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BACKGROUND: The unmanned aerial spraying systems (UASS) have gained widespread use for plant protection in recent years. However, spray drift from UASS is a major concern when controlling weeds over large areas and warrants a thorough investigation. This study examined the atomization characteristics of the herbicide florpyrauxifen‐benzyl under downwash airflow using a UASS spray test platform. Potential spray drift was assessed using a test bench (TB) and airborne drift collectors (ADCs) in the field under low wind speeds (<1 m s−1). RESULTS: Atomization characteristics were significantly affected by the spray liquid, adjuvant, nozzle type and spray pressure. The addition of an adjuvant reduced the liquid sheet length, improved physicochemical properties and increased droplet size under the downwash airflow field. Drift evaluation in the field using the TB revealed that sediment spray drift predominantly occurred from the middle to the entire length of the device when fine‐to‐medium droplets were produced after the sprayer passed. ADC assessment found that higher flight altitudes and finer droplets resulted in higher drift values, whereas the addition of an adjuvant and the use of an air‐induction nozzle reduced drift <3 m aboveground. CONCLUSION: The combination of using TB in the target area and ADCs in the off‐target area as an alternative method to determine residual droplets in the current airflow provided valuable insights into airborne drift assessment for UASS. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Adjuvants are included in many pesticide spray mixtures to enhance the performance of the applied chemical. Many adjuvants which modify the emulsion or extensional viscosity of the tank‐mixture have been found to offer benefits in drift management, primarily by eliminating or reducing the 'Fine' droplets included in the spray with diameters <100–200 μm that can move off‐target in unfavorable conditions during ground, airblast and aerial pesticide applications. Among wind tunnel and field studies conducted around the world, there is consensus that while some adjuvants are effective for drift management, the performance varies on a case‐by‐case basis, requiring verification for each adjuvant which could be achieved through a programme such as certification based on showing a reduction in Fine droplets and/or a reduction in airborne drift. These can be measured in wind tunnel studies according to international standards. This article provides a review of the current science in this subject area, from the approaches to data collection to a review of existing data and regulatory application for encouraging and rewarding the use of appropriate adjuvants that have been demonstrated to reduce airborne spray drift potential and therefore the size of no‐spray buffer zones appropriate to protect nontarget sensitive areas from drift exposure. Some adjuvants can offer the same reduction in drift as offered by hooded sprayer retrofits. A drift reduction programme based on adjuvant use could include testing candidate adjuvants for their effect on droplet size and reduction in Fine droplets when sprayed through reference nozzles and compared against sprays without the adjuvant. Testing could also be based alternatively on measurements of drift potential on collectors such as monofilament line in wind tunnel or field studies. Once shown to be effective in reducing 'Fines' or spray drift, adjuvants could be certified and then referenced on pesticide labels and/or regulatory or best management practice schemes to encourage their use and offer reductions in use restrictions or no‐spray buffer zone sizes based on drift management. Studies have shown that some adjuvants can reduce pesticide leaching into soils and contamination of groundwater, as well as runoff of active ingredients from plants into the environment. Performance depends on the adjuvant type, the pesticide with which it is used, the soil or plant type, the timing and mass of water input from rainfall and climatic factors. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Spray systems in agriculture serve essential roles in the precision application of pesticides, fertilizers, and water, contributing to effective pest control, nutrient management, and irrigation. These systems enhance efficiency, reduce labor, and promote environmentally friendly practices by minimizing chemical waste and runoff. The efficacy of a spray is largely determined by the characteristics of its droplets, including their size and velocity. These parameters are not only pivotal in assessing spray retention, i.e., how much of the spray adheres to crops versus becoming environmental runoff, but also in understanding spray drift dynamics. This study introduces a real-time deep learning-based approach for droplet detection and tracking which significantly improves the accuracy and efficiency of measuring these droplet properties. Our methodology leverages advanced AI techniques to overcome the limitations of previous tracking frameworks, employing three novel deep learning-based tracking methods. These methods are adept at handling challenges such as droplet occlusion and varying velocities, ensuring precise tracking in real-time potentially on mobile platforms. The use of a high-speed camera operating at 2000 frames per second coupled with innovative automatic annotation tools enables the creation of a large and accurately labeled droplet dataset for training and evaluation. The core of our framework lies in the ability to track droplets across frames, associating them temporally despite changes in appearance or occlusions. We utilize metrics including Multiple Object Tracking Accuracy (MOTA) and Multiple Object Tracking Precision (MOTP) to quantify the tracking algorithm's performance. Our approach is set to pave the way for innovations in agricultural spraying systems, offering a more efficient, accurate, and environmentally responsible method of applying sprays and representing a significant step toward sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

Background: Insecticides are sprayed on external building walls for treatments against crawling and flying insects. These applications can lead to drift into non-target areas and thus to undesirable environmental pollution. This emission pathway needs to be considered during exposure assessments within product authorisations to assess potential environmental risks. However, now, there is only one default value for deposition that is used in all calculations based on the Emission Scenario Document of the Organization for Economic Co-operation and Development at a distance of 50 cm to the treatment area. This is not sufficient for a risk assessment. Results: When applying a chemical barrier of 50 cm at the bottom of the building wall, wind direction had the greatest influence on drift, while changing the nozzle type had no significant effect. Compared with the measured ground sediments, the OECD default value was deemed to be realistic at a distance of 57 cm from the treatment area. When treating the entire building wall, the wind direction as well as the nozzle used show significant influence on the measured values of drift. The default value for deposition proposed for modelling environmental exposure in OECD document ESD PT18 No. 18 was exceeded. Thus, the exposure estimation might not be protective enough. Conclusion: Drift values used for the environmental exposure assessment of biocidal products during treatments of building walls should be adapted. This is especially relevant for treatments of entire building walls, where the current default value was exceeded for all distances from the building wall. Wind direction and nozzle type can reduce environmental impact. This finding can be used as a measure to reduce unnecessary exposure in the environment in the future. [ABSTRACT FROM AUTHOR]

Highlights Mosquito adulticiding over operationally relevant areas is feasible using UASS. Wind speed plays an important role in the spray landing position, as expected based on previous studies using CASA. Results are based on both passive and active collectors, including flat cards, rotary impingers, and bottle brushes. Over 1900 total samples were collected in 8 trials, and elevated samplers allowed analysis of the descent of the droplet cloud. A spatially extensive experiment was designed to evaluate the effectiveness of Uncrewed Aerial Spray Systems (UASS) in mosquito adulticiding. The practice of adulticiding uses very fine droplets (DV0.5 <50µm). The objective is to fill a volume of air with fine droplets that a flying adult mosquito will encounter in flight. A field program was designed with samplers as far as 500 m downwind from the UASS flight line. A total of over 1900 samples were collected over the course of eight trials. Both passive and active collectors were deployed. Tests were conducted in the early morning and were generally successful in terms of meteorological conditions and data collection. Elevated samplers successfully tracked the descent of the spray cloud, and spray was collected from the most distant samplers. The known dependence of spray movement on wind speed that has been widely observed and codified into label language for Crewed Aerial Spray Aircraft (CASA) was observed. Very low wind speed conditions are problematic for adulticiding in general, and undesirable near-field deposition of adulticiding spray was observed in the data presented here under low wind speed conditions. It needs to be emphasized that much more data needs to be collected before statistically robust conclusions can be drawn. Generally, these data show that UASS can be used to disperse very fine spray droplets over areas representative of operational adulticiding. This paper presents and discusses spray movement and deposition, a second paper is in preparation comparing these data to existing models of spray dispersion and deposition from UASS spraying. A third paper examining mortality from UASS adulticiding has been published. [ABSTRACT FROM AUTHOR]

The increase in pesticide regulations, diminished pesticide options due to resistance concerns, and narrowing grower profit margins require each application to be optimised to reduce spray drift and enhance coverage. However, alternative strategies outside of increasing droplet size are needed as reductions in pest control have been observed. This research explored the potential of a magnetic-assisted sprayer (MAS) to aid in spray coverage and determine its impact on spray droplet size and velocity. The MAS minimally impacted spray droplet size characteristics across the four nozzle types tested (only five of twenty F-tests were statistically significant) and did not impact average or maximum droplet velocities when measured 51-cm from the nozzle compared to the conventional sprayer. Although statistically, the MAS increased droplet size by only 4.6 and 12.5% in two of 12 parameter instances compared to the conventional sprayer, there were indications it may reduce spray drift potential as the driftable fines (% of individual droplets measured with diameters less than 200 μm) were numerically less across all nozzle types tested. Across the five experiments, an improvement in spray coverage and deposition by the MAS compared to the conventional sprayer was only observed in one treatment from one experiment. Overall, the MAS minimally to negatively impacted the measured coverage and calculated deposition from water-sensitive paper. Future research is needed to measure actual spray drift from a MAS as well as to evaluate other potentially influential variables such as water quality, pesticide active ingredient, and plant species. • Magnetic-assist increased droplet size in 2 of 12 comparisons with a stock sprayer. • Slight drift reduction potential (reduced fines in 1 of 4 comparisons) observed. • Droplet velocity was not altered by a magnetic-assisted sprayer. • Coverage and deposition improved in 1 of 58 treatments compared to a stock sprayer. • Future research should evaluate more spray variables combined with magnetic effect. [ABSTRACT FROM AUTHOR]

An effective spray of agrochemicals is inevitable for crop production for viable agriculture. Spraying inherently suffers from drift, which has always been one of the major concerns in agriculture, affecting the intent of agrochemical spraying and posing serious environmental hazards. Complete elimination of spray drift is impractical under field conditions but can be minimized using precision spraying techniques. Agricultural spray drift has several detrimental effects, such as environmental damage, polluting water bodies, human and animal health risks, chemical exposure, and economic losses, and may also lead to conflicts between neighboring farmers. Hence, the assessment of spray drift is a salient part of the design process of plant protection equipment to achieve maximum deposition in both chemical and biological pesticide applications. The different methods used to study the drift of a sprayer include test bench, wind tunnel and phase Doppler particle analyzer (PDPA) methods. In the fieldlevel assessment, the fluorometric tracer sampling method conforming to ISO-22866:2005 was used. Plume dispersion, particle tracking and computational fluid dynamics (CFD) are the major mathematical modeling approaches for spray drift simulation studies. Among various methodologies and techniques, an appropriate method for spray drift assessment should be adopted in accordance with factors such as crop parameters, mode of application, and environmental conditions. [ABSTRACT FROM AUTHOR]

BACKGROUND: The use of unmanned aerial vehicles (UAVs) for the application of plant protection products (PPPs) in paddy fields is becoming increasingly prevalent worldwide. Despite its growing usage, UAV spraying for rice pest control faces practical challenges, including limited canopy penetration, uneven deposition, and significant spray drift. This study investigated the impact of two tank‐mix adjuvants, Wonderful Rosin (Adjuvant‐1) and Tiandun (Adjuvant‐2), at six volume concentrations, on the spray liquid's physicochemical properties, spray drift, plant deposition, and the biological efficacy of rice insecticides using a quadrotor UAV sprayer. RESULTS: The physicochemical characteristics of the spray liquid influenced spray performance and biological efficacy. Incorporating Adjuvant‐1 and Adjuvant‐2 led to a decrease in surface tension and contact angle while increasing the viscosity of the spray solution. These alterations in surface tension and viscosity contributed to an optimized droplet size distribution, reduced spray drift, enhanced deposition uniformity and penetration, and improved control efficacy against the rice planthopper in UAV applications. The highest control efficacy was observed at a concentration of 0.5%, showing an improvement of 35.12% (Adjuvant‐1) and 20.23% (Adjuvant‐2) over applications without tank‐mix adjuvant 7 days after treatment. CONCLUSION: The judicious selection of tank‐mix adjuvants for UAV PPP applications can significantly enhance spray performance and biological efficacy in controlling rice insects. This study's findings offer valuable insights for integrating tank‐mix adjuvants into UAV spraying applications. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

While the pesticide formulations are widely used for pest control, the combined effects of these formulations with adjuvants on droplet behavior, spraying characteristics, and pest control still need to be studied. To clarify their impact on droplet behavior, spraying characteristics, and control efficacy, six formulations of acetamiprid and six adjuvants were examined. A series of laboratory and field experiments were conducted to analyze the physicochemical properties, toxicity against cotton aphids, droplet deposition characteristics, and droplet drift. The results indicated that 5% acetamiprid micro-emulsion (ME) enhanced the physicochemical features and effectiveness in pest control compared to other formulations. The nongjianfei considerably enhanced the efficiency of all acetamiprid formulations when added. The addition of selected adjuvants to pesticide formulations improved the performance of certain physicochemical properties such as viscosity and surface tension and led to higher aphid mortality rates, demonstrating enhanced pest control effectiveness during the present study. In the field experiments, the combination effect of acetamiprid formulations and adjuvants exhibited a higher droplet size, coverage, and density within the cotton canopy. However, 5% acetamiprid ME was found to be most effective followed by nongjianfei. Furthermore, 5% acetamiprid ME with adjuvant reduced the droplet drift and provided better deposition when compared with other formulations. Overall, the combination of specific formulations and adjuvants led to improved physicochemical properties, enhanced droplet deposition characteristics, reduced spray drift, and increased pesticide deposition. These findings highlighted the significance of selecting appropriate pesticide formulations and adjuvants and provided a solid foundation for efficient pesticide spraying through UAVs. [ABSTRACT FROM AUTHOR]

The effectiveness of a hybrid unmanned aerial vehicle (UAV) for optimizing crop booster application on cotton crops (variety Co-14) at Tamil Nadu Agricultural University is evaluated in this research. The hybrid UAV, featuring a 12-litre sprayer tank and powered by an internal combustion engine and brushless direct current motor, was tested at heights of 1 and 2 m and speeds of 3 and 4 m s –1. The objective was to determine optimal parameters for maximizing droplet deposition and minimizing spray drift. The results indicated that at 1 m and 3 m s –1, the droplet density in the target area was 148 ± 8 drops/cm², compared to 136 ± 4 drops/cm² at 2 m. The volume median diameter at 1 m and 3 m s –1 was 361 µm, and the number median diameter was 392 µm, showing higher deposition and uniform droplet sizes at lower heights and lower speeds. Spray drift analysis indicated reduced off-target movement at 1 m and 3 m s –1, showing a non-target droplet density of 54 ± 4 drops/cm² compared to 42 ± 6 drops/cm² at 2 m. The study concludes that the optimal UAV operation parameters are 1 m height and 3 m s –1 speed, enhancing droplet deposition, minimizing drift, and improving spray efficiency. [ABSTRACT FROM AUTHOR]

The effectiveness of agricultural spraying processes depends considerably on the ability of the atomized droplets to reach the target site in the desired amount. In this work, two mathematical models to study the trajectories and deposition of atomized droplets are implemented and compared. On the one hand, a computational fluid dynamics (CFD) coupled with discrete phase model (DPM) is implemented to calculate the trajectories of atomized droplets and determine distances at which the droplets are deposited. The continuous phase (atmospheric air) is modelled by continuity, momentum, and energy equations. On the other hand, a Lagrangian random‐walk (LRW) model based on force and energy balances to predict the pulverization process of a nozzle is formulated and implemented in Python. Both models take into account the effects of drag, gravity, buoyancy, and evaporation on individual droplets, as well as the impact of atmospheric stability and dispersion. By tracking a large number of trajectories, meaningful estimates of dispersal statistics can be obtained. The LRW model accurately replicated the trajectories, deposition distances, and final diameters of atomized droplets for three atmospheric stability cases, compared with CFD simulation results. The results of both models agreed that 100 μm droplets were most susceptible to wind‐induced spray drift, depositing at the furthest distances from the nozzle. In addition, 50 μm droplets exhibited a significant tendency to evaporate entirely before reaching the ground. The LRW model is found to be a cost‐effective alternative for estimating spray drift compared to the computationally intensive CFD approach. [ABSTRACT FROM AUTHOR]

Air assist for apple orchard spray applications is a necessity to deliver pesticides to target crops. However, conventional orchard sprayers use axial fans to provide air assists which are generally designed for tall crops. Thus, these systems have very limited capabilities to control airflows to match canopy densities. An electric air assist system (EAAS) was developed with an electric fans, pulse width modulation (PWM) controllers, a custom-design air channel, and a 400-Ah LiFePO4 battery to address such limitations. The system could ramp up its airflow to nearly 80% of its maximum in 2.5 s, while it took approximately 4 s to reach 100% airflow from no air assist. The EAAS provided airflow of 11.3 and 5.3 m s-1 at the fan outlet and 1 m away, respectively, with 100% duty cycles (DC) of PWM. It was capable of modulating its average air velocities from 0 to 11.3 ms-1 by changing DCs. Spray coverage samples of constant rate applications with different air assist levels were collected from the behind apple tree canopies throughout the 2023 growing season to characterize the potential for off-target spray drift. A multivariable regression model for controlling DCs was developed with the spray coverage data and leaf area index (LAI) to minimize the off-target drift. The EAAS was a promising approach to developing more advanced air assist spraying systems to enable the adjustment of both air and liquid flows based on canopy characteristics to maximize spray depositions on intended targets while minimizing spray drift. [ABSTRACT FROM AUTHOR]

BACKGROUND: Canopy density is high during mid‐to‐late soybean growth as a result of dense planting to improve yield, which seriously affects the control of pests and diseases. The dilemmas of difficult droplet penetration, nonuniform deposition, and droplet drift in field spraying remain challenges to the precise control of droplet distribution. This paper proposed a novel spraying application mode combined flexible shield canopy opener (FSCO) with rotor wind. The design of the key components of the new boom‐spraying machine are described. The effects of the comparative spraying modes on spray deposition and droplet drift were studied in a field validation test to explore the feasibility of the novel spraying application. RESULTS: The study found that droplet coverage inside the soybean canopy was significantly affected by spraying mode, rotor wind speed and opener depth. The spraying operation that used the FSCO and rotor wind integrated mode was optimal for droplet uniformity on the adaxial and abaxial surfaces of the canopy leaves, with droplet uniformity indices of 0.966 and 0.934, respectively. At a rotor wind speed of 6 m s−1 and opener depth of 15 cm, the soybean canopy droplet coverage uniformity effect achieved the highest composite score of 0.937. The spraying mode used in this study improved droplet coverage uniformity by 82.30% and droplet anti‐drift performance improved by 99.73% compared to the conventional boom‐spraying mode. CONCLUSION: The study shows validity of the spraying mode combined FSCO with rotor wind to open dense canopy and improved droplet deposition uniformity in canopy and anti‐drift performance. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Vortex generators (VGs) attached to the leading edge of an agricultural aircraft are purported to control airflow over the upper surface of the wing by creating small vortices that delay boundary layer separation, thereby improving the performance of the aircraft. These devices are commercially available for use in the aviation industry, primarily to increase pilot control of the aircraft. The benefits attributed to VGs remain largely descriptive and anecdotal in nature without rigorous empirical assessment in the field. The intent of this study was to evaluate whether this aerodynamic device could improve deposition or reduce drift when mounted on an agricultural aircraft. Airborne drift and ground deposition were measured with monofilament lines and Mylar cards, respectively. Deposits were expressed as percent of fluorometric response using a spectrofluorophotometer. There were 46% fewer downwind drift deposits on monofilament lines when VGs were installed than when VGs were not installed. Whether or not VGs were installed on the aircraft was the predominant factor which influenced deposition on monofilament lines. Spray deposits on Mylar cards placed at ground level downwind of the applications at three different locations (5, 10, and 20 m) varied significantly (p < 0.0001) between treatments, with corresponding 31, 54, and 61% reductions in downwind deposits when VGs were installed. While these findings overall are positive, this is the first known study of its type, and more research is warranted to better understand the role of vortex generators in the reduction in drift relative to aerially applied sprays. [ABSTRACT FROM AUTHOR]

The application of anti-drifl nozzles, such as air-induction nozzles, is the most common recommendation for reducing spray drift; To reduce the risk of coarse droplets bouncing and rolling produced by anti-drift nozzles, various types of adjuvants were screened by comparing their atomization performance, surface tension and contact angle, in order to identify favourable adjuvants that are compatible with anti-drift nozzles. It was found from the study results that the addition of 50% neem crude oil emulsifiable concentrate (neem oil), isomeric alcohol ethoxylates and BYK-405 all significantly decreased distribution span (5) and the percentage of droplet size less than 150/zm (OVol<150/,m) values, but significantly promoted the median volume (Z>50) value. And the surface tension measurement results showed that all tested adjuvants significantly reduced the surface tension, while neem oil, FC4430 and silwetl-77 were observed with a most significant effects; Furthermore, all tested adjuvants except BYK-051N could also significantly decrease the contact angle, and the difference between neem oil, FC4430 and silwetl-77 was significant. Wind tunnel test results clearly demonstrated that the application of IDKA (a combination of air-induction nozzle IDK120-01 and neem oil) substantially decreased the drift deposition amount; In addition, the field experiments revealed that IDKA possessed a significantly improved deposition amount per unit area on canopy or bottom, leading to a more effective deposition. These results suggest that the use of IDK120-01 nozzle and neem oil can effectively reduce spray drift, lessen surface tension and enhance spreading. [ABSTRACT FROM AUTHOR]

Exposure to pesticide spray drift during the application of plant protection products (PPP) in orchards poses potential health risks to bystanders and residents. To address this concern, this study aimed to gather novel field data on exposure to spray drift in orchards. The research was conducted by the Julius Kuehn-Institute (JKI), the Federal Office of Consumer Protection and Food Safety (BVL), and the German Federal Institute for Risk Assessment (BfR). From 2018 to 2021, the method for conducting the field trials and analysis was implemented. The data from multiple series of performed field trials conducted between 2021 and 2022 allowed for collecting data on potential dermal exposure (PDE), inhalation exposure, and ground sediment. The trials considered various distances from the treatment area and drift-reducing techniques. Adult and child mannequins were used to simulate bystanders' exposure, and petri dishes were used to measure ground sediment. The results showed that drift reduction settings (75% drift reduction) considerably reduced exposure levels on the mannequins. Furthermore, a strong correlation between PDE values for adults and children located next to each other at the same distance was observed. This finding suggests a possibility to convert exposure results from adult to child mannequins. The study produced realistic exposure data for bystanders and residents next to a treated area. It contributes to a better understanding of exposure risks from PPP application and includes data for different distances and spray drift reducing technique. If taken into account for further development of the current risk assessment models, new risk management options for the safe application of PPP, including buffer strips or application of drift reducing systems, might be available in near future. [ABSTRACT FROM AUTHOR]

Soybean aphid (Aphis glycines) insecticides are used throughout the Upper Midwest and Great Plains regions of North America, including the farmland region of Minnesota, USA, to combat insect pests. These broad‐spectrum, foliar spray insecticides have the potential to drift beyond target fields into nearby grassland cover where birds and other insectivores forage. Arthropods serve important roles in grassland ecology and are susceptible to mortality and sublethal effects from exposure to these pesticides. Our objective was to assess effects of soybean aphid insecticides on grassland arthropods, especially those that are important in grassland bird diets. We measured the abundance, consumable biomass, and family richness of insects and spiders in grasslands adjacent to soybean fields in an agricultural landscape. Soybean fields were treated with chlorpyrifos and lambda‐cyhalothrin, which were the 2 most common foliar pesticides used to control soybean aphids in Minnesota. We compared measures at focal sites to samples collected at reference sites adjacent to corn fields not sprayed for aphids during 3 periods in mid‐to‐late summer: 1–3 days before spraying, 3–5 days post‐spraying, and 19–21 days post‐spraying. The abundance of arthropods in focal grasslands was lower 3–5 days after pesticide applications. Coleoptera family richness at focal sites was also lower than at reference sites 3–5 days after pesticide applications. These measures 19–21 days after application were similar to pre‐spraying levels, indicating that arthropod populations rebounded during this period. Measures of consumable dry biomass, bird prey abundance, bird prey biomass, family richness of Araneae, family richness of Hemiptera, and family richness of Orthoptera were not different between focal and reference sites after spraying. Our results reveal that reductions in arthropod food abundance for grassland birds are associated with pesticide applications up to 5 days after spraying. We suggest that natural resource managers factor proximity to row crop fields and susceptibility to pesticide drift into decisions about where to add grassland cover to landscapes. [ABSTRACT FROM AUTHOR]

Uncrewed Aerial Spray Systems (UASS) are being adopted at a rapid pace in agricultural applications of crop protection products. The data required to effectively regulate their use must be gathered to position UASS in terms of equivalency with other conventional practices. In Fall 2021, the CropLife America Drones Working Group initiated an effort to collect published information on establishing the equivalency of UASS applications with conventional application types as it relates to spray drift, operator exposure, crop residue, and efficacy. Based on the published literature, our comparison demonstrated that UASS spray drift is lower than aerial, higher than ground boom, and similar to orchard airblast applications. However, this comparison is based on limited data and needs further confirmation. Individual use cases and other application variables will need to be considered to determine if this generalization applies (e.g., adjuvant use, rotor and nozzle configuration, etc.). For operator exposure, this work supported the current consensus that applications with UASS have less potential for exposure in some respects (e.g., compared to backpack applications), but for other job steps that are unique to UASS (such as mixing and loading) more information is needed. With respect to crop residue, UASS applicators follow the label for conventional application techniques with the same directions for use (i.e., application rate, pre-harvest interval, and number of applications), but there is no evidence that pesticide residues resulting from a UASS application are any different to conventional application techniques. In terms of efficacy, applications with UASS tend to be equivalent to conventional methods; however, more information is needed, especially where good coverage is a requirement. The assessment of published literature on UASS demonstrates potential equivalency in certain key areas and supports the responsible use of this emerging technology, while more information on spray distribution within the target zone, off-target droplet movement, operator and bystander exposure, and pesticidal efficacy continues to be generated. [ABSTRACT FROM AUTHOR]

Herbicide volatility and drift are serious problems for chemical weed control. The extended use of dicamba, especially due to the commercial release of dicamba-resistant crops, revealed many off-target dicamba injury issues for sensitive crops. The objective of the present study is to give information on the chemical properties and volatility of dicamba and highlight some key issues, while a systematic review of the recently reported cases is attempted. Unfortunately, the problem is increasing, with a huge majority of the injuries reported in the USA, but it is also present in many other countries. Several arable, horticultural, and perennial crops suffer from such damage. Specific measures and approaches are suggested in order to quantify, reduce, and prevent such problems, while the training of farmers and stakeholders and further research are certainly required for the optimization of the several alternative options. [ABSTRACT FROM AUTHOR]

Nozzles are ubiquitous in agriculture: they are used to spray and apply nutrients and pesticides to crops. The properties of droplets sprayed from nozzles are vital factors that determine the effectiveness of the spray. Droplet size and other characteristics affect spray retention and drift, which indicates how much of the spray adheres to the crop and how much becomes chemical runoff that pollutes the environment. There is a critical need to measure these droplet properties to improve the performance of crop spraying systems. This paper establishes a deep learning methodology to detect droplets moving across a camera frame to measure their size. This framework is compatible with embedded systems that have limited onboard resources and can operate in real time. The method leverages a combination of techniques including resizing, normalization, pruning, detection head, unified feature map extraction via a feature pyramid network, non-maximum suppression, and optimization-based training. The approach is designed with the capability of detecting droplets of various sizes, shapes, and orientations. The experimental results demonstrate that the model designed in this study, coupled with the right combination of dataset and augmentation, achieved a 97% precision and 96.8% recall in droplet detection. The proposed methodology outperformed previous models, marking a significant advancement in droplet detection for precision agriculture applications. [ABSTRACT FROM AUTHOR]

BACKGROUND: Suspension concentrate (SC) is one of the most widely used formulations for agricultural plant protection. With the rapid development of unmanned aerial vehicle (UAV) plant protection, the problems of spray drift, droplet rebound and poor wettability in the application of SC from UAVs have attracted wide attention. Although some tank‐mix adjuvants have been used to enhance dosage delivery for UAV, their effects and mechanisms are not fully clear, and few formulations are specifically designed for UAV. RESULTS: The type and concentration of tank‐mix adjuvant affect the dosage delivery of SC. MO501 can significantly reduce DV<100μm, and inhibit droplet rebound on peanut leaves at concentrations ≥0.5%. Silwet 408 can achieve complete wetting and superspreading after adding ≥0.2% concentrations, but only ≥0.5% can inhibit rebound. XL‐70 shows excellent regulation ability even at low concentration, and 0.2% concentration can simultaneously suppress impact and promote spreading. Besides, the formulation oil dispersion (OD) can significantly reduce the driftable fine fraction and inhibit rebound at dilution ratios of ≤250‐fold, thus enhancing dosage delivery. CONCLUSION: SC is prone to rebound on hydrophobic leaf surfaces and shows poor wetting and spreading properties. Appropriate types and concentrations of tank‐mix adjuvants and formulation improvement are two effective strategies for improving the dosage delivery of pesticides, whereas the addition of inappropriate adjuvants may cause potential risks instead. These findings provide guidance for the rational selection of tank‐mix adjuvants and potential applications of OD for UAV plant protection. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: During unmanned aerial vehicles (UAVs) spraying, downwash and crosswind generate back pressure in comprehensive, which changes in spatial atomization characteristics of spraying droplets. However, the process of such atomization characteristics needs to be clarified. This study focuses on the effect of rotor speed and crosswind speed on spatial atomization characteristics. The computational fluid dynamics (CFD) models of the distributions of airflow, back pressure and atomization characteristics were established, and verification was conducted by developing a validation platform. RESULTS: The CFD results indicated that small droplets of 65–130 μm atomized by negative pressure would be coalesced near the nozzle, while large droplets of 390–520 μm atomized by positive pressure would be aggregated further away. Crosswind caused atomization stratification with droplet sizes of approximately 90 μm, 320 μm and 390 μm. When crosswind speed increased from 3 m/s to 6 m/s, the spraying drifted from 0.5 m to 1 m. When rotor speed increased from 2000 RPM to 3000 RPM, droplet distribution was expanded and droplet particle size was more uniform. Verification results demonstrated that the spraying distribution and the droplet size variation were consistent with the CFD. CONCLUSIONS: Spatial atomization characteristics were highly correlated with airflow and back pressure. Moreover, as crosswind generated droplet drift and atomization stratification and downwash could improve the uniformity of droplet distribution, spraying performance was superior by enhancing downwash to restrain the adverse effect of crosswind in real applications. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The pulse-width modulation (PWM) variable spray system is the most widely used variable spray system in the world at present, which has the characteristics of a fast response, large flow adjustment range, and good atomization. Recently, the pressure fluctuation and droplet deposition uniformity of the PWM variable spray system caused by the intermittent spray mode of the nozzle have attracted more and more attention. In this study, a method for eliminating the inhomogeneity of ground deposition in low-frequency PWM variable sprays based on a staggered-phase drive mode was proposed, and a PWM variable spray system was built. The experimental results indicated that the pressure fluctuation amplitude upstream of the nozzle of the PWM variable spray system with the staggered-phase drive was reduced by 40.91%, and the dispersion rate of the pressure fluctuation was reduced by 62.78% (the initial pressure was 0.3 MPa, solenoid valve frequency was 5 Hz, and duty cycle was 50%). The PWM control parameters had a significant effect on the upstream pressure fluctuation (initial pressure > duty cycle > frequency). The droplet spectrum relative span of the staggered phased PWM variable spray system decreased by 24.83%, the coefficient of variation of the droplet particle size decreased by 4.40%, the particle size was more uniform, and the atomization effect was improved. The average deposition of droplets in the forward direction driven by the staggered phase was 4.87% greater than that in the same phase, and the variation rate decreased by 20.87%. The average deposition amount increased, and the deposition became more uniform. Staggered-phase spray control could effectively reduce the inhomogeneity of deposition in low-frequency PWM intermittent spraying. This research provides strong technical support for a precision variable spraying effect and droplet drift prevention. [ABSTRACT FROM AUTHOR]

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BACKGROUND: We designed an umbrella wind‐field‐type anti‐drift spraying device to improve droplet deposit in the fruit tree canopy, reduce spray drift between fruit tree rows, and avoid uneven droplet deposit in the canopy. RESULTS: We used Computational Fluid Dynamics combined with wind field tests to optimize the parameters of the anti‐drift spray device, and the results showed that airflow velocity at the outlet of the device after optimization was 24.5 m s−1, which is 48% higher than that before optimization (16.5 m s−1) airflow velocity. We designed wind tunnel tests and field tests to analyze the anti‐drift characteristics of the anti‐drift spraying device. Wind tunnel test results showed that the side airflow velocity, outlet diameter, spray distance, and spray drift ratio were correlated. The mathematical models established by vertical and horizontal multifactor orthogonal tests were significant (P < 0.05, R2 0.947, 0.878, respectively). The results of the field tests showed that side airflow, velocity spray pressure and outlet diameter had significant effects on the droplet deposit characteristics (in descending order: the side airflow velocity, spray pressure, and outlet diameter). The maximum droplet deposit was 6.34 μL cm−2 when the side airflow velocity was 2 m s−1, the spray pressure was 0.4 MPa, and the outlet diameter was 70 mm2. When the side airflow velocity exceeded 2 m s−1, the outlet diameter and spray pressure had to be reduced to ensure better droplet deposit. CONCLUSION: The results indicated that the umbrella wind field could reduce spray drift and ineffective deposit in off‐target areas and provides a reference for the comprehensive analysis of the spray drift deposit law. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Plant pathogens with a broad host range are commercially more attractive as microbial bioherbicides than strictly host‐specific pathogens as a result of the wider market potential of a product capable of controlling multiple species. However, the perceived spatiotemporal disease risk to nontarget plants is a barrier to their adoption for weed control. We consider two approaches to managing this risk. First, we consider safety zones and withholding periods for bioherbicide treatment sites. These must ensure inoculum spreading from, or surviving at the site, exposes nontarget plants to no more inoculum than from natural sources. They can be determined using simple dispersal models. We show that a ratio of added:natural inoculum of 1.0 is biologically reasonable as an 'acceptable risk' and a sound basis for safety zones and withholding periods. These would be analogous to the 'conditions of use' for synthetic chemical herbicides aimed at minimizing collateral damage to susceptible plants from spray drift and persistent soil residues. Second, weed‐specific isolates of broad host‐range pathogens may avoid the need for safety zones and withholding periods. Such isolates have been found in many broad host‐range pathogen species. Their utilization as bioherbicides may more easily meet the requirements of regulators. Mixtures of different weed‐specific isolates of a pathogen could provide bioherbicides with commercially attractive spectrums of weed control activity. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Under soybean–corn intercropping in China, quizalofop-p-ethyl is recommended as a herbicide for stem and leaf treatment after soybean seedling. Nonetheless, herbicide drift during spraying may lead to environmental contamination and damage to the corn plants. In order to clearly show the threshold of the drift deposition amount of quizalofop-p-ethyl that causes herbicide damage to corn, we used a bioassay spray tower to spray quizalofop-p-ethyl herbicide on corn in the laboratory and a boom sprayer to spray quizalofop-p-ethyl herbicide, which drifts to corn in the field, to study and evaluate the damage quizalofop-p-ethyl herbicide causes to corn under different spray volumes and drift deposition rates. The results showed that under a drift deposition rate of 1% of three spray volumes, the corn showed no symptoms of herbicide damage and their plant height was not inhibited 14 days after spray; under a spray volume of 150 L/ha and a drift deposition rate of 5%, the corn showed symptoms of mild herbicide damage but their plant height was not inhibited 14 days after spray, while the corn showed symptoms of moderate herbicide damage and their plant height was slightly and moderately inhibited, respectively, under the spray volumes of 300 L/ha and 450 L/ha; under drift deposition rates of 10% and 30% of three spray volumes, half or more of the corn in each treatment withered and their plant height was severely inhibited or completely inhibited. Under the same spray volume, the symptoms of herbicide damage and the inhibition rate of plant height increased with the increase in the drift deposition rate; under the same drift deposition amount, the symptoms of herbicide damage and the inhibition rate of plant height increased with a decrease in the spray volume. The effect of the drift deposition rate on the symptoms of herbicide damage and plant height was extremely significant, but the spray volume was not significant. The drift deposition rates for 10% inhibition and no inhibition of corn plant height were 5.70% (R10) and 5.05% (R0) under spray volume of 150 L/ha, 4.56% (R10) and 1.23% (R0) under 300 L/ha, and 3.31% (R10) and 1.86% (R0) under 450 L/ha, respectively. When the herbicide was sprayed in the field using a soybean–corn-dedicated plant protection machine under the spray volume of 450 L/ha, the drift deposition rate ranged from 1.22% to 1.69%, and the corn did not produce symptoms of herbicide damage and plant height was not inhibited 14 days after the spray. In actual weeding operations, it is better to ensure that the drift deposition rate of quizalofop-p-ethyl is below R0 by setting reasonable operational parameters, using anti-drift nozzles or additives, and so on, and, at most, not more than R10. This study clarified the drift hazard of quizalofop-p-ethyl herbicide on corn and the safety value of the herbicide drift deposition amount, which provided data support for the standardized use of quizalofop-p-ethyl herbicide under soybean–corn intercropping and guidance for the safe production of field corn. [ABSTRACT FROM AUTHOR]

Avermectins (AVMs) are categorised as highly effective but toxic natural products isolated from Streptomyces avermitilis and are widely applied as antihelminthic and antiparasitic agents in agriculture and aquaculture. AVMs accumulated in the environment through runoff, spray drift, field drainage, or from pharmaceutical drugs used for aquatic farming, which resulted in toxic effects on nontarget aquatic and terrestrial organisms and caused residues in food products of animal origin. There was a lack of comprehensive overview for residual risk of AVMs in food products of animal origin and their research progress on toxicity and determination. This paper introduced the structure and chemical properties of AVMs, then updated and classified residue limits of AVMs in food products of animal origin established by Codex Alimentarius Commission (CAC), European Union (EU), United States, Japan, and China. The toxicity of AVMs and analytical methods of AVMs in food products of animal origin were summarized. Besides, the residues of AVMs in food products of animal origin were analyzed. Further researches for impacts of AVMs on environment and potential toxicological significance of food contamination by AVMs are needed to understand their risk in the environment and food chain. [ABSTRACT FROM AUTHOR]

In this research, the Volumetric Median Diameters (VMDs), Relative Span (RS), percentage of droplets with a diameter smaller than 100 µm (V100), and percentage of drift (% drift) of four droplet classes (Fine, Medium, Coarse, and Very Coarse) were analyzedin two spray volumes (77 L.ha-1and 144 L.ha-1) employinga tank-mix of atrazine and nicosulfuron herbicides (2500 + 15 gaiha-1), usingParticle/Droplet Imaging Analyze (PDIA) and wind tunnel techniques. The experiments were performed under Completely Randomized Design, in a 4 × 2 factorial scheme (droplet classes × sprayvolumes). Data underwent analysis of variance and Tukey's test at 5%, and the correlation between variables was computedconsidering Pearson's coefficient at 1% and 5%. The VMD of all droplet classes was considerably distinct in the two spray volumes. In both application spray volumes, the minimum VMD for the Coarsedropletclass classification was not attained. The highest means of RS were detectedin the spray volume of 77 L.ha-1. All treatments demonstratedsignificant differences in the analysis of V100 and % drift, with the highest means observed in the Fine droplet (144 L.ha-1) and Medium (77 L.ha-1). A negative correlation existed between VMD × V100 and VMD × % drift and a positive correlation between V100 × % drift in the two spray volumes. RS was negatively correlated with VMD and positively with V100 and % drift, in the spray volume of 77 L.ha-1. In the spray volume of 144 L.ha-1, the correlation between RSand VMD, V100, and % drift was insignificant. [ABSTRACT FROM AUTHOR]

Plant protection unmanned aerial vehicles (UAVs), which are highly adapted to terrain and capable of efficient low-altitude spraying, will be extensively used in agricultural production. In this paper, single or several independent factors influencing the deposition characteristics of droplets sprayed by plant protection UAVs, as well as the experimental methods and related mathematical analysis models used to study droplet deposition and drift, are systematically investigated. A research method based on farmland environmental factors is proposed to simulate the deposition and drift characteristics of spray droplets. Moreover, the impacts of multiple factors on the droplet deposition characteristics are further studied by using an indoor simulation test system for the spraying flow field of plant protection UAVs to simulate the plant protection UAVs spraying flow field, temperature, humidity and natural wind. By integrating the operation parameters, environmental conditions, crop canopy characteristics and rotor airflow, the main effects and interactive effects of the factors influencing the deposition of spray droplets can be explored. A mathematical model that can reflect the internal relations of multiple factors and evaluate and analyze the droplet deposition characteristics is established. A scientific and effective method for determining the optimal spray droplet deposition is also proposed. In addition, this research method can provide a necessary scientific basis for the formulation of operating standards for plant protection UAVs, inspection and evaluation of operating tools at the same scale, and the improvement and upgrading of spraying systems. [ABSTRACT FROM AUTHOR]

Efficient collection of airborne spray is crucial to reduce environmental contamination and ensure effective pesticide application in agriculture. This study explored the efficacy of passive spray drift samplers, focusing on string collectors for capturing airborne spray droplets. String collectors were assessed in laboratory experiments using a spray drift tunnel. A notable average recovery rate of 82% was observed when string collectors were examined immediately after pesticide capture. Collection efficiency was found to increase with wind speed. Of all the string collectors, string #5, a yarn type, demonstrated consistent collection efficiency, meeting the criteria for passive samplers. This includes effective droplet capture at low wind speeds, a high recovery rate of 93.31%, and suitability for field experiments. Field evaluations further underlined the efficiency of string #5, showcasing its ability to capture spray drift across a wider area and varied heights with less effort and manpower compared to traditional nylon screens. [ABSTRACT FROM AUTHOR]

In orchard plant protection application, an anti-drift strategy can effectively reduce drift in the non-target area, reduce spray drift in the environment, and avoid spray leakage and overspraying. To clarify the future development direction of orchard plant protection mechanization technology, this review introduces the development status of an anti-drift spray nozzle and the impact of different types of spray nozzles on the potential of drift, and then, it analyzes the research progress on air-assisted spraying, recycling spraying, profiling spraying, target variable spraying technologies, and plant protection UAVs. It also provides a general analysis of the above spraying technologies on the amount of drift and the impact of pesticide deposition. Finally, combined with the characteristics of orchard plant protection, the paper presents the research and development of anti-drift nozzles, pesticide adjuvant, air-assisted spraying technology, electrostatic, recycling spraying technology, profiling and target variable spraying technology, and plant protection UAVs. The review provides a reference for the development of an anti-drift strategy for orchard plant protection production. [ABSTRACT FROM AUTHOR]

One practice to reduce spray drift during pesticide application is the addition of certain chemical adjuvants to spraying solutions, which change their physicochemical properties and result in larger droplets. The environmental impact of these agrochemicals continues however also after application, depending on surface processes occurring upon treated surfaces. While the impact of anti-drift adjuvants has been studied regarding spray drift, their impact on the fate of deposited pesticides has received little attention. Here, the effect of a polymer-based adjuvant (polyacrylamide) on the photolysis and evaporation rates of pyrimethanil (common fungicide) from dry films were investigated under controlled laboratory conditions and during two field studies. The laboratory results indicate that the adjuvant enhances the volatilization and photolysis rate both on hydrophobic lemon leaves and hydrophilic glass substrates. These results can be attributed to an increase in the geometrical area of residual film and a widening of its circumference rim, where solutes are likely to concentrate, when generated from adjuvant-containing droplets. Such morphological differences may enhance the exposure of deposited pesticides to interact with the overlaying atmosphere and incident radiation. The field data was less conclusive, suggesting a small impact of the anti-drift adjuvant on the fungicide's secondary drift from crops and an even lower effect on volatilization from bare soil. [ABSTRACT FROM AUTHOR]

The application of pesticides is not simply delivering chemicals to the target area. It also involves considering the negative aspects and developing strategies to deal with them during the application process, to ensure the maximization of pesticides use efficiency and the maintenance of the ecosystem. Unmanned aerial vehicle (UAV) sprayers demonstrate unique advantages compared to traditional ground sprayers, particularly in terms of maneuverability and labor intensity reduction, showed great potential for chemical application in pest control. It is undeniable that there exist challenges in the practice of UAV spraying, such as higher potential risks of pesticide drift or pathogen transmission, uncertainty canopy deposition for different crops, and unexpected leaf breakage induced by downwash flow. Maximizing the utilization of downwash flow while avoiding lateral air movement outside the intended target crop area is a major issue for chemical application with UAV sprayers, particularly in light of the increasingly apparent consensus on the need for enhanced environmental protection during the chemical application process. It must be considered that the operation strategy in different scenarios and for different crop targets is not the same, unique requirements should be given on nozzle atomization, flight parameters, adjuvants and aircraft types in specific working situations. In future, the implementation of spray drift prediction, technical procedures development, and other solutions aimed at reducing pesticide drift and improving deposition quality, is expected to promote the adoption of UAV sprayers by more farmers. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Pesticide spray drift, which is the movement of pesticide by wind to any location other than the intended area, is hazardous to human, animal, food safety and environmental health. It is not possible to completely eliminate spray drift during spraying with field crop sprayers, but spray drift can be reduced by developing new technologies. The most common methods to reduce spray drift are carrying the droplets to the target with air‐assisted spraying, electrostatic spraying, preferring air induction nozzles and boom shields. With these methods, it is not possible to make a change on the sprayer depending on the wind intensity during spraying. In this study, a novel servo‐controlled spraying system was designed and developed to change the nozzle orientation angle in the reverse direction of the wind current to reduce the ground spray drift in real time and automatically in a wind tunnel. The displacement in the spray pattern (Dc) was used as a ground drift indicator for each nozzle to evaluate the spray drift. Results: The developed system, operated by LabVIEW software, calculated different nozzle orientation angles depending on nozzle types, wind velocities and spraying pressures. Orientation angles calculated for different test conditions achieved in reduction were up to 49.01% for XR11002 nozzle, 32.82% for AIXR11002 nozzle and 32.31% for TTJ6011002 nozzle at 400 kPa spray pressure and 2.5 m s−1 wind velocity. Conclusion: The developed system, which has a self‐decision mechanism, calculated the nozzle orientation angle instantaneously according to the wind velocity. It has been observed that the adjustable spraying nozzle system, sprayed with high precision towards the wind in the wind tunnel, and the developed system have advantages compared to conventional spraying systems. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

To obtain a more consistent droplet distribution and reduce spray drift, it is necessary to keep the entire spray boom parallel to the crop canopy or ground and maintain a certain distance from the spray nozzles to the crop canopy or ground. A high-performance boom active control system was developed for boom trapezoid suspension. The hydraulic system and hardware circuit of the boom control system were designed based on analyzing the configuration of active trapezoid suspension. The mathematical models of valve-controlled hydraulic cylinders and active boom suspensions were developed. Step response and frequency domain response analysis of passive suspension were conducted by Simulink simulations, and then key parameters of the boom suspension and hydraulic system were determined. A feedforward proportion integration differentiation (FPID) control algorithm was proposed to improve the tracking performance. The designed control system was assembled on a 24 m boom with trapezoid suspension. The response characteristic of the active boom control system was tested by the step signal and the sinusoidal signal from a six-degree-of-freedom hydraulic motion platform. Firstly, the tracking performance of the active balance control system for the PID (proportion integration differentiation) and FPID control algorithms was compared for a given 0.2 Hz sine signal. Then, for the ground-following control system, the response characteristics in challenging terrain and tracking performance in less challenging terrain were tested. Field experiment results indicate that the maximum rolling angle of the chassis was 3.896 ° while the maximum inclination angle of the boom was 0.453 ° . The results show that the designed boom adjustment and control system can effectively adjust the boom motion in real time and meet the requirements of field operation. [ABSTRACT FROM AUTHOR]

Pesticides have been widely used in agriculture, resulting in significant pollution that affects both the environment and human health. This pollution is particularly prevalent in nearby agricultural areas, where sensitive resources are contaminated through spray drift exposure and surface runoff. Spray drift is a critical concern when it comes to environmental hazards. It poses health risks not only to farmers and pesticide applicators, but also to individuals living in nearby farm areas. To address this issue, developing reliable models and techniques for estimating spray drift and reducing its impact has become a crucial and efficient research topic. The current research has three primary objectives: firstly, to estimate the average pesticide application rates, trend analysis, and concentration distribution; secondly, to estimate the temporal variations of pesticide concentrations and identify the areas most likely to be affected by pesticide spray drift close to agricultural fields; and lastly, to develop a model for field spray drift and deposition integration between the OpenAir package for the R programming environment and the AgDRIFT atmospheric model. The drift model, along with precise supervised classifications, allowed for a more accurate estimation of potential drift in agricultural areas at a spatial resolution of 15 m. Additionally, multiple scenarios were conducted to evaluate the potential risks of pesticide drift outside of the target areas. This novel method effectively estimated organophosphate pesticide spray drift over two case studies in Macon County using a combination of OpenAir and AgDRIFT models and remotely sensed data. This method allowed for field simulations within completely defined exposure areas with little prior knowledge of pesticide quantities. This study concluded that 6% of total cropland is in danger of pesticide spray drift, with around 8% of crop areas exposed to potential strong drift on land use. Furthermore, 11% of cropped land is vulnerable to moderate drift, whereas around 75% of land use land cover is not vulnerable to pesticide drift. Through this research, an accurate and efficient approach has been developed to estimate spray drift and reduce its impact in agricultural areas, contributing to a safer and healthier environment for all. [ABSTRACT FROM AUTHOR]

New spraying systems embedded with different technologies have been developed for pesticide application in 3D crops. However, while applied to specific tree crops, the potential spray drift mitigation for advanced spraying systems needs to be classified due to the great variability of spray equipment and canopy structure. Here a precision spraying system was developed and compared with two typical spraying systems (conventional system, optimized system following the best management practices) for the applied volume/pesticide and spray drift in an apple orchard at two growth stages following the ISO22866-2005 protocol. Compared to the conventional system, the other two advanced systems significantly reduced the amount of ground drift (> 60%) at most of the sampling distances at the growth stage BBCH 72, while the precision system demonstrated the best drift mitigation (57.3% reduction) at the stage BBCH 99. For the airborne drift, a remarkable drift reduction was also achieved with the two advanced systems. Specifically, the optimized spraying system exhibited a drift reduction by approximately 80% at the first growth stage, and the precision application demonstrated its considerable advantages in minimizing drift loss for the sparse canopy at the stage BBCH 99. Moreover, the saving of applied volume/pesticide was achieved by 12% with the optimized system and 43% with the precision system. This study revealed the necessity and prospect of the advanced spraying systems to reduce the environmental contamination and health risk from pesticide applications in fruit tree production. [ABSTRACT FROM AUTHOR]

Spray drift is a major contributor to pesticide losses in the atmosphere leading to nontargeted ecosystem exposure. An overview of currently used ground-application spray drift models highlighted gaps in the description of the processes occurring during and after spraying. The ADDI-Spraydrift model was developed to bridge some of these gaps and provide a comprehensive, yet concise description of spray drift processes. The model is based on a random walk approach that describes droplet emission, dispersion and evaporation, ground deposition and canopy interception, and accounts for atmospheric stability regimes, and in-canopy turbulence. It predicts airborne concentration, canopy interception and deposition to the ground downwind from the sprayer. The sensitivity analysis to wind speed, active matter content, leaf angle, canopy height, leaf area index, ejection angle and velocity demonstrated the consistency of the model behaviour. The model was calibrated and evaluated against the Ganzelmeier et al. (1995) sedimentary spray drift data in vineyards. The model satisfactorily predicted droplets deposition to the ground downwind from the field boundary with a mean deviation between modelled and measured deposition of 1.3%. A discrepancy was observed at 3 and 5 m downwind from the field boundary attributed to the sensitivity to spraying conditions for which several hypotheses are discussed. Bearing in mind the need to explicitly describe the emitted droplet size and velocity, the overall predictive performance of the model appeared to be sufficient for assessing and comparing application techniques efficiency, quantifying pesticide loss and bystanders or resident exposure and evaluating the efficiency of mitigation measures. [Display omitted] • Model estimates spray drift and crop interception for ground sprayers. • Model is based on a random walk approach integrating spray drift key processes. • Model predictions are highly sensitive to droplet ejection characteristics. • Model predictions well represent Ganzelmeier drift experiments on vineyards. • Model is expected to be valuable for impact studies of spray drift. [ABSTRACT FROM AUTHOR]

Use of hooded sprayers to mitigate spray particle drift during pesticide applications in cotton has not been investigated. Therefore, experiments were conducted in cotton fields in 2021 and 2022 to compare particle drift of dicamba applied with open and hooded broadcast sprayers at six different spray qualities: Fine (F), Medium (M), Coarse (C), Very Coarse (VC), Extremely Coarse (EC), and Ultra Coarse (UC). A fluorescent tracer dye was mixed and applied with the dicamba solution to measure drift deposition at different downwind distances up to 105 m from the target area. Results showed particle drift for F and M spray qualities applied with a hooded sprayer were reduced up to 94% and 77%, respectively, out to 10 m downwind from the application area compared to the open boom sprayer. Hooded sprayer decreased particle drift for C and VC spray qualities as well but only for short distances downwind (= 5 m). Sprayer type did not affect the particle drift for EC and UC spray qualities and it was also significantly lower than other spray qualities across both sprayer types. From 20 to 60 m downwind, dicamba applications with hooded sprayer exhibited as much as 42% less drift than open boom sprayer applications regardless of the spray quality. These data suggested that hooded sprayers are effective in reducing particle drift in cotton and thus can be utilized as a viable spray drift management technique for herbicide applications in cotton. [ABSTRACT FROM AUTHOR]

Wind drift and evaporation loss (WDEL) of mid-elevation spray application (MESA) and low-elevation spray application (LESA) sprinklers on a center pivot and linear-move irrigation machines are measured and reported to be about 20% and 3%, respectively. It is important to estimate the fraction of WDEL that cools and humidifies the microclimate causing evapotranspiration (ET) suppression, mitigating the measured irrigation system losses. An experiment was conducted in 2018 and 2019 in a commercial spearmint field near Toppenish, Washington. The field was irrigated with an 8-span center pivot equipped with MESA but had three spans that were converted to LESA. All-in-one weather sensors (ATMOS-41) were installed just above the crop canopy in the middle of each MESA and LESA span and nearby but outside of the pivot field (control) to record meteorological parameters on 1 min intervals. The ASCE Penman–Monteith (ASCE-PM) standardized reference equations were used to calculate grass reference evapotranspiration (ETo) from this data on a one-minute basis. A comparison was made for the three phases of before, during, and after the irrigation system passed the in-field ATMOS-41 sensors. In addition, a small unmanned aerial system (UAS) was used to capture 5-band multispectral (ground sampling distance [GSD]: 7 cm/pixel) and thermal infrared images (GSD: 13 cm/pixel) while the center pivot irrigation system was irrigating the field. This imagery data was used to estimate crop evapotranspiration (ETc) using a UAS-METRIC energy balance model. The UAS-METRIC model showed that the estimated ETc under MESA was suppressed by 0.16 mm/day compared to the LESA. Calculating the ETo by the ASCE-PM method showed that the instantaneous ETo rate under the MESA was suppressed between 8% and 18% compared to the LESA. However, as the time of the ET suppression was short, the total amount of the estimated suppressed ET of the MESA was less than 0.5% of the total applied water. Overall, the total reduction in the ET due to the microclimate modifications from wind drift and evaporation losses were small compared to the reported 17% average differences in the irrigation application efficiency between the MESA and the LESA. Therefore, the irrigation application efficiency differences between these two technologies were very large even if the ET suppression by wind drift and evaporation losses was accounted for. [ABSTRACT FROM AUTHOR]

Spraying is the most widely used method for pesticide application and the resulting spray drift has become a major concern. Reliable spray simulations can help to better understand this phenomenon and evaluate methods to prevent it. This paper proposes a methodology to set up a computational fluid dynamics simulation of sprays. A number of benchmark flows were studied to assess the accuracy of the proposed method. The simulation of a jet in a crossflow was able to capture counter-rotating vortex pairs and the predicted trajectory agreed with experimental data. A multiple-injector technique is then used to replicate the velocity distribution of sprays without modelling the liquid sheet breakup. Spray simulations were able to capture air entrainment and predicted a realistic droplet distribution pattern. The volume of droplets deposited on the collector lines in drift simulations was in good agreement with experimental data in the near field. As the droplets moved further downstream, however, a deviation between the simulation results and experimental data was observed. The drift simulation results indicated that in a wind speed of 2 m s − 1 , droplets of diameter < 75 μ m are prone to drift. • Trajectory and velocity of a jet in crossflow agreed well with experimental data. • Droplet deposition on collector lines in drift simulations was predicted well. • Multi-injector technique successfully replicated velocity distribution. • Droplets <75 μm diameter were prone to drifting long distances from the nozzle. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate dicamba off‐target movement during and after applications over soybean at two growth stages. Dicamba‐tolerant soybean [Glycine max (L.) Merr.] at V3 and R1 growth stages in Nebraska and Mississippi fields were treated with diglycolamine salt of dicamba (560 g ae ha−1), potassium salt of glyphosate (1260 g ae ha−1), and a drift‐reducing adjuvant (0.5% v v−1). Filter papers positioned outside the sprayed area were used to determine primary movement and air samplers positioned at the center of sprayed area were used to calculate dicamba flux from 0.5 up to 68 hours after application (HAA). Flux was calculated using the aerodynamic method. Soybean growth stage did not affect dicamba deposition on filter papers from 8 to 45 m downwind from the sprayed areas. At 33 m downwind (i.e., distance of the labeled buffer zone), a spray drift of less than 0.0091% (0.05 g ae ha−1) of applied rate is estimated. Dicamba secondary movement may not be affected by soybean growth stage during the application. Although dicamba was detected in air samples collected at 68 HAA, the majority of the secondary movement was observed in the first 24 HAA. Dicamba cumulative loss was lower than 0.77% of applied rate. Results suggest the more stable the atmospheric conditions, the higher the dicamba flux. Thus, meteorological conditions after applications must be considered, and tools to predict the occurrence of temperature inversion are needed to minimize secondary movement of dicamba. Core Ideas: Soybean growth stage had minor influence on off‐target movement of dicamba.The highest dicamba flux was observed in the first 30 h after application.Dicamba cumulative loss was lower than 0.77% of applied rate. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Air-assisted spraying technology is widely used in orchard sprayers to disturb canopy leaves and force droplets into the plant canopy to reduce droplet drift and increase spray penetration. A low-flow air-assisted sprayer was developed based on a self-designed air-assisted nozzle. The effects of the sprayer speed, spray distance, and nozzle arrangement angle on the deposit coverage, spray penetration, and deposit distribution were investigated in a vineyard by means of orthogonal tests. The optimal working conditions for the low-flow air-assisted sprayer working in the vineyard were determined as a sprayer speed of 0.65m/s, a spray distance of 0.9m, and a nozzle arrangement angle of 20°. The deposit coverages of the proximal canopy and intermediate canopy were 23.67% and 14.52%, respectively. The spray penetration was 0.3574. The variation coefficients of the deposit coverage of the proximal canopy and intermediate canopy, which indicate the uniformity of the deposition distribution, were 8.56% and 12.33%, respectively. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A model canopy offers the advantage of being able to compare drift characteristics of sprayers under standardized conditions and independently from the season. A steel structure covered with a net similar to the EvaSpray- Viti viticulture test stand was developed to mimic a common orchard. The selection of the net was made on the basis of preliminary tests on droplet and wind permeability. A net with mesh size of 1.38 mm by 1.38 mm was found best suited to reproduce the characteristics of a natural foliage and was used to cover the six-row model layout. Drift measurements were carried out with different types of sprayer design in the model system and in orchards. The drift reduction values showed a good congruence. The drift behaviour of the sprayers could be realistically reproduced in the model system. The effect of different nozzles and reduced working pressure could also be shown in the model canopy. Further measurements at other locations are required to demonstrate reproducibility. [ABSTRACT FROM AUTHOR]

Residents and bystanders may be exposed to spray drift during application of plant protection products. The assessment of possible risks is carried out on the basis of a harmonized exposure model of EFSA. For orchards and vineyards, there are currently still gaps in the assessment. These data gaps have been addressed by BVL, JKI and BfR in a joint project. The development of a robust method to perform reproducible field trials was a core element of the project. The fluorescent dye pyranine served in the trials as a readily detectable substitute for real plant protection products. In the course of several years of optimization, suitable clothing was identified for mannequins representing adults and children. Tyvek® coveralls proved suitable for detecting even small amounts of dye with high accuracy. The development process provides the basis for a JKI guideline for preparing and conducting field trials. The different development stages are described here. The data generated with the developed method will enable EFSA to improve the exposure assessment models. [ABSTRACT FROM AUTHOR]

Field experiments according to ISO 22866 were conducted to determine the spray drift from Unmanned Aerial Spraying Systems (UASS) applying plant protection products (PPP) in vineyards in order to collect data that can be used for drift risk assessment by authorities. Different octocopters, nozzles (standard and air induction), application parameters (height, speed) and flight patterns (longitudinal and lateral flight lines) were used. The drift sediment at distances up to 20 m was compared to the German basic drift values for crewed helicopters and ground based air blast sprayers. In comparison to PPP applications with crewed helicopters, the spray drift risk is substantially lower when using UASSs. For air induction nozzles, the 90th percentile values of drift sediment are even lower than the basic drift values for ground equipment. This is why, similar to crewed helicopters, UASSs should be equipped with drift reducing atomisers, such as air induction nozzles. Providing this, the existing basic drift values for vineyards would apply also for drift risk assessment for UASS applications. [ABSTRACT FROM AUTHOR]