Infestation by invasive horse-chestnut leaf miner, Cameraria ohridella Deschka & Dimi?, permanently lowers the aesthetic and cultural value of horse-chestnut in Central Europe. In 2017-2018, in urban zones in the cities Parchovany and Str?ske in the eastern part of Slovakia, we assessed the efficacy of systemic applications of TreeAzin^®, an azadirachtin-based product, in controlling Cameraria ohridella in trials in which it was microinjected into tree trunks. A total of 16 Aesculus hippocastanum trees were treated with 3 ml of TreeAzin^® per centimetre diameter at breast height [DBH] and another 17 were treated with 5 ml of the same product per centimetre at DBH, at two study plots. In total, 18 trees were left untreated as controls. In this field experiment, we confirmed significantly higher efficacy in the year of application and the following season. Statistically significant differences were found in the average leaf damage caused by C. ohridella, between treated (4.2-24.5% avg. leaf damage) and untreated trees (75.5-94.3% avg. leaf damage). At the end of the first growing season, 81.2-95.0% of the untreated control tree crowns were defoliated while defoliation of the treated trees was 19.2-31.6%. Both the 3 and 5 ml/cm doses were equally effective in terms of crown and leaf damage; no statistical differences were found in average leaf and crown damage between trees treated with doses of 3 ml/cm and 5 ml/cm. Similar results were also obtained the following year. Leaf damage of treated trees was 40.4-16.8% and of untreated trees 67.9%. Crown damage of treated trees was 49.7-59.8% and of untreated trees 78.8%. During the period of this study, the crowns of all the treated trees were statistically and visually healthier and fuller than those of untreated trees. Thus, the efficacy of this systemic insecticide in controlling C. ohridella in Europe is very promising and provides a suitable treatment for reducing the incidence of this invasive pest.

The emerald ash borer, Agrilus planipennis Fairmaire, 1888 (Coleoptera: Buprestidae), is an invasive pest in Europe and North America, responsible for extensive mortality of ash (Fraxinus spp.). This study reports its first confirmed occurrence in Slovakia and summarises the subsequent delimiting survey. On 25 June 2026, specimens morphologically resembling A. planipennis were collected from a monitoring trap in a park in Streda nad Bodrogom, south-eastern Slovakia. Eighteen adults were identified as A. planipennis by the national quarantine diagnostics laboratory, with confirmation by the European Union Reference Laboratory in France. Initial field inspections revealed characteristic galleries and D-shaped exit holes on ash trees at the detection site, in nearby forests, and along roads within approximately 7 km. By 31 July 2026, 2250 survey points had been recorded, of which 149 showed evidence of A. planipennis, including adults, larvae, galleries, or exit holes. Old galleries together with living larvae indicate that the pest had probably been established in Slovakia for several years before detection in 2026. Symptom assessment was complicated by widespread ash dieback caused by Hymenoscyphus fraxineus (T. Kowalski) Baral, Queloz & Hosoya, 2014.

Gnathotrichus materiarius Fitch, 1858 is a North American ambrosia beetle that has progressively expanded its distribution across Europe during the twentieth and twenty-first centuries. The aim of this study was to assess its occurrence in Slovakia based on multi-year surveys conducted in the Záhorie region and to document its first national record. Monitoring was carried out in 2021 and 2025 in pine-dominated stands using traps baited with pheromone and kairomone attractants. No individuals were detected in 2021. In 2025, two adults of G. materiarius were captured at a single site during the first inspection of traps baited with a (+)-α-pinene and ethanol blend. A large volume of stored pine timber was present in close proximity to the capture site, providing suitable breeding material. The findings suggest a recent introduction or early stage of establishment in Slovakia. Although the species is regarded as a technical pest of coniferous wood, it does not colonize healthy trees and currently poses a limited risk to vital forest stands. Continued targeted monitoring is important to assess its further spread.