Orchard Sprayer Research Articles

BDS/IMU Integrated Auto-Navigation System of Orchard Spraying Robot

To improve the accuracy and reliability of orchard spraying robots, an integrated navigation system was developed, consisting of a real-time kinematic positioning-Beidou satellite navigation system (RTK-BDS) receiver, an inertial measurement unit (IMU), a navigation controller, and servo motors. Using the loose coupling combination method, an error Kalman filter algorithm based on the measurement of position and heading angle is implemented to correct the error of the inertial measurement unit in real time. Combining the kinematics model and the pure pursuit model of the spraying robot, a path-tracking control algorithm is proposed. Path planning was conducted according to the terrain characteristics of orchards. Field experiments were carried out on a spraying robot to evaluate the proposed auto-navigation system. The results showed that when the spraying robot was static, the positioning performances of BDS alone and that of the BDS/IMU combined system were similar, the positioning error was less than 1.5 cm, and the heading angle errors were within 0.3°; when the spraying robot moving alone to a straight line at the speed of 0.4 m/s, the position error of the navigation system only using BDS was less than 5.29 cm, the heading angle error was within 3°, while the position error of BDS/IMU integrated navigation system was less than 2.49 cm, and the heading angle error was within 2°. The accuracy of BDS/IMU integrated navigation system is significantly improved. When the orchard spraying robot was moving at the speed of 0.4 m/s, the maximum offset error was lower than 10.77 cm, the average offset error was not higher than 3.55 cm, and the root mean square error (RMSE) of the lateral deviation was 1.19 cm. The results showed that the proposed auto-navigation system could make the spraying robot track the pre-set path smoothly and stably.

Multibody Dynamics Simulation and Vibration Test for High Clearance Orchard Sprayer

High clearance sprayer is a high-efficiency pesticide application machine in orchard management. In this paper, operational safety of high clearance sprayers is validated by using finite element simulation and vibration testing. The 3D model of the frame is simplified by using shell units instead of solid units, the static performance of high clearance sprayer frames under static full load and ultimate torsional conditions was studied by means of finite element simulation tests, the mechanical properties of the frame under step excitation were studied by multi-body dynamic simulation test. The simulation results show that, at a safety factor of 1.5, the maximum stress extremes in the frame are within the safe permissible stress range. During the dynamics analysis, a tire-ground contact simplified model was proposed. The results of the modal analysis show that the inherent frequency distribution of the high clearance sprayer is compact, and the vibration test has measured a large difference between the engine vibration frequency with the inherent frequency of the frame, this means that resonance will not occur. The theoretical analysis shows that the designed high clearance sprayer meets the requirements of large cross-row field operations, the study provides a reference for the overall design of the high clearance sprayer.

Design and development of orchard autonomous navigation spray system.

Driven by the demand for efficient plant protection in orchards, the autonomous navigation system for orchards is hereby designed and developed in this study. According to the three modules of unmanned system “perception-decision-control,” the environment perception and map construction strategy based on 3D lidar is constructed for the complex environment in orchards. At the same time, millimeter-wave radar is further selected for multi-source information fusion for the perception of obstacles. The extraction of orchard navigation lines is achieved by formulating a four-step extraction strategy according to the obtained lidar data. Finally, aiming at the control problem of plant protection machine, the ADRC control strategy is adopted to enhance the noise immunity of the system. Different working conditions are designed in the experimental section for testing the obstacle avoidance performance and navigation accuracy of the autonomous navigation sprayer. The experimental results show that the unmanned vehicle can identify the obstacle quickly and make an emergency stop and find a rather narrow feasible area when a moving person or a different thin column is used as an obstacle. Many experiments have shown a safe distance for obstacle avoidance about 0.5 m, which meets the obstacle avoidance requirements. In the navigation accuracy experiment, the average navigation error in both experiments is within 15 cm, satisfying the requirements for orchard spray operation. A set of spray test experiments are designed in the final experimental part to further verify the feasibility of the system developed by the institute, and the coverage rate of the leaves of the canopy is about 50%.

Timing of Ethylene Inhibition Affects Internal Browning and Quality of 'Gala' Apples in Long-Term Low Oxygen Storage.

The objective of this study was to evaluate the timing of ethylene inhibition with preharvest and postharvest 1-methylcyclopropene (1-MCP) treatments on internal browning and quality of ‘Gala’ apples in long-term low O2 storage. ‘Gala’ apples were obtained from the same commercial orchard during their harvesting period for 2 years of study. Preharvest 1-MCP orchard spray (3.8% a.i) was applied at the label rate of 60 g 1-MCP per acre in the first year. Postharvest 1-MCP (1 μl L−1) treatments were made for 24 h at 0.5°C either at harvest time (1 day after harvest) or after storage in controlled atmosphere (CA) in both years. Apples were stored in 1.5 kPa O2 + 0.5 kPa CO2 or 0.6 kPa O2 + <0.5 kPa CO2 for 9 months in the first year and 1.5, 1.0, or 0.5 kPa O2 + 0.5 kPa CO2 for 8 months in the second year. Storage regimes with O2 concentrations less than 1 kPa were based on fruit respiration using SafePod™ technology. After removal from storage, all apples were then evaluated for internal browning and other quality attributes after 1, 7, and 14 days at room temperature (RT, 21–22°C). Internal browning developed in ‘Gala’ apples during both years of study, with up to 16% incidence across treatments in the first year and up to 84% in the second year. Apples stored in 0.5–0.6 kPa O2 had significantly less internal browning during both years of study, compared to apples stored in higher O2. The effect of 1-MCP on internal browning was negligible in 0.5–0.6 kPa O2 storage. ‘Gala’ stored in 1.5 kPa O2 and treated with postharvest 1-MCP after storage had significantly less internal browning with preharvest 1-MCP than those without preharvest treatment. Apples treated with postharvest 1-MCP at harvest time, instead of after storage, did not exhibit this same effect. Preharvest 1-MCP-treated fruit maintained greater firmness retention than those without preharvest 1-MCP, and this effect was further enhanced when 1-MCP was applied after storage. Postharvest 1-MCP had no effect on firmness retention in fruit without preharvest 1-MCP, but lower O2 maintained greater firmness in those apples. Preharvest 1-MCP had no significant effect on internal ethylene concentration, whereas it was reduced by postharvest 1-MCP at harvest time in the first year of study, regardless of storage regimes. However, internal ethylene was only affected by storage regime in the second year, with lower concentration in fruit from 0.5 kPa O2 than in those from higher O2. Greasiness developed only in the second year and postharvest 1-MCP consistently reduced it, regardless of treatment timing and storage regime. There was no greasiness in apples treated with postharvest 1-MCP at harvest and then held in 0.5 kPa O2 for 8 months plus 14 days at room temperature. Soluble solids concentration and malic acid content were slightly higher in ‘Gala’ apples with preharvest 1-MCP compared to those without, whereas there was little and inconsistent effect of postharvest 1-MCP on these attributes. Overall, storage regimes with less than 1 kPa O2 provided the least amount of internal browning and best quality attributes. Ethylene inhibition provided further benefits, but this was dependent on the timing of 1-MCP treatment.

Canopy Segmentation Method for Determining the Spray Deposition Rate in Orchards

The effective quantification of deposition rate is of vital importance in optimizing the application performance and the utilization of pesticides; meanwhile, the canopies of fruit tree orchards are large, with dense branches and leaves shading each other, making it difficult to quantify spraying efficiency. Therefore, it is imperative to develop a facile methodology for assessing the performance of different spraying techniques in terms of distribution and utilization rate in orchards. To evaluate spraying efficacy in orchards, a canopy segmentation method was developed in to be able to determine the spray deposition rate. The distribution and deposition rate of spray liquid applied using three kinds of orchard sprayer were measured in a pear orchard and a peach orchard. The test results showed that the trailer sprayer had the highest deposition rates, with values of 31.54% and 56.92% on peach and pear trees, respectively. The deposition rates of the mounted sprayer in the peach and pear canopies were 21.75% and 40.61%, and the rates of the hand-held sprayer were 25.19% and 29.97%, respectively. The spray gun had the best droplet distribution uniformity, with CVs of the spray in the peach and pear canopies of 20.54% and 25.06%, respectively. The CVs in the peach and pear canopies were 35.98% and 26.54% for the trailer sprayer, and the CVs of the mounted sprayer were 92.52% and 94.90%, respectively. The canopy segmentation method could effectively be used to calculate the deposition rate and drioplet distribution in orchard application, while a great deal of time was consumed by counting the number of leaves in the different areas of the fruit tree canopies. Therefore, research on the density of branches and leaves in fruit tree canopies should be carried out in order to improve the efficiency of fruit tree canopy information extraction.

Numerical Experiment and Optimized Design of Pipeline Spraying On-Line Pesticide Mixing Apparatus Based on CFD Orthogonal Experiment

Pipeline spraying can be adopted for greatly improving spraying efficiency in hillside orchard spraying operations. However, residual phytosanitary product still remains in the pipeline after the completion of pipeline spraying operations. Currently, residual phytosanitary liquid is handled according to the following general method: pipeline flushing with fresh water. The method can easily lead to pesticide waste and environment pollution. On-line pesticide mixing technology can be adopted for reducing pesticide waste and environmental pollution. However, on-line pesticide mixing technology is not applied in pipeline spraying operations. Therefore, the mixing principle of jet-mixing apparatus is adopted as a reference in the paper for designing the basic structure of on-line pesticide mixing apparatus based on pipeline spraying. The structure is mainly composed of a constricted tube, suction chamber, Venturi, and diffusion tube. An analysis method based on the CFD orthogonal experiment is adopted for studying the influence of the changes of four key structure parameters on on-line pesticide mixing apparatus, pesticide dissolution performance, and pesticide mixing performance; the four parameters include constricted tube falloff angle, diffusion tube divergence angle, Venturi diameter, and Venturi length. Since there may be interaction among them, three experiment evaluation indexes of lifting height, turbulent kinetic energy, and pressure recovery distance are set for judgment. The change of three evaluation indexes with change of constricted tube falloff angle, diffusion tube divergence angle, Venturi diameter, and Venturi length, respectively, is revealed through single-index variance analysis; the three indexes include lifting height, turbulent kinetic energy, and pressure recovery distance. The primary and secondary sequences of respective influences of all structure parameters and their interaction on all evaluation indexes are obtained. Analysis results of all evaluation indexes are comprehensively considered in order to finally discover the comprehensive optimal pesticide mixing apparatus structure parameters, namely: constricted tube falloff angle is 22°, diffusion tube divergence angle is 9°, Venturi diameter is 2 mm, Venturi length is 6 mm, and pesticide mixing apparatus structure parameters are optimized. Theoretical reference is provided in the paper for on-line pesticide mixing apparatus prototype production on the basis of pipeline spraying.

Characterisation of activation pressure, flowrate and spray angle for hollow-cone nozzles controlled by pulse width modulation

Pulse width modulation (PWM) solenoid valves are used for controlling flowrates of hollow-cone nozzles on variable-rate air-assisted orchard sprayers. However, little information is available on the spray characteristics of these PWM-controlled nozzles. Laboratory tests were performed to evaluate the influences of duty cycles of two different design PWM solenoid valves along with five operating pressures on spray characteristics of five hollow-cone nozzles with different disc-core combinations. Parameters of the spray characteristics investigated were nozzle flowrates, upstream and downstream pressures of the PWM valves, nozzle activation pressures and times, and spray angles of water discharged from nozzles. Test results illustrated that these parameters except for the spray angle were greatly affected by the operating pressure, nozzle selection (disc orifice size and quantity of holes on core), PWM duty cycle and solenoid valve design. Spray angles were affected by the duty cycle but not by the PWM valve design. In general, nozzles with larger disc orifice and higher operating pressures resulted in higher flowrates as expected, whilst the nozzle activation pressure and the spray angle decreased as the duty cycle decreased. Thus, when designing orchard sprayers for precision variable-rate pesticide applications, variations in spray characteristics of disc-core type hollow-cone nozzles controlled by PWM solenoid valves should be considered and minimised. This prospect could be facilitated by establishing a digital database of these characteristics.

Evaluation of the Effects of Airflow Distribution Patterns on Deposit Coverage and Spray Penetration in Multi-Unit Air-Assisted Sprayer

Efficient utilization is a pre-requisite for pesticide reduction, and appropriate airflow distribution pattern plays a key role in enhancing the effectiveness of pesticide application by air-assisted orchard sprayers, yet the mechanism of this is unclear. In order to clarify the specific effects of airflow velocity and direction on spraying efficacy, a series of spray tests on pear and cherry and airflow distribution tests in open areas were conducted by a multi-unit air-assisted sprayer on ten different fan settings. Several deposit indicators were analyzed and contrasted with the air distribution. The results showed that an increase in airflow velocity inside the canopy improved the abaxial side deposit coverage of both pear (from 3.33% to 11.80% in the Top canopy and from 6.26% to 11.00% in the Upper canopy) and cherry leaves (from 3.61% to 10.87% in the Top canopy, from 1.36% to 9.04% in the Middle canopy, and from 3.40% to 9.04% in the Bottom canopy), but had no significant effect on the spray penetration. The correlation between deposit indicators and airflow velocities/directions was evaluated, and the results indicated that the enhanced airflow velocities, both in the forward and horizontal direction, improved the abaxial side deposit coverage (CAB) on the outside of pear canopy (p &lt; 0.001), but for cherry, none of the airflow indicators had a significant impact on the CAB independently. On the other hand, the increased airflow direction angle in the cross-row plane for pear, as well as the increased airflow velocities in forward and vertical direction for cherry, both showed negative effects on the adaxial side deposit coverage (p &lt; 0.01). The findings in this study might be helpful to improve the performance of pesticide application in orchards, especially for abaxial side deposition, and could provide a reference for the further investigations about the effect of airflow on spray canopy deposition.

Pesticide dose based on canopy characteristics in apple trees: Reducing environmental risk by reducing the amount of pesticide while maintaining pest and disease control efficacy

Although many different designed air-assisted sprayers can be used for pesticide application in apple orchards, the lack of adequate adjustments according to specific crop characteristics leads to application inefficiencies and failures. To evaluate the spray coverage and biological efficacy of different application techniques combined with an alternative dosage adjustment based on tree row volume (TRV), field tests with five different techniques were carried out at three crop stages on a commercial apple orchard. The results showed that conventional mist-blower with a high application volume (800 L ha−1) exhibited an excessive coverage with a high risk of contamination at the early crop stage (BBCH19), whereas other treatments using different application techniques, with a reduced volume rate and pesticide dose of 75%, were equivalent with good uniformity, revealing the great importance of suitable adjustment for the sprayers. For the middle and late stages (BBCH64 and 75), the orchard sprayer equipped with vertical booms provided the maximum coverage, and the pneumatic sprayer achieved significantly higher impacts density, which revealed their advantages and high efficiency for dense apple trees. The newly developed multi-fan sprayer and pneumatic sprayer achieved consistent coverage during the entire crop stage, independent of the changes in canopy structure (TRV). This indicates that a suitable setting and adjustment of the sprayer can contribute to a consistent spray quality. In general, benefiting from these new spraying technologies, an average reduction of 60.7% in pesticide dose and volume rate were achieved within the entire season, maintaining the same threshold of pest and disease control as that of the higher reference dose normally applied. These results demonstrate the importance of an alternative dose adjustment method to meet the requirements of the Farm to Fork strategy.

Real-time growth stage detection model for high degree of occultation using DenseNet-fused YOLOv4

Real-time detection of agricultural growth stages is one of the key steps of estimating yield and intelligent spraying in commercial orchards. However, due to considerable degree of occultation in surrounding leaves, significant overlapping between neighboring fruits, differences in size, color, cluster density, and other growth characteristics, traditional detection methods have the limitation in the accuracy of detecting different growth phases. The current work proposes a real-time object detection framework Dense-YOLOv4 based on an improved version of the YOLOv4 algorithm by including DenseNet in the backbone to optimize feature transfer and reuse. Furthermore, a modified path aggregation network (PANet) has been implemented to preserve fine-grain localized information. The model has been applied to detect different growth stages of mango with high degree of occultation in a complex orchard scenario. At a detection rate of 44.2 FPS, the mean average precision (mAP) and F1-score of the proposed model have reached up to 96.20% and 93.61%, respectively. The proposed Dense-YOLOv4 has outperformed the state-of-the-art YOLOv4 with 7.94%,13.10%,10.47%, and 4.73% increase in precision, recall, F1-score, and mAP, respectively. The present work provides an effective and efficient framework to detect different growth stages under a complex orchard scenario and can be extended to different fruit and crop detection, disease detection, and different automated agricultural applications.

Droplet Size Distributions from Hollow-Cone Nozzles Coupled with PWM Valves

HighlightsVolumetric diameters DV0.1, DV0.5, and DV0.9 for PWM-controlled hollow-cone nozzles were investigated.Droplet sizes were influenced greatly by nozzle size, operating pressure, duty cycle, and slightly by PWM valve type.Volume fractions were reported for droplets smaller than 100 µm, between 100 and 300 µm, and greater than 300 µm.Measured droplet sizes were classified as different categories based on the ASABE standard 572.3.Abstract. Integration of variable-rate disc-core nozzles in orchard sprayers is the optimal solution to achieve precision spray applications of agrochemicals; however, little information is available on the droplet size distribution and classification for these hollow-cone nozzles. Investigations were performed for the comprehensive understanding of spray droplet size spectrum discharged from hollow-cone nozzles which were manipulated with pulse width modulation (PWM) valves to produce variable flow rates. Test variables included five disc-core hollow-cone nozzle sizes (D2-DC25, D2-DC45, D4-DC25, D4-DC45, and D5-DC25), two 10-Hz PWM valve designs, five operating pressures (276, 414, 552, 689, and 827 kPa), and 10 duty cycles (DUCs) ranging from 10% to 100% at 10% intervals. Droplet diameters were measured with a laser imaging particle system. Volumetric diameters (DV0.1, DV0.5, and DV0.9) varied greatly with the nozzle orifice size, operating pressure, and DUC, and varied slightly by PWM valve type. Higher operating pressures and larger nozzles generated droplets with more consistent size distributions across DUCs from 10% to 100%. The differences in relative spans among DUCs increased with the nozzle size increase and the operating pressure decrease. Droplet size classifications from very fine to coarse, based on ASABE 572.3 standard definitions, varied with the nozzle size and operating pressure but were similar for two PWM valve designs at all DUCs. Spray volume fractions also varied with the droplet size range, DUC and pressure. For droplets smaller than 100 µm, the volume fraction remained relatively consistent or slightly decreased as DUC increased, but increased as the pressure increased. In comparison, the fraction increased as both DUC and pressure increased for droplets between 100 and 300 µm and decreased for the portion of droplets greater than 300 µm. As a result, the discovered information would be implemented for the improvement of precision variable-rate spray systems equipped with PWM valves. Keywords: Atomization, Droplet diameter, Orchard sprayer, Precision agriculture, Variable rate.

Spray Coverage and Spray Coverage Profiles from a Pecan Orchard Sprayer Operated at Different Speeds and Volumes, and with and Without a Volute

Spray Coverage and Spray Coverage Profiles from a Pecan Orchard Sprayer Operated at Different Speeds and Volumes, and with and Without a Volute

Research on profiling tracking control optimization of orchard sprayer based on the phenotypic characteristics of tree crown

The performance of the profiling tracking control system was one of the important factors affecting the spray deposition and drift characteristics of the profiling variable spray. This paper proposed a dynamic threshold function to improve the CMAC-PID control algorithm to improve the real-time response speed and robustness of profiling tracking control system. The optimal parameters of dynamic threshold function was determined through a response surface experiment and optimal calculation. The continuous profiling tracking experiment results for outdoor tree canopy within 0–2.5 s showed that, compared with the CMAC-PID control algorithm, when the improved CMAC-PID control algorithm adopted by the profiling control system, the rise time was respectively shortened by 71.5%, 66.1% and 67.3%, the adjustment time was respectively shortened by 67.6%, 57.6% and 50.0%, and the overshoot was respectively 0.658%, 0.552% and 3.46% for the profiling angle position step response of the profiling mechanism module A_up, B and A_down. The continuous profiling tracking experiment results for outdoor tree canopy within 2.5–11.5 s showed that, compared with the CMAC-PID control algorithm, when the improved CMAC-PID control algorithm was adopted by the profiling control system, the profiling tracking response curves and the profiling target angle curves were closer to coincidence, and the average error of profiling tracking has been reduced by 35.9%, 57.4% and 38.1% respectively for the profiling mechanism module A_up, B and A_down. It showed that the profiling control system using the improved CMAC-PID algorithm had better response speed and profiling tracking performance.

Design and Test of a Jet Remote Control Spraying Machine for Orchards

Aimed at issues associated with the poor air supply and poor automatic targeting accuracy of existing orchard sprayers, this paper designs a jet-type orchard remote control sprayer with automatic targeting which is suitable for standardized orchards in hilly and mountainous areas. By optimizing the structure of the diversion box, the uniformity of deposition and penetration ability of the pesticide droplets to the fruit tree canopy are improved, and a uniform wild field distribution is realized simultaneously. An accurate positioning of the fruit tree canopy space orientation is achieved through automatic targeting and azimuthal adjustment systems. When the target is detected, the solenoid valve is controlled to open, and vice versa, and the distance from the nozzle to the fruit tree canopy is adjusted in real time to improve the utilization rate of pesticides. The test results show that the effective range of the jet-type orchard remote control sprayer is no more than 3.5 m, and the maximum flow rate range is 6~6.5 L/min. Within the effective spraying range, the farther the distance is, the higher the automatic targeting accuracy. The pesticide droplets sprayed by the spraying machine have a certain penetration ability, and the uniformity of the droplets is good, which solves solidification problems caused by the penetration of pesticide into the soil. This research provides a reference for jet spraying operation and automatic targeting spraying structure design.

Determination of the optimum operating parameters of an axial fan used on the conventional air blast orchard sprayer

The pesticide droplets are carried to the tree canopy with the assist of the air flow which is generated by an axial fan of orchard sprayer. The designers manufacture the fan of orchard sprayer with ability of 6 different working conditions under constant PTO speed. Previous studies were related to evaluating the effectiveness of sprayers. In this study, 6 different options that presented to farmers was evaluated with view of energy consumption and air flow. A Conventional orchard sprayer having an axial fan with 36” diameter was operated at two fan revolutions (1890 and 2430 rpm) and at three blade angles (15º, 30º, 45º), and measured air capacity, the fuel consumption, variations of air velocities in air jet profile of the fan and calculated power consumption for each operating parameters potentially to be chosen by farmers. As a result, for each blade angle, if the fan speed increase, the air jet of the fan become more uniform than before. The maximum fan efficiency and system efficiency were %73,25 and %59,98 respectively which were obtained 30o blade angle and 2430 rpm fan rotation speed condition. The minimum fuel consumption and torque need was obtained under conditions of 15o blade angle and 1890 rpm fan rotation speed. However, considering maximum air capacity and the best air velocity uniformity in the profile of fan jet was established at, 45o blade angle and 2430 rpm fan rotation speed operating parameters.

Reducing ground and airborne drift losses in young apple orchards with PWM-controlled spray systems

Pulse Width Modulated (PWM) solenoid valves can be used to control nozzle flow rates for precision spray applications to reduce pesticide use, thereby reducing environmental risk and production cost. Field tests in a two-year-old young apple orchard were conducted to investigate spray losses to the ground and in the air for an air-blast sprayer equipped with three spray systems: 1) manually controlled constant-rate system enabled with the PWM spray system (Manual-PWM), 2) laser-guided variable-rate system enabled with the PWM spray system (Laser-PWM); and 3) conventional constant-rate system with disabled PWM valves (Disabled-PWM). Artificial targets (plastic plates and water sensitive papers) were placed under twelve trees randomly selected from four rows of the orchard to collect spray losses to the ground. Airborne spray losses were determined by using nylon screens, mounted at five heights on each of seven poles distributed at different distances from the first sprayed row. Laser-PWM and Manual-PWM produced significantly lower airborne and ground spray drift losses inside and outside the orchard than Disabled-PWM, and these losses decreased significantly as the distance away from the first sprayed row increased. Laser-PWM reduced the total airborne drift by 90.3% and total ground loss by 85.0% compared to Disabled-PWM whereas Manual-PWM decreased the same airborne and ground drift by 84.1% and 7.9%, respectively. Disabled-PWM produced detectable airborne losses that reached 88.4 m away from where the sprayer was operated. Thus, the air-blast orchard sprayer equipped with PWM solenoid valves controlled by either the automatic laser-guided system or manual system would have great potentials to improve pesticide application efficiency with significant reductions in both pesticide consumption in young apple orchards, and off-target drift loss to the environment.

Quality Analysis of Some Spray Parameters When Performing Treatments in Vineyards in Order to Reduce Environment Pollution

There is a worldwide trend that supports the rational use of chemicals in agriculture. It has become common knowledge that irresponsible application of pesticides can cause food security issues, by endangering human and animal health while also having negative environmental consequences. The aim of this experiment was to assess the qualitative parameters of spraying treatments in vineyards. To achieve this, a vineyard and orchard sprayer machine was used for the application of treatments under a gradient of pressures (3, 5, 7, 9 bar). Water-sensitive collectors were placed at three heights (0.8 m, 1.5 m, 2.5 m). Following spraying was determined using DepositScan: the volume median diameter characterization of droplets (DV 1, DV 5, DV 9), and coverage degrees of sprayings. Results indicated that best coverage degree and larger droplets tend to be deposited 1.5 m from the ground, which corresponds with the highest proximity to the positioning of the nozzles of the machine during application, and lowest coverage is found at the top, where droplets deposited also tend to be smaller. For the anti-drift nozzle model used in the study, the best coverage was obtained at a pressure of 5 bar. For sustainability of agricultural practices and rational use of pesticides, more research is required for optimization of increased precision spraying that could ensure high coverage at lower doses of chemicals and coarse droplets. In this way the quantity of product sprayed is expected to be reduced, due to minimization of off-target losses and increased efficiency. This can ensure that negative environmental impacts are lowered. Improved treatment application at higher positioning of the canopy remains a challenge and shall receive more attention.

Microscale mechanism of microstructure, micromorphology and Janus wettability of the banana leaf surface

As a result of natural selection, the adaxial and abaxial sides of banana leaves show different wetting states and anisotropy. Janus wettability between the adaxial and abaxial sides of the banana leaf surface is revealed for the first time in this work. This has relevance for the preparation of bionic materials and an important role in the efficient and high-quality production management of pesticide spraying in banana orchards. The main purpose of this research is to analyze and study the microscale mechanism and coupling relationship between the Janus wettability of banana leaf surface and the microstructure and micromorphology. We adopt advanced modern instrument analysis technology, such as contact angle (CA) measurements, field emission scanning electron microscopy (FESEM), X-ray spectrometric analysis (EDS), and Fourier transform infrared spectroscopy (FTIR), and performed tests on the adaxial and abaxial sides of banana leaves to investigate the cause of Janus wettability. The results show that banana leaves exhibit different degrees of anisotropy, mainly due to the surface micromorphology. Banana leaves exhibit a hydrophilic Wenzel state on the adaxial side and a weakly hydrophobic Cassie-Baxter state on the abaxial side. We focused on studying the coupling effect and found that the main coupling element impacting the Janus wettability of the banana leaf surface is the nanopillars microstructure, and the secondary coupling element is the content of hydrophilic functional groups on the surface. This work may lead to the design and fabrication of Janus wetting surfaces by mimicking the nanopillar structure on banana leaf surfaces and help explore the potential application of efficient and high-quality pesticide spraying in banana orchards.

Evaluation of the Effects of Spray Technology and Volume Rate on the Control of Grape Berry Moth in Mountain Viticulture

The current work evaluated spray coverage and pest control effectiveness against the grape berry moth (Lobesia botrana) by two different spray technologies and volume rates: A spray gun (high-volume sprayer—HVS) calibrated at 1000 L ha−1 and a conventional orchard sprayer calibrated at 500 L ha−1 (OS500) or 250 L ha−1 (OS250). Experiments were carried out in three different grape varieties over two years in mountain vineyards on the Mediterranean island of Cyprus. The median coverage for HVS remained above 80% for all three varieties, while that for OS500 ranged from 26% to 56%, and that for OS250 from 18% to 37%. Infestation by the grape berry moth varied from about 2.5% for Palomino, to 8% for Carignan and 3.2% for Xynisteri. Infestation in sprayed plots remained below 1.8% for all treatments, varieties and study years. Although infestation levels in OS250 were not different than the control in two varieties, the infestation levels among sprayer treatments did not differ by more than one percentage point. The current work suggests that lowering application volume and pesticide amount to 50% or more, in some cases, provides adequate control and represents an effective option for reducing pesticide use in vineyards.

Development of a LiDAR-guided section-based tree canopy density measurement system for precision spray applications

An unmanned ground-based canopy density measurement system to support precision spraying in apple orchards was developed to precisely apply pesticides to orchard canopies. The automated measurement system was comprised of a light detection and ranging (LiDAR) sensor, an interface box for data transmission, and a laptop computer. A data processing and analysis algorithm was developed to measure point cloud indices from the LiDAR sensor to describe the distribution of tree canopy density within four sections according to the position of the trellis wires. Experiments were conducted in two orchard sites, one with GoldRush (larger trees) and the other one with Fuji (smaller trees) apple trees. Tree leaves were counted manually from each section separated by trellis wires. Field evaluation results showed a strong correlation of 0.95 (R2 = 89.30%) between point cloud data and number of leaves for the Fuji block and a correlation of 0.82 (R2 = 67.16%) was obtained for the GoldRush block. A strong correlation of 0.98 (R2 = 95.90%) was achieved in the relationship between canopy volume and number of leaves. Finally, a canopy density map was generated to provide a graphical view of the tree canopy density in different sections. Since accurate canopy density information was computed, it is anticipated that the developed prototype system can guide the sprayer unit for reducing excessive pesticide use in orchards.