Herbicide selectivity on macauba seedlings and weed control efficiency

Abstract Seedlings of macauba (Acrocomia aculeata (Jacq.) Lodd. ex Mart.) palm spend ∼10 months in nursery before being taken to the field. Since there are no registered herbicides for macauba, weed control in seedling containers is done manually; however, macauba leaves have thorns that injure workers' hands. In this work, the selectivity of indaziflam, isoxaflutol, oxyfluorfen and sulfentrazone was evaluated on macauba seedlings produced in nurseries, incorporated (INC) to the substrate and/or applied before (PRE) and after (POST) transplantation, as well as its efficacy for the weed control. Seedlings were no intoxicated by the herbicides regardless of the application method. However, considering the height, leaf area and dry weight and root volume, the INC and PRE applications of indaziflam were not selective for macauba. In contrast, POST-indaziflam applications stimulated the growth of seedlings (