Toxicity of Fumaria officinalis, Euphorbia paralias , Hyoscyamus sp. and Rosae sp. were tested on southern and northern strains of plum curculio (Conotrachelus nenuphar). The plant extracts exhibited varying toxicity to both strain ranging from 20 – 100% after 48 h incubation and Fumaria officinalis, and Hyoscyamus sp. extracts resulted in significantly higher mortality than the control. Generally, prolonged incubation time resulted in an increase in mortality. Hyoscyamus sp. extract, the most toxic extract among those tested, caused 100% mortality which is similar the mortality caused by the chemical standard. In the second series of experiments, dose-response bioassay using of Hyoscyamus sp. was carried out on southern and northern strain of the insect. The results exhibited that certain plant extracts were toxic to the beetle and may have potential for controlling this destructive pest under field conditions.