EN
Field experiments were carried out in 2006–2008, at the Department of Agronomy, University of Life Sciences in Poznań, on the area of Didactic and Experimental Farm in Swadzim. The subject of studies was the effect of magnesium doses (soil and foliar applied) on the extent of damage caused by the frit fly (Oscinella frit L.) and by European corn borer (Pyraustia nubilalis Hbn.). The percentage of damage caused by the pests was conditioned by the weather conditions dominating prevailing in the period from sowing phase to the maize developmental phase BBCH 17/18. In years with cool spring, the damage was higher. Foliar application of magnesium, or both soil and foliar applied magnesium reduced the percentage of damage caused by the pests, in comparison with only soil applied magnesium. Neither the magnesium dose nor the methods of its application differentiate the extent of damage by Pyraustia nubilalis Hbn.