Bioecological peculiarities and economic significance of large fruit bark beetle (Scolytus mali Bechstein, 1805) and fig bark beetle (Hypoborus ficus Erichson, 1836) in the southern slopes of the Great Caucasus (Azerbaijan)

Background. Bark beetles (Coleoptera, Curculionidae, Scolytinae) are major pests of wood-fruit trees, and infestations often accelerate tree death. Bark beetles are insects that are closely related to their host trees. According to the type of feeding they belong to xylophages [7]. They prefer weakened, sick or damaged trees. Thus, bark beeteles can more easily penetrate into trees affected by various natural phenomena (wind, storm, rain) or primary pests. They are hardly ever found in rotting trees. The research was carried out on the southern slopes of the Great Caucasus during the period 2013–2016. The great difference in the altitude in the study area results in a variety of natural conditions. This, in turn, leads to the richess of fauna and flora of the area. Thus, valuable fruit trees grow both in the forests and fruit farms of the study region. However, large numbers of fruit trees are attacked by bark beetles every year, which negatively affects the numbers and the quality of trees. Untimely processing of the trees leads to their drying and destruction. According to modern systematics, bark beetles belong to the Scolytinae (Latreille, 1804) subfamily of the Curculionidae (Latreille, 1802) family. There are about 6,000 species of bark beetles from 28 triba and 230 genera in the world [8]. These insects also cause serious damage in countries neighboring of Azerbaijan [1, 2, 9, 11 ]. Despite the fact that bark beetles are of great agricultural importance, they are not sufficiently studied in Azerbaijan. Materials and Methods.The material for research was collected and treated according to common entomological methods. The vegetative organs of various trees were cut and dissected to detect adult beetles, eggs and larvae of bark beetles. Identification of bark beetles was carried out according to keys. MBS-9 microscope was used to determine the morphological features of beetles. Results. As a results of the research, we analyzed 241 samples (237 adults and 4 pupae) of bark beetles collected in 7 districts of the southern slopes of the Greater Caucasus, of which 54 specimens belonged to Scolytus mali and 187 to Hypoborus ficus. Conclusion. Out of 30 species of bark beetles detected on the southern slopes of the Greater Caucasus, 7 ones (Scolytus mali Bechst., S. amygdali Guer., S. fasciatus Rtt., S. rugulosus Ratz., Hypoborus ficus Er., Xyleborus dispar F., X. saxeseni Ratz.) were determined as fruit trees pests. Two of them (Scolytus mali and Hypoborus ficus) are widely distributed in the area and cause serious damage to fruit trees.