Aplicação de produtos fitossanitários e sua relação com os polinizadores.

Abstract

The use of pesticides to control pests and diseases in agricultural areas is among the main causes of the phenomenon of declining pollinator populations worldwide. However, like pollinators, these compounds are of great need for food production, especially in the face of a world population that is growing rapidly. Given this fact, it is necessary to look for ways to assess how these products affect pollinators, as well as looking for ways to minimize these effects, combining phytosanitary control with the benefits of pollination. The objectives of this work were: (i) To evaluate the effect of the application of different classes of pesticides on the richness and abundance of pollinators in the sunflower, during the flowering period of the crop, as well as if the use of different spectra of droplets of spraying can act by minimizing the toxic effects of these products, observing in the end the impact on crop production; (ii) To study the effect of neonicotinoid insecticides, as well as the number of their applications, during the pre- flowering period, on the visitation of bees, and their impacts on production in sunflower cultivation; and (iii) Evaluate, through meta-analysis, the effects of neonicotinoid insecticides on the pollinators' feeding behavior and nest vigor, based on field and laboratory studies. The studies related to objectives (i) and (ii) took place at the experimental farms Água Limpa and Capim Branco, both belonging to the Federal University of Uberlândia, during the years 2018, 2019 and 2020. Random block designs were adopted, considering if, respectively, different classes of pesticides (herbicide, fungicide and insecticide), applied with different spectra of droplets (extremely coarse and fine) and the number of applications of the main neonicotinoids used in agricultural crops. The applications of the products, regardless of the class, promoted a repellency effect on the pollinators, being more or less significant depending on the species. The use of fine droplets contributed to the reduction in the toxicity of the products, increasing the abundance of visits. The application of the different neonicotinoid insecticides did not reduce the pollinators' visit to sunflower cultivation, regardless of the number of applications or the active ingredient used. Meta-analysis (iii) indicated the presence of divergent results between studies carried out in the field and in the laboratory only in relation to the vigor of the nests, demonstrating non-significant effects when the studies were carried out in the laboratory. However, the results in general showed that neonicotinoids interfere both in the feeding behavior of pollinators and in the vigor of their nests. However, these effects were of low magnitude. This fact corroborates the understanding that neonicotinoids are not the main cause of the phenomenon of CCD, but one of the several factors acting in a synergistic way. And that its prohibition of use would probably not be the definitive solution to the end of this problem.