Dados de campo e modelos de estimação de deriva nas aplicações de agrotóxicos na cultura do café

The objective of this work was to generate drift curves from pesticide applications on coffee plants and to compare them with two European drift‑prediction models. The used methodology is based on the ISO 22866 standard. The experimental design was a randomized complete block with ten replicates in a 2x20 split‑plot arrangement. The evaluated factors were: two types of nozzles (hollow cone with and without air induction) and 20 parallel distances to the crop line outside of the target area, spaced at 2.5 m. Blotting papers were used as a target and placed in each of the evaluated distances. The spray solution was composed of water+rhodamine B fluorescent tracer at a concentration of 100 mg L‑1, for detection by fluorimetry. A spray volume of 400 L ha‑1 was applied using a hydropneumatic sprayer. The air‑induction nozzle reduces the drift up to 20 m from the treated area. The application with the hollow cone nozzle results in 6.68% maximum drift in the nearest collector of the treated area. The German and Dutch models overestimate the drift at distances closest to the crop, although the Dutch model more closely approximates the drift curves generated by both spray nozzles. O objetivo deste trabalho foi gerar curvas de deriva a partir de aplicações de agrotóxicos em cafeeiro e compará‑las a dois modelos europeus de simulação de deriva. A metodologia utilizada baseia-se na norma ISO 22866. Utilizou-se o delineamento experimental de blocos ao acaso, com dez repetições, em arranjo fatorial 2x20 com parcelas subdivididas. Os fatores avaliados foram: dois tipos de pontas de pulverização (cone vazio com e sem indução de ar) e 20 distâncias paralelas à linha de cultivo fora da área‑alvo, espaçadas em 2,5 m. Foram colocados papéis filtrantes como alvo, em cada uma das distância avaliadas. A calda foi composta por água+corante fluorescente rodamina B na concentração de 100 mg L‑1, para detecção por fluorimetria. Aplicou-se volume de calda de 400 L ha‑1, por pulverizador hidropneumático. A ponta com indução de ar reduz a deriva até 20 m de distância da área tratada. A aplicação com ponta de jato cônico resulta em deriva máxima de 6,68% no ponto de coleta mais próximo da área tratada. Os modelos Alemão e Holandês superestimam a deriva nas distâncias mais próximas à cultura, embora o modelo Holandês se aproxime mais das curvas de deriva geradas por ambas as pontas de pulverização

Controle estatístico de processo em pulverização hidropneumática na cultura do café

The objective of this work was to study the quality and variability, from a statistical process control point of view, of the deposition on coffee crop leaves and the loss to the soil promoted by pulverization with an air-blast sprayer using different application volumes and droplet sizes. The experiment was carried out in Arabica coffee crop using the 2x2 factorial design and eight replicates, with the factors being the droplet sizes generated by two types of nozzles (hollow cone - ATR - which produced fine droplets, and hollow cone with air induction - TVI - which produced extremely large drops) and spray application volumes (200 and 500 L ha-1). Brilliant Blue tracer was used to quantify by spectrophotometry the spray deposits on the leaves of the top and bottom halves of the plant and on the ground targets. The statistical quality of sprays was evaluated using statistical process control. Control charts show that there is no detectable patterns of non-randomness within treatments, ensuring the good quality of the pulverizations in the coffee crop. The spraying using the volume of 500 L ha-1 provides flexibility in the choice of hydraulic nozzle, keeping quality and low variability of deposition in the coffee leaves.Objetivou-se, com este trabalho, estudar a qualidade e a variabilidade, do ponto de vista do controle estatístico de processo, da deposição de calda pulverizada em folhas de cafeeiro e da perda para o solo, promovida pela aplicação com pulverizador hidropneumático, empregando diferentes volumes de calda e tamanhos de gotas. O experimento foi conduzido em café arábica no esquema fatorial 2x2, com oito repetições, sendo os fatores tamanhos de gotas (jato cônico vazio – ATR - que produziu gotas finas; e jato cônico vazio com indução de ar – TVI – que produziu gotas extremamente grossas) e volumes de calda (200 e 500 L ha-1). Utilizou-se o traçador Azul Brilhante para quantificar por espectrofotometria os depósitos de calda nas folhas da parte superior e inferior e em lâminas de vidro localizadas no solo. Avaliou-se a qualidade estatística das pulverizações, utilizando-se controle estatístico de processo. As cartas de controle mostram que não se detectam padrões de não aleatoriedade dentro dos tratamentos, assegurando a boa qualidade das aplicações realizadas na cultura do café. A aplicação utilizando o volume de 500 L ha-1 proporciona flexibilidade na escolha da ponta hidráulica, mantendo qualidade e baixa variabilidade de deposição nas folhas do cafeeiro

Deriva e espectro de gotas de dicamba pulverizado, com ou sem adjuvantes, com uso de pontas com indução de ar

The objective of this work was to evaluate the spray drift and droplet spectrum of dicamba applied alone or with potential drift-reducing adjuvants, using air-induction flat fan nozzles. Standard (XR and TT) and air-induction (AIXR and TTI) nozzles were evaluated in a wind tunnel. The adjuvants used were polymer, ammonium sulfate, vegetable oil, and phosphatidylcholine. The applications were conducted at 276 kPa pressure and 3.5 m s-1 wind speed. The droplet spectrum was measured using a laser diffraction system. Round strings were used as drift collectors, positioned perpendicularly to the wind direction, at 2, 3, 4, 5, 6, 7, and 12 m from the nozzle. Drift was calculated by quantifying, through fluorimetry, a fluorescent tracer added to each solution at 1 g L-1. Droplet spectrum and dicamba drift depend on the interaction between spray composition and nozzle type. Air-induction nozzles are more recommended for dicamba applications, especially the TTI nozzle. Polymer and ammonium sulfate increase droplet size in all nozzle types, which may reduce drift to nearby crops.O objetivo deste trabalho foi avaliar a deriva e o espectro de gotas provenientes de aplicações de dicamba, com ou sem adjuvantes com potencial de redução de deriva, com uso de pontas de jato plano com indução de ar. Foram avaliadas pontas-padrão (XR e TT) e pontas com indução de ar (AIXR e TTI) em túnel de vento. Os adjuvantes usados foram polímero, sulfato de amônio, óleo vegetal e fosfatidilcoline. As aplicações foram feitas à pressão de 276 kPa e à velocidade do vento de 3,5 m s-1. O espectro de gotas foi avaliado por um sistema de difração a laser. Fios de nylon foram usados como coletores de deriva, posicionados transversalmente à direção do vento, a 2, 3, 4, 5, 6, 7 e 12 m da ponta de pulverização. A deriva foi calculada pela quantificação, por fluorimetria, de um corante fluorescente adicionado à calda à concentração de 1 g L-1. O espectro de gotas e a deriva de dicamba dependem da interação entre a composição da calda e o tipo de ponta de pulverização utilizada. Pontas de pulverização com indução de ar são mais recomendadas nas aplicações de dicamba, especialmente a ponta TTI. O polímero e o sulfato de amônio aumentam o tamanho das gotas em todos os tipos de pontas, o que pode reduzir a deriva para culturas adjacentes

Controle de plantas daninhas avaliado visualmente e por imagens aéreas

The employment of remotely piloted aircraft (RPA) for obtaining images in the field has grown and can assist the of management of weeds, however, the software for analysis and processing of images need to be tested under different conditions for the development of routines and validation of results. Therefore, the objective of this work was to correlate the results of the methodology of visual assessment (using scale of notes) with the results of the processing of aerial images with the software SisCob® and ImageJ® for the analysis of the occurrence and effectiveness of weed control. The comparisons were made in ten areas with different levels of weed infestation. A fallow area with four months has been submitted to the different treatments of chemical control with glyphosate herbicide, including a control without application, varying application rate (50, 90 and 150 L ha-1), the addition of adjuvant and presence of electrostatic spray. After 35 days of herbicide application, each area was assessed visually, and, in parallel, the area was overflied done the overflying the area with a RPA for image collection and subsequent digital processing, using both softwares for quantification in percentage of the control with the herbicide. All tested correlations (Pearson, Spearman and Kendall) were significant and positive, indicating that the use of RPA for image collection and their processing by means of the software demonstrated potential as an alternative for the evaluation of weed control, which may replace the visual assessment with operator in the field, avoiding the subjectivity and slowness in the evaluations.O emprego de aeronaves remotamente pilotadas (ARPs) para obtenção de imagens no campo tem crescido e pode auxiliar o manejo de plantas daninhas, contudo, os softwares para análise e processamento das imagens precisam ser testados sob diferentes condições para o desenvolvimento das rotinas e validação dos resultados. O objetivo deste trabalho foi correlacionar os resultados da metodologia de avaliação visual, com escala de notas, com os resultados do processamento de imagens com os softwares SisCob® e ImageJ®, na análise da ocorrência e eficácia de controle de plantas daninhas. As comparações foram feitas em dez áreas com diferentes níveis de infestação de plantas daninhas. A partir de uma área em pousio há quatro meses, submeteu-se a mesma a diferentes tratamentos de controle químico com herbicida glifosato, incluindo uma testemunha sem aplicação, variando taxa de aplicação (50, 90 e 150 L ha-1), adição de adjuvante e presença de pulverização eletrostática. Após 35 dias da aplicação do herbicida, cada uma das áreas foi avaliada visualmente, e paralelamente foi feito o sobrevoo com uma ARP para coleta das imagens aéreas e posterior processamento digital, usando os dois softwares para quantificação em percentagem do controle com o herbicida. Todas as correlações testadas (Pearson, Spearman e Kendall) foram significativas e positivas, indicando que o uso de ARPs para coleta de imagens e seu processamento através dos softwares demonstraram potencial como alternativa para a avaliação da infestação e controle de plantas daninhas, podendo substituir a avaliação visual com operador a campo, evitando a subjetividade e a morosidade

Avaliação de três mecanismos de distribuição de sementes

Three seed distribution mechanisms, conic, spiral, and helical shaped, assembled on three manual seeders were evaluated with regard to sowing density (number of seeds per meter), distribution uniformity (acceptable spacing), slippage and forward velocity. Maize, soybeen, and wheat seeds were used in the evaluation tests. The percentage of acceptable spacing (0.5 - 1.5 nominal spacing) varied from 32.8%, for the spiral mechanism, to 54.8%, for the conic mechanism, both using maize seed. The soybeen sowing density varied from 454,167 to 491,667, for a target density of 450,000 seeds/ha; with maize, it varied from 55,833 to 70,000, for a target density of 60,000 seeds/ha; and with wheat, it varied from 3,920,000 to 4,111,100, for a target density of 3,770,000 seeds/ha. The driven wheel slippage varied from 0.3%, for the spiral type, to 0.5% for the helical and conic shaped.Três mecanismos de distribuição de sementes do tipo cônico, espiral e helicoidal, montados sobre três semeadoras manuais, foram avaliados em relação à densidade de semeadura (número de sementes por metro), uniformidade de distribuição de sementes (percentagem de espaçamentos aceitáveis), patinagem da roda motriz e velocidade de deslocamento da semeadora. Para os testes dos referidos mecanismos utilizaram-se sementes de milho, soja e trigo. Verificou-se que a percentagem de espaçamento aceitável (0,5 - 1,5 do espaçamento nominal) variou de 32,8%, no mecanismo do tipo espiral a 54,8%, no mecanismo cônico, ambos com sementes de milho. A densidade de semeadura variou, com sementes de soja, de 454.167 a 491.667, quando a esperada era de 450.000 sementes/ha; com sementes de milho, de 55.833 a 70.000, quando a esperada era de 60.000 sementes/ha; e com sementes de trigo, de 3.920.000 a 4.111.100, quando a esperada era de 3.770.000 sementes/ha. A patinagem das rodas acionadoras dos mecanismos variou de 0,3%, no mecanismo espiral, a 0,5% nos mecanismos helicoidal e cônico

Fitotoxicidade na cultura de soja causada por deriva simulada de dicamba

The objective of this work was to evaluate injury symptoms on soybean not tolerant to dicamba (3,6-dichloro-2-methoxybenzoic acid), as well as crop yield, after the application of sub-rates of the herbicide to simulate physical drift in tropical conditions. Dicamba rates of 0, 5.8, 14.4, 28.8, 57.6, and 576 g acid equivalent per hectare were applied at the vegetative (V3) and reproductive (R1) stages of soybean, using a backpack sprayer pressurized with CO2, equipped with air-induction flat fan spray nozzles; the pressure and rate of application were 250 kPa and 200 L ha-1, respectively. Visible injury, the soil-plant analysis development (SPAD) index (leaf chlorophyll content) at 14 days after herbicide application, and soybean crop yield were evaluated. These variables were influenced by the crop stage in which the dicamba rates were applied. Rates below 28.8 g ha-1 caused less injury to soybean when applied at the R1 stage; however, there were no differences in yield between stages. A 1% dicamba drift in tropical conditions reduces soybean yield by 12%.O objetivo deste trabalho foi avaliar os sintomas de injúria em soja não tolerante ao dicamba (ácido 3,6-dicloro-2-metoxibenzóico), bem como a produtividade da cultura, após a aplicação de subdoses do herbicida para simulação da deriva física em condições tropicais. Doses de dicamba de 0, 5,8, 14,4, 28,8, 57,6 e 576 g de equivalente ácido por hectare foram aplicadas nos estádios vegetativo (V3) e reprodutivo (R1) da soja, com uso de pulverizador costal acionado por CO2, dotado de pontas de jato plano com indução de ar; a pressão e a taxa de aplicação foram de 250 kPa e 200 L ha-1, respectivamente. Foram avaliados injúria visual, índice “soil-plant analysis development” (SPAD) (teor de clorofila das folhas) aos 14 dias após a aplicação do herbicida e produtividade da cultura de soja. Essas variáveis foram influenciadas pelo estádio da cultura em que as doses de dicamba foram aplicadas. Doses inferiores a 28,8 g ha-1 causaram menor injúria na soja quando aplicadas no estádio R1; contudo, não houve diferenças de produtividade entre os estádios. A deriva de dicamba de 1%, em condições tropicais, reduz a produtividade da soja em 12%

Spray drift and efficacy from glyphosate and 2,4-D applications with adjuvants

Weed plants are one of main factors that affect the production of oilseed crops. Their management have been based on chemical control with herbicides, like glyphosate and 2,4-D, due to usefulness and efficiency of applications. However, their use must be managed correctly to mitigate the spray drift. Therefore, this study aimed to evaluate efficacy and spray drift from glyphosate and 2,4-D applications with adjuvants. The drift evaluation of herbicide solutions was conducted in a split-plot arranged in a randomized block design with five replications. Main plots consisted of three herbicide solutions at 150 L ha-1 (glyphosate + 2,4-D, glyphosate + 2,4-D + sodium lauryl ether sulphate, and glyphosate + 2,4-D + fatty acid esters). Sub-plots consisted of five downwind distances (1 to 10 m) from the sprayed area. It was used a fluorecent tracer and drift colectors. The efficacy trial was performed in a randomized block design with four replications in a 3 x 2 factorial scheme, being the same herbicide solutions and two carrier volumes (75 and 150 L ha-1). Droplet spectrum and weed depositon were evaluated and physicochemical properties of the herbicide solutions were characterized. Glyphosate + 2,4-D with or without adjuvants, sprayed using 75 or 150 L ha-1, resulted in similar deposition of tracer on weeds and their control. Those herbicides associated or not with sodium lauryl ether sulphate and fatty acid esters produce similar droplet spectrum and deposition of tracer on drift collectors

Control of Dalbulus maidis in maize crop with electrostatic spraying

Among the pests that attack the maize, the maize leafhopper, which causes direct damages by sap-sucking and indirect ones, stands out as being a vector of pathogens and viruses, and can cause losses of up to 100% of the production. An alternative to improve the chemical control of this pest is the use of electrostatic spraying technology. However, there is no research support. This study aimed to evaluate the deposition of spray in the maize crop and the effectiveness in the chemical control of the maize leafhopper, using the electrostatic spraying system, at different application rates, compared to the conventional spraying system. The experiment was conducted in a randomized block design with five treatments, in a 2x2 + 2 factorial scheme: presence or absence of electrostatic spraying system, two application rates (35 and 50 L ha-1), an additional treatment using a hydraulic spray nozzle and a rate of 100 L ha-1, and other additional treatment without the application of insecticide, in order to support the study of pest infestation. Each treatment consisted of eight replicates, in which the spray deposition in the maize canopy and the efficiency in the control were evaluated. For the insecticide applications, a boom sprayer with induction electrostatic spraying system was used with indirect electrification. To evaluate the deposition, the Brilliant Blue FCF marker was added to the spray to be detected by absorbance in spectrophotometry. For the biological efficacy of the maize leafhopper, the insecticide composed of thiamethoxam and lambda-cyhalothrin was used compared with the control without the application. There was a significant increase in the spray deposition, both in the upper and lower maize leaves, with the use of electrostatic spray technology compared to the conventional spray system. The control of the maize leafhopper was also superior. The electrostatic spraying also made it possible to reduce the application rate by approximately three times in relation to that used in conventional hydraulic spraying

Adjuvants plus phytosanitary products and the effects on the physical-chemical properties of the spray liquids

The frequent tank mixing of phytosanitary products, adjuvants, and foliar fertilizers highlights the lack of information which sustains decisions about what products can be mixed for spray application. Thus, the aim of this study was to evaluate the physical and chemical characteristics of fungicides, herbicides, and insecticides in combination with some adjuvants on the Brazilian market. The experimental design was completely randomized and spray mixes of the phytosanitary products: fungicide (azoxystrobin+benzovindiflupir), herbicide (diamônio salt of N-(phosponomethyl)) or insecticide (fenpropathrin) were evaluated in combination with adjuvants (mineral oil base, foliar fertilizer or lecithin + propionic acid), and in two application rates (95 and 52 L ha-1); all with four replications. Surface tension, electrical conductivity, pH, dynamic viscosity and density of spray mixes were evaluated. The adjuvants presented characteristics capable of significantly altering the physicochemical properties of the phytosanitary spray mixes, and thus, alter the biological effectiveness and efficiency of the spray applications. However, its effects are also dependent on the phytosanitary product added to the spray mix, which makes general recommendations a difficult task. The greatest pH reduction, as well as the greatest increase in electrical conductivity, were caused by the adjuvant lecithin + propionic acid. All phytosanitary products and adjuvants studied, associated or not, resulted in a reduction in the surface tension of the spray mix in relation to water. The magnitude of change of density and dynamic viscosity promoted by adjuvants was lower than the other characteristics evaluated