Selectivity of some herbicides applied to Bulgarian variety of perennial ryegrass (Lolium perenne L.) IFK Harmoniya during stand establishment and seed production.

During the period 2014-2016 on the experimental field of the Institute of Forage Crops - Pleven a study was conducted with the purpose to determine the selectivity of some herbicides to Bulgarian variety of perennial ryegrass (Lolium perenne L.) IFK Harmoniya during stand establishment and seed production. It was found that herbicides Accurate 60 WG (600 g/kg of metsulfuron-methyl) - 10 g/ha, Ally Max (143 g/kg tribenuron methyl + 143 g/kg metsulfuron methyl) - 35 g/ha and Eagle 75 WG (750 g/kg chlorsulfuron) - 20 g/ha showed high selectivity to perennial ryegrass (Lolium perenne L.) and can be applied at the growth stage BBCH 12-14 on the crop, during establishing year of the stand for control of broadleaf weeds. Accurate 60 WG - 10g/ha and Ally Max - 35 g/ha applied at the growth stage (BBCH 28-30) in the year of seed production had a high selectivity to perennial ryegrass and can be applied for control of broadleaf weeds. Applied low dose of Axial One (45 g/l pinoxadene + 5 g/l florasulam) - 350 ml/ha had hormesis effect to perennial ryegrass and can be used for stimulation the accumulation of fresh and dry biomass during the year of stand establishment and, as well as in the years of seed formation. The herbicide tolerance of perennial ryegrass to key herbicides with complex action (for weed control against annual monocotyledonous and dicotyledonous weeds) has been determined, which could serve as a means of increasing the efficiency of the breeding process. [ABSTRACT FROM AUTHOR]