Abstract:-The objective of this work was to generate drift curves from pesticide applications on coffee plants and to compare them with two European drift-prediction models. The used methodology is based on the ISO 22866 standard. The experimental design was a randomized complete block with ten replicates in a 2x20 split-plot arrangement. The evaluated factors were: two types of nozzles (hollow cone with and without air induction) and 20 parallel distances to the crop line outside of the target area, spaced at 2.5 m. B… Show more
“…Thus, for all studied conditions, drift decreased exponentially as downwind distance from the nozzle increased. Drift distributions have been based on a potential function by Alves and Cunha (2014), Ganzelmeier et al (1995), and Meli et al (2003); on a four-parameter exponential decay function by Holterman and van de Zande (2003); and on a logistic function by Koger et al (2005). One type of function cannot be generalized for all conditions, as seen in the drift data shown here, which are variable and dependent on the physicochemical properties of the spray solution, nozzle type and orifice size, wind speed, and location of the study (wind tunnel, bench or field). Figure 5 Percent drift in dicamba (dic) and dicamba plus glyphosate (dic+gly) applications made using four different nozzle types in two experimental runs.…”
With the recent introductions of glyphosate- and dicamba-tolerant crops, such as soybean and cotton, there will be an increase in POST-applied tank-mixtures of these two herbicides. However, few studies have been conducted to evaluate drift from dicamba applications. This study aimed to evaluate the effects of dicamba with and without glyphosate sprayed through standard and air induction flat-fan nozzles on droplet spectrum and drift potential in a low-speed wind tunnel. Two standard (XR and TT) and two air induction (AIXR and TTI) 110015 nozzles were used. The applications were made at 276 kPa pressure in a 2.2 ms−1 wind speed. Herbicide treatments evaluated included dicamba alone at 560 gaeha−1 and dicamba+glyphosate at 560+1,260 gaeha−1. The droplet spectrum was measured using a laser diffraction system. Artificial targets were used as drift collectors, positioned in a wind tunnel from 2 to 12 m downwind from the nozzle. Drift potential was determined using a fluorescent tracer added to solutions, quantified by fluorimetry. Dicamba droplet spectrum and drift depended on the association between herbicide solution and nozzle type. Dicamba alone produced coarser droplets than dicamba+glyphosate when sprayed through air induction nozzles. Drift decreased exponentially as downwind distance increased and it was reduced using air induction nozzles for both herbicide solutions.
“…Thus, for all studied conditions, drift decreased exponentially as downwind distance from the nozzle increased. Drift distributions have been based on a potential function by Alves and Cunha (2014), Ganzelmeier et al (1995), and Meli et al (2003); on a four-parameter exponential decay function by Holterman and van de Zande (2003); and on a logistic function by Koger et al (2005). One type of function cannot be generalized for all conditions, as seen in the drift data shown here, which are variable and dependent on the physicochemical properties of the spray solution, nozzle type and orifice size, wind speed, and location of the study (wind tunnel, bench or field). Figure 5 Percent drift in dicamba (dic) and dicamba plus glyphosate (dic+gly) applications made using four different nozzle types in two experimental runs.…”
With the recent introductions of glyphosate- and dicamba-tolerant crops, such as soybean and cotton, there will be an increase in POST-applied tank-mixtures of these two herbicides. However, few studies have been conducted to evaluate drift from dicamba applications. This study aimed to evaluate the effects of dicamba with and without glyphosate sprayed through standard and air induction flat-fan nozzles on droplet spectrum and drift potential in a low-speed wind tunnel. Two standard (XR and TT) and two air induction (AIXR and TTI) 110015 nozzles were used. The applications were made at 276 kPa pressure in a 2.2 ms−1 wind speed. Herbicide treatments evaluated included dicamba alone at 560 gaeha−1 and dicamba+glyphosate at 560+1,260 gaeha−1. The droplet spectrum was measured using a laser diffraction system. Artificial targets were used as drift collectors, positioned in a wind tunnel from 2 to 12 m downwind from the nozzle. Drift potential was determined using a fluorescent tracer added to solutions, quantified by fluorimetry. Dicamba droplet spectrum and drift depended on the association between herbicide solution and nozzle type. Dicamba alone produced coarser droplets than dicamba+glyphosate when sprayed through air induction nozzles. Drift decreased exponentially as downwind distance increased and it was reduced using air induction nozzles for both herbicide solutions.
“…Droplet size, droplet velocity, leaf surface structure (waxy or hairy), the chemical composition of the spray solution, and meteorological conditions (air temperature, wind velocity, and relative humidity) may greatly influence the coverage area and consequently control of weeds, diseases, mites, and insects. The proper ASA used in the pesticide tank mix may contribute to improving the performance of the application (Alves & Cunha, 2014;Sasaki et al, 2015).…”
Agricultural spray adjuvants (ASA) are widely used in pesticide applications to enhance the performance of pesticides. The aim of this research was to investigate the effects of ASA on static surface tension (SST) and foliar spray retention on coffee leaves. The SST of ASA at different concentrations was determined by the drop weight method. Spray retention on adaxial and abaxial coffee leaf surfaces was performed using a micro-sprayer at solution concentrations of 0, 0.01, 0.1, 0.5, and 1.0% v v-1. The ASA assessed were: polyether-polymethylsiloxane-copolymer (PPC); Nonylphenol ethoxylate; nonyl polyethylene glycol ether; mineral oil; nonylphenoxy polyethoxy ethanol; carboxyl copolymer of styrene and butadiene; primary aliphatic oxyalkylated alcohol plus carboxyl copolymer of styrene and butadiene; and soyal phospholipids and propionic acid. All ASA reduced the SST of the aqueous solutions. PPC provided the best performance in decreasing SST, reaching values below 20 mN m-1 at a concentration of 0.05% v v-1. Spray retention on leaves was influenced by adjuvant type as well as concentration. A very strong positive correlation between SST and spray retention on coffee leaves was observed. Decreasing the SST of the solution provided a reduction of spray retention when spraying was performed until runoff point.
“…The drift is considered one of the biggest problems of agriculture, and it can be defined as the trajectory deviation that prevents the produced droplets to hit the target, a fact that is mainly related to the droplet size and wind speed (CHECHETTO et al, 2013;ALVES & CUNHA, 2014).…”
ABSTRACT:The aim of this study was to evaluate the spectrum, the velocity and the potential drift risk of droplets sprayed by nozzles with and without air induction, with the addition of mineral oil to the spray solution. The experiment was conducted in a completely randomized design with five replications; in a factorial model 2 x 2 (two spray nozzles and spray solution with and without mineral oil Assist ® ). Spray nozzles with and without air induction were evaluated, with nominal flow rate of 1.14 L min -1 and pressure of 300 kPa. The spectrum and the velocity of droplets were evaluated directly, using a droplet analyzer (VisiSize D30) in real time based on the analysis of high-resolution images. The drift potential was evaluated in an open circuit wind tunnel. The data were submitted to analysis of variance and comparison test. In general, the addition of mineral oil (1.5% V V -1 ) resulted in an increase in the velocity of droplets, reduced drift and more homogeneous droplet spectrum. Air induction nozzles promoted larger and less homogeneous droplets, but they little affected the velocity of the droplets. There is an inverse correlation between drift potential and volume median diameter (VMD), which indicates that VMD can be used to predict the behavior of drift risk.
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