EN
Field experiments were carried out in 1997-1999 at Experimental Station Swadzim near Poznań. Yields of three varieties (Costella-FAO 240, Noella-FAO 260, Felicia- FAO 280) were evaluated on three sowing dates (early - 10 days earlier, recommended - III decade od April, late - 10 days later) after additional seed dressing with insecticides Gaucho 350 FS, Promet 400 SC and Zaprawa Marshal 250 DS. It was shown that additional maize seed dressing, under the conditions of the Wielkopolska region, caused a significant grain yield increase. Regardless of the dressing type applied, over three years, yield increase was slightly above 2%. The late sowing date caused significant grain yield decrease. An additional seed dressing made this decrease lower. The best effect was obtained in the case of using Gaucho 350FS for seed dressing. Simplified economic calculation of maize seed dressing in particular years, under the conditions of the Wielkopolska region, showed that only the use of Promet 400 SC was economically viable. Application of the other two dressings caused losses in all years. The results did not show significant changes in content of protein, fat, fibre, N-free extract and ash in grain after seed dressing with insecticides. Moreover, a significantly higher protein content in corn grain was found after sowing 10 days earlier than the recommended date. Protein, fat, fibre and ash content was characteristic of the variety, but N-free extract content wasn’t changed under this factor.