In 1993–1995 from the cabbage aphid colonies, fed on nine different varieties of Brassica oleracea L. syrphid larvae and pupae were collected. The remaining emerged adults of Syrphidae were classified to eight species. The parasitization varied within the years of observation and oscillated from 14,4% to 46,4%. Four parasitic Hymenoptera: Diplazon laetatorius (F.), Diplazon sp., Pachyneuron grande (Thoms.), and Syrphophagus aeruginosus (Dalm.) were reared. The parasitoids identified belong to the following three families Ichneumonidae, Pteromalidae, and Encyrtidae. The largest group of reared parasitoids belonged to the family Ichneumonidae of which the most frequent was Diplazon laetatorius (F.). It occurred in each year of observations. The parasitization by D. laetatorius reached 21,7%.

In the years 2002–2004 strains of Bacillus thuringiensis and 37 species of entomopathogenic fungi were isolated and identified in the Polish and Belarussian parts of Białowieża Forest (BF). Mitosporic fungi and bacteria dominated in litter sperficial soil layer, forest, litter and floor vegetation whereas entomophtoralen fungi prevailed in bushy undergrowth layers and tree crowns. The dominant species Beauveria bassiana was observed in forest floor, subcortical habitats on dead trees, meadows and rushes. The species Entomophthora israelensis, Beauveria cf. bassiana, Paecilomyces suffultus and P. tenuipes were for the first time described as insect pathogens in BF. Entomophthorales seem to hold much greater part than mitosporic forms in the whole diversity of entomopathogenic fungi. Relatively rich sets of these fungi recognised in BF during last decades confirm the predestination of this area as highly significant refuge for other groups of arthropod pathogens, and it should encourage scientists to widen their research and contribute to a rather scarce knowledge in this field.