The investigations were carried out in 1996–2005 on the fields of Agricultural Experimental Station Department of SGGW Chylice in Mazowieckie voivodeship. The occurrence of diseases was assessed in 1996–2000 on winter wheat cv. Kobra, and in 2001–2005 on cv. Mikon. Weather conditions in ten-year experimental period were differentiated and had a distinct influence on plant infection by pathogens, as well as on the level of winter wheat yielding. In the first part of experimental period (1996–2000) the weather was characterized by higher temperatures compared to long-term average and higher amount of rainfall, with the exception of the year 2000 when the summer drought occurred. The highest for that period grain yield (54.70 dt/ha) was obtained in 1998. This was related to the lowest total infection of leaf surface area (22.76%) and a relatively low index of infection of stem base by Tapesia yallundae. In that year mass of 1 000 grain was also the highest. The lowest grain yield (40.80 dt/ha) was recorded in 2000 due to summer drought. In 1997 characterized by a high level of infection by T. yallundae (eyespot) obtained grain yield was also relatively low. In the second part of the experiment conducted on cv. Mikon (2001–2005) the lowest grain yield was recorded in 2001 (28.85 dt/ha) when per cent of leaf area infection of 2 upper leaves by Puccinia recondita (brown rust) was very high (44.79%), and the highest yield was obtained in 2003 (57.27 dt/ha). This was due to a moderate level of total leaf infection (30.21%) with fungal pathogens and favourable weather conditions for wheat development. In that year mass of 1 000 grain was also the highest. The occurrence of stem base infection by Fusarium spp. was maintained in the years 1996–2005 on differentiated level and it was lower in earlier years compared to the later period. The infection of ears by Leptosphaeria nodorum and Fusarium spp. was usually not high and its influence on the amount of grain yield not clearly evident. Chemical control of diseases influenced grain yield increase which was the highest in 2001 when winter wheat leaves were heavily infected by Puccinia recondita. The yield increase on fungicide treated plots was in that year 53.15%. It was evident that brown rust may pose a serious threat to winter wheat in the years of its high occurrence.

Research performed in the years 1999–2002 was carried out in Great Poland region on varieties of winter wheat Elena and Tercja. Experiments included three programmes of wheat cultivation: 1 – Conventional winter wheat protection based on recommendations for commercial fields; 2 – Integrated pest management programme where the control of diseases and insect pests was carried out on the background of thresholds of harmfulness/noxiousness, and weather forecasts; 3 – Untreated, without protection against diseases and pests. Two levels of nitrogen fertilization were applied in the experiments (120 kg N/ha and 170 kg N/ha) and the newest plant protection products were used for controlling fungal pathogens and noxious insects. The occurrence of diseases and insect pests, as well as beneficial entomofauna was determined in relation to each experimental variant, and occurring changes were analysed. Effectiveness of disease and pest control were calculated. Grain yield and its quality were determined and economical profitability for both conventional and integrated programmes calculated. It was shown that a high profitability can be obtained through the application of integrated pest management, as a result of correct choice and application of plant protection products, as well as proper choice of wheat cultivars and appropriate nitrogen fertilization.