Invasion of the oak lace bug Corythucha arcuata (Say.) in Romania: a first extended reporting. Ann. For. Res. 61(2): 161-170.

Abstract. Scolytids constitute an insect group of forest ecosystems that is very important both ecologically and economically, and which has been well studied in most European countries. However, new species are found quite often, especially in regions searched less intensively to date. In this paper three species of scolytid fauna not previously known in Romania are reported for the first time: Trypodendron laeve, Xylosandrus germanus and Hylastes linearis. Individuals of all three species were collected in the north-eastern part of Romania. T. laeve was found only in natural coniferous forests, at altitudes above 1230 m and in association with T. lineatum, but in much lower abundance. The Asian species X. germanus was found in an old beech forest situated at a much higher altitude (760-900 m) than observed in western and central Europe. The third species, H. linearis, was captured as a single specimen in a plateau region (375 m).

The native range of each species, the first report and the present distribution in Europe and in Romania are discussed. The new records suggest that all the analysed species have established populations in our country and a more widespread distribution than that previously known. Some of them attain sometimes locally or zonally high population levels and are regarded as important pests. For the most species, new observations are necessary, both concerning their presence in the areas where they were not found so far, but also to assess the impact of insect populations on their hosts and on the recipient biocoenoses. A particular attention should be paid to the species H. axyridis, whose swarms invade the houses of the people during the autumn and could cause annoyance and possibly allergy. Citizen participation in observing and reporting of these new "guests" is encouraged.

Ips duplicatus (Sahlberg, 1836), Xylosandrus germanus (Blandford, 1894) and Neoclytus acuminatus (Fabricius, 1775) are invasive species reported in Romania, but their current distribution is poorly known. The research aim was to provide new information on this issue. A survey was conducted over the period 2015–2017 in 82 locations, using flight-interception traps and bottle traps, baited with different attractants. Data obtained in our other unpublished studies were also taken into account. A total of 35,136 I. duplicatus beetles were collected in 30 survey locations. The highest captures were in the log yards of some factories processing logs of Norway spruce (Picea abies (L.) H. Karst.). Considering all known records so far, most of these are in the eastern part of Romania, where an outbreak took place during the years 2005–2014, mainly in spruce stands growing outside their natural range. During the survey, 4259 specimens of X. germanus were collected in 35 locations, but in our other studies the species was found in 13 additional places. It was collected at altitudes of 18–1200 m, and the largest catches were from beech stands, growing at 450–950 m. N. acuminatus was found in only six locations, in the western and southern parts of the country, at low altitudes, in tree stands composed of Fraxinus excelsior L., Quercus spp. and other broadleaf species, as well as in broadleaf log yards. The results suggest that I. duplicatus is established in most parts of the Norway spruce’s range, X. germanus is still spreading in the country, with some areas having quite high populations, while N. acuminatus is present only in the warmest regions of the country.

Biological invasions in forest ecosystems are recognised as a global scale challenge. However, our current knowledge of invasive alien forest insect species (IAFIS) in Romania is still lacking and rather insufficient to support clear policies. The aim of this study is to contribute to a better understanding of the distribution of IAFIS in the Muntenia and Dobrogea provinces of Romania. For this purpose, direct observations and insect collections were made two consecutive years, in 76 locations. Of these, 67 sampling locations forming a long field observation route were visited only once, and nine sampling locations were fixed monitoring points with primed traps used in first year for regular collection of insects at 1-2-week intervals. Seventeen non-native forest insect species from five orders and 11 families were detected: Aproceros leucopoda, Cameraria ohridella, Corythucha arcuata, Cydalima perspectalis, Dasineura gleditchiae, Eopineus strobus, Euura tibialis, Gilletteella cooleyi, Hyphantria cunea, Ips duplicatus, Macrosaccus robiniella, Neoclytus acuminatus, Obolodiplosis robiniae, Parectopa robiniella, Phyllonorycter issikii, Prociphilus fraxinifolii and Xylosandrus germanus.  Eleven IAFIS species originate from North America, four from Asia and two from Europe. All detected species were previously reported from Romania, but eight species had not been recorded in these two provinces. Seven species live on native tree species, while 10 thrive on exotic trees or shrubs. The highest number of IAFIS was recorded in urban areas. Except for E. tibialis, all found IAFIS have a significant ecological or economic impact across invaded habitats. The risks posed by biological invasions need more thorough consideration that deserves greater attention and scientific support.

All countries, including Romania, are increasingly affected by biological invasions. As a result, the need to study this phenomenon has become increasingly apparent. The aim of the present paper is to report the presence of five new forest insect species recently found in the northeastern part of Romania and data on their distribution in the region. The detection of the insect presence was done using identification sheets based on their morphological aspect and the characteristics of the attack, following a protocol that would make investigating work more efficient. Of the alien species found, five are new to the area of Moldova and are discussed in the present paper. They are: Dasineura gleditchiae (Osten Sacken, 1866), Appendiseta robiniae (Gillette, 1907), Prociphilus fraxinifolii (Riley, 1879), Corythucha arcuata (Say, 1832) and Nematus (Pteronidea) tibialis Newman, 1837. The first three are also new species for Romania's fauna. For each species, data are presented concerning the syste matic classification and the host species, where and when it was found, the type of crop and the age of the infested trees, the frequency and severity of the attack, the region from which it originated, where it was reported for the first time in Europe and in the neighboring countries of Romania, and to what extent it is a potentially harmful pest. All species presented in the work come from North America and four of them have been found on host species from their native area (black locust, honey locust and green ash), while the fifth is mainly found on native species of the genus Quercus. Except for C. arcuata, all of them have been present in Romania, including the studied region, for at least a decade or even longer, but have gone unnoticed in the absence of research like those presented in this paper. Currently they are present almost everywhere where their host species are grown. Apart from N. tibialis, the insect species reported have the potential to become important pests of their hosts. As a result, it is necessary to study their biology and ecology in the ecosystems in which they entered in Romania.

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For non-native tree species with an origin outside of Europe a detailed compilation of enemy species including the severity of their attack is lacking up to now. We collected information on native and non-native species attacking non-native trees, i.e. type, extent and time of first observation of damage for 23 important non-native trees in 27 European countries. Our database includes about 2300 synthesised attack records (synthesised per biotic threat, tree and country) from over 800 species. Insects (49%) and fungi (45%) are the main observed biotic threats, but also arachnids, bacteria including phytoplasmas, mammals, nematodes, plants and viruses have been recorded. This information will be valuable to identify patterns and drivers of attacks, and trees with a lower current health risk to be considered for planting. In addition, our database will provide a baseline to which future impacts on non-native tree species could be compared with and thus will allow to analyse temporal trends of impacts.