INSECT AND FUNGAL DISEASE THAT CAUSED DAMAGES ON INTERNATIONAL PROVENANCES TRIALS OF PEDUNCULATE OAK AND EUROPEAN BEECH IN CROATIA

Pedunculate oak (Quercus robur L.) and European beech (Fagus sylvatica L.) are economically and ecologically important deciduous trees in Europe. In Croatia, the International pedunculate oak provenance trials and International European beech provenance trials were established in order to study growth traits and adaptive potential at selected sites. The aim of this study was to examine the health condition, to identify causes of damages on oak and beech trees and to detect insects and fungal diseases. The study areas were pedunculate oak provenance trials in Koška (2015) and Jastrebarski lugovi (2015, 2016) and beech provenance trial in Medvednica (2015). Tree crown condition survey was performed by using the visual tree assessment method. In oak provenance trials five types of damages were recorded: powdery mildew, chewing damages, leaves spots, galls and sooty mold. In beech provenance trials five types of damages were recorded, as well: aphids, galls, chewing damages, anthracnose and cankers. Plant material with typical symptoms of damage was collected for phytopathological and molecular genetic testing. In oak provenance trials the powdery mildew was caused by fungus Erysiphe alphitoides. The galls were caused by insects: Neuroterus quercus-baccarum, N. numismalis, N. anthracinus, Cynips quercuscalicis, C. quercus folii. The chewing damages were caused by Stigmella samiatella, Caliroa annulipes, Tortrix viridana and Geometrid caterpillar. Leave spots were caused by Apiognomonia quercina and Septoria quercicola. Sotty mold causing by various fungi were present in provenance trial in Jastrebarski lugovi in 2016. In beech provenance trial, anthracnose damage were caused by fungus Apiognomonia errabunda, cankers were caused by fungi Nectria cinnabarina and Neonectria ditissima. The damage from aphids was caused by Phyllapis fagi. The gall was caused by Mikiola fagi. The chewing damages were caused by Phyllonorycter maestingella and Rhynchaeus fagi. We concluded that the occurrence and intensity of the diseases and pests depended on microclimatic conditions on the international provenance trials localities.