Herbicide mixtures to control dayflowers and drift effect on Coffee cultures

Abstract

The dayflower species Commelina benghalensis and C. diffusa are among the main weeds in coffee crops. The purpose of this study was to evaluate the efficacy of herbicides/herbicide mixtures in controlling dayflower species and to evaluate the possible intoxication of coffee cultures, as well as the effect of mixture interactions. Two experiments were conducted, the first one in a 12 x 2 factorial arrangement with 12 herbicides/mixtures (glyphosate, glyphosate + metsulfuron- methyl, glyphosate + flumioxazin, glyphosate + 2.4-D, glyphosate + oxyfluorfen, glyphosate + carfentrazone-ethyl, metsulfuron-methyl, flumioxazin, 2.4-D, oxyfluorfen and carfentrazone-ethyl) and two dayflower species (C. benghalensis and C. diffusa) and the second one, in a 6 x 2 + 1 factorial arrangement, with six herbicides/mixtures (glyphosate, glyphosate + metsulfuron-methyl, glyphosate + flumioxazin, glyphosate + 2.4-D, glyphosate + oxyfluorfen and glyphosate + carfentrazone-ethyl) and two application forms on coffee plants (reaching 1/3 of the coffee canopy and with a protected canopy), plus a control treatment without herbicides. There was tolerance variation within the dayflower species to the tested herbicides. Commelina benghalensis was controlled by glyphosate, 2.4-D, glyphosate + 2.4-D and glyphosate + metsulfuron-methyl, while C. diffusa was controlled by 2.4-D and glyphosate mixtures by + metsulfuron-methyl, glyphosate + oxyfluorfen and glyphosate + flumioxazin. The mixture glyphosate + 2.4-D is effective in controlling dayflower, but it caused intoxication and growth reduction of the coffee. There was antagonism in the mixture glyphosate + carfentrazone-ethyl in controlling both species, as well as for glyphosate + oxyfluorfen and glyphosate + flumioxazin for C. benghalensis.As espécies de trapoeraba Commelina benghalensis e C. diffusa estão entre as principais plantas infestantes na cultura do café. Objetivou-se com este trabalho avaliar a eficácia de herbicidas/misturas de herbicidas no controle das espécies de trapoeraba e a possível intoxicação na cultura do café. Foram conduzidos dois experimentos, sendo o primeiro em esquema fatorial 12 x 2, com 12 herbicidas/misturas (glyphosate, glyphosate + metsulfuron-methyl, glyphosate + flumioxazin, glyphosate + 2,4-D, glyphosate + oxyfluorfen, glyphosate + carfentrazone-ethyl, metsulfuron-methyl, flumioxazin, 2,4-D, oxyfluorfen e carfentrazone-ethyl) e duas espécies de trapoeraba (C. benghalensis e C. diffusa), e o segundo, em esquema fatorial 6 x 2 + 1, com seis herbicidas/misturas (glyphosate, glyphosate + metsulfuron-methyl, glyphosate + flumioxazin, glyphosate + 2,4-D, glyphosate + oxyfluorfen e glyphosate + carfentrazone-ethyl) e duas formas de aplicação nas plantas de café (atingindo 1/3 da copa do café e