Tecnologias de aplicação do imidacloprido no controle do pulgão-dos-cereais (Schizaphis graminum) em trigo e seus efeitos sobre inimigos naturais Uberlândia Minas Gerais – Brasil 2017

Abstract

One of the main species found in wheat is the grain aphid, Schizaphis graminum (Rondani, 1852), which substantially reduces grain production, slows down root growth and impairs tillering. As a consequence of the attack, the application of insecticides that are poorly managed leads to a series of economic and environmental damages. The objective of this work was to study the combinations of application rates, tips and adjuvants on the chemical control of wheat aphid in wheat and the environmental impacts on the populations of its natural enemies. Imidacloprid insecticide applications were carried out in two seed multiplication fields of cultivar BRS 404. Two application rates (75 and 150 L.ha-1) were used with and without the addition of two adjuvants of different chemical characteristics combined with three types of hydraulic spray tips. For the laboratory studies of evaluation of the physicochemical properties of the grouts, through the evaluation of variance there was a significant interaction of the conductivity and surface tension properties with the adjuvants evaluated. In relation to the technologies used, the deposition of the applied syrup on the flag and ears leaves at the lower application rate (75 L ha-1) was statistically similar to the deposition at a higher application rate (150 L ha-1), regardless of the use of adjuvant. The treatments with high efficiency throughout the control period were those containing adjuvants in the two application rates tested (75 L ha-1 and 150 L ha-1) demonstrating that it is possible to reduce the volume of syrup in applications that have as objective the control of the aphid-cereals without loss of effectiveness in the treatment. The insecticide imidacloprid showed to be highly harmful to predators of Chrysoperla externa and Orius insidiosus, causing mortality in the first three days after application, regardless of the application technology used.