Estratégias de controle de pragas em soja e suas implicações na comunidade de artrópodes e na rentabilidade da cultura

Abstract

Soybean cultivation stands out as one of the main agricultural products of the Brazilian economy. However, there are limitations in its cultivation such as the occurrence of insect pests. Among the insect pests present in the crop are defoliators, caterpillars, colepterans, stinkbugs and whiteflies. To minimize the use of agricultural pesticides, Integrated Pest Management (MIP) has being an important tool to remain the pest insect populations at acceptable levels of infestattion as well as the presence of natural enemies. Therefore, we aimed to evaluate the communities of insect pests and natural enemies in an experiment about pest control strategies adopting or not the pests thresholds using insecticides of large spectrum or selectives to natural enemies. Two trials were carried out, one located at Lucas do Rio Verde and another one in Campo Verde, both located in the state of Mato Grosso. The parameters evaluated were insect pests present in the crop by means of beat cloth, and natural enemies community by sweep net and pitfall traps. The soybean productivity as measure as well. To compare the distribution of the abundance of species of natural enemies and pests we used the multidimensional non-metric scale (NMDS). The productivity data were submitted to variance analysis and the means compared by the Tukey test (P ≤ 0.05). The caterpillar species Chrysodeixis includens and Spodoptera eridania and the stinkbug Euchistus heros were the predominant pests. Preventive spraying reduced the pest insect community only in Campo Verde. The number of sprays in treatments 17 using the thresholds were lower than preventive treatments. The most frequent natural enemies were Coleoptera and Dermaptera, and the treatment control was the one that most favored the population of natural enemies in the culture. Both managements presented similar yields, however the IPM system presented lower production costs.