First Record of the Invasive Scale Insect, Pulvinaria hydrangeae Steinweden, 1946 (Hemiptera: Coccomorpha: Coccidae) in Romania

SIMPLE SUMMARY: Invasive insect species are organisms that cause significant damage to native flora and fauna after their introduction into a new geographic area, through human activity. Both the early detection and fast reporting of a new species in a country are essential. These enhance public knowledge and enable authorities to take measures to limit their spread and evaluate the potential risks that they pose. In this paper, we report on the apparition of a scale insect to Romanian fauna. This insect is native to Asia and has caused significant damage to the ornamental plants, shrubs and trees of Europe after its introduction to the continent. In Romania, this species was found on two native tree species: linden and sycamore. We believe that the species was brought to Romania via infested plants from abroad. In this paper, we summarize the worldwide distribution of this species and report on its hosts to highlight the pathways of infestation and to assess the potential risk that it poses to native flora. Moreover, we provide some morphological features of the species to aid in its identification in the field and in the laboratory. ABSTRACT: Over the last few decades, globalization and global trade have increased the risk of the vehiculation of invasive organisms, which has had multiple negative effects, both economic and ecological. Through this study, we aimed to produce a report on the first record of the invasive scale insect Pulvinaria hydrangeae (Stein. 1946) in Brașov County in central Romania. It was found on two native tree species: sycamore (Acer pseudoplatanus) and linden (Tilia cordata). In this paper, we (i) highlight the list of possible hosts, (ii) provide a general outlook on infestations and (iii) review the control options for this particular pest. Because early detection and quick reporting are the most important actions in the successful management of invasive species, in general, we also provide a synthetic morphological description of the adult female specimens and ovisacs. Due to natural occurrence, our findings highlight the potential risks posed by the infestation of this insect to native tree species belonging to the Acer and Tilia genera. Because of the temperate climate in Romania and the fact that females are wingless, the new infestations will probably be made through the vehiculation of infested plants, rather than through natural spreading. However, because of global warming, the chances of this species surviving during the winter are likely to increase, making northern expansion of the cottony hydrangea scale feasible.