Studies on occurrence and harmfulness of celery fly on Sosnowski’s hogweed plants were performed in 1999–2002 in three plots at Minikowo, Mochełek and Topolno. At Mochełek, Minikowo and Topolno 40.65, 39.42 and 32.14% ofleaves, respectively were occupied by generation I ofthe fly while 14.8, 18.12 and 10%, respectively by the generation II. Most mines were caused by generation I in 2000 and 2002 at Minikowo and Mochełek. Generation II was characterized by a low population density in all plots.
European corn borer (ECB) (Ostrinia nubilalis Hbn.) is currently the most dangerous maize pest in Poland. During last five years the pest was recorded in 14 Polish voivodeships, covering over half of the country's area. The greatest harmful activity of the caterpillars was observed in warm southern regions of Poland. Field experiments carried out in southern Poland in the 2006-2007 growing seasons demonstrated that the average plant damage of non-Bt hybrids by O. nubilalis caterpillars varied between 40.0% and 44.0% in 5 locations and two seasons. Under the same pest pressure a high level of resistance of genetically modified (GM) Bt maize (MON 810) cultivars, expressing Cry1Ab toxic protein to infestation by ECB was noted. The average plant infestation of transgenic hybrids was equal to 0.5-0.7% in the same locations. Only some slight symptoms of injuries, such as small number of holes in stalks and gnawing of cobs was observed. Moreover, the tested transgenic hybrids demonstrated a high suitability for climate and soil conditions in Poland, providing early crops of high yield.