Sensitivity of common bean plants to the herbicide dicamba applied at pre-sowing

Abstract

Dicamba is an herbicide with residual activity in the soil and may affect crops sown after its application, mainly eudicotyledon species, as common bean (Phaseolus vulgaris L.). Thus, this work was developed with the objective of evaluating the sensitivity of common bean plants (Carioca cultivar BRS Estilo) to the herbicide dicamba applied at pre-sowing, based on different herbicide rates and different intervals between application and sowing. Three experiments were carried out, two under greenhouse and one under field (experimental beds) conditions. One of the greenhouse experiments was carried out to assess the correlation between different dicamba rates (720, 480, 240, 120, and 60 g ha^-1) and the sensitivity of common bean plants, with checkplots without herbicide. The other two experiments, one in greenhouse and other in field conditions, were carried out to evaluate the different intervals between dicamba application and common bean sowing. The evaluated intervals were 28, 21, 14, 7 and zero days, including checkplots without herbicide. Considering these intervals, lower symptoms were found under greenhouse conditions. In this environment, 14 days were sufficient to ensure the emergence and initial development of common bean plants. In the field experiment, 28 days were needed for a satisfactory emergence and initial development of common bean plants. On average, 14 days were sufficient for dissipation of more than 90% of the herbicide applied. A 28-day interval after dicamba application is recommended for a safe sowing of common bean crops.