The biocoenotic relations are estimated in the cabbage aphid colonies on the cabbage fields. The role of carnivorous insects in the decrease of the pest abundance is much greater than that of egg parasites. The former exterminated up to 20% and the latter up to 10% of the potential numbers of aphids on plants. The dependence of increase in the numbers of entomophages on the pest abundance is described quantitatively. Nutrition; Diet; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Ecology; Land and freshwater zones; Palaearctic region; USSR Coccinellidae; Cecidomyiidae; Syrphidae; Chrysopidae (Neuroptera ); Prey; Brevicoryne brassicae (Hemiptera); Russian SFSR; Amur region; Hemipteran prey Aphidiidae (Braconidae); Hemipteran hosts; Brevicoryne brassicae; Russian SFSR; Amur region Brevicoryne brassicae (Aphidoidea); Hymenopteran parasites; Aphidiidae; Predators; Insecta; Russian SFSR; Amur region; Insect predators & parasites no species