Agrilus planipennis is a devastating invasive pest of ash trees. This wood-boring insect native to Asia and established in European Russia about 20 years ago poses a serious threat to ash trees all over Europe. In 2019 we first detected Agrilus planipennis in Ukraine. More than 20 larvae have been collected from under the bark of Fraxinus pennsylvanica trees on 5 September 2019 in Markivka District of Luhansk Region. Coordinates of the localities of collection: 49.614991 N, 39.559743 E; 49.614160 N, 39.572402 E and 49.597043 N, 39.561811 E. The photos of damaged trees with larval galleries, exit holes and larvae are presented. There is no doubt that the pest is established in Ukraine. This fact is important for development of quarantine protocols to prevent or at least slow the further spread of this invasive pest in Europe.

Emerald ash borer (EAB), Agrilus planipennis, an invasive phloem-boring beetle, was detected in the Luhansk Region of Ukraine in 2019. In the following years, it expanded to a large part of the Kharkiv region and the parks of Kyiv. Previous research proved that the climate in Luhansk and neighboring regions is favorable for EAB, and the lack of a host plant (Fraxinus sp.) cannot prevent pest expansion in Ukraine. Considering the necessity to detect inhabited trees in time, our current research aimed to identify the most attractive EAB forest subcompartments considering forest site conditions and stand structure. MaxEnt model predicted the potential distribution of EAB with high accuracy (AUC = 0.842). The most significant five variables provided 82.9% to the model, particularly «Age of trees, years», «Area of forest subcompartment, ha», «Mean height of trees, m», «The proportion of Fraxinus excelsior in the stand composition, %», and «Hygrotope index (humidity level), point». A very high probability of EAB expansion in the Luhansk region (>90 %) is predicted at 20 % of the forest area with Fraxinus sp. in the stand composition. The probability of EAB spread above 30% is predicted for 75 % of such area. To improve the forecasting accuracy, it could be necessary to consider the data on road localization along which the pest can spread passively, as well as dominate wind speed.

Emerald ash borer (EAB), Agrilus planipennis, is an invasive beetle of East Asian origin that in North America and Russia killed millions of ash trees (Fraxinus spp.). In September 2020, EAB was de-tected in Saint Petersburg, becoming resonant event for the metropolitan city. The aim of the present study was to investigate occurrence and ecology of EAB in Saint Petersburg. The presence of two distinct enclave populations of EAB was revealed, each of which has (very likely) been established by separate events of “hitchhiking” transport vehicles. Following the invasion, further spread of EAB in Saint Petersburg was slow and locally restricted, main explanation for which is climatic factor. Due to spread by “hitchhiking”, the possibility of EAB further long-distance ge-ographic spread of EAB in the Baltic Sea region (EU) is high, and not only by ground transport (120–130 km distance from EU borders), but also by ferries transporting cars (traditional means of transportation across the Baltic Sea). In certain cases, development of EAB on F. excelsior was more successful (stem portion colonized, larval densities, number of galleries, exit holes, viable larvae, emerged beetles) than in (adjacent) F. pennsylvanica trees. Observed relatively high EAB-sensitivity of F. excelsior therefore questions the efficacy and benefits of the currently ongoing selection and breeding projects against ash dieback (ADB), caused by Hymenoscyphus fraxineus. Inventory, mapping, and monitoring of surviving F. excelsior trees in areas infested by both ADB and EAB are necessary to acquire genetic resource for work on strategic long-term restoration of F. excelsior, tackling (inevitable) invasion of EAB to the EU.

Field observations of external wounds associated with two common tree injection methods compared open (plug-less) and sealed (plug) systems in green ash (Fraxinus pennsylvanica Marshall) trees . A wound from any cause within 1.37 meters above the ground was common with 28.8% of all trees. The open system had statistically fewer (p<0.001) trees with at least one wound (11.6% of trees) than the sealed system (47.4% of trees). The open system had fewer (P<0.001) wounds (0.17, 0.04 SE) per tree and a smaller (P<0.001) total wound area (25.5 cm2, 8.7 SE) per tree, compared to the sealed system wounds (1.14, 0.13 SE) per tree and the total wound area (99.7 cm2, 16.2 SE) per tree. The incidence of a tree with a wound(s) within 1.37 m above the ground was 7.2 times more likely with trees treated though the sealed system. Wounds in the sealed system were observed to appear to have a high rate of improper application of plugs, which was associated in 77% of the cases to explain the wounds. Implications of study results are further provided to best protect ash trees, while at the same time reducing the incidence external wounding on ash trees.