MANAGEMENT OF VOLUNTEER CASTOR BEAN IN THE GLYPHOSATE-RESISTANT SOYBEAN CROP¹

Manejo de Mamoneira Voluntária na Cultura da Soja Resistente ao Glyphosate

ABSTRACT

The goal of this study was to evaluate the management of volunteer castor bean with herbicide applications used in pre and post-seeding of soybean crop resistant to glyphosate. Two experiments were conducted in a greenhouse in a completely randomized design with three replications. The first experiment corresponded to applications of desiccation with treatments: glyphosate (1,080 g ha^-1); glyphosate + 2,4-D (1,080 + 670 g ha^-1); glyphosate + carfentrazone-ethtyl (1,080 + 20 g ha^-1); glyphosate + flumioxazin (1,080 + 25 g ha^-1); glyphosate + saflufenacil (1,080 + 35 g ha^-1); glyphosate + chlorimuron-ethyl (1,080 + 12.5 g ha^-1); diuron + paraquat (300 + 600 g ha^-1); and the control without application. In the second experiment, the treatments corresponded to doses of 0, 90, 180, 360, 720, 1,440, 2,880 and 5,760 g ha^-1 of glyphosate for applications in post-emergence in soybean RR. The applications took place when the castor bean plant had four to six true leaves. The evaluations done in both experiments were: control and plant height at 7, 14 and 21 days after application (DAA); and stem diameter, leaf area, root volume, dry mass of shoots and roots at 21 DAA. The treatments with diuron + paraquat and glyphosate associated with 2,4-D, carfentrazoneethyl, flumioxazin or saflufenacil are more efficient for castor bean control in desiccation in pre-seeding of soybean. Glyphosate doses from 720 g ha^-1 are effective to control castor bean in post-emergence of the glyphosate-resistant soybean crop.

Keywords:
Ricinus communis; Glycine max; control; herbicide