Search Results (9)

The oak lace bug, Corythucha arcuata (Say, 1832) (Hemiptera: Tingidae), has emerged as an ecologically disruptive invasive pest across Eurasian Quercus forests, severely impairing foliar photosynthetic capacity and overall woodland vitality. By systematically reviewing 111 peer-reviewed studies, this comprehensive synthesis examines the biology, geographic invasion dynamics, ecological adaptability, and management of this species. We trace the spatio-temporal expansion of C. arcuata, highlighting how sub-zero thermal tolerance, climate-driven polyvoltinism, and phenological plasticity facilitate its rapid establishment across diverse climatic zones. Furthermore, we analyze monitoring frameworks—including MODIS satellite remote-sensing and citizen science networks—while acknowledging both their broad-scale utility and limitations in early detection. Given the severe ecotoxicological constraints of conventional synthetic insecticides, we critically evaluate sustainable Integrated Pest Management (IPM) paradigms. Specifically, we investigate biorational formulations (such as spinosad) alongside promising biological control agents, notably the entomopathogenic fungus Beauveria pseudobassiana and the oophagous micro-hymenopteran parasitoid Erythmelus klopomor. Ultimately, long-term silvicultural biosecurity requires a multifaceted IPM approach underpinned by continuous geospatial monitoring and rigorous ecological risk assessments prior to classical biocontrol deployments. Full article

The invasive expansion of the oak lace bug (Corythucha arcuata) represents a major threat to European oak forests, yet the synergistic roles of climatic stressors remain poorly understood. This study investigates the phenological plasticity and adaptive thermoregulation of C. arcuata in the specific microclimatic conditions of the Rășinari Forest District, Romania. Monitoring across an altitudinal gradient (525–825 m) identified a complex voltinism, characterized by a highly successful second generation (G₂) and a restricted third generation (G₃, <12% emergence due to early frosts). By utilizing a physiological time scale (GDD), we demonstrated that G₂ exhibits a 15% temporal compression in development duration compared to G₁. A critical tipping point for host vulnerability was identified at a De Martonne Aridity Index (I_Ar) value of 20. Below this threshold, oak trees underwent a linear physiological decline, with a 74.5% decrease in chlorophyll content and a 58.8% accumulation of soluble sugars. These findings support the metabolic bait hypothesis, where drought-stressed foliage becomes a high-quality nutritional resource. Furthermore, we established a critical thermal threshold of 32 °C, which triggers active vertical migration from the sun-exposed canopy to shaded interiors to avoid heat stress. Our results provide a predictive framework for sustainable forest management, identifying aridity as an injury amplifier that facilitates pest impacts under a warming climate. Full article

This study presents an integrated analysis of climate-driven phenology and infestation dynamics of the invasive oak lace bug (Corythucha arcuata) in foothill oak ecosystems of Rășinari, Romania. Using reconstructed microclimatic data for 2024–2025, systematic field monitoring, degree-day (GDD) modeling, and the De Martonne aridity index, we assessed the combined effects of thermal accumulation and hydric stress on multigenerational development. Results indicate that warm springs and sustained summer temperatures enabled the completion of two full generations (G₁–G₂) in both years, while recurrent late-summer aridity intensified foliar vulnerability and accelerated nymphal development. A third generation (G₃) was initiated but remained incomplete due to declining autumn temperatures and photoperiod constraints. Strong habitat-specific differences were observed: exposed forest-edge stands exhibited the highest damage levels (up to 90%), whereas closed-canopy stands benefited from microclimatic buffering. The combined GDD–aridity framework showed close agreement with observed phenological transitions, providing a robust tool for identifying high-risk infestation periods. Climatic projections for 2026 suggest further advancement of generational timing under continued warming and increasing aridity. These findings highlight the growing climatic suitability of foothill oak ecosystems for C. arcuata and support the development of early-warning systems and adaptive strategies for sustainable oak forest management. Full article

The effect of biopesticide compound spinosad in different concentrations was tested for the first time under laboratory conditions against the rapidly spreading forest pest, oak lace bug (Corythucha arcuata, Say 1832), and its effects were compared with the synthetic pesticide lambda-cyhalothrin. These results revealed a significant effect of spinosad at 2 mL/4 L and 2 mL/2 L water concentrations against C. arcuata nymphs. The mortality rate after 3 days was similar to synthetic insecticide effects and reached 94% and 98%, respectively. Overall, it can be concluded that spinosad is an effective biological method to control oak lace bug; treatments under field conditions should consider the high diversity of other insects in oak forests. Full article

Corythucha arcuata, commonly known as the oak lace bug (OLB), is an insect species originally native to North America that has become an invasive species of significant concern in Europe. This invasive pest has been observed in various European countries, raising concerns about its impact on forest ecosystems. In 2015, it was first documented in Romania, further highlighting the need for research on its bioecology and life cycle. This study investigated the bioecology of the OLB in the southern region of Romania, focusing on its life cycle, development, and population dynamics. The results indicated that the OLB has three generations per year and overwinters in the adult stage in sheltered locations. Temperature significantly influenced the timing of egg hatching, nymph appearance, and adult development, with variation observed between generations. Additionally, a life table analysis provided insights into the population dynamics of the OLB in its natural environment, revealing variation in egg laying trends across generations. This research contributes to a better understanding of the OLB’s bioecology and provides essential data for forest managers developing science-based management strategies to mitigate its impact. By elucidating the life cycle and development patterns of the OLB in southern Romania, this study aids in the development of predictive models and life tables tailored to the region. These findings empower forest managers with the knowledge needed to make informed decisions for effective OLB management, ultimately preserving the health of forest ecosystems. Full article

This scientific paper examines the impact of climate change on the spread and survival of the invasive species Corythucha arcuata Say, 1832 (oak lace bug, or OLB) in Romania. The OLB is native to the Eastern USA and Canada, and in its native habitat, it coexists with minimal impact to the preferred host plant species Quercus. However, in Europe, the OLB in high density causes early defoliation, slowing tree growth. As Quercus spp. is a keystone species, the impact of the OLB on European forests is significant. This paper aims to address several gaps in knowledge about the OLB by presenting findings from a study conducted by the Lucian Blaga University of Sibiu (ULBS) in Romania. The study identified the species’ chronology of spread, ecology, ethology and biology of the species, in addition to foliage classification to determine the extent of attack. The study found a direct link between the temperature and the speed of the generational lifecycle. The findings support the thesis that climate change is enabling the healthy, rapid density growth of OLB, which is a danger to the Quercus spp. Further research is needed in the area of the thermal tolerance of the OLB, and the research conducted by the ULBS represents the first documented research into the thermal constant of the insect. The paper concludes that further research must be in the direction to understand how and where these insects survive during winter to find future management measures and identify chemical or biological methods as solutions to eradicate and stop the expansion of the invasion of the OLB, and the potential consequences for the Quercus sp. Full article

To control a forest pest, it is necessary to understand the biotic and/or abiotic factors that can lead to population regulation. Such knowledge is even more critical if the pest is an invasive alien species. This is the case for Corythucha arcuata (Say, 1832), commonly known as the oak lace bug (OLB), an alien insect species that has invaded oak forests on a large scale, both in Romania and other European countries. In this study, we set out to examine the relationship between adults of this species and meteorological factors, such as air temperature and humidity. The study lasted for two years (2019–2020) and was performed on three plots in Romania, in Ilfov, Giurgiu, and Călărași counties. In the first year, the seasonal dynamics of the OLB populations and the meteorological factors potentially influencing those were studied, whilst in the second year, the dynamics of the diurnal activity of the insect population were examined. We found that Corythucha arcuata experienced two population peaks—in July and August—and a diurnal population dynamic that reached a maximum at midday. Data analysis indicated that, for most of the time, the adult activity was influenced by both temperature and humidity. In addition, the population dynamics were not constant over the course of the day, preferring relatively high temperatures and low humidity but not exceeding certain thresholds of thermal discomfort. Full article

In addition to the classic biotic and abiotic factors that have disrupted the health of forests throughout history, lately, the balance of forest ecosystems has been disturbed by different phenomena such as climate change, pollution, and, especially, biological invasions of invasive alien species. One of the alien species that has invaded Europe relatively quickly is an insect species of North American origin, the oak lace bug (Corythucha arcuata Say, 1832 Heteroptera: Tingidae). In the context of the rapid spread of infestations and the severity of attacks on oak trees in infested forests, this paper aims to assess measures to manage this species in the future. Namely, the effect of aerial chemical treatments on oak lace bug has been investigated with two influencing factors: the mode of insecticide action (contact and systemic) and the treatment volume (low volume and ultra-low volume). The experiment was conducted in two forests over a total area of 350 hectares. The results show that the reduction of the nymph population varied from 91% to 96%. However, the residual population was sufficient to allow differentiated re-infestations over time, more quickly after contact insecticide sprays (22 days after treatment) and slowly after systemic insecticide sprays (more than a month after treatment). This re-infestation time difference had implications on attack intensity as well, with stronger leaf discoloration observed in areas treated with a contact insecticide compared with those treated with a systemic insecticide. Full article

The oak lace bug (OLB), Corythucha arcuata (Hemiptera: Tingidae), was first identified as an invasive pest in Europe in northern Italy in 2000 and since then it has spread rapidly, attacking large forested areas in European countries. The OLB is a cell sap-sucking insect that is native to North America, with Quercus spp. as its main host. Its rapid expansion, successful establishment in invaded countries, and observations of more damage to hosts compared to native areas are most likely due to a lack of natural enemies, pathogens and competitors. In its native area, various natural enemies of OLBs have been identified; however, little is known about the occurrence and impact of OLB pathogens. None of the pathogenic fungi found on OLBs in natural conditions have been identified until now. In this study, we provide evidence of four entomopathogenic fungi that are naturally occurring on invasive OLBs found in infested pedunculate oak forests in eastern Croatia. On the basis of their morphology and multilocus molecular phylogeny, the fungi were identified as Beauveria pseudobassiana, Lecanicillium pissodis, Akanthomyces attenuatus and Samsoniella alboaurantium. The sequences generated for this study are available from GenBank under the accession numbers MT004817-MT004820, MT004833-MT004835, MT027501-MT27510, and MT001936-MT0011943. These pathogenic species could facilitate biological control strategies against OLBs. Full article