A comparison of the performance and biological efficiency of new knapsack sprayers and a controlled droplet application (CDA) sprayer for the control of the diamondback moth, Plutella xylostella L. (Lepidoptera : Plutellidae)

Field trials and laboratory bioassays were undertaken to compare the performance and efficacy (mortality of diamondback moth larvae) of insecticides applied to cabbages with three high volume hydraulic knapsack sprayers (NS-16, PB-20 and Selecta 12V) and a controlled droplet application (CDA) sprayer. In field experiments, the high volume knapsack sprayers (application rate 500-600 L ha(-1)) provided better spray coverage on the upper and lower surfaces of inner leaves, the upper surfaces of middle and outer leaves, and greater biological efficacy than the CDA sprayer (application rate 20similar to40 L ha(-1)). The PB-20 provided better spray coverage on the upper surface of middle leaves and both surfaces of outer leaves when compared with the Selecta 12V. However, its biological efficacy in the field was not significantly different from that of the other high volume sprayers. Increasing the application rate from 20 to 40 L ha(-1) for the CDA sprayer significantly increased droplet density but had no impact on test insect mortality. Laboratory evaluations of biological efficacy yielded higher estimates than field evaluations and there was no significant difference between the performance of the PB-20 and the CDA sprayer. Significant positive relationships were detected between insect mortality and droplet density deposited for both the PB-20 and the CDA sprayers.

Microfabricated dual sprayer for on-line mass tagging of phosphopeptides.

Phosphopeptides tagging reactions by dinuclear zinc(II) complexes (1,3-bis[bis(2-pyridylmethyl)amino]-propan-2-olato dizinc(II)3+, called tag) were performed with a dual-channel microsprayer in electrospray ionization mass spectrometry. The reaction is first studied ex situ and analyzed with a commercial electrospray source. In situ reactions (i.e., inside the Taylor cone) were achieved with a dual-channel microsprayer both with the tag synthesized chemically before the experiments and with the tag electrogenerated by in situ oxidation of a zinc electrode, also used to apply the electrospray current. The device consists of a polyimide microchip with two microchannels (20 microm x 50 microm x 1 cm) etched on each side of the structure and connecting only at the tip of the microchip. We demonstrate here that mixing two solutions with different physicochemical properties inside the Taylor cone can be used to selectively tag target molecules.

Calibration of angles of nozzles and deposition of an axial-flow sprayer on dwarf cashew

The study aimed to determine an optimum angle for the nozzles axial-flow sprayers a deposition for better vertical distribution focused on cashew. In laboratory tests were conducted adjusting the angle of the nozzle axial-flow sprayers. The experimental design was randomized blocks in a 2x3 factorial with four replications. The treatment for this test were two settings (with and without the adjustment of the angles of the nozzles ) and tree application volumes 273, 699 and 954 L ha-¹.The study was conducted in an orchard of dwarf cashew, with eight years of age. It was concluded that the volumetric distribution profile showed better vertical distribution uniformity when the angles of the nozzles were regulated for the canopy, the adjustment of the angles of the nozzles for the canopy provided greater deposition of droplets, the increased volume of application resulted in higher depositions in the leaves of the crop.

Air flow humidification for air-assisted boom sprayer

The air-assisted ground spray is fairly widespread. However, due to the unpredictable weather conditions, the operational efficiency is impaired by stops on grounds of low humidity and high temperatures. The aim of this work was to assess an air humidification method and evaluate its impact on temperature and air humidity for the air curtain of the air-assisted sprayer. With respect to relative air humidity, it has increased in 6.59%, being the maximum change when inserting 1.92 L min-1. So, it is concluded that the pipeline humidification might significantly reduce temperature and enhance air humidity. The treatments performed in this study consisted of a varied flow of a humidity device, related to weather conditions. Temperature and relative air humidity were measured at 1.0 m height from right to left of middle point of the machine, corresponding to the end of the spray boom, in the middle and end of right spray boom. The readings were also performed at three different distances from the end of the pipeline and at 0.25 and 0.50 m from that to the soil. The results show that 0.48 L min-1 in the humidification system has promoted a better efficiency in reducing air-temperature, on average 2.52 ºC when compared to the non-humidified one.

Air-assisted boom sprayer and spray deposition on bean plants

A possibilidade do desenvolvimento de técnicas de aplicação de produtos fitossanitários mais seguras, com menores volumes de calda, número de aplicações e deriva, aliados à necessidade de se obter melhores níveis de controle dos agentes nocivos às plantas cultivadas, justificam o uso da assistência de ar junto à barra de pulverização. Com o objetivo de avaliar a deposição da pulverização na cultura do feijoeiro (Phaseolus vulgaris), em presença e ausência da assistência de ar junto à barra de pulverização, com diferentes pontas de pulverização e volumes de calda, foi conduzido um experimento em delineamento inteiramente casualizado, utilizando-se como traçador o óxido cuproso. Alvos artificiais (papel filtro com 3 x 3 cm) foram afixados nas superfícies adaxial e abaxial de folíolos posicionados nos terços superior e inferior de plantas, selecionadas ao acaso, distribuídas perpendicularmente ao deslocamento do pulverizador. Após a aplicação do traçador os coletores foram lavados individualmente em solução extratora de ácido nítrico a 1,0 mol L-1. A determinação quantitativa dos depósitos foi realizada com o uso da espectrofotometria de absorção atômica. A assistência de ar junto à barra de pulverização não aumentou a deposição do traçador em folíolos de feijoeiro, aos 48 dias após a emergência da cultura.

Non-linear dynamics of a tower orchard sprayer based on an inverted pendulum model

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Spray deposition and losses in potato as a function of air-assistance and sprayer boom angle

A cultura da batata possui grande expressão econômica dentro do cenário agrícola. Para isso, equipamentos e técnicas de aplicação de produtos fitossanitários vêm sendo desenvolvidos visando melhorar o rendimento econômico da cultura. Neste sentido, experimentos foram conduzidos no delineamento em blocos ao acaso na cultura da batata cv. Ágata. Objetivando avaliar o efeito da assistência de ar combinada a diferentes ângulos de aplicação sobre a deposição da pulverização, bem como as perdas da calda para o solo utilizou-se um pulverizador com e sem assistência de ar junto à barra de pulverização posicionada a +30º, 0º e -30º (sinal + a favor e - contrário ao deslocamento) em relação a vertical. O volume de calda foi 400 L ha-1 utilizando-se pontas de jato cônico vazio JA-4 na pressão de 633 kPa. Para a avaliação dos depósitos utilizou-se um traçador cúprico. Os depósitos foram removidos dos folíolos por lavagem com água destilada, em ambas as superfícies foliares, nas posições superior e inferior das plantas de batata e quantificados por espectrofotometria de absorção atômica. As perdas da pulverização foram avaliadas em coletores plásticos colocados nas entrelinhas das parcelas experimentais. Os níveis dos depósitos do traçador cúprico nas diferentes posições da planta foram analisados pelo teste estatístico T² de Hotteling. Os maiores depósitos foram obtidos com a barra posicionada a 0º e +30º, em presença da assistência de ar, tanto na posição superior quanto inferior da planta. A presença do ar, além de propiciar maiores depósitos na parte inferior das plantas, possibilitou maior uniformidade na distribuição deles. As perdas da pulverização ficaram abaixo de 4%.

Efficiency of safety measures applied to a manual knapsack sprayer for paraquat application to Maize (Zea mays L.)

The objectives of the present study were to evaluate the safety of mixer/loaders and applicators of paraquat to maize crop by knapsack sprayers and to determine the efficacy of safety measures applied to the sprayers. Potential dermal exposure (PDE) was evaluated in 22 worker body parts. The Cu2+ cation of a copper-based fungicide was used as tracer in the spray solution. Sanitary pads and cotton gloves were used to collect the pesticide solution on the sampled body parts. It was observed that paraquat application in front of the applicator's body (0.5 and 1.0 m lance) is unsafe because PDE was 1,979.8 ml/day (for 0.5 m lance) and 1,290.4 ml/day (for 1.0 m lance) and needs 50-80% and 37-69% control of PDE respectively. Control can be achieved by the use of protective garment on the legs and feet only, which received 92-93% of the PDE. Switching the spray nozzle to the back of the operator reduced the PDE by 98% and was sufficient to make working conditions safe, while maintaining the efficiency of application and making the work lighter and more comfortable. Mixer/loaders received 86% of the PDE to the hands and the work condition was safe (MOS > 1), however impermeable gloves could be used as a further safety measure.

Effect of nozzle angle and air-jet parameters in air-assisted sprayer on biological effect of soybean asian rust chemical protection

Aiming at improving the efficiency control of Phakopsora pachyrhizi, this research evaluated different application techniques, using spray deposits and yield parameters of soybean crop. Two experiments were carried out in the experimental area of FCA/UNESP - Botucatu, SP, Brazil, in the soybean crop, Conquista variety, in the 2006/2007 season. The first experiment was arranged in random blocks with eight treatments and four replications. The treatments were conducted in factorial arrangement 4×2 (four air levels 0, 9, 11 and 29 km/h combined at two nozzle angles 0 and 30°) using AXI 110015 nozzles. Ten plants on each plot were selected for sampling spray deposits. Artificial targets were fixed on plants, two in the top and another two in the bottom part of plants (abaxial and adaxial leaf surface each one). For deposit evaluations, a cupric tracer was used and the amount of deposits was determined by a spectrophotometer. The second experiment was carried out in the same place and the treatments were of the same arrangement as the previous experiment, including control treatment (untreated plants). The spraying with triazole fungicide was realized in R2 and R5.2 growth stages of soybean with 142 l/ha spray volume. The nozzle angled of 30° combined with maximum air speed promoted the highest spray deposits on the soybean crop and influenced positively the control of the soybean Asian rust as well in the productivity of this crop.

Optimal moment to change pressure regulator and sprayer kit on center pivot irrigation machines: a theoretical proposal

A theoretical model was developed in order to determine the optimal moment for substituting the sprayer and pressure regulator kit on a center pivot irrigation machine. The model is based on the hypothesis that pressure regulator and sprayer deterioration decrease irrigation uniformity. To compensate the deficit that happens at under irrigated areas, an increase on irrigation depth is required. The model considers: additional water consumption and energy costs, maintenance and labor costs, as well as yield losses associated with under or over irrigated areas. The sum of all these components is compared to buying and installing a new spray kit cost, allowing the farmer to decide the best moment to renovate the sprayer and pressure regulator kits on a center pivot irrigation machine based on economic criteria.

Optimal moment to change pressure regulator and sprayer kit on center pivot irrigation machines: application to a study case

A theoretical model developed by the authors for determining the optimal moment to substitute sprayer and pressure regulator kit on a center pivot irrigating potatoes and beans has been applied. The methodology compares the sum of the costs due to additional consumption of water and energy, maintenance and labor, as well as yield losses associated to areas with deficit or over irrigation to the costs due to buy and install a new sprinkling set on the pivot. The results showed that for a reduction of 3.07% of the Hermann and Hein’s Uniformity Coefficient (UCh), the substitution of the sprinkling module on the pivot is justified when potatoes and beans are cultivated.

Air flow humidification for air-assisted boom sprayer

The air-assisted ground spray is fairly widespread. However, due to the unpredictable weather conditions, the operational efficiency is impaired by stops on grounds of low humidity and high temperatures. The aim of this work was to assess an air humidification method and evaluate its impact on temperature and air humidity for the air curtain of the air-assisted sprayer. With respect to relative air humidity, it has increased in 6.59%, being the maximum change when inserting 1.92 L min-1. So, it is concluded that the pipeline humidification might significantly reduce temperature and enhance air humidity. The treatments performed in this study consisted of a varied flow of a humidity device, related to weather conditions. Temperature and relative air humidity were measured at 1.0 m height from right to left of middle point of the machine, corresponding to the end of the spray boom, in the middle and end of right spray boom. The readings were also performed at three different distances from the end of the pipeline and at 0.25 and 0.50 m from that to the soil. The results show that 0.48 L min-1 in the humidification system has promoted a better efficiency in reducing air-temperature, on average 2.52 ºC when compared to the non-humidified one.

Organizational, direct, and general support, and depot maintenance repair parts and special tools list : sprayer, insecticide, skid mounted, gasoline driven, 40 gal per hour, fog (Curtis Automotive Devices model CFR-40000) FSN 3740-790-6188.

Includes index.

The effect of mode of exposure to Beauveria bassiana on conidia acquisition and host mortality of Colorado potato beetle, Leptinotarsa decemlineata

The effects of the mode of exposure of second instar Colorado potato beetles to Beauveria bassiana on conidia acquisition and resulting mortality were investigated in laboratory studies. Larvae sprayed directly with a B, bassiana condial suspension, larvae exposed to B, bassiana-treated foliage, and larvae both sprayed and exposed to treated foliage experienced 76, 34, and 77% mortality, respectively. The total number of conidia and the proportion of germinating conidia were measured over time for four sections of the insect body: the ventral surface of the head (consisting mostly of ventral mouth parts), the ventral abdominal surface, the dorsal abdominal surface, and the legs. From observations at 24 and 36 h posttreatment, mean totals of 161.1 conidia per insect were found on sprayed larvae, 256.1 conidia on larvae exposed only to treated foliage, and 408.3 conidia on larvae both sprayed and exposed to treated foliage, On sprayed larvae, the majority of conidia were found on the dorsal abdominal surface, whereas conidia were predominantly found in the ventral abdominal surface and mouth parts on larvae exposed to treated foliage, Between 24 and 36 h postinoculation the percentage of conidia germinating on sprayed larvae increased slightly from 80 to 84%), On the treated foliage, the percentage of germinated conidia on larvae increased from 35% at 24 h to 50% at 36 h posttreatment, Conidia germination on sprayed larvae on treated foliage was 65% at 24 h and 75% at 36 h posttreatment, It is likely that the gradual acquisition of conidia derived from the continuous exposure to B. bassiana inoculum on the foliar surface was responsible for the increase in germination over time on larvae exposed to treated foliage, The density and germination of conidia were observed 0, 4, 8, 12, 16, 20, and 24 h after being sprayed with or dipped in conidia suspensions or exposing insects to contaminated foliage, Conidia germinated twice as fast on sprayed insects as with any other treatment within the first 12 h, This faster germination may be due to the pressure of the sprayer enhancing conidial lodging on cuticular surfaces. (C) 2001 Academic Press.

Uniformity of liquid distribution in the canopy of the bean plant, using the spectrophotometric analysis

Fungal diseases are important factors limiting common bean yield. White mold is one of the main diseases caused by soil pathogens. The objective of this study was to quantify the distribution of a fungicide solution sprayed into the canopy of bean plants by spectrophotometry, using a boom sprayer with and without air assistance. The experiment was arranged in a 2 x 2 x 2 factorial (two types of nozzles, two application rates, and air assistance on and off) randomized block design with four replications. Air assistance influenced the deposition of solution on the bean plant and yield increased significantly with the increased rate of application and air assistance in the boom sprayer.