Suspension Concentrate crop protection formulation design and performance for low spray volume and UAS spray application.

BACKGROUND: Unmanned aerial systems (UAS) are providing interesting disruptive solutions for spray application of crop protection products with very-low spray volumes (VLV) down to 8 L/ha that offer improved sustainability through reduced water volumes and reduced soil compaction. However, the efficacy of products can be reduced by the significantly lower crop/plant spray coverage and formulation designs that can compensate for this are highly important here. RESULTS: Suspension Concentrate (SC) formulations designed for VLV use containing and delivering low dose rates (g/ha) of organosilicone alkoxylate high-spreading surfactants were found to result in leaf coverage of VLVs comparable to those observed at higher spray volumes. High spreading was observed on textured leaf surfaces containing sub-micron sized epicuticular wax crystals. Greenhouse fungal disease studies showed enhanced efficacy with these SC formulations compared to standard SC formulations without these additives and maintained the observed increase in efficacy when applied at VLV. Alternatively, SC formulations without high spreading formulants but containing uptake promoting nonionic surfactants showed enhanced cuticle penetration through isolated cuticles at VLV in comparison to higher spray volumes, with coffee-ring spray deposit microstructures present at VLVs. Similarly, greenhouse studies showed enhanced efficacy that was maintained at VLV relative to SCs without these additives. CONCLUSION: At VLVs, SC formulations applied at relatively low dose rates (g/ha) of formulants (adjuvants) enhancing spreading on the leaf surface and/or uptake of the active ingredient(s) maintained good spreading, uptake and biological efficacy in greenhouse studies overcoming the coverage limitations of SC formulations without these additives. This result is unexpected considering the low dose rate of adjuvants used. © 2023 Bayer AG. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Control Efficacy and Deposition Characteristics of an Unmanned Aerial Spray System Low-Volume Application on Corn Fall Armyworm Spodoptera frugiperda.

As a major global pest, fall armyworm (FAW), Spodoptera frugiperda, invaded China in 2019, which has seriously threatened the safety of China's food production and raised widespread concerns. As a new low-volume application technology, an unmanned aerial spray system (UASS) is playing an important role in the control of FAW in China. However, the studies on the effect of the water application volume on the efficacy of FAW using UASS have been limited. In this study, Kromekote® cards were used to sample the deposition. The method of using a sampling pole and sampling leaf for the determination of deposition. Four water application volumes (7.5, 15.0, 22.5, and 30.0 L/ha) were evaluated with regard to the corn FAW control efficacy. A blank control was used as a comparison. The control efficacy was assessed at 1, 3, 7, and 14 days after treatment (DAT). The tested results showed that sampling methods have a significant effect on deposition results. The number of spray deposits and coverage on the sampling pole were 35 and 40% higher than those on the sampling leaves, respectively. The deposition and control efficacy gradually increased as the water application volume increased. The control efficacy at 14 DAT under different water application volumes was in the range of 59.4-85.4%. These data suggest that UASS spraying can be used to achieve a satisfying control of FAW, but the control efficacy of the water application volume of 30.0 and 22.5 L/ha did not differ significantly. Considering work efficiency, a water application volume of 22.5 L/ha is recommended for field operation.

Assessing the application of spot spray in Nanguo pear orchards: Effect of nozzle type, spray volume rate and adjuvant.

BACKGROUND: Aerial spray is one of the most important applications of unmanned aerial vehicles (UAVs) in agriculture. This work aimed to promote the use of UAVs as an alternative to knapsack electric sprayers in pesticide application in Nanguo pear orchards planted in mountain terraced orchard scenarios. The spray deposition of four types of nozzles (SX110015, XR80015, IDK90015 and TR80015), two spray volume rates (45 and 90 L ha-1 ) and with or without a commercial surfactant adjuvant were evaluated based on the spot spray mode. RESULTS: The air- assisted IDK90015 nozzle showed significantly higher deposition and penetration, and its large droplet size also reduced the risk of drift. Increasing the spray volume rate can increase the amount of droplets deposition. The adjuvant showed excellent potential to improve spray technology in Nanguo pear trees, with a mean deposition of 0.175-0.574 µL cm-2 and penetration of 3.09-66.73%. The droplet size also increased significantly, with volume median diameter (DV0.5 ) of 469 µm. CONCLUSION: The nozzle type, spray volume rate and adjuvant should be well considered when using the spot spray in orchard. Compared with increasing spray volume rate, the use of air-induction nozzles and surfactant-based adjuvants can improve the spray deposition better. © 2022 Society of Chemical Industry.

Relative efficiencies of experimental and conventional foliar sprayers and assessment of optimal LWA spray volumes in trellised wine grapes.

BACKGROUND: Leaf wall area (LWA) has been proposed as an appropriate dose expression for field testing of plant protection products (PPPs) applied via foliar spray in trellised grapes. However, its efficiency could change depending on the characteristics of the crop or the pesticide application equipment (PAE). Herein, three spray technologies were evaluated. A traditional air-assisted tractor-mounted sprayer was compared with two portable knapsack sprayers: a backpack mistblower and a backpack hydraulic sprayer. Trials were conducted in trellised wine grapes at three selected crop stages (BBCH 55, 65, 75) covering the main period of canopy development. In each canopy stage, leaf deposition and coverage were sampled for each technology. The tractor-mounted sprayer was working at 200 L ha-1 of LWA spray volume for the earliest stage and 370 L ha-1 for the other two. Three higher volume rates were used for backpack sprayers up to 800 and 1250 L ha-1 for the mistblower and the hydraulic system, respectively. RESULTS: Optimal LWA spray volumes differed among application devices in terms of efficiency and uniformity of deposition on the canopy. The efficiency of each spray application also was conditioned by the spray volume. CONCLUSION: LWA is useful for defining optimal spray volumes in trellised grapes. However, both canopy density and spray technology should be considered to assist this process. Field testing of PPPs and subsequent label recommendations should consider the relative efficiencies of corresponding experimental and conventional spray technologies. © 2021 Society of Chemical Industry.

Activity of the Novel Fungicide Mefentrifluconazole Against Colletotrichum scovillei.

The prevalence and destructiveness of anthracnose, caused by Colletotrichum scovillei, in pepper production regions seriously affects pepper yield and quality. Mefentrifluconazole, the first of the isopropanol-azole subgroup of triazole fungicides, was introduced for the control of pepper anthracnose. However, the growth characteristics of pepper fruit and rapid spread of anthracnose suggest that the fungicide application method must be optimized to enhance fungicide efficacy. The sensitivity of C. scovillei to mefentrifluconazole was determined by mycelial growth and germ tube elongation assays using 157 single-spore isolates with mean 50% effective concentration values of 0.462 ± 0.138 and 0.359 ± 0.263 mg/liter, respectively. The in vivo data also showed that mefentrifluconazole had favorable protective and curative effects against pepper anthracnose. Mefentrifluconazole significantly affected C. scovillei infection on pepper by reducing appressorium formation and sporulation, shriveling spores and germ tubes, and causing the abnormal development of appressoria and conidiophores. Mefentrifluconazole could move acropetally, horizontally, and basipetally in pepper plants. Compared with a knapsack sprayer, mefentrifluconazole applied by mist sprayer exhibited significantly better activity against pepper anthracnose. Additionally, as the spray volume increased from 45 to 150 liters/ha, the control efficacy of mefentrifluconazole first increased and then tended to be steady, with an optimal spray volume of 90 liters/ha. The difference in disease control efficacy was related to the deposition and droplet distribution of mefentrifluconazole on the pepper fruit. These results provide scientific guidance for the application of mefentrifluconazole in pepper fields and improved fungicide utilization.

Analysis of diesel engine injector nozzle spray characteristics fueled with residual fuel oil.

Experimental analysis on the spray characteristics of a diesel engine injector nozzle fueled with Residual Fuel Oil (RFO) was carried out in this study. To achieve this, the fuel was characterized to determine its physicochemical properties, and an experimental set up was designed to visualize and capture the spray pattern of the fuel. The images obtained were processed and analysed using Image J software to determine the spray length, spray cone angle, spray area, spray volume, and spray velocity values of the fuel. Experimental results obtained agree with validation models and reveal that spray parameter values of RFO are higher than those of diesel fuel. The values of spray parameters of RFO such as 456mm spray length, 2.85mm Sauter Mean Diameter (SMD) and the low spray cone angle of 12.69°, led to a higher spray volume causing the engine to run on a rich mixture after initial start-up conditions. This would create such challenges as reduction in power and clogging of injector nozzle tip due to an increase in carbon deposits. Regression models generated reveal that these challenges could be eliminated when the spray parameters run on optimal values of 256mm, 6.41cm2, 16.18cm3, 0.96 mm/s and 13.59° for the spray length, spray area, spray volume, spray velocity and the spray angle respectively. These optimal values were obtained when the engine fuel injection time was set to 500µs while running on fuel of viscosity 4.305 mPa.s and temperature of 48 °C.

Low-drift nozzles vs. standard nozzles for pesticide application in the biological efficacy trials of pesticides in apple pest and disease control.

The coarse spray air-induction nozzles have documented pesticide drift reducing potential and hence pose lower risk of environmental pollution than the standard fine spray hollow cone nozzles. However, it is questioned that use of the low-drift nozzles might not provide as effective crop protection as the standard nozzles. The objective of work was to assess the pest and disease control efficacy as affected by spray volume rate and nozzle type. The experiment was carried out in apple orchard, cv Jonagold/M26. The evaluated treatments were combinations of three spray volume rates: 250, 500 and 750lha-1, and two types of nozzles: hollow cone nozzles generating very fine spray, and flat fan air induction nozzles producing coarse droplets. The biological performance of treatments was determined based on severity of diseases: apple scab (Venturia inaequalis), powdery mildew (Podosphaera leucotricha) and bull's eye rot (Pezicula spp.), as well as population or damage caused by pests: green apple aphid (Aphis pomi), rosy apple aphid (Dysaphis plantaginea Pass.), woolly apple aphid (Eriosoma lanigerum), apple rust mite (Aculus schlechtendali) and apple blossom weevil (Anthonomus pomorum L.). In general apple scab was equally controlled by all treatments. Only in the years of high infection pressure efficacy of powdery mildew control was better for fine spray nozzles and high volume rates. Green and rosy apple aphids were better controlled with higher volume rates, though significance of the advantage over the lower rates was occasional. No effect of spray quality on efficacy of aphid and mite control was found for any spray volume rate. Better control of apple blossom weevil and woolly apple aphid was achieved with the high spray volume rate providing heavy coverage to the point of run-off. The air induction nozzles having drift reducing potential are biologically efficacious alternative to conventional hollow cone nozzles.

Droplets population spectrometry and its effect on costal hydraulic spraying dispersion / Espectrometria da população de gotas e seu efeito na dispersão da pulverização hidráulica costal

The droplets population and spectrum produced during a spraying influence the pesticides distribution efficiency. Through the droplets population and spectrum is possible to determine the quality of spraying and the implications on applicator and consumer safety, application efficiency and environmental impact. Droplet density (droplets cm-2), percentage of coverage, coefficient of uniformity and relative amplitude were studied in this experiment. The experimental design was a factorial scheme 3 x 2: three spray volumes and two insecticides doses. During the tests all factors were analyzed on six parts of the plant canopy: on the top and external, top and internal, middle part and external, middle part and internal, bottom and external, and bottom and internal, using the completely randomized design with three replications. The objective of this study was to assess the characteristics of droplets population and spectrum produced during the hydraulic spraying. In general, for all factors assessed there was no significant difference between the parts of the plant canopy studied, having the greater values on the external parts of the plant canopy.

A população e o espectro de gotas produzidas durante a pulverização influencia a eficiência da distribuição do defensivo agrícola. Por meio da população e do espectro de gotas é possível avaliar a qualidade da pulverização e as implicações na segurança do aplicador e do consumidor, na eficácia do tratamento e no impacto ambiental da pulverização. Foram estudadas, durante os ensaios, a densidade de gotas (gotas cm-2), a porcentagem de cobertura, o coeficiente de homogeneidade e a amplitude relativa. Foi montado um esquema fatorial 3 x 2 três volumes de pulverização e duas doses do inseticida. Durante os ensaios todos os fatores foram analisados considerando-se as amostras coletadas em seis posições na planta superior externo, superior interno, mediano externo, inferior externo e inferior interno, utilizando-se o delineamento inteiramente casualizado, com três repetições. Objetivou-se com esse trabalho avaliar as características das populações e o espectro de gotas produzidas durante a pulverização hidráulica. De maneira geral, para todos os fatores avaliados não houve diferença significativa entre os volumes e as doses utilizadas, entretanto houve diferença significativa entre as posições das plantas, sendo os maiores valores obtidos nas posições externas do dossel da planta.

Assessing the optimal liquid volume to be sprayed on isolated olive trees according to their canopy volumes.

The application of pesticides to traditional and intensive olive orchards in Southern Spain has led to environmental problems. More specifically, the lack of an accurate, useful criterion to regulate the spray volume in relation to canopy characteristics has led to spray drift and runoff, which are threats to local ecosystems. The aim of this study was to determine the optimal relationship between canopy volume and the spray application volume, called specific spray volume, CV, through laboratory and field trials. In the laboratory trial, 6 specific spray volumes (0.05, 0.08, 0.10, 0.12, 0.15, and 0.20Lm(-3)) were tested in a specially designed structure containing small, live olive trees in order to simulate an intensive plantation system. The model aimed to evaluate the coverage of pesticide application on water sensitive paper (WSP) collectors. In the field trial, the three laboratory specific spray volumes that gave the best coverage values were tested on live, intensively managed trees, whose crown volume was manually measured. Food dye E-102 was used to determine the spray deposition on artificial targets (10×10cm absorbent paper pieces), and WSP was used to evaluate spray coverage. The spray penetration and deposit homogeneity inside the canopy were also evaluated. Weather conditions during the field trial were monitored with a weather station. The results of the laboratory trial showed that the three best specific spray volumes were 0.08, 0.10, and 0.12Lm(-3), resulting in mean coverage values of approximately 30%. The ANOVA of the field trial results showed that the 0.12Lm(-3) was the optimal specific spray volume for isolated olive trees. This specific spray volume gave the highest mean deposits, the best efficiency (as measured by the greatest normalized deposit), the most favourable penetration and homogeneity, and the highest coverage values.

Tecnologia de aplicação de fungicida no controle da ferrugem asiática da soja: resultados de oito anos de estudos em Minas Gerais E Goiás / Technology of fungicide application in the control of soybean soybean: results of studies in Minas Gerais and Goiás

Diante da importância do controle eficiente e seguro da ferrugem asiática da soja, foi conduzido um projeto de pesquisa de oito anos nesta área focando principalmente a avaliação de métodos de aplicação, pontas de pulverização, volumes de calda e adjuvantes. Este artigo resume os resultados encontrados nestes estudos objetivando avaliar e relacionar os diversos fatores envolvidos na tecnologia de aplicação de fungicidas na cultura da soja. Foram realizados sete ensaios em diferentes áreas, abrangendo as regiões do Triângulo Mineiro e Goiás, conduzidos em lavouras de soja semeadas em safras de verão. Estudaram-se diferentes pontas de pulverização (13), volumes de calda (7), adjuvantes (3) e métodos de aplicação (aéreo e terrestre). As principais variáveis analisadas foram: deposição de calda, severidade da ferrugem, massa de 1.000 grãos e produtividade. A partir da análise dos resultados, observou-se que pontas que produzem gotas médias parecem ser mais adequadas ao controle da ferrugem asiática da soja, evitando também elevados riscos de deriva. Há viabilidade técnica no uso de volumes de calda reduzidos, próximos a 130 L ha-1, na aplicação terrestre. A aplicação aérea também se mostrou viável. A utilização de adjuvantes mostrou-se uma boa ferramenta para auxiliar no controle da ferrugem, contudo seu efeito está relacionado ao tipo de ponta utilizada e ao modo de ação do fungicida, ou seja, ação local ou protetora e mesostêmica ou ação sistêmica. É preciso buscar estratégias que incrementem a deposição de calda na parte inferior da cultura, visto que todos os métodos apresentam dificuldade de cobertura nesta área.

Asian soybean rust is a serious disease of soybeans. In this way, a research project was conducted focusing primarily on evaluating methods of application, spray nozzles, spray volumes and adjuvants on chemical control of rust. This article summarizes the results of a eight-year study to evaluate factors involved in technology application of fungicides on soybeans. Seven experiments were conducted in different areas, including regions of Goiás and Triângulo Mineiro (Brazil), on soybean crops sown in summer. It was studied different spray nozzles (13), spray volumes (7), adjuvants (3) and application methods (aerial and ground). The main evaluated variables were: spray deposition, disease severity, weight of 1,000 grains and yield. It was observed that medium droplets seem more appropriate to control Asian rust, also avoiding high risk of drift. There are technical feasibility in using reduced spray volumes (near 130 L ha-1) in the ground application. Aerial application also proved feasible. The use of adjuvants proved to be a good tool to assist in controlling the disease, but its effect is related to the type of nozzle used and action mode of fungicides, if them not penetrate in the sub epidermis parts of leaves (topic or mesostemic action) or to penetrate inside the leaves (systemic fungicides action). It is necessary to find strategies to increase the spray deposition at the bottom part of the crop canopy, since all methods have difficulty covering this area.

Effect of spray angle and spray volume on deposition of a medium droplet spray with air support in ivy pot plants.

BACKGROUND: Spray boom systems, an alternative to the predominantly-used spray guns, have the potential to considerably improve crop protection management in glasshouses. Based on earlier experiments, the further optimization of the deposits of a medium spray quality extended range flat fan nozzle type using easy adjustable spray boom settings was examined. Using mineral chelate tracers and water sensitive papers, the spray results were monitored at three plant levels, on the upper side and the underside of the leaves, and on some off-target collectors. In addition, the deposition datasets of all tree experiments were compared. RESULTS: The data showed that the most efficient spray distribution with the medium spray quality flat fan nozzles was found with a 30° forward angled spray combined with air support and an application rate of 1000 L ha(-1) . This technique resulted in a more uniform deposition in the dense canopy and increased spray deposition on the lower side of the leaves compared with the a standard spray boom application. Applying 1000 L ha(-1) in two subsequent runs instead of one did not seem to show any added value. CONCLUSION: Spray deposition can be improved hugely simply by changing some spray boom settings like nozzle type, angling the spray, using air support and adjusting the spray volume to the crop.

Cobertura de gotas de pulverização obtida com diferentes pontas e taxas de aplicação na parte aérea da cana-de-açúcar / Spray droplet coverage achieved with different nozzles and application rates in the aerial part of sugar cane

A aplicação de produtos fitosssanitários no setor sucroalcoleiro, até recentemente, estava focada principalmente no controle de plantas daninhas. Com o aparecimento da ferrugem alaranjada, como doença de importância agrícola na cultura da cana-de-açúcar, passou a ser imperioso conhecer como a aplicação chega na parte aérea da planta. Dessa forma, o presente estudo foi desenvolvido com o objetivo de avaliar a qualidade da deposição da calda em pulverização terrestre, conduzido em esquema fatorial 2x2x2 (duas pontas de pulverização, duas taxas de aplicação e duas posições dos cartões de papéis hidrosensíveis no dossel da planta), seis repetições, com dez papéis cada. Foram utilizadas as pontas de pulverizacão XR110.02 (jato plano de uso ampliado) e TTJ60 - 110.02 (jato plano duplo, com ângulo de 60 graus entre si) utilizando-se as taxas de aplicação de 120 e 160L ha-1. Os cartões de papel hidrossensível utilizados para avaliar a deposicão das pulverizações foram distribuidos sobre as folhas de cana-de-açúcar, em duas posições distintas em relação ao dossel da planta (parte superior e inferior, aproximadamente, 0,80 e 0,50 metros do solo, dispostos na horizontal e inclinado em relação à superfície do solo, respectivamente). A cultivar utilizada foi 'RB 96-6928', com altura de 0,80m aos 120 dias do plantio. Um scaner de mesa foi utilizado para digitalizar as imagens dos papéis e avaliou-se as coberturas através do programa Conta-Gotas®. Os dados de deposição/cobertura foram submetidos à análise de variância e as médias comparadas pelo teste Tukey ao nível de 5% de probabilidade de erro. No dossel superior da cana-de-açúcar observou-se maior cobertura, quando comparado ao dossel inferior, sendo que não se observaram diferenças entre as taxas de aplicação de 120 e 160L ha-1,. A ponta TTJ60-110.02 promoveu cobertura superior à ponta XR 110.02 quando se utilizou 160L ha-1 (40,34 e 36,50%, respectivamente).

The terrestrial application of agricultural defensives in the sugar-alchool producer sector until recently was focused on weed control. After the appearance of orange rust, a disease of agricultural importance in sugar cane production, it has become imperative to know how the application arrives at the plant canopy. In such a way, the present study was developed with the objective of evaluate the quality of the deposition in terrestrial spraying, lead in factorial project 2x2x2 (two nozzles of spraying, two rates of application and two positions of the water-sensitive papers in the canopy of plant), six repetitions, with ten papers each. It has been used the nozzles of spraying XR110.02 (plain jet of extended range) and TTJ60 - 110,02 (double plain jet, with angle of 60 degrees between itself) using the rates of application of 120 and 160L ha-1. The water-sensitive papers cards used to evaluate the deposition of the sprayings had been distributed on the leaves of sugar cane in two distinct heights (upper and lower, approximately 0,80 and 0,50 meters above ground level, arranged in horizontal and inclined with respect to the road surface, respectively). A table scanner was used to generate the digital images of the papers and evaluated the coverings through the Conta-Gotas® program. The deposition data/covering had been submitted to the variance analysis and the averages compared with the Tukey test at 5% of significance. It was observed in the superior canopy of the sugarcane a bigger covering when compared with the inferior, there was no difference between the application rates, 120 and 160L ha-1. The TTJ600110.02 nozzle promoted bigger covering the XR110.02 nozzle when using 160L ha-1 (40,34 and 36,50%, respectively).