Seletividade de herbicidas pré-emergentes a cultivares de feijão-comum

Abstract

Common bean has a limited number of herbicides registered for pre-emergence application. In this context, this study aimed to evaluate the selectivity of different pre-emergence herbicides in four common bean cultivars. Four experiments were conducted per growing season, one for each bean cultivar, at the Center for Development and Technology Transfer (CDTT) of the Federal University of Lavras, in Ijaci, Minas Gerais, Brazil, during the 2024/2025 and 2025/2026 growing seasons. The experimental design was a randomized complete block design (RCBD), with four replications. Eleven herbicides were applied in pre-emergence, either individually or in mixtures, as follows (g a.i. ha⁻¹): flumioxazin + pyroxasulfone (80 + 120); flumioxazin + imazethapyr (100 + 200); S-metolachlor + fomesafen (1294 + 284); flumioxazin + S-metolachlor (31.5 + 630); ethoxysulfuron (24); flumioxazin (50); pyroxasulfone (150); imazethapyr (106); S-metolachlor (960); pendimethalin (910); and linuron (450), in addition to two controls, with and without mechanical weed control. Four common bean (Phaseolus vulgaris L.) genotypes were evaluated: IAC 1849, IAC 1850, IAC 2051, and TAA Marhe. Herbicides were applied immediately after crop sowing. Each plot consisted of five rows, six meters in length, spaced 0.6 m apart, with the three central rows considered the experimental unit. At 7, 14, 21, and 28 days after application (DAA), visual assessments of crop injury and weed control were performed in the useful area of each plot. Before harvest, the final bean plant population, plant height, number of pods per plant (NPP), and number of grains per plant (NGP) were evaluated. After bean harvest, the thousand-grain weight and yield were assessed, with yield corrected to 13% moisture content. Data were subjected to analysis of variance (ANOVA). When a significant effect was detected, herbicide treatment means were grouped using the Scott-Knott test at 5% significance level. In the 2024/2025 growing season, lower levels of crop injury and greater weed control efficiency were observed compared with the 2025/2026 growing season. It was concluded that ethoxysulfuron was selective for the TAA Marhe cultivar and S-metolachlor + fomesafen was selective for the IAC 1849 cultivar when applied in pre-emergence. The herbicides linuron, flumioxazin + S-metolachlor, S-metolachlor, S-metolachlor + fomesafen, flumioxazin, and pendimethalin were selective for the IAC 1850 cultivar, whereas linuron, flumioxazin + S-metolachlor, S-metolachlor + fomesafen, ethoxysulfuron, flumioxazin + pyroxasulfone, pendimethalin, and imazethapyr were selective for the IAC 2051 cultivar.