The 1987-1992 microplots experiment was conduced in agricultural field conditions under routine crop, and herbicide rotation. Over the experimental time only the endoparasitic species, Pratylenchus neglectus revealed significant changes in the population dynamics. In a sugar beet the nematode population decreasad in microplots treated with chloridazon (3.25 kg/ha) or cycloate (4.44 kg/ha) but increased in the control. In a winter rape the population ofP neg/ecrus increased in microplots treated with benazolin (0.45 kg/ha) but it decreased in the control. The observed trends in the dynamics of the nematode population persisted for one year only, and they were changed with the rotation of crop and herbicides. No differences betwen herbicides treated, and control microplots were observed with linuron + bentazone (10 kg/ha + 1.5 kg/ha, respectively) was applied to pea culture, metabenzthiazuron (2.8 kg/ha) was applied to a winter wheat, and MCPA as sodium salt + dicamba as sodium salt (0.725 kg/ha + 0.08 kg/ha, respectively) was applied to a spring wheat. The examined crops and herbicides did not markedly affect the population dynamics of ectoparasitic Tylenchorhynchus dubius, Helicotylenchus digonicus and Mesocrico nema curvatum.

The subject of this study was Rhizopertha dominica F. population. The primary question referred to was the process of the lesser grain borer population spread depending on nutritional preferences of this species. The aim of performed laboratory experiments was to examine the adults’ ability to choose preferred kinds of food i conditions of free migration among them and to analyze the dynamics of population size. Sex ratio and the migration rate were also analyzed. Four types of food were used during the experiments: wheat, oat flakes, pearl barley and semolina. The experiments were conducted at 28°C and 60 ± 5% of relative humidity. Results of the study revealed that oat flakes were the most favourable nutriment for adult R. dominica whereas wheat grain was the most favourable for the population size since larvae were protected by grains and thus their increased number could survive. No population development in semolina was observed. It was the result of too small granulation of this food.

The subject of this study was the lesser grain borer Rhizopertha dominica F. The aim of the experiments was to verify the hypothesis suggesting that the course of simultaneous vertical migration and horizontal spread of the R. dominica population is determined by nutritional and habitat selectivity. The following products were used as nutrients in the experiments: wheat, oat flakes, pearl barley and semolina. It was found that the course of a migration process is connected with nutritional preferences determined mainly by a nutrient type and its granulation. At the initial stage of the study the highest emigration was noted in the oat flakes. After a time the highest migration was directed to as follows: wheat, oat flakes, pearl barley and semolina. Females showed a higher migratory activity.