Revista Brasileira De Herbicidas 2013; 12(1): 14-22
Burndown programs in winter wheat crop and residual activity in soybean crop
The winter field system has impacted the Conyza spp. infestation on the next Field. Thus, the aim of the research was evaluate burndown efficacy to Conyza spp. control in wheat crop area during the winter season, as well as at monitoring the residual effect of herbicides in soil on weed control within soybean cycle. The same experiment was conducted in two locations during the months of November 2010 and January 2011, in two locations in Rio Grande do Sul state (Condor and Estação) where have been cultivated with wheat winter crop. The treatments were composed by check without herbicide and for herbicides tank mixture. All the tank mixtures were glyphosate 720 g a.e. ha-1. The glyphosate was mixture with 2,4-D (402 g a.e. ha-1), diclosulam (25,2 g a.i. ha-1), chlorimuron-ethyl (10, 20 e 25g a.i. ha-1) and chlorimuron + flumioxazin (15+50; 20+50; 25+50; 15+60; 20+60 e 25+60 g a.i. ha-1). Was evaluated the burndown control at 7, 15 and 40 DAA and the density of weeds per m2 and the growth stage of the weeds at 40 DAA. The tank mixtures of glyphosate with chlorimuron-ethyl + flumioxazin, chlorimuron-ethyl and diclosulam, independently of rates, were efficient to Conyza spp. burndown control. Treatments with glyphosate + chlorimuron-ethyl + flumioxazin were the only treatments efficient to suppress the growth of new fluxes of E. heterophylla in Condor. All the tank mixtures with chlorimuron-ethyl + flumioxazin, chlorimuron-ethyl or diclosulam suppressing the initial development of Digitaria spp., Sida rhombifolia and Ipomoea triloba in Estação.
125