Mapeamento e alternativas de controle para o capim-pé-de-galinha (Eleusine indica L.) resistente aos herbicidas inibidores da ACCase e EPSPS

Abstract

The weed Eleusine indica has emerged as a significant challenge in agriculture, particularly in soybean and corn crops, due to its high tolerance to climatic adversities and the growing resistance to herbicides with different mechanisms of action. This resistance has made effective control difficult, requiring new management strategies. The first study aimed to monitor biotypes of Eleusine indica resistant to various herbicides in the state of Mato Grosso do Sul. Seed samples were collected from soybean and corn fields in municipalities such as Chapadão do Sul, Amambai, Ponta Porã, among others, between 2020 and 2022. The plants were subjected to dose-response assays to evaluate resistance to herbicides like glyphosate, haloxyfop, fenoxaprop, and clethodim. The results showed varying resistance across municipalities, with some biotypes resistant to glyphosate, haloxyfop, and fenoxaprop, while others showed no resistance to clethodim. The municipality of Rio Brilhante exhibited the highest selection pressure, requiring higher herbicide doses for effective control. The second study focused on alternative strategies for controlling Eleusine indica, including the evaluation of herbicides applied alone or in combinations during the post-emergence stage, as well as pre-emergence control options. The experiments were conducted both in the field and in a greenhouse, emphasizing plants with confirmed multiple resistance. In the first experiment, the combinations of glufosinate + mesotrione and flumioxazin + mesotrione + clethodim provided the best results, with control exceeding 90%. In the second experiment, which involved plants with multiple resistance, no treatment showed satisfactory control, highlighting the challenge of managing highly resistant biotypes. The third experiment, focusing on pre-emergence herbicides, showed that treatments with isoxaflutol + thiencarbazone and s-metolachlor provided the best control, with efficacy close to 75%, while atrazine showed very low effectiveness. These studies highlight the complexity of controlling Eleusine indica due to multiple resistance and the urgent need for integrated management strategies, such as the combination of post and pre-emergence herbicides, along with constant monitoring of resistance evolution in the fields.