EN
A field experiment in winter wheat was carried out at Czesławice (central part of Lublin region) in 2007–2009. The research included 3 doses of herbicides, fungicides and a retardant (100, 75, 50%) as well as the type of adjuvant (superficially active, oil, mineral). Control objects without adjuvant were also taken into consideration. It was shown that the reduction of pesticides doses by 50% caused a considerable increase in the number, and air-dry weight of weeds in winter wheat canopy as compared with the 75% dose and with the maximum dose. Due to the addition of adjuvants (especially oil adjuvant) to spraying liquid the reduction of pesticides doses by 25% did not cause the increase in winter wheat weed infestation. Further reduction (by 50%) of pesticide doses, in spite of interaction with adjuvants, had a negative effect on the analysed weed infestation indicators.