Low-volume Spray Research Articles

PROFITABILITY OF THE SPRAYING SYSTEM USING THE METHOD OF DIFFERENTIATED APPLICATION

Most of the agrochemicals used are dispersing in the environment, which negatively affects the environment and health. One of the ways to solve this problem is to use a differentiated method of applying plant protection products. In addition to reducing environmental pollution, this method allows you to save on the consumption of plant protection products. The economic efficiency of agricultural machinery is assessed by the final indicators of agricultural production, profit growth due to increased crop yields, improved product quality and reduced production costs. The article presents the technical and economic efficiency of using a robotic device for precise application of agrochemical agents. (Research purpose) The research purpose is analyzing the economic effectiveness of the differentiated method of applying agro-chemical agents. (Materials and methods) GOST 34630-2019 «Agricultural machinery. Machines for plant protection. Sprayers. Test methods» has been analyzed. The economic efficiency analysis was carried out on the basis of field tests. A robotic device has been tested on the territory of the Agrofirm «POISK» (Ramenskoye city district, Moscow region). (Results and discussion) The consumption of insecticide by the technology of differentiated application decreased by 38 percent. The cost of an autonomous field robot is 25.04 percent lower than the cost of the basic technology. The operational cost reduction in the treatment of cabbage with insecticides by means of differentiated application is 61 percent in comparison with the basic low-volume spraying. (Conclusions) On the basis of the calculation of the economic efficiency of an autonomous field robot for differentiated application of agrochemical agents it was revealed that the payback of additional investments is less than one year; the robot has high maintainability, interchangeability of elements, adaptability of structural parameters; the total economic effect is 1,662,979.63 rubles.

Research advances of the drift reducing technologies in application of agricultural aviation spraying

With the gradual deterioration of the ecological environment and the increase in requirements for the quality of modern life, the use of pesticides is bound to develop towards higher pesticide utilization and less environmental pollution, and the low-volume spraying for agricultural aviation operation combined with the Drift Reducing Technologies (DRTs) may be a useful way to achieve this goal. Based on an analysis of the spray drift mechanism and the primary factors influencing aerial spraying, previous research on DRTs in aerial spraying were reviewed and summarized, and it was found that DRTs in aerial spraying can effectively reduce the environmental pollution caused by pesticide drift by reducing the spraying amount of pesticides and improving the control effect of pesticides, included aerial electrostatic spray technology, aerial spray adjuvant, aerial air-assisted spray technology, drift reducing nozzles and aerial variable-rate spray technology. And according to the analysis of the current research status, some suggestions and countermeasures to reduce droplet drift of agricultural aviation spraying were put forward from the aspects of strengthening the research on DRTs for plant protection Unmanned Aerial Vehicle (UAV) and adopting reasonable DRTs methods. It is hoped that provide reference and guidance for the enterprises’ product improvement and users’ practical operation, and play the advantages of precision agricultural aviation spraying fully. Keywords: agricultural aviation spraying, pesticide, drift, DRTs, precision agriculture DOI: 10.25165/j.ijabe.20211405.6225 Citation: Chen S D, Lan Y B, Zhou Z Y, Deng X L, Wang J. Research advances of the drift reducing technologies in application of agricultural aviation spraying. Int J Agric & Biol Eng, 2021; 14(5): 1–10.

Validation of post-harvest antimicrobial interventions to control Shiga toxin-producing Escherichia coli (STEC) on market hog carcass surfaces

Although swine are less associated with STEC foodborne disease outbreaks, the potential for swine to serve as a source of STEC infections in human beings cannot be disregarded. This study compared eight USDA-approved antimicrobial intervention technologies to quantify their ability to reduce STEC contamination on market hog carcasses. Hogs were harvested to provide skin-on carcass sides, and eight sides (per three replications) were inoculated with a 7-strain STEC cocktail (ca. 5 log CFU/cm2 across all external and body cavity surfaces). Each side was randomly assigned to a final pre-chill wash treatment administered in a commercial Chad carcass cabinet using a low-volume spray [3% lactic acid (lLA; 130 °F), 400 ppm peracetic acid (lPAA), or acidified 400 ppm peracetic acid (laPAA)] or a high-volume wash [ambient water (hAW), 400 ppm PAA (hPAA), 400 or 600 ppm hypobromous acid (hDBDMH), or 71 °C water (hHW)] treatment according to a randomized complete block study design. Post-treatment (after a 10-min hanging drip) and post-chilling (18 h at 2 °C) STEC reductions were compared for external skin-on surfaces and internal body cavity lean surface tissue. Post-treatment color changes were determined for lean, adipose, and skin carcass surfaces before and after chilling. When applied to the external, skin-on surface, the hHW, hPAA, and hDBDMH600 deluge washes were significantly (P ≤ 0.05) more effective than the other intervention technologies, achieving STEC reductions of 3.8, 3.4, and 3.2 log CFU/cm2, respectively. In comparison, the hAW control reduced STEC by 1.7-log CFU/cm2 on the external, skin-on surface. The carcass interventions were less effective at reducing STEC populations attached to interior body cavity (diaphragm region), with post-chill populations reduced by 0.9–2.2 log cycles, while the hAW control wash achieved a 0.6-log reduction. None of the treatments negatively impacted instrumental carcass color. While all market hog carcass interventions reduced STEC populations, larger reductions were observed when applied to the external, skin-on surface, with the largest reductions achieved by the hHW, hPAA, and hDBDMH600 deluge washes. These data equip pork processors with the information necessary to support decision-making when selecting an intervention technology.

Spray Coverage and Biological Efficacy of Single, Twin Symmetrical, and Twin Asymmetrical Flat Fan Nozzles

Abstract Proper selection of nozzle type and spray volume is essential to optimize herbicide dose, reducing its adverse environmental effects. It has not been sufficiently evaluated which nozzle type (twin symmetrical flat fan nozzle or the twin asymmetrical one) is more efficient and whether pinoxaden application is more efficient at a low or high spray volume. The spray coverage of a single, twin symmetrical, and twin asymmetrical flat fan nozzles, each in the sizes of 110015, 11002, 110025, 11003, 11004, and 11005 on the moisture-sensitive papers (MSPs) was investigated. The biological efficacy of treatments using pinoxaden against wild oat was investigated. Unlike other nozzle types, the single flat fan nozzle could not cover MSP placed vertically behind the nozzle trajectory. Except for the latter, each nozzle type could cover the MSPs more efficiently with increase in nozzle size. Generally, the nozzles’ performance was twin symmetrical > single = twin asymmetrical flat fan nozzles. A larger nozzle size improved the coverage of MSPs but increased the effective dose (ED50; dose that gives a 50% reduction in dry weight), indicating a decrease in the efficacy of pinoxaden. Among all treatments, the lowest ED50 value was obtained by the twin symmetrical flat fan nozzle 110015 (5.2 g a.i. ha−1). The smaller, more concentrated droplets are required to achieve optimal pinoxaden efficacy against wild oat, which can be provided by a twin symmetrical flat fan nozzle with a smaller size.

The spraying process simulation of the low-volume sprayer working body

The article presents the developed mathematical models that describe the process of spraying the working body of a low-volume sprayer. Theoretical studies show that with an increase in the supply of working fluid to the atomizing disc, the rotational speed of the pneumatic disc atomizer decreases, and in order to ensure the effect of the air flow on the droplet formation process, the radius of the disc should be larger than the radius of the base of the cone-shaped fairing, but less than its maximum critical value and for obtaining a monodisperse spray with the main droplet diameter d = 80 … 120 μm, at an axial air flow velocity of the fan installation U = 40 … 60 m/s, the parameters of the disk the sprayer and the propeller are linked together when the following values: disk radius r = 65 … 85 mm, the number of radial channels on the disk nр = 2 … 6 pcs, the width of the radial channel bр = 3 … 4 mm, and to obtain a high-quality air-droplet flow, the initial velocity of the main drops discharged from the periphery of the spraying disc must be less than the speed of the air flow and, at the same time, the rotational speed of the pneumatic disc sprayer is recommended to be used in the range of ω = 60… 200 s-1.

Substantiation of technological parameters of equipment for application of plant protection products using multicopters

Annotation Purpose. Improving the efficiency of field spraying and creating safe working conditions for maintenance personnel through the use of unmanned multicopters, the air jets from the propellers of which will not distort the flares of the sprayed solution of plant protection products (PPE). Methods. The method of analysis of variable time components of agricultural units is used. Results. Dependences of technical and operational indicators of technological equipment of a multicopter on this design and mode parameters and their rational values are received. Comparative data of multicopter and ground sprayers were obtained, which revealed the indisputable advantages of the former over the latter. Conclusions 1. One of the successful alternatives to ground sprayers is the use of unmanned aerial vehicles – multicopters, which, unlike ground vehicles, do not need to leave in the field among the plants technological tracks that reduce up to 5 % usable area and do not depend on soil and plant height. Due to the significant high working speed in comparison with ground means (from 3 m/s to 10 m/s) and practically absence of time for turns at the end of a run (3–5 s) one multicopter with width of capture of 10–12 m, can replace ground sprayer with a width of 50 m and five times the cost. 2. The rational structural and functional scheme of the technological equipment of the multicopter for plant protection must be similar to the ground sprayers of the frame construction, on the sides of which the screws of the multicopter are installed, and between them the spraying equipment. 3. Reducing the rate of application of PPE solution from low-volume (50 l/ha) to ultra-low-volume (10 l/ha) spraying increases productivity by only 1,3 times and significant complexity of the equipment. 4. Reducing battery time during multicopter operation from 180 minutes to 10 minutes reduces performance by only 10 %. 5. For low-volume spraying, a sufficient tank capacity for the PPE solution is 30 liters. 6. To increase productivity and reduce material costs for batteries, the multicopter must be equipped with a hybrid power plant with an internal combustion engine, which will recharge the battery to drive its propellers. 7. Increasing the capacity of the tank for the solution of PPE in ground sprayers from 3000 liters to 15000 liters is not economically feasible due to a slight (up to 10 %) increase in productivity, increased soil compaction and energy consumption. Keywords: agricultural multicopter, multicopter-sprayer, agricultural drone, liquid sprayers, ultra-low-volume spraying, parameters, modes.

Influence of Spray Technology and Application Rate on Leaf Deposit and Ground Losses in Mountain Viticulture

Leaf deposit and ground losses generated from spray application in mountain viticulture were evaluated. Four treatments were examined: A spray gun (1000 L ha−1, High-Volume Sprayer—HVS), a motorized knapsack sprayer (200 L ha−1, Low Volume Sprayer—LVS), and a conventional orchard mist blower calibrated at 500 L ha−1 (OS500) or 250 L ha−1 (OS250). The four treatments were assessed using the same tank concentration of tracer in two training systems: a trellis and a goblet. Sprayer treatment, vine side, and vine height significantly affected leaf deposit (p < 0.05). The absolute amount of leaf deposit increased with application volume, but when the amount of deposit was standardized to 1 kg ha−1, LVS resulted in the highest deposit, followed by HVS, OS250, and OS500. Deposition for the goblet system was ca. half that for the trellised vineyard. Ground losses standardized to 1 kg of tracer ha−1 were twice as high for HVS than for LVS, and four times as high for HVS than for OS250 and OS500, in both training systems. The current work suggests that low volume applications in vineyards are a viable and more environmentally friendly alternative than high volume treatments.

Carrier Volume and Nozzle Effect on 2,4-D and Glufosinate Performances in Hazelnut Sucker Control

Hazelnut (Corylus avellana L.) basal sprouts, or suckers, are removed to train trees as a single trunk, facilitating mechanization. Suckers are routinely controlled with herbicides, often by using nozzles that generate fine droplets and spray volumes as high as 934 L·ha−1, making spray drift a concern. Spray nozzle type and carrier volume can impact herbicide efficacy and drift. Field studies compared the efficacy of 2,4-D and glufosinate in controlling suckers when applied with a flat-fan nozzle, producing fine droplets, to a TeeJet air-induction nozzle, producing ultra-coarse droplets. These nozzles were evaluated at 187 and 374 L·ha−1. Nozzle and carrier volume did not affect the efficacy of 2,4-D based on control, sucker height, or dry weight. The efficacy of glufosinate was unaffected by nozzle type or spray volume in most evaluations. These results indicate that hazelnut suckers can be effectively controlled using drift-reduction nozzles with lower carrier volumes (187 L·ha−1). Drift-reduction nozzles, coupled with lower spray volume, can maintain herbicide efficacy, minimize drift risk, and reduce cost.

Evaluating the effectiveness of low volume spray application using air-assisted knapsack sprayers in wine vineyards

We evaluated spray coverage on grape leaves and bunches by a high-volume sprayer (HVS), an air-assisted, low volume knapsack sprayer (LVS), and a motorized knapsack dust applicator modified to spray liquid formulations (common sprayer – CS). At the full development of the vine canopy 1400, 250 and 150 L ha−1 were applied via HVS, CS and LVS, respectively. Sprayer type, leaf or bunch orientation, leaf position and leaf side significantly affected spray coverage (P < 0.001). Mean spray coverage on leaves or bunches was below 21% for CS, and above 40 and 55% for LVS and HVS, respectively. Downy mildew leaf infection was below 5% throughout the season, with a significant effect of sprayer, time and an interaction between sprayer and time (P < 0.001). Grape berry moth damage did not differ between sprayers and the untreated control. The current work suggests that LVS might be a viable alternative to HVS, but further work is needed to establish whether differences in spray coverage affect biological efficacy.

Исследование влияния препарата «Биопаг» на микробиологическое состояние и потери от болезней клубней картофеля при хранении

В работе изучена фунгицидная активность препарата Биопаг при осеннем опрыскивании клубней. Целью исследований явилось изучение влияния осенней обработки клубней препаратом Биопаг на микробиологическое состояние клубней и потери от болезней, а также выявление наиболее эффективных доз препарата, обеспечивающих максимальный защитный эффект при хранении картофеля. Для обработки использовали клубни двух сортов картофеля одной группы спелости (раннеспелой) – Жуковский ранний и Ред Скарлет. Обработку клубней осуществляли через две-три недели после уборки путем опрыскивания их из малообъемного опрыскивателя ПУМ-30 МК раствором препарата в дозировках 0,5 л/т; 075 л/т и 1,00 л/т. Контролем служили клубни, обработанные водой. После обсушивания клубни закладывали на хранение в отдельный закром модульного картофелехранилища. Температура в основной период хранения составила 4-6°С, относительная влажность воздуха – 85-90%. Состояние поверхностной микрофлоры клубней оценивали дважды – перед закладкой на хранение (сентябрь) и в конце хранения (апрель); количественные потери клубней от микробиологических болезней учитывали в конце хранения. При этом использованы стандартные методы исследований. После 7 месяцев хранения установлено улучшение микробиологического состояния обработанных клубней по сравнению с контрольными. Особенно эффективно действие Биопага против таких потенциально опасных для человека микроорганизмов, как дрожжи и плесени. В среднем за два года выявлено снижение по отношению к контролю потерь от микробиологических болезней клубней на 0,11-8,69% в зависимости от сорта и дозировки препарата. Максимальный защитный эффект вызывает дозировка препарата 0,75 л/т.

Assessment of Spray Deposition and Losses in an Apple Orchard with an Unmanned Agricultural Aircraft System in China

Highlights Field tests were performed in an orchard to evaluate spray performance of an unmanned agricultural aircraft system. A conventional air-assisted orchard sprayer was applied as a reference for comparing the feasibility of UAAS. The canopy deposition, airborne drift, loss to ground, and sprayer external contamination were tested. Field test results can provide a reference for the application of UAAS for pest control in orchards. Abstract. Unmanned agricultural aircraft system (UAAS) technology has developed rapidly in China in recent years. Due to their high application efficiency, all-terrain operation, and low-volume spraying, UAASs have been widely used for pest management in field crops, achieving good pest control and reduced pressure on farmers. In this study, the applicability of UAAS for orchard protection was tested in an apple orchard by spraying with a four-rotor UAAS and a conventional air-assisted orchard sprayer. The spray characteristics of both sprayers, including canopy deposition, drift in the air, loss to the ground, and external contamination on the sprayer, were measured and compared. The field results showed that the effective spray swath width of the UAAS was 2.23 m, and the maximum droplet density was 132 droplets cm -2 in the center of the flight line. The actual deposition in the tree canopy was lower with the UAAS than with the air-assisted sprayer, but the normalized deposition of the UAAS was equivalent to that of the air-assisted sprayer, and the coefficient of variation for deposition in all parts of the canopy was obviously higher for the UAAS than for the air-assisted sprayer. Due to the airflow produced by the high-speed rotors, the spray drift in the air was much higher with the UAAS than with the air-assisted sprayer, whereas the ground loss of the UAAS was 1/5 that of the air-assisted sprayer. Moreover, the rotor airflow of the UAAS caused a large amount of droplets to attach to the sprayer fuselage, causing the external contamination on the UAAS to be five times that of the air-assisted sprayer. Results showed that the use of a multirotor UAAS for plant protection in an orchard had considerable influence on the spray drift and external contamination of the spray equipment. Based on the results, the following recommendations can be made: (1) plant protection with a UAAS should be attained by spraying at a reasonable height to reduce the drift in the air, and (2) UAAS manufacturers should develop adequate spraying systems as well as appropriate UAAS designs for plant protection. Keywords: Air-assisted orchard sprayer, Apple orchard, Spray deposition, Spray loss, UAAS.

Ecological evaluation of technologies for application of plant protection measures by spraying method

The biological and economic effectiveness of plant protection measures depends not only on the correct choice of pesticide, but also on the quality of its application to the processed target objects. The article discusses the results of assessing the quality of applying herbicides by spraying using low-volume spraying technology, ULV spraying without forced and forced precipitation of small droplets, and treatment with cold aerosol. To assess the impact of the quality of the application of plant protection products on the environmental safety of the use of herbicides, two main indicators were used: – uniform distribution of the working fluid over the treated area: – the amount of drift of small drops from the treatment area. The analysis of methodological approaches and regulatory documents for assessing the potential risk of pesticides for the environment in European countries and in Russia is given.Based on the obtained experimental data on the coefficients of variation in the distribution of the drug over the effective coverage width, an expert assessment of the drug overuse was carried out using various technologies. An expert assessment of the drift of small drops of the working fluid from the treatment zone was also carried out. A comparative assessment of technologies was carried out according to the indicated environmental safety indicators for the use of the herbicide Gezagard WP on potato plantings.

초미립자 살포기를 이용한 살균제의 온실 약해검정

초미립자 살포기를 이용한 살균제의 온실 약해검정

Residual Activity of Certain Insecticides Sprayed on Peach Orchard to Control Green Peach Aphid, Myzus persicae (Sulzer); by Using Certain Ground Equipment at Qualiubia Governorate.

The present work was carried out to evaluate the spray quality produced by two hydraulic ground sprayers using rates of application 113 and 147 L/fed , respectively. Three insecticides were used Acetamiprid 20% SP. , using a dose rate of 25 gm /100 L. water, neutral Potassium detergent at a dose rate ½ kg / 100 L. water and plant extract Saponins solution at a dose rate one liter / 30 L. water against green peach aphid Myzus persicae (Sulzer) on Peach orchard. Data showed that droplet sizes induced by Matabi sprayer with manual pump were bigger than motorized Solo sprayer , however, more coverage homogeneity was obtained by Solo sprayer with a motor pump. Data, showed also that, spray coverage of upper and middle levels of Peach trees in all treatments reached homogeneity factor 2.5 for hydraulic nozzles according to FAO , but the lower levels of Peach trees which revealed not homogenous spray. The rate of Performance (fed / day) for Solo sprayer was 5 fed. / day, while was 3 fed./ day in case of Matabi sprayer. Bioassay results indicated that all tested compounds induced negative significant influence on Myzus persicae (Sulzer) nymphs survival. Saponins gave promising results in controlling Myzus persiace nymphs on Peach trees with least hazard to emergence rate of natural enemy Parasitoid Aphidius matricariae (Haliday) larvae, while Acetamiprid gave the highest reduction in both of Myzus persicae and Aphidius matricariae larvae in case of two sprayers. Data also showed that replacement spray application form high volume spraying to low volume spraying (L/fed); decreases the total operating cost/fed / L. E. , saving spraying time i. e. the rate of performance of low volume equipment increases, and suitable spray coverage was obtained

Harvest aids efficacy applied by unmanned aerial vehicles on cotton crop

Chemical harvest aids applied by ground-based machines with heavy wheels and high-volume spraying in cotton (Gossypium hirsutum L.) fields to defoliate leaves and ripen bolls before harvest threaten soil health and result in cotton yield loss. For example, ground-based machines roll over cotton plants at corners and pull the cotton branches between rows, resulting in yield loss. Furthermore, heavy wheels can cause soil compaction, resulting in decreased soil biodiversity. High-volume spraying often results in harvest aids polluting the soil. A new harvest-aid application method that can save water, increase harvest-aid utilization rate without damage to soils and crops is needed to apply chemical harvest aids before harvest. Small plant protection unmanned aerial vehicles (UAVs) with low-volume spraying methods have emerged as pesticide application technologies in recent years in China due to their high efficiency, high flexibility, low labor requirements, water savings and lack of damage to crops and soils. Here, UAVs are developed for chemical harvest-aid application by evaluating the cotton defoliation efficacy, boll opening rate, lint cotton yield and fiber quality components at two cotton field experimental sites in Xinjiang Uygur Autonomous Region of China in 2016 and 2017. Ground-based machine treatment is used as a reference. The assessment is proceeded with the following steps: (1) The spray volume of UAV is optimized in 2016; (2) The experiment of 2016 is repeated to determine the optimal spray volume in 2017. The results show the following: (1) The harvest-aid performance is sensitive to the spray volume in the UAV low-volume spraying treatment, and optimal defoliation efficacy is achieved when the spray volume is 22.5 L/ha and flight velocity is 4 m/s, according to the field tests in 2016 and 2017. (2) Low-volume spraying using UAV has no negative influence on the lint cotton yield and fiber quality components. In conclusion, it is feasible to use plant protection UAV for cotton harvest-aid applications in preparation for machine harvesting.

Work-related information needed by farmers for changing to sustainable cropping practices

Farmers are being urged to change their practices in order to reduce agricultural pollution. These changes may affect working times and organization, and farmers often mention this to explain the difficulties they have in adopting a new practice. But little is known about the work-related changes (e.g., working time, organization, skills) engendered by a change of farming practice, or about the information that farmers need for deciding on and implementing a new practice. In order to design tools to help farmers when adopting more agroecological practices, the objective of this paper is to identify what work-related information is useful to them for changing their practices. We interviewed 16 farmers in France and we then characterized the types of work-related information they had applied. We focused both on changes that were systemic (reducing tillage or diversifying crops) or less systemic (low-volume spraying or mechanical weeding). We performed a qualitative analysis with an iterative method, alternating between gathering data from the farmers and theorizing about what happens on the work front. We then performed a quantitative analysis of the results, based on chi-squared tests, to identify which factors influence farmers’ work-related information needs. Our findings showed, for the first time, that farmers apply a wide range of information about work changes, concerning performance of new operations, resources used, work organization and competition between activities, and the arduous or rewarding nature of farm work. We showed that the types of information needed change during the process of introducing a new practice. In the first phase, farmers gather mainly generic information about the focal operation and the resources required. In the next phase, they run innovation experiments, producing their own information on how their work is changing and how to reorganize it. Based on these results, we suggest some paths for designing support tools.

Optimization of parameters of the spraying device at etching of potato tubers

The article considers the treatment of potatoes with protective and stimulating substances before planting, using a slit-type disperser, a finely dispersed low-volume spray on the surface of the processing object. The article has a research character, which is expressed in the fact that the analysis of methods and means for processing potatoes with protective and stimulating substances, as well as excerpts from the works of leading scientists on the subject under study are promising scientific developments in the form of patent analysis, which provide optimal flow of the technological process, there were shown their shortcomings and solutions to these problems. There was formulated the main problem of general etching constructions. Also, there was specified the technology of potato tubers treatment with protective-stimulating preparation, the description and the course of technological process are cited. As a result of the work done, a constructive scheme of the device for the treatment of tubers with protective and stimulating liquids by means of slit sprayers is proposed. The article also provides the optimization of parameters of a pneumatic slit sprayer for treatment of tubers with protective and stimulating liquids. The conclusions set out the main results achieved so far.

Effect of aerial spray adjuvant applying on the efficiency of small unmanned aerial vehicle for wheat aphids control.

Small unmanned aerial vehicles (UAVs) have been widely used in different aspects of modern farming management, including pest and disease control in China in recent years. In this study, the spray performance of a small plant protection UAV at low volume spray was evaluated by adjusting the pesticide dosage and adding aerial spraying adjuvants. Droplet deposition, droplet density, coverage, control effect and pesticide residue from field trials were assessed. In addition, the residue and control effect of UAV spray were compared to manual knapsack at high volume spray. The results showed that, the adjuvant applying improved the efficiency of UAV spray. Also, the adjuvant applying reduced the dosage of imidacloprid by 20%. However, there was no significant difference on initial residue between UAV spray and knapsack spray. Thus, plant protection UAV spraying pesticide by adding appropriate adjuvant showed the ability of improving the pesticide effectiveness by improving the control efficiency, reducing the pesticide dosage and residue. Keywords: unmanned aerial vehicle (UAV), aerial spraying adjuvant, deposition, control efficiency, pesticide residue, wheat aphid DOI: 10.25165/j.ijabe.20181105.4298 Citation: Meng Y H, Lan Y B, Mei G Y, Guo Y W, Song J L, Wang Z G. Effect of aerial spray adjuvant applying on the efficiency of small unmanned aerial vehicle on wheat aphids control. Int J Agric & Biol Eng, 2018; 11(5): 46–53.

Adjusting Product Timing during the Powdery Mildew Critical Window to Improve Disease Management

Summary Goals: This project was designed to answer questions about the timing of different cultural (leaf removal) and chemical (fungicide rotation) disease management practices and how they influence the overall efficacy of a powdery mildew management program. Key Findings: The timing of specific chemical modes of action plays an important role in the overall efficacy of powdery mildew fungicide programs. In this study, programs in which the evaluated products were applied once during the critical window performed as well as programs in which the same products were applied twice (during the critical window and at bunch closure). This finding indicates that disease control depends on application of sprays during the critical window rather than later in the season. As expected, leaf removal significantly improved spray coverage in the fruit zone; however, this improved coverage did not last the entire season. Canopy refill, which occurred as summer laterals developed, reduced fruit-zone coverage later in the season. Leaf removal also did not result in any positive additive effects on overall disease control. Impact and Significance: These findings can be used to aid growers in the selection and rotation of products used for powdery mildew management programs to maximize the efficacy of disease control and minimize the risk of fungicide resistance. While early fruit zone leaf removal did not improve overall disease control in this high-pressure scenario, leaf removal resulted in improved spray coverage, which may enhance disease control when low-volume spray applications or contact-active chemistries are emphasized in a commercial program.

Effects of Dosage and Spraying Volume on Cotton Defoliants Efficacy: A Case Study Based on Application of Unmanned Aerial Vehicles

Plant protection unmanned aerial vehicles (UAVs) consist of light and small UAVs with pesticide spraying equipment. The advantage of UAVs is using low-volume spray technology to replace the traditional large-volume mass locomotive spray technology. Defoliant spraying is a key link in the mechanized cotton harvest, as sufficient and uniform spraying can improve the defoliation quality and decrease the cotton trash content. However, cotton is planted at high density in Xinjiang, with leaves in two adjacent rows seriously overlapped, making the lower leaves poorly sprayed. Thus, the defoliation effect is poor, and the cotton quality is degraded. To improve the effect of defoliation and reduce the losses caused by boom sprayer rolling, the effect of defoliant dosage on defoliation, boll opening, absorption and decontamination in cotton leaves and the effect of spraying volume on absorption and decontamination in cotton leaves sprayed by UAVs are studied. The pooled results indicate that plant protection UAVs could be used for cotton defoliants spraying with a twice defoliant spraying strategy, and the defoliant dosage has no significant effect on seed cotton yield and fiber quality in Xinjiang. The residue of thidiazuron in cotton leaves reaches the maximum at four days after spraying, the residue of diuron in cotton leaves reaches the maximum at one day after second spraying. The thidiazuron and diuron residues are increased with spraying volume at rang of 17.6–29.0 L/ha. When the spraying volume is less than 17.6 L/ha, the residue of thidiazuron and diuron is reduced. The research results could provide a reference for further optimization of the spraying parameters of cotton defoliant by plant protection UAVs.