HERBICIDAS PRÉ-EMERGENTES PARA CONTROLE DE VASSOURINHA-DE-BOTÃO (Spermacoce verticillata L.) EM SOJA

Abstract

The management of pre-emergent herbicides in commercial soybean crops offers a promising alternative for reducing the seed bank of difficult-to-control weeds, such as button broom (Spermacoce verticillata L.). The objective of this study is to evaluate the performance of the best pre-emergent herbicides for soybean crops as a preventive alternative for controlling S. verticillata. The experiment was conducted in a greenhouse at the Instituto Federal Goiano, Urutaí Campus, in a completely randomized design, with 17 treatments and 4 replicates, in pots with a capacity of 8 liters of soil. Fifty button broom seeds were sown in each pot, with 200 seeds in total per treatment, and subsequently 3 cm of soil was sieved on the surface. The herbicides were applied 24 hours after planting, with the soil moist, using a CO2 backpack sprayer. After obtaining data on emergence (control inefficiency) and control (no emerged seedlings), they were assessed using a visual scale at 7, 14, 21, 28 and 35 days after application (DAA) and weighing to measure dry mass in an oven with a circulation chamber at 35 DAA at 65ºC for 72 hours. All four treatments that contained the active ingredient flumioxazine in a mixture and two ready-made commercial mixtures based on sulfentrazone obtained 100% control of the seed bank up to 35 DAA.