Selectivity of halosulfuron-methyl applied in preemergence of castor bean crop/Seletividade do halosulfuron-methyl aplicado em pre-emergencia da cultura da mamoneira

• Published in: Revista brasileira de engenharia agrícola e ambiental 2015-07, Vol.19 (7), p.693
• Main Authors: da Silva, Renata L.M, Costa, Augusto G.F, Sofiatti, Valdinei, Ribeiro, Valeria V, Maciel, Cleber D. de G, Monteiro, Danilo R
• Format: Article
• Language: Portuguese
• ISSN: 1415-4366
• DOI: 10.1590/1807-1929/agriambi.v19n7p693-697

Castor bean is very sensitive to competition, being necessary to expand the alternatives for weed management, principally considering the selective herbicide options, aiming to contribute to the expansion of the cultivated areas. The aim of this study was to evaluate the selectivity of the herbicide halosulfuron-methyl applied to castor bean crop in preemergence, before seeding. Two trials were conducted under greenhouse conditions, one with sandy and other with sandy clay loam soil, in a completely randomized design with four replications. The treatments corresponded to five periods between herbicide application and seeding (0, 7, 14, 21 and 28 days) and a control without application. The evaluations made were: plant height at 7, 14, 21 and 28 days after emergence (DAE); stem diameter, leaf area, root volume, dry mass of aerial part and roots at 28 DAE. Halosulfuron-methyl (112.5 g [ha.sup.-1]) is selective to castor bean crop, when applied at preemergence modality, before seeding. Key words: herbicide tolerance Ricinus communis L. no-tillage A mamoneira e bastante sensivel a competicao, havendo necessidade de ampliar as alternativas de manejo de plantas daninhas, considerando-se principalmente as opcoes de herbicidas seletivos, visando favorecer a expansao das areas de cultivo. O objetivo deste trabalho foi avaliar a seletividade do herbicida halosulfuron-methyl para a cultura da mamoneira aplicado em pre-emergencia, antes da semeadura. Dois experimentos foram conduzidos em condicoes de casa-de-vegetacao, um com solo arenoso e outro com francoargilo-arenoso, em delineamento inteiramente casualizado com quatro repeticoes. Os tratamentos se constituiram de cinco periodos entre a aplicacao do herbicida e a semeadura (0, 7, 14, 21 e 28 dias) e uma testemunha sem aplicacao. As avaliacoes realizadas foram: altura de plantas aos 7, 14, 21 e 28 dias apos a emergencia (DAE); diametro do caule, area foliar, volume de raizes, massa seca de parte aerea e raizes aos 28 DAE. Halosulfuron-methyl (112,5 g [ha.sup.-1]) e seletivo para a cultura da mamoneira quando aplicado na modalidade de pre-emergencia, antes da semeadura. Palavras-chave: herbicida toleranda Ricinus communis L. plantio dheto