Análises físico-químicas das caldas e espectro de gotas com diferentes formulações de inseticidas em simulação de aplicação aérea
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Data
2017-10-16
Autores
Jesus, Marcella Guerreiro de [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A pulverização aérea é uma técnica de aplicação com grande demanda de uso devido a seu elevado rendimento operacional e eficiência. Pesquisas voltadas para essa área são cada vez mais necessárias, para um melhor entendimento do comportamento de cada técnica de aplicação de defensivos nas condições operacionais de aplicação aérea. O objetivo deste trabalho foi avaliar a interferência de adjuvantes e formulações nas caraterísticas físico químicas da calda, espectro de gotas gerados pela ponta de jato plano de impacto CP-03 em diferentes ângulos de saída durante a simulação da aplicação aérea de inseticidas em condições de laboratório. Selecionou-se o inseticida lambda- cyhalothrin em duas formulações, concentrado emulsionável (EC) e suspensão concentrada (SC), cujas doses recomendadas em bula foram diluídas para uma taxa de aplicação de 28,1 L ha-1 (equivalentes a 3 galões americanos por acre). Foram utilizados dois adjuvantes em mistura com o inseticida, sendo um óleo vegetal e um surfatante. Executaram-se três experimentos, em delineamento inteiramente casualizado, a fim de verificar a influência das soluções na interação com o ângulo defletor de 30 o (experimento 1), na interferência com o ângulo defletor de 55 o (experimento 2) e com o ângulo de 90 o (experimento 3), configurando um fatorial de 2 x 3 (2 formulações x 3 soluções), 6 caldas por experimento (cada um dos inseticidas de maneira isolada e em mistura com os dois adjuvantes) para conhecimento do comportamento dessas variáveis. A ponta CP-03 foi ajustada em cada um dos três ângulos possíveis do anteparo (30, 55 e 90o). As pulverizações foram efetuadas em túnel de vento de alta velocidade, ajustado para 180 km h-1, onde obteve-se os resultados do espectro das gotas através de um analisador de partículas por difração de laser Sympatec HELOS/VARIO KF (Sympatec Inc., ClausthalZellerfeld, Germany). Analisaram-se também as caraterísticas físico-químicas das soluções (tensão superficial e viscosidade). Os resultados foram submetidos a análise de variância e, quando pertinente, ao teste de tukey para comparação de médias. Os resultados mostraram que houve interação entre as caldas e os ângulos de ajuste das pontas, com diferenças significativas na análise estatística. De maneira geral observou-se que as caldas que continham emulsão na sua constituição (todas as caldas do inseticida EC e as caldas do inseticida SC em que houve mistura de óleo) apresentaram menores valores de diâmetro mediano volumétrico (DMV) e maiores valores do percentual de gotas menores do que 100 µm (V100), representando situações de aplicação com maior risco de deriva. Os maiores valores de DMV e menores valores de V100 (representando as caldas com menor risco de deriva) foram obtidas da mistura do inseticida SC com o surfatante. Nos ajustes da ponta CP-03, os maiores valores de DMV foram encontrados na utilização do ângulo defletor de 30o. A interação que produziu a pulverização com menor risco de deriva foi a calda com o inseticida SC em mistura com o surfatante, aplicada com o ângulo de 30o na ponta CP-03.
Aerial spraying is an application technique with high demand because of its high operational efficiency and efficiency in hard areas to access. Research on this area is increasingly necessary, in order to better understand the behavior of each technique for the application of pesticides in the aerial application operational conditions. The objective of this work was to evaluate the interference of adjuvants and formulations in the spectra of drops generated by the CP-03 plane impact jet tip in the simulation of the aerial application of insecticides under laboratory conditions The active ingredient insecticide lambda-cyhalothrin was selected in two formulations, emulsifiable concentrate (SC) and concentrated suspension (EC), with an application rate of 28.1 L ha-1 (equivalent to 3 US gallons per acre). Two adjuvants were used in combination with the insecticides, being a vegetable oil and a surfactant. Three experiments were carried out in a completely randomized design, in order to verify the influence of the solutions on the interaction with the deflecting angle of 30 (experiment 1), on the interference with the deflecting angle of 55 (experiment 2) and with the angle 90 (2 formulations x 3 adjuvants), 6 samples per experiment (each of the insecticides in an isolated manner and in a mixture with the two adjuvants) to know the behavior of these variables. The CP-03 nozzle has been adjusted at each of the three possible angles of the bulkhead (30, 55 and 90o). The CP-03 nozzle was adjusted at each of the three possible angles of the bulkhead (30, 55 and 90 °). In this way, a 6 x 3 factorial (six treatments x three angles) was set up, totaling 18 treatments, with 3 replicates. The spraying was performed in a high-speed wind tunnel, adjusted to 180 km h-1, where the spectra of the droplets were obtained through a Sympatec HELOS / VARIO KF laser diffraction particle analyzer (Sympatec Inc., ClausthalZellerfeld, Germany). The physical property measurements of the solutions (surface tension, density and viscosity) were also analyzed. The results were submitted to analysis of variance and, when pertinent, to the Tukey test for comparison of average. The results showed that there was interaction between the solutions and the adjustment angles of the nozzles, with significant results in the statistical analysis. In general, it was observed that the solution emulsion-containing (all EC insecticide and SC insecticide solution in which the oil mixture was mixed) had lower volume median diameter (DMV) values and higher percent volume less than 100 μm (V100), representing application situations with higher risk of drift. The highest values of DMV and lower values of V100 (representing the solution with the lowest risk of drift were obtained from the mixture of the insecticide SC with the surfactant adjuvant. The highest values of DMV were found in the use of the deflection angle of 30o, since this produces lower impact energy and, therefore, lower droplet cracking. The interaction that produced the solution with less risk of drift was the interaction between the solution with the insecticide SC in mixture with the surfactant, applied with the angle of 30o at the nozzle CP-03.
Aerial spraying is an application technique with high demand because of its high operational efficiency and efficiency in hard areas to access. Research on this area is increasingly necessary, in order to better understand the behavior of each technique for the application of pesticides in the aerial application operational conditions. The objective of this work was to evaluate the interference of adjuvants and formulations in the spectra of drops generated by the CP-03 plane impact jet tip in the simulation of the aerial application of insecticides under laboratory conditions The active ingredient insecticide lambda-cyhalothrin was selected in two formulations, emulsifiable concentrate (SC) and concentrated suspension (EC), with an application rate of 28.1 L ha-1 (equivalent to 3 US gallons per acre). Two adjuvants were used in combination with the insecticides, being a vegetable oil and a surfactant. Three experiments were carried out in a completely randomized design, in order to verify the influence of the solutions on the interaction with the deflecting angle of 30 (experiment 1), on the interference with the deflecting angle of 55 (experiment 2) and with the angle 90 (2 formulations x 3 adjuvants), 6 samples per experiment (each of the insecticides in an isolated manner and in a mixture with the two adjuvants) to know the behavior of these variables. The CP-03 nozzle has been adjusted at each of the three possible angles of the bulkhead (30, 55 and 90o). The CP-03 nozzle was adjusted at each of the three possible angles of the bulkhead (30, 55 and 90 °). In this way, a 6 x 3 factorial (six treatments x three angles) was set up, totaling 18 treatments, with 3 replicates. The spraying was performed in a high-speed wind tunnel, adjusted to 180 km h-1, where the spectra of the droplets were obtained through a Sympatec HELOS / VARIO KF laser diffraction particle analyzer (Sympatec Inc., ClausthalZellerfeld, Germany). The physical property measurements of the solutions (surface tension, density and viscosity) were also analyzed. The results were submitted to analysis of variance and, when pertinent, to the Tukey test for comparison of average. The results showed that there was interaction between the solutions and the adjustment angles of the nozzles, with significant results in the statistical analysis. In general, it was observed that the solution emulsion-containing (all EC insecticide and SC insecticide solution in which the oil mixture was mixed) had lower volume median diameter (DMV) values and higher percent volume less than 100 μm (V100), representing application situations with higher risk of drift. The highest values of DMV and lower values of V100 (representing the solution with the lowest risk of drift were obtained from the mixture of the insecticide SC with the surfactant adjuvant. The highest values of DMV were found in the use of the deflection angle of 30o, since this produces lower impact energy and, therefore, lower droplet cracking. The interaction that produced the solution with less risk of drift was the interaction between the solution with the insecticide SC in mixture with the surfactant, applied with the angle of 30o at the nozzle CP-03.
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Palavras-chave
Tecnologia de aplicação, Deriva, Túnel de vento