Pesquisa | SciELO

RESUMO As doenças foliares da soja afetam o índice de área foliar (IAF) e a estrutura principal para a fotossíntese e a produtividade. O objetivo deste estudo foi propor uma nova metodologia para determinar o início das aplicações de fungicidas, com base no IAF, na taxa de aplicação e na inclusão de um fungicida multissítio, para controlar a ferrugem asiática da soja (FAS). O estudo foi implementado no delineamento de blocos casualizados e em dois locais, com quatro repetições em um esquema fatorial triplo mais um tratamento adicional (4 × 2 × 2 + 1), sendo 4 IAF da soja (0,9, 1,8, 3,6 e 6,1) indicadas para iniciar as aplicações de fungicida; dois volumes de pulverização (70 e 120 L ha-1); com ou sem fungicida multissítio (mancozeb), e tratamento sem fungicidas. A deposição de calda sobre as plantas não diferiu entre os manejos estudados para o IAF de 1,8 e 3,6. Os tratamentos incluindo fungicida multissítio em IAF de soja entre 3,6 e 6,1, em ambos os volumes, apresentaram resultados de controle superior. Os maiores rendimentos foram observados quando a aplicação de fungicida começou em 3,6 de IAF para os dois volumes. A melhor relação entre controle de doenças e produtividade ocorreu quando as aplicações começaram em 3,6 de IAF com 70 L ha-1 e fungicida multissítio.

ABSTRACT Soybean foliar diseases negatively affect leaf area index (LAI) and compromise the main structure for photosynthesis and grain yield. The objective of this study was to propose a new methodology to determine the commencement of fungicide application based on the soybean LAI, spray volumes, and the inclusion of a multisite fungicide to control Asian soybean rust (ASR). The study was implemented in a randomized block design at two locations, with four replicates in a factorial scheme plus one additional treatment (4 × 2 × 2 + 1) - four soybean LAI (0.9, 1.8, 3.6, and 6.1) indicating the initiation stages of fungicide applications, two spray volumes (70 and 120 L ha-1), with or without multisite fungicide (mancozeb), and a control treatment without fungicide. The spray deposition on plants did not differ between the treatments for 1.8 and 3.6 LAI. Treatments including the multisite fungicide for LAI between 3.6 and 6.1 for both spray volumes presented superior ASR control results. The highest soybean yields were observed when fungicide application started at 3.6 LAI for both spray volumes. The best correlation between disease control and grain yield occurred when the applications started at 3.6 LAI with 70 L ha-1 spray volume and the multisite fungicide.

https://doi.org/10.1590/1807-1929/agriambi.v26n10p735-742

Ablação Septal com Cateteres e Radiofrequência Guiada pela Ecocardiografia para Tratamento de Pacientes com Cardiomiopatia Hipertrófica Obstrutiva: Experiência Inicial
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Valdigem, Bruno P.

; Correia, Edileide B.

; Moreira, Dalmo A. R.

; Bihan, David Le

; Pinto, Ibraim Masciarelli Francisco

; Abizaid, Alexandre A. Cunha

; Andalaft, Rogério Braga

; Paladino Filho, Antonio Tito

; Silva, Halstead Alarcão Gomes Pereira da

; Viesi, Joao Henrique Zucco

Arquivos Brasileiros de Cardiologia

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Mai 2022, Volume 118 Nº 5 Páginas 861 - 872

Resumo: Pt En | Texto: Pt En | PDF: Pt | PDF: En

Resumo Fundamentos A cardiomiopatia hipertrófica (CMH) pode causar obstrução da via de saída do ventrículo esquerdo (VSVE) e ser responsável pelo surgimento de sintomas limitantes, como cansaço físico. Quando tais sintomas são refratários ao tratamento farmacológico, os tratamentos alternativos intervencionistas podem ser úteis, como a ablação septal por meio da infusão de álcool na artéria coronária ou por meio da miectomia cirúrgica. Recentemente, o uso de cateter de radiofrequência (RF) para ablação do septo endocárdico guiado por mapeamento eletroanatômico mostrou-se eficaz apesar da elevada incidência de bloqueio atrioventricular total. Uma alternativa seria a aplicação de radiofrequência no ponto de início do gradiente septal guiada pelo ecocardiograma transesofágico (ETE). O ecocardiograma é um método de imagem com elevada acurácia para determinação da anatomia septal. Objetivo Avaliar o efeito em longo prazo da ablação septal para alívio do gradiente ventrículo-arterial, utilizando o ETE para auxiliar no posicionamento do cateter na área de maior obstrução septal. Avaliar também os efeitos da ablação na classe funcional e parâmetros ecocardiográficos. Métodos Doze pacientes sintomáticos com obstrução da VSVE, refratários à terapia farmacológica, foram submetidos à ablação endocárdica septal com cateteres com ponta de 8 mm, cujo posicionamento foi orientado na região de maior obstrução com auxílio do ETE. Foram realizadas aplicações de radiofrequência (RF) termocontrolada e escalonadas sobre a área alvo. Após cada aplicação, o gradiente era reavaliado e nova aplicação era realizada de acordo com critério clínico. Foram avaliados os efeitos das aplicações de RF tanto para o gradiente em repouso como para o provocado por meio da manobra de Valsalva, e considerado o gradiente. As diferenças foram significativas quando o valor de p foi menor ou igual a 0,05. Resultados Observou-se que a redução da média dos gradientes máximos obtidos foi de 96,8±34,7 mmHg para 62,7±25,4 mmHg ao final de três meses do procedimento (p=0,0036). Após um ano, a média dos gradientes máximos obtidos foi de 36,1±23,8 mmHg (p=0,0001). O procedimento foi bem tolerado e não houve registro de bloqueio atrioventricular total e nem complicações graves. Conclusão A ablação septal guiada pelo ETE foi eficaz e segura, com resultados mantidos durante o período de seguimento clínico. É uma opção razoável para o tratamento intervencionista da obstrução da VSVE em CMH.

Abstract Background Hypertrophic cardiomyopathy (HCM) can cause obstruction in the left ventricular outflow tract (LVOT), and be responsible for the onset of limiting symptoms, such as tiredness. When such symptoms are refractory to pharmacological treatment, interventionist alternative therapies can be useful, such as septal ablation through the infusion of alcohol in the coronary artery or through myectomy. Recently, the use of a radiofrequency (RF) catheter for endocardial septal ablation guided by electroanatomic mapping has proven to be efficient, despite the high incidence of complete atrioventricular block. An alternative would be the application of RF at the beginning point of the septal gradient guided by the transesophageal echocardiography (TEE). The echocardiography is an imaging method with high accuracy to determine septal anatomy. Objective To assess the long term effect of septal ablation for the relief of ventricular-arterial gradient, using TEE to help place the catheter in the area of larger septal obstruction. Besides, to assess the effects of ablation on the functional class and echocardiographic parameters. Methods Twelve asymptomatic patients, with LVOT obstruction, refractory to pharmacological therapy, underwent endocardial septal ablation with 8mm-tip catheters, whose placement was oriented in the region of larger obstruction, assisted by the TEE. Temperature-controlled and staggered RF applications were performed. After each application, the gradient was reassessed and a new application was performed according to the clinical criterion. The effects of RF applications were assessed both for the gradient at rest and for that provoked by the Valsalva maneuver, and considering the gradient. The differences were significant when p-value was lower than or equal to 0.05. Results It was possible to observe that the mean reduction of the maximum gradients was from 96.8±34.7 mmHg to 62.7±25.4 mmHg three months after the procedure (p=0.0036). After one year, the mean of maximum gradient was 36.1±23.8 mmHg (p=0.0001). The procedure was well tolerated, without records of complete atrioventricular block nor severe complications. Conclusion The TEE-guided septal ablation was efficient and safe, and the results were maintained during the clinical follow-up period. It is a reasonable option for the interventionist treatment of LVOT obstruction in HCM.

https://doi.org/10.36660/abc.20200732

USE OF ULTRA COARSE DROPLETS AT DIFFERENT SPRAY VOLUMES TO CONTROL WEEDS WITH DICAMBA AND GLYPHOSATE HERBICIDES
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da Cunha, João P. A. R.

; Antuniassi, Ulisses R.

; Chechetto, Rodolfo G.

; Palhano, Matheus G.

; Ovejero, Ramiro F. L.

; Deon, Aline

Engenharia Agrícola

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2022, Volume 42 Nº 4 elocation e20220004

Resumo: En | Texto: En | PDF: En

ABSTRACT The use of ultra-coarse droplets for herbicide application reduces the risk of drift but may compromise the coverage and efficacy of the treatment. The objective of this work was to evaluate the use of ultra-coarse droplets, in different spray volumes, in the application of dicamba herbicide in association with glyphosate, for the control of weeds in two field trials. The first trial was conducted in a 5 x 2 factorial design, with five spray volumes (58, 72, 96, 144, and 177 L ha-1) and two air induction flat-fan spray tips (MUG 110015 - MagnoJet and TTI 110015 - Teejet). The control efficiency of Commelina benghalensis and the spray deposition on the target were evaluated by detecting a tracer using spectrophotometry. The second was conducted in a 2 x 2 factorial scheme, using two volumes (100 and 125 L ha-1) and two tips (MUG 11002 and TTI 11002). The control efficiency of Conyza spp. and fresh matter were evaluated. The different spray volumes and tips did not differ in relation to the deposition of the tracer. The use of ultra-coarse droplets was adequate for weed control. The TTI and MUG tips gave similar and adequate control performance starting at 96 L ha-1. Increasing the volume above 100 L ha-1 did not result in better control.

https://doi.org/10.1590/1809-4430-eng.agric.v42n4e20220004/2022

MOBILE APPLICATION FOR ADJUSTING AIR-BLAST SPRAYERS IN COFFEE PLANTATION
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Cunha, João P. A. R. da

; Alves, Thales C.

; Penha, Rafael S. A.

Engenharia Agrícola

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2022, Volume 42 Nº 5 elocation e20220034

Resumo: En | Texto: En | PDF: En

ABSTRACT Mobile application development advances, particularly for smartphones and tablets, have allowed farmers to make decisions more assertively in their agrobusiness management. This article addresses the development and evaluation of an app aimed at people who deal with the pesticide application technology in coffee farming, more specifically, adjustment and calibration of sprayers. This mobile app provides the main data necessary for a correct calibration of air-blast sprayers to apply pesticides in coffee planting. Its functionalities include calculation of the application rate for each situation (L ha-1) based on data obtained in the field, such as canopy volume. The app, called SprayCafé, was developed for the Android platform using the Java programming language in the integrated development environment Android Studio. After the development, the application was evaluated, based on a questionnaire answered by 139 users, who ranked the following requirements: ease of use, loading time, adequacy of screen resolution, data relevance, sequence of information, and applicability, among others. The system proved to be simple and robust; it was thus assessed as adequate to the field and to be of great value for coffee planting, especially because it allows safer and more adequate pesticide application. The graphical user interface is interactive and easy to use.

https://doi.org/10.1590/1809-4430-eng.agric.v42n5e20220034/2022

MULTIVARIATE ANALYSIS APPLIED TO SPRAY DEPOSITION IN GROUND APPLICATION OF PHYTOSANITARY PRODUCTS IN COFFEE PLANTS
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Palma, Roxanna P.

; Cunha, João P. A. R. da

; Guimarães, Ednaldo C.

; Santana, Denise G. de

; Assunção, Heli H. T. de

Engenharia Agrícola

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Ago 2021, Volume 41 Nº 4 Páginas 458 - 467

Resumo: En | Texto: En | PDF: En

ABSTRACT An adequate combination of factors involved in the technology used for phytosanitary product application contributes to an efficient spray deposition on the target. The objective of this study was to use multivariate analysis to characterize the magnitude of effects and the order of influence of three factors that interfere with the quality of phytosanitary product application in coffee plants. An entirely randomized design was adopted, with four repetitions, using a 2 × 2 × 3 factorial scheme, with two classes of droplets quality (fine and coarse), two application rates (250 and 400 L ha-1), and the use of adjuvants (with no adjuvant or with Fighter®and Aureo® adjuvants). The quality of the application was determined by jointly analyzing the spray deposition on three thirds of leaves, in their internal and external layers, the runoff to soil, coverage, droplet density, relative amplitude, and the volumetric median diameter. The results underwent analysis of variance (ANOVA) to measure the effect sizes (η2). After testing the assumptions of multivariate analysis, clustering and principal component analyses were performed. The class of droplets was found to be the most influential factor in the quality of the phytosanitary product application (spray deposition and runoff to soil). When focusing on spray deposition on leaves, the second-most influential factor was the application rate and the relation between the application rate and the adjuvants. For the other variables, the second-most influential factor was the application rate.

https://doi.org/10.1590/1809-4430-eng.agric.v41n4p458-467/2021 65 downloads

USE OF REMOTELY PILOTED AIRCRAFTS FOR THE APPLICATION OF PLANT PROTECTION PRODUCTS
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Cunha, João P. A. R. da

; Alvarenga, Cleyton B. de

; Rinaldi, Paula C. N.

; Marques, Matheus G.

; Zampiroli, Renan

Engenharia Agrícola

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Abr 2021, Volume 41 Nº 2 Páginas 245 - 254

Resumo: En | Texto: En | PDF: En

ABSTRACT The use of remotely piloted aircrafts (RPAs) to apply plant protection products has grown a lot in agriculture worldwide. However, little research data are available regarding the efficiency and safety of this method, especially in Brazil. Thus, this review aimed to present the current scenario of scientific research involving RPAs in the application of pesticides. Several factors interfere with the quality of this type of application. Among them are height and flight speed, droplet generator elements, application rate, and spray solution properties. In general, applications have been performed between 1.0 m and 3.0 m of height and 1.0 m s-1 and 7.0 m s-1 of speed. As for the droplet generator element, there is still no clarity as to the ideal system. Efficacy studies involving RPA applications demonstrate the potential of this method in replacing applications performed mainly by using knapsack equipment in an effort to reduce occupational risks. However, it is essential to observe the advantages of RPA use, while also taking into account the risk of drift. The aerodynamic effect in the droplets, qualified personnel, appropriate formulations, regulations, and details in labels are challenges that still need to be addressed for this new technology to be successful.

https://doi.org/10.1590/1809-4430-eng.agric.v41n2p245-254/2021 406 downloads

The Program for Biodiversity Research in Brazil: The role of regional networks for biodiversity knowledge, dissemination, and conservation
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ROSA, CLARISSA

; BACCARO, FABRICIO

; CRONEMBERGER, CECILIA

; HIPÓLITO, JULIANA

; BARROS, CLAUDIA FRANCA

; RODRIGUES, DOMINGOS DE JESUS

; NECKEL-OLIVEIRA, SELVINO

; OVERBECK, GERHARD E.

; DRECHSLER-SANTOS, ELISANDRO RICARDO

; ANJOS, MARCELO RODRIGUES DOS

; FERREGUETTI, ÁTILLA C.

; AKAMA, ALBERTO

; MARTINS, MARLÚCIA BONIFÁCIO

; TOMAS, WALFRIDO MORAES

; SANTOS, SANDRA APARECIDA

; FERREIRA, VANDA LÚCIA

; CUNHA, CATIA NUNES DA

; PENHA, JERRY

; PINHO, JOÃO BATISTA DE

; SALIS, SUZANA MARIA

; DORIA, CAROLINA RODRIGUES DA COSTA

; PILLAR, VALÉRIO D.

; PODGAISKI, LUCIANA R.

; MENIN, MARCELO

; BÍGIO, NARCÍSIO COSTA

; ARAGÓN, SUSAN

; MANZATTO, ANGELO GILBERTO

; VÉLEZ-MARTIN, EDUARDO

; SILVA, ANA CAROLINA BORGES LINS E

; IZZO, THIAGO JUNQUEIRA

; MORTATI, AMANDA FREDERICO

; GIACOMIN, LEANDRO LACERDA

; ALMEIDA, THAÍS ELIAS

; ANDRÉ, THIAGO

; SILVEIRA, MARIA AUREA PINHEIRO DE ALMEIDA

; SILVEIRA, ANTÔNIO LAFFAYETE PIRES DA

; MESSIAS, MARILUCE REZENDE

; MARQUES, MARCIA C.M.

; PADIAL, ANDRE ANDRIAN

; MARQUES, RENATO

; BITAR, YOUSZEF O.C.

; SILVEIRA, MARCOS

; MORATO, ELDER FERREIRA

; PAGOTTO, RUBIANI DE CÁSSIA

; STRUSSMANN, CHRISTINE

; MACHADO, RICARDO BOMFIM

; AGUIAR, LUDMILLA MOURA DE SOUZA

; FERNANDES, GERALDO WILSON

; OKI, YUMI

; NOVAIS, SAMUEL

; FERREIRA, GUILHERME BRAGA

; BARBOSA, FLÁVIA RODRIGUES

; OCHOA, ANA C.

; MANGIONE, ANTONIO M.

; GATICA, AILIN

; CARRIZO, MARÍA CELINA

; RETTA, LUCÍA MARTINEZ

; JOFRÉ, LAURA E.

; CASTILLO, LUCIANA L.

; NEME, ANDREA M.

; RUEDA, CARLA

; TOLEDO, JOSÉ JULIO DE

; GRELLE, CARLOS EDUARDO VIVEIROS

; VALE, MARIANA M.

; VIEIRA, MARCUS VINICIUS

; CERQUEIRA, RUI

; HIGASHIKAWA, EMÍLIO MANABU

; MENDONÇA, FERNANDO PEREIRA DE

; GUERREIRO, QUÊZIA LEANDRO DE MOURA

; BANHOS, AUREO

; HERO, JEAN-MARC

; KOBLITZ, RODRIGO

; COLLEVATTI, ROSANE GARCIA

; SILVEIRA, LUÍS FÁBIO

; VASCONCELOS, HERALDO L.

; VIEIRA, CECÍLIA RODRIGUES

; COLLI, GUARINO RINALDI

; CECHIN, SONIA ZANINI

; SANTOS, TIAGO GOMES DOS

; FONTANA, CARLA S.

; JARENKOW, JOÃO A.

; MALABARBA, LUIZ R.

; RUEDA, MARTA P.

; ARAUJO, PUBLIO A.

; PALOMO, LUCAS

; ITURRE, MARTA C.

; BERGALLO, HELENA GODOY

; MAGNUSSON, WILLIAM E.

Anais da Academia Brasileira de Ciências

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2021, Volume 93 Nº 2 elocation e20201604

Resumo: En | Texto: En | PDF: En

Abstract The Program for Biodiversity Research (PPBio) is an innovative program designed to integrate all biodiversity research stakeholders. Operating since 2004, it has installed long-term ecological research sites throughout Brazil and its logic has been applied in some other southern-hemisphere countries. The program supports all aspects of research necessary to understand biodiversity and the processes that affect it. There are presently 161 sampling sites (see some of them at Supplementary Appendix), most of which use a standardized methodology that allows comparisons across biomes and through time. To date, there are about 1200 publications associated with PPBio that cover topics ranging from natural history to genetics and species distributions. Most of the field data and metadata are available through PPBio web sites or DataONE. Metadata is available for researchers that intend to explore the different faces of Brazilian biodiversity spatio-temporal variation, as well as for managers intending to improve conservation strategies. The Program also fostered, directly and indirectly, local technical capacity building, and supported the training of hundreds of undergraduate and graduate students. The main challenge is maintaining the long-term funding necessary to understand biodiversity patterns and processes under pressure from global environmental changes.

https://doi.org/10.1590/0001-3765202120201604 1034 downloads

PERFORMANCE OF AIR INDUCTION SPRAY NOZZLE MODELS UNDER DIFFERENT OPERATING CONDITIONS
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Cunha, João P. A. R. da

; França, Jorge A. L.

; Alvarenga, Cleyton B. de

; Alves, Guilherme S.

; Antuniassi, Ulisses R.

Engenharia Agrícola

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Dez 2020, Volume 40 Nº 6 Páginas 711 - 718

Resumo: En | Texto: En | PDF: En

ABSTRACT For the successful application of phytosanitary products, it is essential to understand the spraying process well. The present work aims to evaluate the spectrum and speed of the droplets produced by different spray nozzle models with air induction, working under different operating conditions. The experiment was conducted using an entirely randomized design with five repetitions in a 3 × 3 × 3 factor scheme that incorporates three nozzle models (ADIA, AIXR, and GA), three nominal flows (0.76, 1.14, and 1.51 L min−1), and three operating pressures (200, 300, and 400 kPa). The spectrum and speed of the droplets were determined directly using a real-time droplet analyzer based on high-resolution image analysis. The spray nozzle model interfered with the results. The ADIA promoted Dv0.5 (VMD) higher than AIXR and GA, reaching differences of up to 90%. The increase in pressure promoted a reduction in the droplet size; however, there was no well-defined behavior for the relationship between the flow rate and droplet size. The ADIA and AIXR gave rise to greater uniformity of the droplets in most of the evaluated conditions. The increase in pressure promoted an increase in the speed of the droplets. However, the effect of the nozzle model on this parameter was dependent on the flow.

https://doi.org/10.1590/1809-4430-eng.agric.v40n6p711-718/2020 525 downloads

SPRAY DEPOSITION ON MAIZE USING AN ELECTROSTATIC SPRAYER
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Assunção, Heli H. T. de

; Cunha, João P. A. R. da

; Silva, Sérgio M.

; Alves, Guilherme S.

; Lemes, Ernane M.

Engenharia Agrícola

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Ago 2020, Volume 40 Nº 4 Páginas 503 - 510

Resumo: En | Texto: En | PDF: En

ABSTRACT It is a well-known fact that the application of pesticides can be improved using an electrostatic spray due to the reduction of the application rate and increase in deposition on plant targets. However, little information exists on the use of such technology in maize crops. Thus, this study is aimed to evaluate the spray deposition on maize resulting from spray application using an electrostatic sprayer in combination with low application rates and different spray compositions. A field experiment was conducted in a randomized block having a 2×2×2 factorial design with two application rates (95 and 52 L ha-1), with or without the spray electrification, and with or without the synthetic adjuvant. The droplet electrification ability, interference of the electrical conductivity of the spray solution, losses of spray solution to the soil, and spray deposition on maize plants were evaluated for two cases of insecticide applications. The Faraday cage method was used to determine the spray electrification ability of the equipment. The spray deposition on plants and the losses to the soil were analyzed using a tracer (food coloring dye) added to the spray solution that was subsequently detected by spectrophotometry. It was seen that the electrostatic sprayer improved the spray application efficiency, which responded positively to the increase in the electrical conductivity of the spray solution. The deposition of the electrified spray solution on the upper third canopy of maize was found to be higher; the spray solution electrification also reduced the losses to the soil, regardless of the application rate.

https://doi.org/10.1590/1809-4430-eng.agric.v40n4p503-510/2020 500 downloads

10.

WATER HARDNESS AND pH IN THE EFFECTIVENESS OF GLYPHOSATE FORMULATIONS
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Cunha, João P. A. R. da

; Palma, Roxanna P.

; Oliveira, Arthur C. de

; Marques, Matheus G.

; Alvarenga, Cleyton B. de

Engenharia Agrícola

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Ago 2020, Volume 40 Nº 4 Páginas 555 - 560

Resumo: En | Texto: En | PDF: En

ABSTRACT The hardness and pH of the spray water can interfere with the weed control effectiveness with herbicides, but it is not clear the magnitude of this interference, mainly associating different levels of pH and hardness to different glyphosate formulations. This study aimed to evaluate the influence of hardness and pH, in association, of the water used in the application of two glyphosate formulations on the weed control effectiveness. The experiment was conducted in duplicate, in areas with a predominance of Digitaria horizontalis, under a randomized block design with a 4×4×2+1 factorial scheme, composed of four water hardness levels (70, 110, 230, and 430 ppm CaCO3), four pH levels (3.5, 4.5, 5.5, and 6.5), two glyphosate formulations (ammonium salt and potassium salt), and control without application, with four repetitions. The physicochemical characteristics of the spray solutions and the weed control effectiveness were evaluated at 7, 14, and 21 days after application (DAA). The water pH at the studied range did not interfere with the control effectiveness. The increase in hardness reduced the control at 7 DAA, but this difference was not noticed after 21 DAA. Glyphosate ammonium salt promoted higher control of D. horizontalis than that with potassium salt, regardless of water hardness and pH.

https://doi.org/10.1590/1809-4430-eng.agric.v40n4p555-560/2020 898 downloads

11.

ELECTROSTATIC SPRAYING EFFECT ON SPRAY DEPOSITION AND POWDERY MILDEW CONTROL IN SOYBEAN
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Assunção, Heli H. T. de

; Silva, Sérgio M.

; Alves, Guilherme S.

; Zandonadi, Cesar H. S.

; Cunha, João P. A. R. da

Engenharia Agrícola

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Dez 2019, Volume 39 Nº 6 Páginas 721 - 728

Resumo: En | Texto: En | PDF: En

ABSTRACT Electrostatic spray can bring benefits to the pesticide application such as the reduction of application rate and the increase of deposits on targets. Therefore, this study aimed to evaluate the effect of electrostatic spraying using lower application rates and different adjuvants on soybean spray deposition and chemical control of powdery mildew (Microsphaera diffusa Cooke & Peck). The field experiment was conducted in duplicate. A randomized complete block design with four replications in a 2 × 2 × 2 + 1 factorial scheme was used. The factors were two application rates, with and without droplet electrification, two spray solution compositions, and one additional treatment. Deposition on upper and lower leaves, spray loss to the soil, and powdery mildew control effectiveness were evaluated. The electrical conductivity of the spray solution and the charge/mass ratio induced in droplets were also evaluated. All treatments reduced the soybean powdery mildew severity. Electrostatic spraying responded positively to an increase in the electrical conductivity of the spray solution regarding the charge/mass ratio, but it did not increase spray deposition on the lower third of the canopy and did not influence spray loss to the soil, which was higher as the application rate increased.

https://doi.org/10.1590/1809-4430-eng.agric.v39n6p721-728/2019 936 downloads

12.

INTERACTIONS BETWEEN ADJUVANTS AND THE FUNGICIDE AZOXYSTROBIN+BENZOVINDIFLUPYR IN HYDRAULIC SPRAYING
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Landim, Thiago N.

; Cunha, João P. A. R. da

; Alves, Guilherme S.

; Marques, Matheus G.

; Silva, Sérgio M.

Engenharia Agrícola

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Out 2019, Volume 39 Nº 5 Páginas 600 - 606

Resumo: En | Texto: En | PDF: En

ABSTRACT Adjuvants are tools to maximize pesticide spray quality. This study aimed to evaluate the interaction effects between adjuvants and the fungicide azoxystrobin + benzovindiflupyr on the physicochemical characteristics, droplet evaporation time, and spray droplet size. The experiment was carried out using a 2×6 factorial scheme, in which the first factor was the absence or presence of the fungicide mixture (water or water + fungicide) and the second factor was the presence of different adjuvants (water and five adjuvants). The parameters evaluated were surface tension, pH, viscosity, electrical conductivity, droplet evaporation time, volume median diameter, percentage of droplets smaller than 100 μm, and relative amplitude of the droplet spectrum. The silicone and propionic acid + soy lecithin adjuvants reduced the pH of the spray solution, and the sodium lauryl ether sulfate, propionic acid + soy lecithin, and orange essential oil adjuvants reduced droplet evaporation when mixed with the fungicide. All tested adjuvants improved spray quality related to the characteristics of the droplet spectrum, reducing the percentage of droplets smaller than 100 μm, and allowing more uniform droplet size. The fungicide azoxystrobin + benzovindiflupyr affected droplet evaporation time.

https://doi.org/10.1590/1809-4430-eng.agric.v39n5p600-606/2019 707 downloads

13.

ESTIMATING VEGETATION VOLUME OF COFFEE CROPS USING IMAGES FROM UNMANNED AERIAL VEHICLES
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Cunha, João P. A. R. da

; Sirqueira Neto, Matheus A.

; Hurtado, Sandro M. C.

Engenharia Agrícola

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Set 2019, Volume 39 Nº spe Páginas 41 - 47

Resumo: En | Texto: En | PDF: En

ABSTRACT Tree crops, such as Arabica coffee (Coffea arabica L.), present enormous technical challenges in terms of pesticide application. The correct deposition and distribution of the active ingredient throughout the aerial part of these plants depends on knowledge of the canopy volume, but manually determining this volume is time consuming and imprecise. The objectives of this study were to develop a method to determine the vegetation volume of coffee crops from digital images captured by camera onboard unmanned aerial vehicles and to compare this approach with traditional vegetation volume estimation (tree row volume (TRV) method). Manual measurements of the canopy volume of four coffee cultivation areas were compared with data obtained using the method presented in this paper. It was concluded that the vegetation volume of coffee trees, a highly important variable in defining pesticide application techniques (in addition to other uses), could be determined in a practical and precise way by digitally processing the images captured by unmanned aerial vehicles. The method is fast and permits the assessment of large areas. Furthermore, estimates based on this method and the traditional TRV method were not significantly different.

https://doi.org/10.1590/1809-4430-eng.agric.v39nep41-47/2019 1395 downloads

14.

EVALUATION OF DROPLET SPECTRA OF THE SPRAY TIP AD 11002 USING DIFFERENT TECHNIQUES
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Cunha, João P. A. R. da

; Reis, Elton F. dos

; Assunção, Heli H. T. de

; Landim, Thiago N.

Engenharia Agrícola

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Ago 2019, Volume 39 Nº 4 Páginas 476 - 481

Resumo: En | Texto: En | PDF: En

ABSTRACT Knowledge of droplet spectra generated by spray nozzle tips is important to ensure the quality of applications of plant protection products. However, there are different methods for this evaluation, which can cause difficulty in interpreting the results. This study aimed to evaluate the droplet spectra produced by the flat fan spray tip AD 11002 operated under different pressures and using different techniques and equipment. The volume median diameter (VMD), percentage of spray volume in droplets smaller than 100 µm diameter and relative spam (RS), considering pressures of 200, 300, and 400 kPa were determined using two direct measurement equipment (Spraytec and Shadow Sizer), based on laser diffraction and image analysis, respectively, and a measure based on indirect analysis, through the digitization of water-sensitive paper. Thus, the use of different analysis techniques led to variations of the analyzed parameters. Among the direct measurement equipment, a difference of up to 58% was observed in VMD. The use of water-sensitive paper to characterize droplet spectra must be carried out with great discretion because there is an underestimation of fine droplets. Pressure variations of 200 to 400 kPa did not influence VMD and RS.

https://doi.org/10.1590/1809-4430-eng.agric.v39n4p476-481/2019 909 downloads

15.

Characterization and in silico Mutagenic Assessment of a New Betahistine Degradation Impurity
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Mello, Murilo B. M. de

; Oliveira, Antonio A. F. de

; Oliveira, Caroline L. de

; Ultramari, Mariah A.

; Gama, Fernando H. S.

; Mascarello, Alessandra

; Guimarães, Cristiano R. W.

; Freitas, Miller N. de

; Cunha, Carlos E.

; Lourenço, Tiago C.

; Ferreira, Fernanda P.

; Lopes, João L. C.

; Clososki, Giuliano C.

Journal of the Brazilian Chemical Society

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Jul 2019, Volume 30 Nº 7 Páginas 1415 - 1424

Resumo: En | Texto: En | PDF: En

Currently, the pharmaceutical industry devotes great attention to drug degradation products because these compounds can offer risks to patients. A previous degradation study of betahistine (N-α-methyl-2-pyridylethylamine) conducted under different stress conditions detected three main impurities named A, B and C. Degradation products were analyzed by high-resolution mass spectrometry in electrospray source and time of flight analyzer (ESI-TOF) and nuclear magnetic resonance (NMR). Impurity mutagenicity was evaluated by Derek Nexus and Sarah Nexus softwares. Liquid chromatography hyphenate with tandem mass spectrometry (LC-MS/MS) analysis of the betahistine forced degradation sample indicated the presence of a new impurity, which was named impurity C1. 2D NMR experiments allowed the complete structural characterization of the new entity. The active pharmaceutical ingredient and degradation impurities were classified as inactive in the in silico mutagenic studies. Systematic investigation of a forced degradation sample led to the characterization of a new betahistine impurity. The in silico mutagenicity study of the betahistine degradation impurities may be useful in the risk assessment of the drug products.

https://doi.org/10.21577/0103-5053.20190037 853 downloads

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