Biological efficacy of herbicides for weed control in noncropped areas

An increasing problem facing agricultural producers is the invasion of weeds, perennial in particular, so that implementation of industrial technologies is impossible without their highly efficient and rational control. For the purpose of studying efficient herbicides for weed control in noncropped areas (stubbles), a biological study of five total systemic herbicides was conducted in areas under natural weed infestation and pressure from other surrounding weeds at the Institute of Forage Crops in Pleven in 2005-2007. The trials were carried out in field conditions using the block method with plot size of 20 m2. Treatment was conducted at the predominant stage of budding of perennial dicotyledonous weeds and earring of monocotyledonous weeds. Herbicidal efficacy was recorded on the EWRS 9-score scale (0-100% killed weeds = score 9-1). It was found that treatment of noncropped areas (stubbles) with the total systemic herbicides Touchdown System 4 (360 g/l glyphosate); Cosmic (360 g/l glyphosate); Roundup Plus (441 g/l glyphosate potassium salt); Leon 36 SL (360 g/l glyphosate) and Glyphos Super 45 SL (450 g/l glyphosate) was highly efficient, so that it was a successful element of a strategy for controlling weeds of different biological groups, and was especially effective against perennial weeds.