New problems in dendropathology – new and invasive pathogens

Abstract During the last decades, several new and invasive tree pathogens have arrived in the northern Europe, damaging forest and verdant trees. New and invasive species (e.g. Lecanosticta acicola, Dothistroma septosporum, Diplodia sapinea, Hymenoscyphus fraxineus) are considered to cause economic loss and be an important threat to biodiversity. Once the alien species have entered into ecosystem, then it is very difficult to eliminate them. Therefore, it is important to discover new and invasive pathogens from forests and from imported plant material as early as possible. For that reason, the research team of Estonian forest pathologists has worked out a survey strategy with permanent plots across Estonia – for early detection of new pathogens, which essentially includes molecular monitoring of pathogens. An important task in developing of early detection methods for new and invasive pathogens is working out of quick detection methods by creating original PCR primers. Crucial is also the analyses of pathogens biology, of their spreading and finding of all their potential hosts in new for them environment in northern Europe. In cooperation studies with our foreign partners, the Estonian forest pathologists have analysed populations of D. septosporum, L. acicola and H. fraxineus. The population genetic methods give data about the pathogens diversity, vitality and betray potential pathways of them to northern Europe. This information serves for building up the control strategy and helps to find and test resistant tree species progenies. Early detection, molecular monitoring and pathways detection of new and invasive pathogens are currently the most important research tasks of the forest pathology team working in Estonian University of Life Sciences.