Interferência de adjuvantes associados ao clethodim nas características físico-químicas da calda e rainfastness no controle de capim-amargoso
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Data
2021-12-02
Autores
Del Bem Júnior, Luciano
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O uso de adjuvantes junto aos herbicidas inibidores da ACCase é prática comum, porém podem proporcionar alterações físico-químicas na calda, influenciar no espalhamento e espectro das gotas, além da minimização dos impactos ambientais, como a ocorrência de chuvas logo após a pulverização. Assim, objetivou-se neste estudo avaliar o efeito da associação de adjuvantes ao herbicida clethodim na otimização da pulverização, bem como a interferência da ocorrência de chuva, em diferentes intervalos de tempo após aplicação, no controle de capim-amargoso. Para isso, foram conduzidos dois experimentos, com o herbicida clethodim associado aos adjuvantes: Agral, Argenfrut, Assist, Aureo, Integrum, JS, LI-700, Silwet L-77, Veget Oil, X1 (Óleo vegetal + surfatantes), X2 (Óleo vegetal + surfatantes) e Wetcit Gold. O experimento 1 foi realizado em laboratório, onde foram avaliados os parâmetros de condutividade elétrica, pH, viscosidade, tensão superficial estática (TSE) e o ângulo de contato em superfície vegetal. No experimento 2 foi avaliado o espectro das gotas da pulverização pelo medidor de tamanho de partículas em tempo real, a deposição da calda em plantas de capim-amargoso com o marcador Azul Brilhante e o controle de D. insularis com chuva simulada de 10 mm, após a aplicação, em cinco intervalos de tempo (30 min, 60 min, 120 min, 240 min, 480 min), além do padrão sem chuva. O adjuvante LI-700 garantiu a maior redução de pH, bem como o maior aumento na condutividade elétrica da calda herbicida. O surfatante siliconado Silwet L-77 associado ao herbicida clethodim assegurou a maior redução dos parâmetros tensão superficial estática e ângulo de contato em folhas de capim-amargoso. Houve incremento na deposição da calda herbicida pelo acréscimo dos adjuvantes Assist, Aureo, Integrum, JS, LI-700 e Wetcit Gold. O espectro de gotas não foi influenciado pela adição dos adjuvantes à calda herbicida, com exceção do polímero vegetal JS, que apresentou os maiores valores de DV0,5, DV0,9, Span e porcentagem de gotas inferiores a 100 µm. Os adjuvantes Argenfrut, Assist, Aureo, Integrum, Silwet L-77, X1 e X2, em associação com o herbicida clethodim, se mostraram mais eficientes no controle das plantas de capim-amargoso, mesmo com ocorrência de chuva 30 minutos após a aplicação.
The use of adjuvants with ACCase-inhibiting herbicides is a common practice, but they can provide physicochemical changes to the spray liquid, influence the droplets' spread and spectrum, in addition to minimizing environmental impacts, such as the occurrence of rain soon after spraying. Thus, the aim of this study was to evaluate the effect of the association of adjuvants with the herbicide clethodim in optimizing spraying, as well as the interference of the occurrence of rain, at different intervals after application, in the control of sourgrass. For this, two experiments were conducted, with the herbicide clethodim associated with adjuvants: Agral, Argenfrut, Assist, Aureo, Integrum, JS, LI-700, Silwet L-77, Veget Oil, X1 (Vegetable oil + surfactants), X2 (Vegetable oil + surfactants) and Wetcit Gold. Experiment 1 was carried out in a laboratory, where the parameters of electrical conductivity, pH, viscosity, static surface tension (SST) and the contact angle on plant surface were evaluated. In experiment 2, the spray droplet spectrum was evaluated using a realtime particle size meter, spray deposition on sourgrass plants with the Brillant Blue tracer and the control of D. insularis with simulated rainfall of 10 mm, after application, at five time intervals (30 min, 60 min, 120 min, 240 min, 480 min), and without rain. The LI-700 adjuvant ensured the greatest reduction in pH, as well as the greatest increase in electrical conductivity of the herbicide spray. The silicone surfactant Silwet L-77 associated with the herbicide clethodim ensured the greatest reduction in static surface tension and contact angle parameters in sourgrass leaves. There was an increase in the deposition of the herbicide solution by the addition of Assist, Aureo, Integrum, JS, LI-700 and Wetcit Gold adjuvants. The drop spectrum was not influenced by the addition of the adjuvants to the herbicide spray, with the exception of the vegetable Polymer JS, which showed the highest values of DV0.5, DV0.9, Span and percentage of droplets smaller than 100 µm. The adjuvants Argenfrut, Assist, Aureo, Integrum, Silwet L-77, X1 and X2, in association with the herbicide clethodim, proved to be more efficient in controlling sourgrass plants, even with the occurrence of rain 30 minutes after application.
The use of adjuvants with ACCase-inhibiting herbicides is a common practice, but they can provide physicochemical changes to the spray liquid, influence the droplets' spread and spectrum, in addition to minimizing environmental impacts, such as the occurrence of rain soon after spraying. Thus, the aim of this study was to evaluate the effect of the association of adjuvants with the herbicide clethodim in optimizing spraying, as well as the interference of the occurrence of rain, at different intervals after application, in the control of sourgrass. For this, two experiments were conducted, with the herbicide clethodim associated with adjuvants: Agral, Argenfrut, Assist, Aureo, Integrum, JS, LI-700, Silwet L-77, Veget Oil, X1 (Vegetable oil + surfactants), X2 (Vegetable oil + surfactants) and Wetcit Gold. Experiment 1 was carried out in a laboratory, where the parameters of electrical conductivity, pH, viscosity, static surface tension (SST) and the contact angle on plant surface were evaluated. In experiment 2, the spray droplet spectrum was evaluated using a realtime particle size meter, spray deposition on sourgrass plants with the Brillant Blue tracer and the control of D. insularis with simulated rainfall of 10 mm, after application, at five time intervals (30 min, 60 min, 120 min, 240 min, 480 min), and without rain. The LI-700 adjuvant ensured the greatest reduction in pH, as well as the greatest increase in electrical conductivity of the herbicide spray. The silicone surfactant Silwet L-77 associated with the herbicide clethodim ensured the greatest reduction in static surface tension and contact angle parameters in sourgrass leaves. There was an increase in the deposition of the herbicide solution by the addition of Assist, Aureo, Integrum, JS, LI-700 and Wetcit Gold adjuvants. The drop spectrum was not influenced by the addition of the adjuvants to the herbicide spray, with the exception of the vegetable Polymer JS, which showed the highest values of DV0.5, DV0.9, Span and percentage of droplets smaller than 100 µm. The adjuvants Argenfrut, Assist, Aureo, Integrum, Silwet L-77, X1 and X2, in association with the herbicide clethodim, proved to be more efficient in controlling sourgrass plants, even with the occurrence of rain 30 minutes after application.
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Palavras-chave
Tecnologia de aplicação, Digitaria insularis, Intervalo de chuva após aplicação, Controle químico, Application technology, Rain after application, Chemical control