Habilidade competitiva e manejo químico de maria-pretinha na cultura da soja

Abstract

The species Solanum americanum is an important weed infesting many grainproducing crops, characterized by high fruit and seed production. For an efficient management of weeds, it is fundamental to know the competitive behavior of the species, what is the level of tolerance to herbicides and what are the possible strategies to be adopted in combinations to result in greater efficiency. Therefore, the objective of this study was to determine the competitive ability of S. americanum in the soybean crop and the potential herbicides for postemergence management of the weed. For this, two experiments were carried out in a greenhouse simulating field situations. In the first work, the competitive ability of the soybean crop was tested in competition with different back-maria densities. And in the second experiment, the effect of herbicides (chlorimuron-ethyl, nicosulfuron, 2,4-D sal amine, pyroxsulam, glyphosate, paraquat, ammonium glufosinate, carfentrazone, imazethapyr + flumioxazin and flumioxazin for the control of the species in post-emergence was studied. The competitive ability of soybean cultivars in competition with back-maria are similar, resulting in losses of dry mass of roots and shoots, for cultivars BMX Icon IPRO and DM 5958 RR. back-maria there was intraspecific competition from the weed itself, in addition to greater competition with soybean, hindering the growth of both the root and aerial parts imazethapyr + flumioxazin and paraquat. The backmaria has a high competition potential and the herbicides demonstrate, in the evaluated biotype, high control.