Monitoring on appearance and spread of harmful invasive pathogens and pests in Belasitsa Mountain.
Belasitsa Mountain is located on the territory of Southwest Bulgaria, Northern Greece and Northern Macedonia. The Bulgarian part of the mountain includes most of its northern slopes and ridge territories, characterized by variety of vegetation zones and plant communities. At lower altitudes, Quercus spp., are the most distributed, but gradually replaced by the sweet chestnut forests (Castanea sativa). Chestnuts are distributed between 400-1300 m a.s.l., forming the largest natural locality in the country. Along the river valleys in the mountain, natural population of Platanus orientalis occurs. Since 2018, a system for monitoring of two pathogens (Cryphonectria parasitica on Castanea sativa and Ceratocystis fimbriata on Platanus orientalis) and three invasive pests (Corythucha arcuata on different oak species and chestnut, C. ciliata on P. orientalis and Dryocosmus kuriphilus on chestnut forests) has been implemented. Until now, a high density of C. ciliata was established on P. orientalis causing significant damages on host trees. C. arcuata has spread in Bulgaria since 2013. Over the next few years, the species penetrated many regions of the country by affecting predominantly oak forests, but in 2017, it was registered for first time on the chestnut trees. In Bulgaria, D. kuriphilus has not been found yet, but as the pest was established in Greece in 2014, natural spreading of the species to Belasitsa Mt. could be expected. The possible penetration of this pest could increase the rate of damaged stands that had already been severely attacked by the fungal pathogen C. parasitica.