João Paulo Arantes Rodrigues da Cunha

Controle químico da ferrugem asiática da soja em função de ponta de pulverização e de volume de calda

The spray nozzles are one of the most important components of pesticide hydraulic sprayers. This study aimed at evaluating the chemical control of the rust and the deposition of fungicide sprayed on soybean concerning different nozzles, and application volumes. A randomized complete-block design with four replications was used, in a factorial model (4 x 2) + 1: four spray nozzles (standard flat fan, pre-orifice flat fan, air induction flat fan and air induction twin flat fan), two spray volumes (115 and 160L ha-1) and the control (non-treated plot). Emgopa 313 soybean (long cycle) were sown. After the application of the fungicide tebuconazole, with the different nozzles and volume rates, the spray deposition in the plant canopy, the rust severity, and the yield were evaluated. The results showed that, despite the fact of the volume rate of 160L ha-1 and of the use of the standard flat fan nozzles have provided larger fungicide distribution uniformity in the plant canopy, there was not influence of the nozzle type neither of the application volume in the control of the rust as well as in the soybean yield. The fungicide has provided a good control of the rust, increasing the soybean yield, that was, on average, 41% superior to that obtained in the control.

Espectro de gotas de bicos de pulverização hidráulicos de jato plano e de jato cônico vazio

A escolha e o uso adequado de bicos de pulverizacao sao essenciais para a correta aplicacao de agrotoxicos. Este trabalho teve como objetivo avaliar o espectro de gotas de bicos de pulverizacao hidraulicos de jato plano padrao e de jato conico vazio, com diferentes vazoes nominais. Em ambiente controlado, avaliou-se o espectro de gotas por meio de um analisador a laser de gotas em tempo real, nas faixas de pressao de 200 a 400 kPa para os bicos de jato plano, e de 400 a 600 kPa para os bicos de jato conico vazio. Realizou-se tambem um estudo teorico sobre a distância horizontal percorrida por gotas de tamanho conhecido. Os bicos de jato conico vazio apresentaram gotas de menor tamanho em relacao aos de jato plano e, por isso, proporcionaram maior densidade de gotas depositadas sobre a superficie-alvo. Todos os bicos apresentaram densidade de gotas superior a 110 gotas cm-2. No entanto, o potencial de deriva foi alto, principalmente o dos bicos de jato conico, requerendo estrategias para sua reducao. E possivel estimar a distância horizontal percorrida por gotas de tamanho conhecido.

Espectro de gotas de pontas de pulverização com adjuvantes de uso agrícola

The success of an efficient pesticide application depends on the synergy among factors such as droplet size, nozzle type, pressure, spray volume, spray tank mixture and target. The aim of this work was to evaluate the spectrum of droplets produced by turbo flat-fan (TT 11002) and air induction turbo flat-fan (TTI 11002) spray nozzles, with different adjuvants added to the tank mix, using the laser diffraction technique. The experiment was carried out in a completely randomized design, with four replications in a factorial model 2x5, i.e., two spray nozzles (turbo flat-fan and air induction turbo flat-fan) and five spray mixtures (water and water plus four adjuvants (phosphatidylcholine+propionic acid, nonylphenol polyglycolic ether; fatty acid esters and ethoxylated nonylphenol+ethylene oxide). In a controlled atmosphere, the droplet spectrum was evaluated through a real time laser particle size analyzer, at a pressure of 276 kPa. The effect of the adjuvant on the droplet size was shown to be dependent on the spray nozzle. Addition of an adjuvant did not alter drift risk, expressed by the percentage of spray volume in droplets smaller than 100 µm; however, the adjuvant phosphatidylcholine+propionic acid reduced the volumetric median diameter of the droplets produced by the air induction turbo flat-fan nozzle, compared to the evaluation with water alone.

Avaliação do espectro de gotas de pontas de pulverização hidráulicas utilizando a técnica da difração do raio laser

The spray nozzles are one of the most important components of pesticide hydraulic sprayer. This study evaluated the droplet spectrum of hydraulic flat fan (standard and low drift) and hollow cone spray nozzles, available in the market, under different working pressures. In laboratory, droplet spectrum, using a real time laser particle size analyzer, was measured with the operating pressure of 200; 300 and 400 kPa, for flat fan, and 400; 500 and 600 kPa, for hollow cone. The results showed that: the droplet spectrum was affected by the nominal flow and by the liquid pressure; the drift potential of standard flat fan and hollow cone spray nozzles was high; the use of low drift nozzles increased the droplet diameter, which was an effective factor in drift reduction, and the technique of laser diffraction provides a robust means of measuring the droplet size produced by spray systems.

Efeito de pontas de pulverização no controle químico da ferrugem da soja

A composition is provided, including one or more quantum dots and at least one organic emitter. Further, a formulation including the composition, a use of the formulation and a device comprising the composition or formulation is provided.

Deposição e deriva de calda fungicida aplicada em feijoeiro, em função de bico de pulverização e de volume de calda

The fungicide application technology should provide efficient control of vegetable diseases. The objective of this study was to evaluate the deposition and the drift of fungicide sprayed in a common bean crop with different nozzles and two volumes of application. A completely randomized block design with four replications was used, in a factorial model 2 x 2: two spray nozzles (standard flat fan and hollow cone) and two spray volumes (125 and 250 L ha-1). The study of deposition was made by a tracer analysis in different positions of the crop, using spectrophotometer. The drift was evaluated using artificial targets placed outside the application area. The fungicide, with the tracer was applied three times, using a CO2 - pressurized sprayer. The results allowed the following conclusions: the flat fan and hollow cone nozzles provided similar cover of the bean leaves, both in the superior and the inferior position of the crop; the application volume of 250 L ha-1 provided higher retention of fungicide in the leaves and higher uniformity of coverage of the plants than the volume of 125 L ha-1; the droplets formed in the application with hollow cone nozzles were more favorable to the drift than the ones produced with flat fan nozzles, specially when low application volume was used; and the applications, in general, provided low deposition uniformity and high drift potential.

Deposição de calda pulverizada na cultura da soja promovida pela aplicação aérea e terrestre

This study aimed to evaluate the effect of aerial and ground application technology in spray deposition on soybean crop. It was evaluated the spray deposition on the bottom and the top of the plant canopy, after application of a tracer, by spectrophotometric technique. The experiment was conducted in a randomized block design with four replications and eight treatments (application technologies): 1 - Ground (Hollow cone nozzle-TXA 8002 and 180 L ha-1) 2 - Ground (Air induction turbo twin flat fan nozzle-AITTJ 11002 and 150 L ha-1), 3 - Ground (Air induction turbo flat fan nozzle-TTI 11002 and 150 L ha-1), 4 - Ground (Turbo twin flat fan nozzle-TTJ60 11002 and 150 L ha-1) , 5 - Ground (Turbo flat fan nozzle-TT 11002 and 150 L ha-1) 6 - Aerial (Rotary atomizers and 40 L ha-1) 7 - Aerial (Rotary atomizers and 30 L ha-1) and 8 - Aerial (Rotary atomizers and 20 L ha-1). The droplet spectra were also evaluated. It was concluded that ground application with hollow cone nozzle and aerial with rotary atomizers (40 L ha-1) were the most effective in promoting the droplet penetration into soybean canopy, although their droplet spectra were more susceptible to drift. The aerial application was technically feasible in spray deposition, compared to ground treatments.

Simulação da deriva de agrotóxicos em diferentes condições de pulverização

A deriva nas aplicacoes de agrotoxicos e considerada um dos maiores problemas da agricultura. Entre os fatores que a influenciam, o tamanho das gotas pulverizadas e a velocidade do vento tem-se mostrado primordiais. Objetivou-se, no presente trabalho, determinar a distância horizontal teorica percorrida por gotas de tamanho conhecido, submetidas a diferentes alturas de lancamento e velocidades do vento. Utilizando-se de equacoes classicas da mecânica dos fluidos e da metodologia de superficie de resposta, determinou-se a distância que as gotas podem ser arrastadas quando liberadas de alturas variadas, em funcao do tamanho das gotas pulverizadas, da densidade do liquido e da velocidade horizontal. A analise dos dados permitiu estimar a distância horizontal percorrida por gotas de pulverizacao, em diversas condicoes de lancamento, estando os resultados simulados altamente correlacionados com o diâmetro das gotas e com a velocidade de deslocamento horizontal. Nas condicoes avaliadas, a distância horizontal maxima percorrida pelas gotas foi inferior a 40 m.

Efeito da temperatura nas características físico-químicas de soluções aquosas com adjuvantes de uso agrícola

SummARY Pesticide application efficacy on crops can be improved by adding adjuvants to tank mixtures. The present study evaluated the adjuvant effect, in different doses, on the physico-chemical characteristics of aqueous solutions. The hidrogenionic poten tial, electrical conductivity, density, dynamic viscosity, surface tension and stability of aqueous solution with eight commercial adjuvants were evaluated at the recommended dose (full-dose) and at half of it (half-dose), besides the distilled water alone. A randomized design with four replications was used, in a hier archy factorial scheme (8 ×2+1). From the results it can be con cluded that the adjuvant effect on the physico-chemical charac teristics of aqueous solutions was based on their chemical properties and formulation. The performance of these characteristics was not similar, even for additives with the same use recommendation. The physico-chemical characteristics for each adjuvant were affected differently by the dose alteration. The pH, surface tension and viscosity were the most sensitive characteristics to the adjuvant addition.

Avaliação de pontas de pulverização hidráulicas na aplicação de fungicida em feijoeiro

The spray nozzles are one of the most important components of pesticide hydraulic sprayer because they affect the characteristics of the emitted spray. The objective of this study was to evaluate three hydraulic spray nozzles (standard flat fan, low drift flat fan and hollow cone) for bean diseases control upon application of the fungicide chlorothalonil applied at 20, 30, 40 and 50 days after emergency (DAE) in a water volume of 125 L ha -1 . For comparison, a non-treated plot was used. A randomized complete-block design with four replications was used. The first symptoms of anthracnose, angular leaf spot and rust were observed at 20 DAE. The droplet density obtained with the three spray nozzles was above 60 droplets cm -2 . The fungicide applied with the three nozzles provided satisfactory control of the diseases and there were no differences among nozzles. On average, bean yield increased 76% due to the fungicide applications.