Reduction in the spray drift of 2,4-D in tomato using hydraulic nozzles with air induction and LI-700 adjuvant

ABSTRACT The drift of hormonal effect herbicides is a major problem for agriculture, because, even in small amounts, it may cause high losses in crops with plants that are sensitive to their action mechanism. This study aimed to evaluate the efficiency of hydraulic spray nozzles with air induction, as well as the use of the LI-700 adjuvant, in the reduction of the 2,4-D herbicide drift, in tomato crop. A complete randomized split-plot experimental design, with eight replications, was used. Two herbicide solutions were assigned in the plots (with or without the use of adjuvant) [2,4-D (670 g ha-1) and 2,4-D (670 g ha-1) + LI-700 (712.88 g ha-1)], and, in the subplots, five nozzle models [simple fan (JSF11003), simple fan with air induction (AD-IA11003), dual fan with air induction (AD-IA/D11003), simple hammer fan with air induction (TTI11003-VP) and empty cone with air induction (CV-IA10003). The treatments were applied in a wind tunnel, under a pressure of 300 kPa. In a laser analyzer, applying only water, the volumetric median diameter, the relative amplitude and the percentage of drops with diameter lower than 150 µm were measured for all nozzle models. The CV-IA10003 and TTI11003-VP hydraulic nozzles outstand by reducing the 2,4-D herbicide drift and decreasing the damage to tomato plants. The addition of the LI-700 adjuvant to the 2,4-D syrup, independently of the nozzle model, reduces the drift of this herbicide and its effects on the tomato plant root. However, even when adopting these technologies, the application of the 2,4-D herbicide near the tomato crop should be avoided. RESUMO A deriva de herbicidas de efeito hormonal é um grande problema para a agricultura, pois, mesmo em pequena quantidade, pode causar grandes prejuízos em lavouras com plantas sensíveis ao seu mecanismo de ação. Objetivou-se avaliar a eficiência de pontas hidráulicas de pulverização com indução de ar, bem como o uso do adjuvante LI-700, na redução de deriva do herbicida 2,4-D, na cultura do tomate. O delineamento experimental utilizado foi o de parcelas subdivididas, inteiramente casualizado, com oito repetições. Nas parcelas, foram alocadas duas soluções do herbicida (com ou sem o uso de adjuvante) [2,4-D (670 g ha-1) e 2,4-D (670 g ha-1) + LI-700 (712,88 g ha-1)] e, nas subparcelas, cinco modelos de pontas [leque simples (JSF11003), leque simples com indução de ar (AD-IA11003), leque duplo com indução (AD-IA/D11003), leque simples martelinho com indução (TTI11003-VP) e co