ABSTRACT Improving the effectiveness of pesticide application for controlling insects, mites, and pathogens in coffee cultivation has been a major challenge for coffee farmers, researchers, and consultants. The present study aimed to assess the deposition and distribution of a brilliant blue tracer in the coffee canopy using Jacto’s Arbus 2000 Super Export EL and Kuhn’s Twister 2000 air blast sprayers at different application speeds (5 and 7 km h-1). The experiment was conducted using a randomized block design, with a 2 × 2 factorial arrangement (two sprayer models and two application speeds), with six replicates. After spraying, leaves were collected, and the deposition of the tracer was assessed using spectrophotometry. The canopy was divided into lower, middle, and upper heights, and subdivided into external and internal crown positions. The percentage difference in spray deposition between positions was termed relative spray deposition. Spray deposition in the internal crown differed only in the upper third section between sprayers. In the external crown, the application speed affected the deposition of tracer dye for both sprayers, whereas, in the internal crown, the application speed only affected the deposition of tracer dye in the upper crown section only when using the Arbus sprayer.

ABSTRACT. Chemical control is essential for efficient pest management in coffee crops. Application technologies should safely deliver insecticides to the target whilst protecting the environment, insecticide applicators, and consumers. To achieve these goals, application volumes, hydraulic nozzles, and application techniques should be evaluated. This study assessed the biological efficiency of different spray volumes and spray nozzles used to apply insecticides to control coffee berry borer (Hypothenemus hampei) populations. We applied insecticides using a hydropneumatic sprayer with and without an electrostatic spraying system. The experiment followed a randomized block factorial design (2 × 2 + 1) and included two types of spray nozzles [a hollow cone spray nozzle (JA1) and a hollow cone spray nozzle with air induction (TVI)], two spray volumes (200 and 400 L ha-1), one additional treatment (SPE2 nozzle with a 200 system 200 L ha-1), and six replicates. We assessed the control efficiency of the different application methods by evaluating the percentage of fruits damaged 20 and 40 days after the date of application. The spray volume did not affect the biological efficiency of pest control, and the lower spray volume (200 L ha-1) was effective in the control of coffee berry borers. Application of insecticides using coarse droplets was more efficient than the application using very fine and fine droplets. The TVI hydraulic spray nozzle effectively controlled coffee berry borers at 200 and 400 L ha-1. The electrostatic application system performed similarly to the conventional system in terms of the control of the coffee berry borers, and was less efficient than the conventional system under some operational conditions.

RESUMO Para o sucesso do controle fitossanitário no cafeeiro, é importante uma correta deposição de calda ao longo do dossel. Contudo, a estrutura da planta dificulta essa distribuição. Objetivou-se avaliar a deposição de um traçador em folhas e frutos, na cultura do café, em função da taxa de aplicação e do tipo de ponta de pulverização, bem como do emprego de um sistema de pulverização eletrostática. Utilizou-se pulverizador hidropneumático com pontas hidráulicas de jato cônico vazio, da série TVI (gotas grossas com indução de ar) e JA (gotas finas), em taxas de 200 e 400 L ha-1. Também foi avaliado um sistema eletrostático, com ponta SPE-2 e taxa de 200 L ha-1, instalado no mesmo pulverizador. Foram determinadas a deposição do traçador em folhas e frutos dos terços superior, médio e inferior das plantas, bem como as perdas para o solo na projeção da copa, mediante quantificação por espectrofotometria. Os resultados indicaram que a aplicação eletrostática proporciona maior deposição nas folhas do terço superior, em relação à aplicação hidropneumática, independentemente da taxa de aplicação. A ponta TVI produz maior deposição nos frutos do terço médio e maior perda para o solo, em relação à ponta JA. A taxa de aplicação de 400 L ha-1 promove maior deposição nos frutos do terço médio, em relação à de 200 L ha-1, mas também causa maior perda para o solo.

ABSTRACT The correct deposition of spray along the canopy is important for the phytosanitary control in coffee plants; however, the structure of the plant makes this distribution difficult. This study aimed to evaluate the deposition of a tracer on leaves and fruits in coffee cultivation, with respect to the application rate and type of hydraulic nozzle, as well as the use of an electrostatic spraying system. A hydropneumatic sprayer was used, with hydraulic nozzles of empty conical jet of the series TVI (coarse droplets with air induction) or JA (fine droplets), at rates of 200 and 400 L ha-1. An electrostatic system, with SPE-2 nozzle and rate of 200 L ha-1, was also evaluated. The deposition of the tracer on leaves and fruits of the upper, middle and lower thirds of the trees, as well as the losses to the ground in the canopy projection, were quantified using spectrophotometry. The results indicated that the electrostatic application provides a greater deposition on leaves of the upper third than the hydropneumatic application, regardless of the application rate. The use of the TVI nozzle results in a greater deposition on the fruits of the middle third and a greater loss to the ground than the JA nozzle. Although an application rate of 400 L ha-1 results in a greater deposition on the fruits of the middle third than an application rate of 200 L ha-1, it also causes a greater loss to the ground.

ABSTRACT Coffee production faces challenges due to the susceptibility of the crop to insects. Owing to the coffee leaf miner Leucoptera coffeella, which is one of the main insect pests, the technology for the application of phytosanitary measures becomes the main challenge for coffee growers. This study aimed to evaluate the effectiveness of coffee leaf miner control using different methods of application. The study was conducted in an experimental site in the municipality of Monte Carmelo - Minas Gerais. Spray depositions in different positions of the plant canopy and the effective control of coffee leaf miner were evaluated using the following application treatments: a hydropneumatic sprayer with varying spray volumes (200 and 400 L ha-1), two hollow-cone spray nozzles with the presence and absence of agricultural adjuvant, and electrostatic application using a spray volume of 200 L ha-1 with and without spray adjuvant. The addition of an adjuvant to the spray did not influence coffee leaf miner control; in contrast, a spray volume of 200 L ha-1 combined with the application of coarse droplets was efficient in the management of insect pest. The reduction in the rate of the application using coarse droplets increased the operational capacity and reduced spray drift potential.

ABSTRACT The aim of the current study is to develop an electronic system capable of automatically replacing hydraulic spray nozzles, based on psychrometric air conditions such as temperature and relative air humidity, in order to help improving the efficiency of application technologies. The system comprised one microcontroller, two solenoid valves, one temperature and relative humidity sensor, and a control algorithm. The system was installed in a hydropneumatic sprayer adapted with two semi-arcs. One semi-arc was equipped with JA-2 and other semi-arc with CVIA-015 hydraulic nozzles. After the algorithm interpreted the momentary psychrometric air conditions, it activated the JA-2 (when VPD < 20 hPa) or the CVIA-015 nozzle (when VPD > 20 hPa). The system was evaluated based on technical spraying parameters and on the response time to replace the hydraulic nozzle. Based on the results, the smallest-diameter droplets were the most influenced by psychrometric air conditions. VPD > 20 hPa tended to increase the VMD values and to reduce droplet density, although it did not change the SPAN index. The necessary mean time to switch from the JA-2 to the CVIA-015 nozzle was 0.742 s, whereas the necessary mean time to switch from the CVIA-015 to the JA-2 nozzle was 0.684 s.

ABSTRACT Stenoma catenifer is considered the main pest of avocado, making impossible to commercialize the infested fruits. This study was conducted with the objective of evaluating the potential of Heterorhabditis amazonensis MC01 in the field control of avocado borer, as well as the nematode release method. Two treatments were tested, namely: release of dead Tenebrio molitor infected with the nematode and hydraulic nematode spraying; hydraulic application of chemical insecticides was used as a control. The experiment was set up in a randomized complete block design with 15 replicates. The concentration of suspension distribution was 5,500 infective juveniles per m2. At the experimental area traps with sex pheromone were installed to capture adult males. The number of borer fruits was evaluated in the two central plants of each plot, sampling 4 fruits per plant. There was a reduction in the percentage of borer fruits from 15 days of application for all control methods. After the release of nematodes, the adult population was similar to the control, and it can be inferred that, even without chemical control, there was no increase in the number of adults. Thus, H. amazonensis was considered promising under field conditions, reducing the populations of S. catenifer, in all release methods.

RESUMO Condições meteorológicas adversas, ou problemas mecânicos e redução na taxa de aplicação, podem aumentar o tempo de armazenamento da calda no tanque do pulverizador. Objetivou-se avaliar o efeito do armazenamento da calda fitossanitária na germinação de conídios de Beauveria bassiana, com e sem adjuvantes. Utilizou-se delineamento experimental inteiramente casualizado, em esquema fatorial 13 x 5, composto por treze períodos de armazenamento (0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44 e 48 h) e cinco composições para a calda de pulverização (B. bassiana, B. bassiana + Helper Neutrum, B. bassiana + TA-35, B. bassiana + Nimbus e B. bassiana + Orobor). A calda biológica contendo conídios de B. bassiana sem adjuvantes manteve-se viável para uso após seu preparo e a germinação dos conídios reduziu-se 9,2 vezes após 48 h com a adição de adjuvante.

ABSTRACT Adverse weather conditions, or mechanical problems and decrease in the application rate, may increase the storage time of the spray solution in the sprayer tank. This study aimed to assess the effect of the phytosanitary spray solution storage on the germination of Beauveria bassiana conidia, with or without agricultural adjuvants. A completely randomized design was used, in a 13 x 5 factorial scheme, consisting of thirteen storage times (0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44 and 48 h) and five compositions for the spray solution (B. bassiana, B. bassiana + Helper Neutrum, B. bassiana + TA-35, B. bassiana + Nimbus and B. bassiana + Orobor). The biological spray solution containing B. bassiana conidia and no adjuvants remained viable for use after preparation and the conidial germination decreased 9.2 times after 48 h when an adjuvant was added.

O pulverizador costal manual é um equipamento bastante utilizado, devido ao seu baixo custo de aquisição e ampla aplicabilidade. Nos últimos anos, têm surgido pulverizadores costais elétricos que aumentam o conforto do operador e melhoram a qualidade da operação de pulverização. Objetivou-se, com este trabalho, avaliar um pulverizador costal elétrico, utilizando-se quatro pontas de pulverização de jato plano (XR 110.02, AXI 110.03, AXI 110.04 e AXI 110.05). As variáveis estudadas foram: vazão e pressão do líquido, duração da carga da bateria, rotação do eixo e ruído da bomba. O pulverizador elétrico proporcionou vazão e pressão constantes para as pontas XR 110.02, AXI 110.03 e AXI 110.04. Já utilizando-se a ponta AXI 110.05, houve variação na vazão e pressão do líquido, principalmente no final de cada repetição, uma vez que, com o aumento da vazão, aumentou a demanda de potência da bomba. Da mesma forma, a duração da carga da bateria foi proporcional à demanda de potência. Nas vazões estudadas, o ruído da bomba atendeu aos padrões da legislação, para uma jornada de 8 horas de trabalho.

The knapsack sprayer is a very popular equipment, due to its low acquisition cost and wide applicability. In recent years, electric backpack sprayers, which increase the operator's comfort and improve the spraying operation quality, have come up. This study aimed at evaluating an electric backpack sprayer, by using four flat spraying nozzles (XR 110.02, AXI 110.03, AXI 110.04 and AXI 110.05). The variables studied were: liquid flow and pressure, battery charge duration, axis rotation and pump noise. The electric sprayer provided constant flow and pressure for the XR 110.02, AXI 110.03 and AXI 110.04 nozzles. By using the AXI 110.05 nozzle, a variation was observed for the liquid flow and pressure, mainly at the end of each repetition, since the flow increase also increased the pump power demand. Similarly, the battery charge duration was proportional to the power demand. For the flows studied, the pump noise fitted the regulation standards, for a daily working journey of 8 hours.

A pulverização eletrostática, quando utilizada de maneira correta, proporciona vantagens em relação aos sistemas convencionais. No entanto, diversos fatores podem interferir na eficiência do sistema. Por isso, objetivou-se, com este trabalho, avaliar a relação carga/massa (Q/M) em diferentes distâncias de pulverização (0, 1, 2, 3, 4 e 5 m) e a eficiência de deposição de líquido no alvo. Na avaliação da relação Q/M, utilizou-se o método da gaiola de Faraday e, na avaliação da eficiência da deposição de líquido, posicionaram-se alvos artificiais, nos sentidos longitudinal e transversal ao jorro de pulverização. Verificou-se que a distância de pulverização afeta a relação Q/M e, consequentemente, a eficiência na deposição de líquido. Na distância próxima ao alvo, a relação Q/M foi de 4,11 mC kg-1, e, nas distâncias de 1, 2, 3, 4 e 5 m, reduziu-se para 1,38; 0,64; 0,31; 0,17 e 0,005 mC kg-1, respectivamente. Quanto à deposição de líquido, o sistema eletrostático foi afetado pela orientação em relação ao alvo e pela distância de pulverização. Com o alvo na transversal, o sistema não proporcionou aumento da deposição de líquido, já com o alvo na longitudinal, houve aumento na deposição até a distância de 3 m.

When the electrostatic spraying is used correctly, it provides advantages over conventional systems, however many factors can affect the system efficiency. Therefore, the objective of this study was to evaluate the charge/mass ratio (Q/M) at different spraying distances (0, 1, 2, 3, 4 and 5 m), and the liquid deposition efficiency on the target. Evaluating the Q/M ratio the Faraday cage method was used and to evaluate the liquid deposition efficiency the artificial targets were positioned longitudinally and transversely to the spray jet. It was found that the spraying distance affects the Q/M ratio, consequently, the liquid deposition efficiency. For the closest distance to the target the Q/M ratio was 4.11 mC kg-1, and at distances of 1, 2, 3, 4 and 5 m, the ratio decreased to 1.38, 0.64, 0.31, 0.17 and 0.005 mC kg-1, respectively. For the liquid deposition, the electrostatic system was affected by the target orientation and spraying distance. The target transversely to the jet of liquid did not improve the liquid deposition, but longitudinally increased the deposition up to 3 meters of distance.

O trabalho foi desenvolvido visando avaliar os parâmetros da pulverização em culturas arbóreas. A eficiência e a deposição de gotas sobre o alvo são importantes para elevar a rentabilidade na produção de madeira, diminuindo os riscos ambientais, e para a saúde do aplicador, aumentando a eficácia no combate de pragas e doenças. O objetivo deste trabalho foi avaliar os parâmetros operacionais de um pulverizador pneumático para aplicação em florestas adultas de eucalipto, através do estudo da densidade de gotas, da porcentagem de cobertura, do diâmetro da mediana volumétrica, do coeficiente de homogeneidade, da amplitude relativa e da uniformidade de distribuição volumétrica da calda. O pulverizador utilizado mostrou-se eficiente para a aplicação de agrotóxicos em árvores adultas de eucalipto. Observou-se que todos os tratamentos avaliados apresentaram densidade e tamanho de gotas satisfatórias para a pulverização. Quanto aos parâmetros porcentagem de cobertura, deposição e uniformidade de distribuição volumétrica, os melhores resultados ocorreram quando foram utilizados os índices volumétricos de 27 e 20,2 mL m³ de dossel. O índice volumétrico de 20,2 mL m³ de dossel foi o indicado para pulverização.

The study was conducted to evaluate the parameters of the spraying in tree crops. The efficiency and droplet deposition on the target is important to raise the profitability of timber production, reducing environmental risks to health from the applicator, increasing effectiveness in combating pests and diseases. The aim of this study was to evaluate the operational parameters of a pneumatic spray for application to adult eucalypt forests, through the study of droplet density and percentage of coverage, the volume median diameter, the coefficient of homogeneity of relative amplitude and uniform volumetric distribution of the syrup. The sprayer was efficient for the application of pesticides in adult trees of eucalyptus. It was observed that all treatments showed density and droplet size satisfactory for spraying. Regarding the parameters percentage of coverage and uniform volumetric distribution, the best results occurred when we used the volumetric rate of 27 mL and 20.2 m³ of canopy. As the volume index of 20.2 mL m³ of canopy suitable for spraying.

O princípio de fracionamento e o tamanho de gotas são fundamentais para o sucesso do controle fitossanitário. Objetivou-se, com este trabalho, desenvolver e avaliar um sistema automatizado, para controlar os parâmetros do espectro de gotas da pulverização, em função do déficit de pressão de vapor d'água no ar. O sistema de controle automático constituiu-se de um sensor de temperatura e umidade relativa, um microcontrolador, um servomotor e um pulverizador hidropneumático. A pulverização foi realizada em etiquetas de papel hidrossensível, dispostas em suportes de madeira, para diferentes déficits de pressão de vapor d'água no ar. Posteriormente à digitalização e análise das etiquetas, foram selecionadas três pressões de trabalho (633 kPa, 844 kPa e 1.055 kPa), para serem utilizadas no sistema automatizado. Os resultados indicaram que o controlador foi eficiente na manutenção do espectro de gotas da pulverização de agrotóxicos. A automatização permitiu a manutenção do volume de calda, alterando a pressão de trabalho, em função do déficit de pressão de vapor d'água no ar. A pulverização com o sistema automatizado apresentou qualidade do espectro de gotas superior ao sistema manual, à pressão de 633 kPa.

The principle of fractionation and droplets size are crucial for the success of pest control. This study aimed at developing and evaluating an automated system to control the spraying droplet spectrum according to the vapor pressure deficit in the air. The automatic control system consisted of a temperature and relative humidity sensor, a microcontroller, a servomotor and a hydropneumatic sprayer. Spraying was performed on water sensitive paper labels arranged on wooden supports for different vapor pressure deficits in the air. After scanning and analysing the paper labels, three working pressures were selected (633 kPa, 844 kPa and 1,055 kPa) for use in the automated system. The results indicated that the controller efficiently maintained the droplets spectrum when spraying pesticides. Automation enabled the maintenance of the spray volume by altering the working pressure, according to the vapor pressure deficit in the air. Spraying with the automated system presented a droplet spectrum quality superior to the one obtained by using the manual system at the pressure of 633 kPa.