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The composition and variability of the terpenes and their derivatives isolated from the needles of a representative pool of 114 adult trees originating from four natural populations of dwarf mountain pine (Pinus mugoTurra) from the Julian Alps were investigated by GC-FID and GC/MS analyses. In total, 54 of the 57 detected essential-oil components were identified. Among the different compound classes present in the essential oils, the chief constituents belonged to the monoterpenes, comprising an average content of 79.67\% of the total oil composition (74.80\% of monoterpene hydrocarbons and 4.87\% of oxygenated monoterpenes). Sesquiterpenes were present in smaller amounts (average content of 19.02\%), out of which 16.39\% were sesquiterpene hydrocarbons and 2.62\% oxygenated sesquiterpenes. The most abundant components in the needle essential oils were the monoterpenes -car-3-ene, -phellandrene, -pinene, -myrcene, and -pinene and the sesquiterpene -caryophyllene. From the total data set of 57 detected compounds, 40 were selected for principal-component analysis (PCA), discriminant analysis (DA), and cluster analysis (CA). The overlap tendency of the four populations suggested by PCA, was as well observed by DA. CA also demonstrated similarity among the populations, which was the highest between Populations I and II. Ministry of Education and Science of Republic of Serbia {[}173011, 173021]; Slovenian Research Agency {[}P4-0107, P4-0059]

Summary Pathogenic fungi can survive and develop in living plants, often causing diseases in the host. Some theories speculate that pathogenic ophiostomatoid fungi provide benefits to its vectors – bark beetles – by overcoming the tree's defence mechanisms. This study reports the results of an experiment in south-eastern Europe in which mature and seedling Norway spruce trees were artificially inoculated with various ophiostomatoid fungi. The aim of the experiment was to determine the relative virulence of ophiostomatoid fungi by assessing the ability of the fungi to stimulate host tree defence mechanisms through inoculation experiments. Experiments were performed by inoculation of Picea abies in seedling and mature trees. The following fungi were used in low-density and seedling inoculations: Ophiostoma ainoae, O. brunneo-ciliatum, Grosmannia cucullata and an unidentified Leptographium sp., O. bicolor, O. fuscum, O. piceae, G. penicillata and G. piceiperda. Endoconidiophora polonica was used in mass and seedling inoculations. Various characteristics such as host vitality, blue stain, lesion and resin outflow were measured before and after the trees were felled. E. polonica caused blue stain, induced large lesions and killed some of the mature trees and seedlings, confirming earlier reports that it is a strong wound pathogen. Only E. polonica, Leptographium sp. and O. ainoae caused blue stains in the sapwood of inoculated seedlings. In low-density inoculations, G. piceiperda induced intense necrosis and had higher values for all the characteristics monitored. Some of the other ophiostomatoid fungi showed a moderate level of pathogenicity. Fungi with the capacity to stimulate a host defence mechanism could play a role in the establishment of bark beetle populations.

Eutypella canker of maple, caused by the pathogen Eutypella parasitica , has recently been reported for the first time in Europe. A rule-based model of Eutypella parasitica spread risk in Europe is presented. This model incorporates the effects of spatial and temporal variability of multiple variables on pathogen spread and establishment. Model predictions are based on current knowledge of host susceptibility, pathogen reproduction and pathogen transmission, with particular regard to the host species’ distribution and climate suitability. Maps of host species’ distributions and monthly weather conditions were spatially analyzed in a Geographic Information System using the magnitude and direction of each variable’s effect on disease spread. Spread risk predictions were computed for each month and averaged to generate a cumulative risk map. The model was calibrated using data on the natural distribution of Eutypella canker in North America. Extensive areas covering the natural distribution of maples in Europe are at considerable risk from the Eutypella parasitica infection. The most endangered regions are broad areas of the Balkans, the Apennines, France, Central and Eastern Europe and the Caucasus.

DOI 10.1111/j.1365-3059.2010.02262.x.