerial application of Matacil flowable insecticide to control spruce budworm (Lepidoptera: Tortricidae)
Abstract Matacil® (aminocarb)_180F flowable insecticide mixed in both water and insectide diluent ID585 and Matacil 1 · 8D oil-soluble concentrate (OSC) mixed in ID585 were sprayed aerially at 70 g a.i./1 · 51 of spray mix/ha in two applications to control spruce budworm, Choristoneura fumiferana (Clem.). The spray droplet density on Kromekote cards, the spray volume recovered on glass slides, larval population reductions and host tree defoliation were compared. The data indicate that Matacil 180F was as effective in controlling budworm populations and protecting the foliage of host trees as Matacil 1 · 8D and that the aqueous mix was as efficacious as the ID585 mix.