Weed management with post-emergent herbicides in intercropped castor and common bean cultivation

Abstract

The objective of this work was to evaluate the possibility of using herbicides registered for the cultivation of beans in castor crop when intercropped with beans and the influence of weeds in the crops. A randomized block design was used in a 2 x 4 + 1 factorial scheme with three replications. The herbicides chosen were: (A) fluazifop-p-butyl + fomesafen (125 + 125 g ai L-1) and (B) bentazon + imazamox (600 + 28 g ai L-1). They were applied in four different dosages (0.5; 1.0; 2.0 and 4.0 L ha-1) of the commercial product, plus a control as no weed management. The number of racemes per plant, number of berries per raceme, weight of one hundred grains and castor yield were evaluated. In the bean crop, the number of pods per plant, number of grains per pod, weight of one hundred grains and grain yield were evaluated. Weed competition reduced crop yields by 65.5% for castor beans and 71.87% for beans when intercropped. The results suggest that intercropping of beans with castor is viable and weed management can be carried out with the herbicides evaluated in this study, respect to the doses. The herbicides demonstrate selectivity for BRS Paraguaçu castor crop, showing higher productivity at doses of 612.25 g ai ha-1 and 1506.4 g ai ha-1 of the herbicides fluazifop-p-butyl + fomesafen and bentazon + imazamox, respectively.