Selectivity of Chlorimuron-Ethyl to Castorbean Crops

• Published in: Advances in Weed Science 2017-01, Vol.35
• Main Authors: MACIEL, C.D.G., LUSTOSA, S.B.C., HELVIG, E.O., COSTA, A.G.F., RIBEIRO, R.B., MATIAS, J.P.
• Format: Article
• Language: English
• Subjects: Agricultural commodities; Chemical control; Crops; Cultivars; Design of experiments; Developmental stages; dose; Experimental design; formulation; Formulations; Herbicides; Hybrids; Intoxication; Leaves; Organic chemistry; PLANT SCIENCES; Productivity; Ricinus communis; Ricinus communis L; Seeds; Selectivity; Weed control; Weeds
• ISSN: 0100-8358; 1806-9681; 1806-9681; 2675-9462
• DOI: 10.1590/s0100-83582017350100077

Castorbean presents high sensitivity to competition; therefore, it is necessary to develop alternatives for the weed management, mainly for the chemical control of eudicotyledons species. The goal of this work was to evaluate the selectivity of chlorimuron-ethyl to castorbean crops in different development stages. Four experiments differentiated by the genetic material were conducted: Lyra, Íris and Savana hybrids and AL Guarany 2002 cultivar. The treatments corresponded to the application conditions of chlorimuron-ethyl [sample control with no application, doses of 15 e 20 g a.i. ha-1 with the formulations Classic™ and Clorimuron Master Nortox™] in two phenological crop stages (4 to 5 and 7 to 8 true leaf stages). The experimental design was in randomized blocks with four replications, in a factorial scheme of 5 x 2 (herbicide and application stage). The intoxication was more severe for the 7 to 8 leaf stage and with the dose of 20 g ha-1 on day 7 days after application (DAA); there were plant recovery and mild symptoms on day 21 DAA, especially for the 4 to 5 leaf stage. The yield was reduced with the 20 g ha-1 dose for Lyra hybrid with both formulations and for Savana castorbean, only with the Classic™ formulation. The chlorimuron-ethyl herbicide, at 15 g ha-1, showed selectivity to castorbean, regardless of the stage application (4 to 5 or 7 to 8 leaves). RESUMO: A mamoneira apresenta elevada sensibilidade à competição, sendo necessário desenvolver alternativas de manejo de plantas daninhas, principalmente para o controle químico de espécies eudicotiledôneas. Objetivou-se com este trabalho avaliar a seletividade do herbicida chlorimuron-ethyl à cultura da mamoneira em diferentes estádios de desenvolvimento. Foram conduzidos quatro experimentos distintos pelo material genético: os híbridos Lyra, Íris e Savana e o cultivar AL Guarany 2002. Os tratamentos corresponderam acondições da aplicação de chlorimuron-ethyl [testemunha sem aplicação, doses a 15 e 20 g i.a. ha-1 com as formulações Classic® e Clorimuron Master Nortox®] em dois estádios fenológicos da cultura (4 a 5 e 7 a 8 folhas verdadeiras). O delineamento foi de blocos casualizados com quatro repetições, em esquema fatorial de 5 x 2 (herbicida e estádio de aplicação). A intoxicação foi mais severa para o estádio de 7 a 8 folhas e a dose de 20 g ha-1 aos 7 dias após aplicação (DAA), ocorrendo recuperação das plantas e sintomas leves aos 21 DAA, especialmente para o estádio de 4 a 5 folhas. A produt