Harmful entomofauna in forestry and green infrastructure

Abstract

The national invention of the forests of the Republic of Srpska established over 100 species, with the entire volume of wood mass being dominated by deciduous trees (beech 45%, oak 8%, other deciduous trees 7%, tribal deciduous trees 3%). Beech has the largest share in state forests in the supplies (43%), followed by fir about 20%, and spruce by 16%. Of the harmful endomofauna of fir, one third are gradeogenic species, which can cause great economic and environmental damage. Harmful endomofauna of beech number 32 species, of which economically significant primary species are prone to mass occurrences and trophical relations related to the leaf (15.75% of species). Harmful endomofauna of oak species represent 40 most common species. Outbreaking primary species make up one quarter, feed predominantly on leaves and cause defoliation (50%). Harmful for seeds or acorns are 15% of pests, which can have a detrimental effect on the reproduction and regeneration of oak forests. The most common pests in spruce forests are species that occur frequently and can only occasionally cause minor damage (56.25%). The most economically important are bark beetles and wood borers, which tend to outbreak (12.5%) and cause dammage on a hudge area. Outbreaking species are also pest of seed and cones, which participate in the spruce pest complex with 14.58%. Pests in nurseries are important for reproduction in forestry and for providing nursery stock for the establishment of green infrastructure. Of the 54 harmful species, almost a quarter are non-native species (24.07%). Often, non-native pests are transferred from nurseries to public green spaces, green corridors, and entrepreneurs are ofteen serving as a pathway for introduction of non-native harmful species into forest ecosystems. Therefore, ornamental plants are rightly considered the most important pathways for introduction of invasive alien species in mannaged and protective forests. Non-native and invasive species that are introduced in the Republic of Srpska e.g. emerging pests are folowing: Aproceros leucopoda, Cameraria ohridella, Corythucha arcuata, Corythucha ciliata, Cydalima perspectalis, Eopineus strobi, Gillettella cooleyi, Leptoglossus occidentalis, Metcalfa pruinosa, Obolodiplosis robiniae, Phyllonorycter platani, Pseudaulacaspis pentagona, Stictocephala bisonia etc. Most of these species are pests in nurseries and ongreen infrastructure. Some native insect species appear as emerging pests due to their increase of population , as an answer to changing weather conditions. One example is the ash wasp Tomostethus nigritus (F.) (Hymenoptera: Tenthredinidae), which in the last ten years appear in local outbreaks in tree lines or other green areas at the territory of Southeastern Europe from the Balkan Peninsula to the Nordic countries. Increased populations of Zeuzera pyrina (Lepidoptera: Cossidae) were also applied in nurseries and on elements of green infrastructure. Due to the climate change, the species Ovalisia (Palmar) festiva migrated from the Mediterranean area, setting a dangerous pest in nurseries, while the linden bug Oxycarenus lavaterae is common on lindens, building large colonies but so far with no significant damage on trees. In order to prevent introduction and stop the spread of alien invasive species, there is need to ensure the maintenance of a high level of health protection status in agriculture, green infrastrucrure and forestry.