Associação de imazetapir e sulfentrazone em pré-emergência no feijão IPR-URUTAU e Euphorbia heterophylla

Abstract

Euphorbia heterophylla is the primary weed affecting common bean (Phaseolus vulgaris) crops; its management is complex, leading to significant yield losses and increased production costs due to the necessity of weed control. The experiment was conducted in a greenhouse using a completely randomized design (CRD) with a two-factor arrangement (herbicides × rates). Twelve-liter pots were used with three replicates per treatment; separate trials were conducted for the common bean and the weed, totaling 24 experimental units per trial. Treatments consisted of combinations of sulfentrazone and imazethapyr rates (g ha⁻¹ of active ingredient) in the following proportions, respectively: 0+300; 10+250; 20+200; 30+150; 40+100; 50+50; and 60+0, using the commercial products Vezir® (imazethapyr) and Boral® (sulfentrazone). Evaluations included germination rates for both species, phytotoxicity levels in the common bean crop, and weed control efficacy. Final measurements included plant height, stem diameter, and root and shoot dry matter. Data were tabulated and analyzed using the Rbio software, subjected to factorial and simple analysis of variance (ANOVA), followed by the Scott-Knott test for mean comparison at a 5% significance level. Under the controlled environmental conditions of the experiment, results showed that the best treatments involved imazethapyr and sulfentrazone applied alone; these allowed for good bean crop development and achieved weed control levels exceeding 80%. When applied in combination, however, they caused high levels of phytotoxicity to the IPR-Urutau common bean cultivar. Conversely, effective control of Euphorbia heterophylla was achieved; however, the use of these combinations was agronomically unfeasible due to direct interference with the crop's yield potential, caused by a reduction in morphological growth characteristics such as root and shoot development, height, and diameter.