802 AJCS 16(06):802-808 (2022) ISSN:1835-2707 doi: 10.21475/ajcs.22.16.06.p3565 Weed management with post-emergent herbicides in intercropped castor and common bean cultivation Fenelon Lourenço de Sousa Santos*¹, Itamar Rosa Teixeira¹, Gisele Carneiro Silva¹, Marcos Eduardo Araújo², Paulo César Corrêa², Paulo César Timossi³ 1 Plant Production Department, State of University of Goiás, Ipameri-GO, Brazil 2 Federal University of Viçosa, Viçosa-MG, Brazil 3 Federal University of Jataí, Jataí-GO, Brazil 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. Keywords: Phaseolus vulgaris; Ricinus communis; intercropping; weed competition. Introduction Castor bean (Ricinus communis L.) is an oilseed of significant socioeconomic value, with products and by-products used in the ricino-chemical industry and agriculture, enabling its use as a biofuel due to the oil that is extracted from its seeds (Almeida et al., 2007; Ribeiro et al., 2009). The castor plant has a C3 photosynthetic cycle, a metabolism that is characterized by slow initial growth and low ability to compete with other species (Beltrão et al., 2006; Azevedo et al., 2007). Moreover, the spacing used for cultivation, generally wider, makes the crop susceptible to weeds, which in general, have greater competitive capacity. The literature has demonstrated the feasibility of using crops intercropped with castor bean, especially common beans without causing losses in its productivity (Jesen et al., 2010; Teixeira et al., 2012; Cardoso et al., 2013; Pereira et al., 2015; Lisboa et al., 2018). However, normally weed control in crops is carried out by mechanical weeding, mainly due to the low availability of herbicides registered for this purpose, which makes cultivation difficult due to dependence on labor. Beans (Phaseolus vulgaris L.) is one of the most important constituent foodstuffs of the Brazilian diet, as it is an excellent source of protein, carbohydrates and has high levels of iron (Borém and Carneiro, 2015). In addition, it has great socioeconomic importance due to the large amount of labor demanded in its cultivation (Salgado et al., 2012), especially in family farming. Together with rice, it is the basis of the nutrition of the Brazilian people, especially of the lower income classes, where it becomes the main source of protein. In Brazil, beans are cultivated throughout the year, in the "water" seasons (November to January), in the "dry" season (February to April) and irrigated (May to July). The first cultivation crop is responsible for the greater volume of grain of this legume produced (Conab, 2021), practiced in small rural properties under an intercropping system, mostly under low technological level. Despite the socioeconomic importance of castor bean, it has been considered a weed for other crops resulting in a lack of interestment in research for selective herbicides to the crop (Vitorino et al., 2012). One of the major obstacles to expand cultivation of castor bean in both monoculture and intercropping is the issue of weed management, due to the lack of registered selective herbicides to the crop, mainly post-emergence to control dicotyledonous weeds. There are only two herbicides currently registered for use in castor crops, cletodim (annual grasses) and saflufenacil (non- selective) to control species such as viola rope (Ipomoea grandifolia) and bull's weed (Tridax procumbens) in post- emergence, both recommended for monoculture system (Brasil, 2021). Currently, in the bean crop, the main method used to manage weeds is chemical control, with the use of both pre- and post-emergent herbicides (Manabe et al., 2015). This