EN
The aim of investigation was to compare the influence of two doses of herbicide Chwastox Trio 540 SL on the weed infestation of three varieties of spring wheat. A field experiment was carried out randomized blocks method in three replications on grey – brown podsolic soil of loess origin (good wheat complex). Three varieties of spring wheat: Nawra, Zadra, Korynta, full recommended dose and reduced to 50% dose of herbicide Chwastox Trio 540 SL (mecoprop + MCPA + dicamba) were the experimental factors. Control object was not treated with herbicide. The research showed that, the application of reduced by 50% herbicide dose of Chwastox Trio 540 SL did not affect the increase of the weed infestation level in the spring wheat canopy. The number of weeds and air-dry weight of weeds aid not differ significantly in the herbicide treated plots. From among 34 weed species occurring in the spring wheat canopy, 17 weed species showed the same and lower relative abundance index (Ra) in plots treated with 50% dose of herbicide in comparison with the full dose on herbicide treated plots.