The paper presents results of studies on the occurrence and economic importance of maize diseases: common smut tUstilago teae /Beckm./Unger) root et stalk rot iFusarium spp.) and eye spot of leaves (Kabatiella zeae Narita et Hiratsuka) (conducted in 1993-1999) as well as com rust tPuccinia sorghi Schw.) and blotch of leaf sheaths (Pseudomonas andropogoni E. F. Smith/Stapp., P syringae van Hall.) (conducted in 1996-1999).

The paper presents results of studies on the occurrence and economic importance of maize pests: european com borer (Ostrinia nubilalis Hbn.) and frit fly (Oscinellafri1 L.) (conducted in 1977-2000) as well as aphids (Aphididae) and thrips iThysanopterai (in I 982-1983, I 985 and 1988-2000).

Research was carried out in 2001-2002, in the Plant Breeding Station of Mikulice near Przeworsk. The occurrence of European corn borer (Ostrinia nubilalis Hbn.) on corn, as well as the effects of its chemical control were assessed. It was found out that in 2001, caterpillars damaged 40.5% of plants, while in 2002 - 99.3% of plants. As a result of double lambda cyhalothrin application (Karate 025 EC), high pest reduction was achieved: 91.4% in 2001 and 88.9% in 2002. Corn yields increased by 1.8 t/ha in 2001 and 4.3 r/ha in 2002 in comparison with yields in untreated fields.

The paper present results from the studies carried out in the years 1999-2000 on the effectiveness of seed dressing of spring barley with the insecticide Gaucho 350 FS (a.i. irnidachloprid) to control frit flies, gout flies, aphids and thrips in piedmont conditions.