The thesis is based on the study of new alien and spreading over EU insect pests, polyphagous Otiorhynchus sp. (Coleoptera, Curculionidae) weevils. These weevils damage many species of shrubs and trees, ornamental and horticultural plants, and can cause significant harm to red raspberries and strawberries. The pests damage both the underground and the above-ground parts of the plant: larvae feed on roots meanwhile adults on leaves. Since the use of conventional pesticides and the increase in their use is harmful both to the environment and to humans, monitoring and environmentally friendly control measures, which are still not developed today, are necessary. To develop them, chemo-ecological and genetic studies on the insect pests will be carried out. Olfactory and behavioural reactions of the insects to volatiles of host plants will be registered as well as those of conspecifics and electrophysiologically active compounds will be identified for the Otiorhynchus sp. species studied. Attractive compounds of plant origin (kairomones) and those of insects (pheromones) will be tested in the field and the most effective blend will be recommended to use in traps for monitoring or control purposes. The genetic diversity of these pests will be investigated to assess the pathways of spread of alien Otiorhynchus sp. species to Lithuania.