EN
Over the period 2008–2010 field experiments designed to test different time application of herbicides for weed control in maize crops were conducted at the Plant Protection Institute – National Research Insitute in Poznań. Herbicides were applied post-emergence of maize at the growth stages of 12–14 BBCH and 14–16 BBCH. The annual broad-leaved weeds were prevalent in the fields. The most frequent were: Chenopodium album, Polygonum convolvulus, Galium aparine, Viola arvensis, Polygonum persicaria, Solanum nigrum and one grass species – Echinochloa crus-galli. No significant differences between dates of herbicides application were stated. In all plots treated with herbicide the maize yield was significantly higher as compared to untreated plots. Not always the relation between herbicide application date and yield was found.