Drift-reducing Nozzles Research Articles

ДОСЛІДЖЕННЯ ЕФЕКТИВНОСТІ ЗАСТОСУВАННЯ БПЛА ДЛЯ ПРОВЕДЕННЯ УЛЬТРАМАЛООБ’ЄМНОГО ОПРИСКУВАННЯ ПОСІВІВ

The purpose of the work is to study the effectiveness of using UAVs for ultra-small-volume spraying of crops by assessing the degree of coverage of the target plant surface with drops. Methods and materials: The study of the effectiveness of the use of UAVs in agriculture for high-quality spraying of crops was carried out on the lands of UkrNDIPVT named after L. Pohorily, using mobile sprayers «JT 6L-606» and «JT 15L-608P». Research of the «JT 6L-606» mobile sprayer model was carried out with a colored aqueous solution. The evaluation indicators were the median mass diameter of the settled droplets and the density of the coating of the treated surface with drops of the working solution, which were evaluated in accordance with the standard methodology of SOU 74.3-37-266:2005 “Testing of agricultural machinery. Tractor and self-propelled sprayers. Program and test methods”. Results. The size of the drops is a determining qualitative indicator of spraying. It characterizes the degree of grinding of the liquid and significantly affects the effectiveness of action and the rate of consumption of plant protection products. The value of the median mass droplet diameter, obtained as a result of tests of the «JT 6L-606» mobile sprayer, showed that the relative number of droplets whose diameter is less than or equal to 100 μm is 50% of the total number of droplets. However, asymmetry of droplet deposition on the right and left sides of the UAV and high unevenness of the distribution of drops of the working fluid along the width of the grip were found.Therefore, this sprayer model required additional settings in the future. Under the established conditions and modes of testing of the «JT 15L-608P» mobile sprayer, the obtained value of the median mass droplet diameter proved that the relative number of drops whose diameter is less than or equal to 100 μm is 60% of the total number of drops. The degree of coverage with drops of the target surface on the right and left sides of the UAV (grip width) of the «JT 15L-608P» sprayer was relatively symmetrical. Conclusions. According to the results of experimental studies of the effectiveness of the use of unmanned aerial sprayers «JT 6L-606» and «JT 15L-608P», it was established that in both unmanned mobile sprayers, the obtained values of the median mass diameter of drops, which are characteristic of the process of mechanical spraying, meet the requirements of ultra-small-volume spraying. However, the uneven distribution of drops of the working fluid along the width of the UAV was noted, which requires additional settings. When setting up agricultural drones, it is recommended to pay attention to the degree and impact of drift, which can be significantly reduced by following the following recommendations: reduce the distance between the rod and the target (the height of the rod should be approximately the same as the distance between the nozzles); use the coarsest effective droplet size typically achieved with drift-reducing nozzles such as air induction. Keywords: unmanned aerial vehicles, distribution uniformity, aerial spraying, quality of surface coverage, droplet size.

Performance of Drift-Reducing Nozzles in Controlling Small Weed Seedlings with Contact Herbicides

In many EU countries, spray applications should comply with increasingly stringent requirements regarding the drift reduction class of spray nozzles. Many farmers fear that the use of drift-reducing nozzles producing coarse droplet spectra may compromise the performance of contact herbicides on small weed targets. This study examined the effects of various ISO 03 drift-reducing flat-fan nozzles (pre-orifice and single and dual flat-fan air induction nozzles) differing in spray drift reduction class and spray pressure (2.5 bar, 5.0 bar) on (1) spray coverage, (2) droplet characteristics and (3) efficiency of contact herbicides bentazon and phenmedipham against cotyledon and 2-leaf stage plants of Chenopodium album and Solanum nigrum. Performance was compared to that of an ISO 03 standard flat-fan nozzle producing a finer droplet size spectrum. All sprayings were performed at a spray volume of 200 L ha−1. In most dose–response experiments, several drift-reducing flat-fan nozzles performed equally well as standard flat-fan nozzles, regardless of herbicide, spray pressure, growth stage or weed species. However, droplet size spectra of air-induction nozzles were too coarse for an adequate spray coverage and efficient application of contact herbicides on cotyledon stage plants of S. nigrum. In addition, the performance of air-induction nozzles in controlling difficult-to-wet C. album weeds with phenmedipham was better at 5.0 bar than at 2.5 bar. In contrast with droplet size characteristics, spray coverage characteristics determined on water sensitive papers were not good proxies for estimating the biological efficiency of contact herbicides. Air induction nozzles at 5.0 bar allow efficient control of 2-leaf targets, but nozzles emitting finer droplet spectra, such as pre-orifice nozzles, should be preferred for controlling cotyledon stage weeds at low-herbicide doses.

Possibilities to reduce drift by 75 percent in biocidal applications of insecticides with cannon sprayers

BackgroundInsecticides are applied on a large scale in the environment to control the oak processionary moth (Thaumetopoea processionea) for the protection of human health. Drift of the insecticides to non-target areas is a risk for the surrounding biodiversity. Since the habitats of the caterpillars are usually restricted to the treetops, the sprayers used to apply biocidal products must be able to transport the droplets over longer distances. Therefore, cannon sprayers are often used. In this study, spray drift in an oak avenue from a cannon sprayer with hydraulic atomisation was measured with two different nozzles. The aim of this study is to compare spray drift when using a cannon sprayer with different drift-reducing nozzles with cannon sprayers with pneumatic atomisation to find options to reduce drift to non-target areas.ResultsThe results show that compared to the basic drift values for biocidal products using a cannon sprayer with pneumatic atomisation, a cannon sprayer with ID-120-05 POM nozzles achieves a drift reduction of 75% and a classification in this reduction class. No drift reduction could be determined with a cannon sprayer with AirMix 110-05 nozzles.ConclusionsBetter knowledge of drift of biocidal products is of utmost urgency in order to be able to compare and classify the currently used technologies. When using a cannon sprayer, this study shows that specific drift values are recommended based on the type of atomisation, as droplet size is an important factor in reducing drift. By choosing the technology with the highest drift reduction, the drift of biocidal products into the environment can be minimised by 75%, thus ensuring a much better protection of the environment.

Effects of nozzle type and adjuvant selection on common lambsquarters (Chenopodium album) and johnsongrass (Sorghum halepense) control using nicosulfuron in corn

AbstractWeed control in corn is a major challenge due to increasing problems with highly dominant weed species and herbicide resistance evolution. Common lambsquarters and johnsongrass constitute up to 80% to 90% of the weed population in many spring crops, such as soybean [Glycine max (L.) Merr.], sunflower (Helianthus annuus L.), and corn, in Serbia. Currently, acetolactate synthase–inhibiting herbicides, such as the systemic selective sulfonylurea nicosulfuron, are most commonly used for chemical weed control of those species. A better understanding of the impact of nozzle type and adjuvant use on nicosulfuron efficacy can help to improve control of common lambsquarters and johnsongrass and minimize herbicide resistance development. Field trials were conducted in Serbia from 2020 to 2022 to evaluate the impact of two adjuvants (a non-ionic surfactant [NIS] and a mineral fertilizer ammonium sulfate [AMS]) and two nozzle types (drift-reducing nozzles and flat-fan nozzles) on common lambsquarters and johnsongrass control using nicosulfuron. Satisfactory biomass reduction of common lambsquarters (83% to 87%) and johnsongrass (83% to 97%) was achieved after nicosulfuron application. Adding a NIS adjuvant increased the biomass reduction for common lambsquarters (94% to 98%) and johnsongrass (90% to 100%) independently of the nozzle type used. Selection of nozzle type did not show consistent effects on common lambsquarters and johnsongrass control. Nicosulfuron efficacy was increased with NIS adjuvant for both nozzle types compared to nicosulfuron solo for both species, and Extended Range (XR) TeeJet® nozzles on average resulted in a higher efficacy for common lambsquarters compared to Turbo TeeJet® induction. Adding a mineral AMS adjuvant resulted in lower biomass reduction for both nozzle types and weed species (65% to 78% and 61% to 91% for common lambsquarters and johnsongrass, respectively). Corn grain yield was predominantly influenced by annual meteorological conditions and adjuvant type added to nicosulfuron. This research suggests that addition of the non-ionic adjuvant is an essential factor for successful control of common lambsquarters and johnsongrass in corn and enables use of drift-reducing nozzles.

Protection by ordinary light clothing against pesticide spray drift for bystanders and residents

There are stringent EU regulatory requirements to assess pesticide exposure to bystanders and residents to direct spray drift. A “light clothing” adjustment factor (AF) of 0.82 is applied in the exposure assessment, based on simple assumptions for covered body surface and penetration through clothing. To assess the appropriateness of the AF, we collated data from 32 field studies. The mean and 25th percentile % reduction from ordinary light clothing (“reduction %”) in children and adults for all crops and standard and drift-reducing nozzles were 42.7% and 36.2%, resulting in AF of 0.573 and 0.638, respectively. Sources of variation were investigated, e.g. crop type, leaf coverage, buffer, spray pressure, and nozzle type, which indicated that reduction % could be impacted by several conditions. The reduction % is similar between crops; therefore, a single AF value covering all crops can be derived. One exception was for early-stage vineyard scenarios (the reduction % is lower (27%) than late stage (42–47%)) and could be considered individually to avoid unnecessary conservatism for the other scenarios. This evaluation demonstrates the current AF to be overly precautionary, and a more realistic, exposure scenario-relevant value could be applied for bystander/resident risk assessments.

Evaluation of Drift-Reducing Nozzles for Pesticide Application in Hazelnut (Corylus avellana L.)

Spraying pesticides using air induction nozzles is a well-known method to reduce drift. These drift-reducing nozzles have been tested on many different tree crops (such as apples, citrus, and grapes), but we are still lacking information on their utilization on hazelnut (Corylus avellana L.) groves, although hazelnut is a major nut crop in Italy, and in recent years its cultivated area has been constantly growing. This paper reports a comparison between treatments carried out with cone and flat-fan low-drift nozzles versus two conventional nozzles. The distribution quality, the number of droplets per cm2 of the target area, and the drift in non-target trees adjacent to those treated were evaluated by analyzing the impact of the droplets on water-sensitive papers placed on the tree canopies. The results show that because no significative differences in terms of application quality were found between the tested nozzles, low-drift nozzles can be a good alternative to the standard nozzles to reduce the drift of pesticide applications in hazelnuts without altering the chosen distribution of the pesticide.

Wind tunnel investigation of the ability of drift-reducing nozzles to provide mitigation measures for bystander exposure to pesticides

Models recently developed for assessing the potential exposure of residents and bystanders to pesticides through spray drift have highlighted the need for mitigation strategies to reduce exposure of members of the public. Drift-reducing equipment is readily available in many countries and is accepted as mitigation for the exposure of surface water to drifting pesticide sprays but there is concern that the drift-reduction measurement methods used to define the exposure of surface water might not be relevant to bystanders. Airborne spray is an important component in bystander exposure. Two wind tunnel experiments were undertaken to evaluate whether reductions in airborne spray are as great as the reductions in measured spray drift that occur using protocols designed to classify nozzles for protecting surface water. Results, with nozzles and pressures with a range of nominal drift reduction, and three different spray liquid types, suggested very strongly that the nominal drift reduction of a nozzle/pressure combination will give at least the same level of reduction in airborne spray for distances 3–5 m downwind. These data should be considered in the context of field data and model simulations in order to establish robust mitigation measures for regulatory exposure assessment. They indicate that the nominal drift reduction, measured using UK, Netherlands or German protocols, can be used to reduce bystander exposure up to 90%. The BREAM2 model for bystander exposure to spray drift can therefore be extended to include drift mitigation, with reductions in exposure up to 90% for classified equipment used in the appropriate way. • Wind tunnel experiments measured drift reduction and potential bystander exposure. • Reduction in measured airborne spray was as great as the nozzle's drift classification. • Results applied to UK, NL and DE classification systems and a range of formulations.

Spray drift with several nozzles under wind breeze in a vineyard nursery

The area planted with grapes in Chile has grown nearly 50 % in the last 12 years, causing a drastic increase in use of agrichemicals. In particular, herbicides need to be applied more precisely to reach the desired targets. Weeds are a limiting factor in nurseries, mostly because of the reduced distance between rows. The spray nozzles are of vital importance because they distribute the mixture over the target. A comparative study between conventional extended rage flat spray (XR) and drift reducing nozzles (TT, DG and AI) was conducted in Vitis vinifera L. cv. Thompson Seedless plants self-rooted in the nursery, studying the drift detection and quantification, of a 5.8 km.h-1 wind breeze, using the food tracer Brilliant Blue FD & C-1. Under this breeze condition, at the plants level, the drops produced with the XR nozzle suffered a trajectory deviation. A strong decrease in the spray deposits occurred while the spray area distance increased. At ground level, it was appreciated that with wind conditions, there is an increase in all the nozzles of the tanks before the plant, next to it, and after cultivation, but these did not become statistically significant at this wind level

Comparison between standard and drift reducing nozzles for pesticide application in citrus: Part I. Effects on wind tunnel and field spray drift

The objective of this study was to evaluate and to compare spray drift potential and field spray drift from pesticide application in citrus orchards carried out mainly comparing standard nozzles with drift reducing nozzles. Two different standard nozzles (hollow cone and full cone) and one Venturi drift reducing nozzle (hollow cone) were tested. Spray drift potential was measured by means of wind tunnel experiments (ISO 22856:2008 method). To estimate field airborne and sedimenting spray drift, two trials with 5 replicates each were carried out (ISO 22866:2005 method) in two different commercial orchards of Clementine mandarins. Results showed that Venturi nozzles significantly reduced drift with the two methodologies. Moreover, the wind tunnel method showed the same trend as the field results. Additionally, spray drift deposition variability was lower for the Venturi nozzles. Therefore, it could be concluded that Venturi nozzles can be recommended to be used in citrus orchards to prevent human and environmental risks and their use could be appropriate for different scenarios where spray drift risk must be mitigated.

Evaluation of spray nozzles for fungicidal control of tan spot in wheat

Tan spot, caused by Pyrenophora tritici-repentis (Died.) Drechs, is a serious constraint on wheat yields in the Southern Cone region of South America. A 2-year experiment was conducted to evaluate fungicide deposition, disease development and grain yield. Three spray nozzles were evaluated: an air-induction flat fan (AI), a wide-angle flat fan (TT), and an extended-range flat fan (XR). A systemic fungicide containing azoxystrobin and cyproconazole was used in both years. Tan spot severity and the area under non-green leaf area disease progress curve (AUNGLA) were analysed. There were no significant differences in deposition among nozzles, and no significant interactions between nozzles and leaf layers in the first year. In both years, AUNGLAs were similar for the three nozzles types, and the tan spot severity in untreated plots was significantly higher than in fungicide-applied plots. Grain yield was higher in the fungicide-applied plots, and there were no significant differences among nozzles in both years. Droplet size had no effect on the fungicide’s efficacy for tan spot control in Uruguay across three susceptible wheat cultivars. The use of drift-reducing nozzles and a systemic fungicide in these trials led to satisfactory performance for spray deposition, canopy penetration and control of the tan spot disease of wheat in the same way as expected from conventional nozzles.

Comparison between standard and drift reducing nozzles for pesticide application in citrus: Part II. Effects on canopy spray distribution, control efficacy of Aonidiella aurantii (Maskell), beneficial parasitoids and pesticide residues on fruit

Venturi nozzles are often recommended to reduce drift, which is one of the major pollution sources caused by the application of plant protection products on high growing crops. The coarse droplets produced by this type of nozzle could however also affect the spray distribution and therefore the efficacy of pesticide treatments, the population of beneficial parasitoids and levels of residues on fruit. For these reasons, this work aimed at providing scientific evidence of any effect in these parameters when using standard (cone) or drift reducing (Venturi) nozzles for citrus foliar applications against California red scale (CRS) applied with conventional axial fan airblast sprayers. Results showed that Venturi nozzles did not affect efficacy in the conditions of the experiment. Moreover, in general terms, no differences were found in the distribution of the spray deposits over the tree canopy, on levels of residues on fruit or on the effects on the population of parasitoids. All these findings suggest that Venturi nozzles can be regarded as a good alternative to the standard cone nozzles for reducing drift of pesticide applications against CRS in citrus under Mediterranean conditions.

Comparison of the effectiveness of standard and drift-reducing nozzles for control of some winter wheat diseases

Field experiments were conducted over three consecutive growing seasons (20042–2006) to determine the effect of use of drift-reducing nozzles (ISO 03 code) on biological efficacy of fungicides for control of winter wheat diseases and their effect on grain yield. Four drift-reducing flat fan nozzles (VMD 270–440 μm) were compared with three standard nozzles (VMD 170–210 μm) at 300 l ha−1 spray volume. Commercial fungicide mixtures based on 12 different active substances were applied twice a season (BBCH 36–38 and 61–63). When controlling powdery mildew (Blumeria graminis) and wheat brown rust (Puccinia recondita) differences in efficacy of fungicides applied by standard or drift-reducing nozzles were small and mostly non-significant. The differences noticed at control of leaf blotch (Septoria tritici) depended a lot on the combination of growing season and fungicides applied. No general rule could be made regarding to the efficacy of fungicides for control of septoria leaf blotch. The greatest differences were observed by control of fusarium head blight (Fusarium spp.) and septoria glume blotch (Septoria nodorum) where the decrease (5–15%) of fungicide efficacy was determined when using drift-reducing nozzles. Decrease of biological efficacy of fungicides due to the use of drift-reducing nozzles however did not have a significant effect on the grain yield in most of the fungicide programs. According to our results the use of drift-reducing nozzles could be recommended without limitations to wheat producers applying wheat production systems similar to those in our experiment.

Glyphosate Spray Drift Management with Drift-Reducing Nozzles and Adjuvants

Field experiments were conducted to evaluate the effect of five spray-nozzle types and three drift-control adjuvants (DCA) on glyphosate spray drift. The extended-range (XR) flat-fan nozzle at 280 kPa was used as the standard comparison. DCAs were evaluated for drift reduction with the use of the XR and air-induction (AI) nozzles. Wind speed ranged from 1.3 to 9.4 m/s (3 to 21 mph). Lethal drift (DL) and injury drift (DI) were determined by downwind visual observation of grain sorghum response. Drift distances were measured from the spray swath edge. The Turbo FloodJet and AI nozzles reduced DLdistance by 34%. All four drift-reducing (DR) nozzles reduced DIdistance by 22 to 32%. Reducing the pressure of the XR flat-fan nozzle from 280 to 140 kPa did not reduce DLor DIdistance. When applied through AI nozzles, each DCA increased droplet volume diameter, one DCA reduced DIdistance and none reduced DLdistance when applied through XR tips. The DCAs did not affect DLor DIdistance.

Effects of asulam spraying on non-target ferns

The systemic herbicide asulam is used extensively to control the weedy fern bracken ( Pteridium aquilinum (L.) Kuhn). Other ferns were thought to be highly sensitive to asulam exposure, but there has been a dearth of experimental evidence. Eight fern species were exposed to asulam spray at three different application rates or a control of water. Asulam was applied at the recommended field application rate for bracken clearance, and at two further rates corresponding to 10 and 50 m downwind of an aerial spray event. Damage was assessed over two seasons. All ferns tested were severely damaged by exposure to the highest application rate, but sensitivity varied between species. Maximum damage occurred 1 year after spraying, and limited signs of recovery could be seen by the second season. The effects of adding the adjuvant Agral® to applications of asulam were tested on the threatened pteridophyte Pilularia globulifera L. No damage additional to that caused by exposure to asulam was observed. This work supports the view that 50 m buffer zones are sufficient to protect sensitive ferns from the effects of aerial spraying with asulam, provided that drift-reducing nozzles are used and the manufacturer’s application guidelines are observed.

Comparison of the effectiveness of standard and drift-reducing nozzles for control of some pests of apple

A comparison of the biological efficacy of pesticides applied against some apple pests with standard versus drift-reducing nozzles was made in trials in intensive orchards in Slovenia. Standard and drift-reducing nozzles were compared by applying 350L spray per hectare. No significant differences in acaricide/insecticide efficacy between the types of nozzles could be observed when controlling fruit tree red spider mite (Panonychus ulmi) and apple rosy aphid (Dysaphis plantaginea). However, drift-reducing nozzles reduced the efficacy of insecticides against the codling moth (Cydia pomonella), green apple aphid (Aphis pomi) and apple leaf miner (Leucoptera malifoliella).

Drift-Reducing Nozzle Effects on Herbicide Performance1

Abstract: Herbicide efficacy, coverage, and retention were evaluated for spray applied through Drift Guard, Turbo TeeJet, AI TeeJet, and TurboDrop drift-reducing nozzles compared to a conventional flat-fan nozzle. Percentage spray coverage detected on water-sensitive cards was greater for conventional and Drift Guard nozzles than for Turbo TeeJet, AI TeeJet, and TurboDrop nozzles. Spray without adjuvants was retained better by redroot pigweed for treatments applied with conventional and Drift Guard nozzles than Turbo TeeJet, AI TeeJet, and TurboDrop nozzles. However, spray with adjuvants was retained similarly for all nozzle types when averaged over spray adjuvant and two weed species. The efficiency of spray retention was greater for spray applied in 47 than in 190 L/ha spray volume for all nozzles. Paraquat and glyphosate, representing contact and translocated herbicides, respectively, provided similar grass species control for all nozzle types, regardless of spray volume. Paraquat and glyphosate were a...