Otavio Jorge Grigoli Abi Saab

Depósito e perdas de calda em sistema de pulverização com turboatomizador em videira

Winegrowers in the north of Parana State carry on grapevines in arbour and pesticide applications could overcome more than fifty times in a cycle. The aim of this study was to evaluate the features of the air assisted sprayer application system by spray volume deposition and losses. Five treatments and four randomized blocks were used. The treatments varied the droplet size and application volume. The evaluation of the system was done with a 5% spray solution containing KCl being the leaves spray deposit measured through electric conductivity and the losses by the comparison among applied and recovered spray volumes on the leaves. For all of the conditions, the losses were above 48%, the conditions of larger volumes presented the largest depositions and larger droplets presented larger deposit and same loss in relation to smaller droplets. The smallest volumes did not differ regarding the deposition standing out the larger droplets to low volume conditions and the witness used by the winegrower (small droplets and low volume), that presented the smallest losses. The results demonstrate that the air-assisted sprayer is an important tool to maximize the pulverization operations in grape and the alterations of nozzles configuration should be better studied.

Cana-de-açúcar: avaliação da taxa de aplicação e deposição do herbicida glifosato

The growing use of pesticides in agriculture will consume more than six million cubic meters of water annually in Brazil, on sugarcane crop alone. The minor volumes of water can give an increase in autonomy and capacity of sprayer, and reduces the chance of loss by runoff. This work has the purpose to compare different rates of the glyphosate herbicide application, concerning efficiency of control and volume deposition on weeds, at operations of “repass” on sugarcane crop. Eight treatments with four replications were studied in randomized blocks. Application rates evaluated were: 8.8, 73, 96.7, 190, 260, 380 and 467 L ha-1, using a pressurized knapsack sprayer and another with hand operation and a rotative micronizer type CDA. Efficiency on weed control was evaluated considering obtained application effects on each treatment. Qualitative evaluation, comparing obtained deposition on each treatment, was done spraying on weeds with a solution of water plus sodium chloride, using the same equipament and conditions. The results showed the possibility to use lower flow rate of application without problems over the quality.

Pulverização em alvos artificiais: avaliação com o uso do software conta-gotas

The majority of methods, which evaluates the pulverization in agriculture, besides being subjective it has difficult performance. With the development of the computer science, there is a possibility of processing analyses in great number and in a no subjective way. The objective of this work was to evaluate if the Conta-Gotas software can be used to study the effect of the drop size, the wind and the orientation of the spray nozzles in willing targets spraying coverage. From the top to the bottom application, the obtained results for the following variables as covering and droplets cm-2 can be considered as expected and they show that, in spite of being simple, the method has sensibility to detect differences. Considering the top to the bottom and vice-versa spray nozzles orientation the results show how the simple inversion provokes alterations in the behavior of the pulverization drops in relation to its size and effect of the wind. The conta-gotas software is appropriate to be used in similar evaluations like the ones done in this work.

Distribuição da calda na cultura da Videira por turboatomizador com diferentes configurações de pontas

Fine grape varieties are susceptible to a large number of diseases and its control is responsible for the largest production expenses. The agrochemical technology application has great addition importance in this process, to reduce the waste, contamination and resistance. This research had as objectives to evaluate the commonly nozzles configuration used and to propose other more appropriate to the application of agrochemicals with air assisted sprayer. Water sensitive papers were used to evaluate the coverage on 16 vineyard sampling points. Accumulation points and deficiency of spray coverage can be observed. It was possible to get more appropriate configuration opening or closing the spray boom nozzles, using flat fan nozzles or the mixture of hollow cone with different flow rates, for grapevine pesticide application taxes among 250 to 400L ha-1.

Cobertura de gotas de pulverização obtida com diferentes pontas e taxas de aplicação na parte aérea da cana-de-açúcar

The terrestrial application of agricultural defensives in the sugar-alchool producer sector until recently was focused on weed control. After the appearance of orange rust, a disease of agricultural importance in sugar cane production, it has become imperative to know how the application arrives at the plant canopy. In such a way, the present study was developed with the objective of evaluate the quality of the deposition in terrestrial spraying, lead in factorial project 2x2x2 (two nozzles of spraying, two rates of application and two positions of the water-sensitive papers in the canopy of plant), six repetitions, with ten papers each. It has been used the nozzles of spraying XR110.02 (plain jet of extended range) and TTJ60 - 110,02 (double plain jet, with angle of 60 degrees between itself) using the rates of application of 120 and 160L ha-1. The water-sensitive papers cards used to evaluate the deposition of the sprayings had been distributed on the leaves of sugar cane in two distinct heights (upper and lower, approximately 0,80 and 0,50 meters above ground level, arranged in horizontal and inclined with respect to the road surface, respectively). A table scanner was used to generate the digital images of the papers and evaluated the coverings through the Conta-Gotas® program. The deposition data/covering had been submitted to the variance analysis and the averages compared with the Tukey test at 5% of significance. It was observed in the superior canopy of the sugarcane a bigger covering when compared with the inferior, there was no difference between the application rates, 120 and 160L ha-1. The TTJ600110.02 nozzle promoted bigger covering the XR110.02 nozzle when using 160L ha-1 (40,34 and 36,50%, respectively).

Sentidos de aplicação e pontas de pulverização no percentual de cobertura em alvos artificiais, para diferentes situações de orientação de alvo e vento

Several factors influence the efficiency of the application: weather, equipment, chemical products, target and moment of application. Another aspect is the uniformity of the spray in different leave surfaces, because it influences in the absorption, translocation and control of the biological agents by contact products. The aim of this paper was to study the effect of different spray directions and nozzle in the percentage of coverage at artificial target (upper and lower faces) to six different situations about target orientation and wind. The artificial target was cardstock paper. It was realized six different experiments or situations: target orientation, in relation to the soil plan, (horizontal - 0th, inclined - 45th and vertical - 90th) x wind (0 e 10km h-1). For each situation, it was study six applications: three directions (top to bottom, side and bottom to up) x two nozzles (SF 110-02 e LD 110-02). It was evaluated the percentage of coverage in the two faces of the artificial target. Based on this, the experimental design was factorial (spray direction x nozzle x target face) to each situation of target orientation and wind. The results indicate that surfaces opposite to the direction spray receive lower levels of coverage in relation to the surfaces turned to the spray, and that in the surfaces turned to the spray on the inclined (45th) and vertical (90th) orientation the SF 110-02 nozzle promoted higher percentages of coverage, independently of the wind.

Controle da ferrugem da folha do trigo (Puccinia triticina) em diferentes momentos de aplicação de fungicida

The fungicide application is important to the wheat field and its efficacy is related mainly to the biologic timing for the control. The aim of this paper was to study the influence of timing of fungicide application in the damage caused by leaf rust of wheat (P. triticina). A spore trap Siga was installed in the experimental area to assist the prediction of leaf rust before the first symptom. The cultivar used was CD 104 - susceptible to the rust - and the applications were made at 7, 14 and 21 days after the first symptoms of the leaf rust on the plants. It was evaluated in this experiment the area under the disease progress curve, obtained by the disease severity, and the yield (kg/ha) and hectolitre weight (g) indexes of the field. The trap Siga was able to detect spores of leaf rust before the disease symptoms, supporting its identification in the field in the first symptoms. The delay of the fungicide application increased the level of disease severity, reducing significantly the control level and causing considerable damage to the crop yield. It was verified yield losses approximately of 80 kg per day of delay of the application.

Turboatomizador e repasse com pistola manual na cobertura de pulverização de agrotóxicos em caquizeiro (Diospyros kaki L.f.)

Persimmon crop is growing in importance in Brazil, and with the increase of the production area there also has been an increase in the problems related to diseases and pests. For the control and prevention of these problems, most often it is used pesticides spray, and one of the main techniques is the spray with the aid of air flow. The objective of this study was to evaluate the effects of changes in the application rate and transfer with a spray gun on the leaves mixture coverage. The spraying was performed using tractor and air flow sprayer. The application was performed with two forward speeds of the equipment, leading to different application rates. The transfer was made with a spray gun attached to the same equipment. For the assessment of the coverage it was used a mixture prepared with fluorescent tracer dissolved in water. Leaves were collected in the inside and outside of the tree. Later, in dark room with ultraviolet lighting to highlight the area affected by the fluorescent tracer, the upper and lower surfaces of each leaf were photographed with a digital camera. Each image was subjected to analysis generated by software SIARCS 3.0, resulting in percentage of coverage. It was used a randomized block design with subdivided parcels with four replications, being the treatments in a 2x2x2 factorial scheme (high or low application rate, with or without transfer, inside or outside the tree). The evaluations were made in the upper and lower leaf surfaces. There was significant interaction between treatments (application rate and spray gun transfer), leaf position and surface. High application rate promoted a significant increase in the coverage of the lower leaves, regardless the site in the plant (inside or outside). The inside leaves had a better coverage with the spray gun transfer. As most of the agents of plant damage begin to occur in the lower surface of leaves, it can conclude that the spray gun transfer was more effective to cover the leaves inside the plant than increasing the application rate.