Performance comparativa de cultivares de soja transgênica Bt e não-Bt sobre a população de Spodoptera frugiperda (J. E. SMITH, 1797) (Lepidoptera: Noctuidae) e suas implicações agronômicas

Abstract

Soybean (Glycine max (L.) Merrill) is one of the most important agricultural crops globally, with Brazil leading world production. However, pests constantly threaten soybean productivity, notably S. frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae), a polyphagous caterpillar that causes significant damage. Bt technology, which consists of inserting genes from the bacterium Bacillus thuringiensis Berliner (Bt) into plants to express insecticidal proteins (Cry), has been a crucial tool in integrated pest management. However, the effectiveness of this technology can be challenged by the evolution of insect resistance and vary according to edaphoclimatic conditions. This study aimed to evaluate the impact of different transgenic soybean (Bt) cultivars on the S. frugiperda population and its agronomic implications in three municipalities of Mato Grosso do Sul (Ponta Porã, Dourados, and Rio Brilhante). Cultivars with and without Bt technology were compared in terms of productivity, thousand-seed weight, plant height, and caterpillar infestation. The field study results indicated that the Bt cultivar BMX65k67, with Cry1Ac and Cry1F proteins, showed the best overall performance, with an average productivity of 3,273.3 kg/ha and the lowest infestation of large caterpillars (8.8 units), demonstrating the effectiveness of gene pyramiding. Non-Bt cultivars, such as M6101 and BRS 243, showed high susceptibility, resulting in lower productivity and higher pest infestation. The performance of the cultivars was also influenced by edaphoclimatic conditions, with Rio Brilhante presenting higher productivities. These results reinforce the strategic role of pyramided Bt cultivars in the management of S. frugiperda, especially in environments with high pest pressure, for soybean production stability, but it must be integrated with resistance management practices and adapted to local conditions.