Eficiência de diferentes herbicidas pré-emergentes na cultura do feijão em diferentes momentos de aplicação

Abstract

Common bean (Phaseolus vulgaris L.) holds great socioeconomic importance in Brazil, which is currently the second-largest global producer of this legume. Given this relevance, there is a growing demand for research that promotes efficient crop management, especially regarding weed control during the early stages of development, which are considered critical periods for bean growth. The use of pre-emergence herbicides has emerged as a promising strategy, as it reduces early competition and minimizes the need for post-emergence applications. This study aimed to evaluate the efficiency of different pre-emergence herbicides in controlling the weed seed bank (WSB) in the soil and their effects on the development and yield of common bean plants. The experiment was conducted at the Experimental Farm of UTFPR – Dois Vizinhos Campus, in a randomized block design with three replications, arranged in a bifactorial scheme. Factor A consisted of four pre-emergence herbicide treatments, along with two controls (weeded and unweeded) and one post-emergence management treatment. Factor B consisted of two application timings: Apply and Plant (AP) and Plant and Apply (PA). The herbicides tested included pre-emergents such as S-metolachlor, Fomesafen + S-metolachlor, Pyroxasulfone + Flumioxazin, and Diclosulam, and post-emergents including Fomesafen, Bentazon, and Haloxyfop-R-methyl. The evaluated variables were seedling emergence, plant height, leaf area index, weed count and control, yield components, and productivity. Data were subjected to statistical analysis and means were compared using Tukey’s test at a 5% significance level. Results showed that Diclosulam provided the best weed control but negatively affected crop development. In contrast, the combination of Fomesafen + S-metolachlor, especially when applied at the Plant and Apply (PA) timing, achieved a good balance between weed control, yield components, and productivity. Therefore, selecting the appropriate herbicide combined with the optimal application timing is essential to ensure effective, safe, and sustainable weed management in common bean cultivation without compromising crop performance.