Influence of spray nozzles and adjuvants in drift reduction potential in wind tunnel Influência de pontas de pulveriza o e adjuvantes no potencial de redu o de deriva em túnel de vento

The drift is intimately linked to inappropriate use of pesticides and an important factor for reducing it, is the correct selection of spray nozzles and adjuvants. The objective of this work was to evaluate the drift potential in wind tunnel with different spray nozzles and different concentrations of adjuvants. The experiment was composed by six spray solutions (vegetable oil (in three concentrations), mineral oil, surfactant and reducing drift), which were applied with two nozzles, one pre-orifice flat fan (DG 8003 VS) and other with air induction (AI 8003 VS), totaling 12 treatments, with three repetitions. The equipment used was a wind tunnel, where the drift collections were made at different points. The treatments averages were compared using Confidence Interval at 5% probability. The analysis of the percentage of drift showed that the treatments had different behaviors. The nonylphenol ethoxylate adjuvant presented the highest drift when applied with the nozzle of pre-orifice and the lowest drift when applied with the air induction. The behavior of these nozzles when the oil-based adjuvant was used showed apposite results to those obtained for the surfactant. For the DG nozzles the lowest percentage of drift, at all analyzed distances, was observed to the treatment with vegetable oil (1.0%) and with the AI nozzles the lower drift was found for the treatment with nonylphenol ethoxylate (0.0625%), for the four distances in the collection. The result showed that both the spray nozzles and adjuvants alter directly the drift potential. There was no proportionately between the concentration of the oil-based adjuvant and the drift percentage. A deriva está diretamente ligada ao uso inadequado da tecnologia de aplica o de agrotóxicos, sendo a correta sele o das pontas de pulveriza o e adjuvantes importantes variáveis para auxiliar em sua redu o. O objetivo deste trabalho foi estimar o potencial de deriva em túnel de vento com diferentes pontas de pulveriza o e diferentes concentra es de adjuvantes. O ensaio foi composto por seis caldas (óleo vegetal (em três concentra es), óleo mineral, surfatante e redutor de deriva), aplicadas com pontas de pulveriza o anti-deriva, jato plano com pré-orifício (DG 8003 VS) e indu o de ar (AI 8003 VS). O equipamento utilizado foi um túnel de vento, onde as coletas de deriva foram realizadas em diferentes pontos. As médias dos tratamentos foram comparadas pelo Intervalo de Confian a, a 95% de probabilidade. A análise da porcentagem de deriva demonstrou que os tratamentos tiveram comportamentos distintos. O adjuva