MANEJO DE AZEVÉM RESISTENTE AO GLYPHOSATE EM POMARES DE MAÇÃ COM HERBICIDA SELECT (CLETHODIM)

Abstract

Glyphosate is a broad spectrum herbicide, used for more than 15 years in apple orchards in the Vacaria-RS region for vegetation management on the crops row. In general, 3-4 glyphosate applications are done in each crop cycle with the normal herbicide rate of 720-1,080 g e.a. ha-¹ . Lolium multiflorum is a frequently found weed specie in orchards and regularly sensible to glyphosate. Biotypes of Lolium multiflorum resistant to the glyphosate did not show any significant glyphosate symptoms. Clethodim is a highly efficient grass herbicide for Lolium multiflorum control. An experiment was carried out under field conditions during 2004 growing season in order to study the effects of herbicide Select (clethodim) on a ryegrass glyphosate resistant biotypes. The results indicated that the lower tested rate (Select 0,25 L ha-1 or clethodim 60 g ha-1) gave 99% control while the higher rates (0,30 and 0,35 L ha-1) gave 100% control.