Parks and forests are the lungs of our planet. They are constantly exposed to the influence of various environmental factors, which lead to a significant reduction of the areas under them. This, in particular, affects to a significant decrease in natural ecosystems biodiversity. Pests are a significant factor affecting the number and species composition of plants. Harmful insects are almost one of the biggest enemies of natural and artificial plantations. Invasive insects species are particularly harmful. As a result of species expansion that are recognized as invasive, no more than 40 % of the planet's natural ecosystems have survived today. A large number of countries, in turn, are trying to prevent and manage the introduction and spread of invasive alien species on their territories at the legislative level. However, not everyone manages to do this on time. Unfortunately, the list of harmful organisms in Ukraine does not include all organisms that pose a threat to the country’s plantations. The pine seed bug (Leptoglossus occidentalis H.) is an invasive pest that was introduced to Eurasia from the American continents. This is an atypical pest for coniferous vegetation of our territory. However, due to its high adaptability, it has already infested the entire area of Ukraine. The pine seed bug damages more than 40 types of coniferous plants. The insect feeds on young and mature cones, destroying completely or partially the seeds. Obtaining high-quality, full-fledged seeds is an important component in the future establishment of young plantations and obtaining friendly and fullfledged seedlings for the positive self-recovery ability of coniferous plantations. The purpose of our research was to record the presence of the pine seed bug in the territory of Lviv region and to determine the number of productive generations that the insect has per year. It was found out that the pest has expanded its habitat and feeding area to the western borders of Lviv region, which has not been recorded before. The study of the peculiarities and manifestation of pine seed bug pest damage is currently insufficient. In this regard, there are no recommendations on protective measures to prevent mass reproduction of the pest. Therefore, the problem of protection and preservation of productive plantations of coniferous tree species is still unsolved.

Key words: pest, invasive species, damage, pine seed bug, Leptoglossus occidentalis H., pine, forest, biodiversity.