Search Results (399)

International timber trade has accelerated the global spread of the invasive red-haired pine bark beetle H. ligniperda, posing persistent challenges to phytosanitary inspection and border biosecurity. Rapid isothermal amplification assays are increasingly deployed in frontline quarantine settings to support timely regulatory decisions. However, their performance under the heterogeneous biological backgrounds typical of traded timber remains insufficiently evaluated, particularly with respect to the practical implications of low-level false-positive signals. We re-evaluated a previously reported isothermal assay for H. ligniperda using conditions that simulate timber transport and routine customs workflows. Fifty non-target arthropod species (predominantly insects), selected from quarantine interception records, were included to represent taxa likely to co-occur in operational contexts. Material from Lema decempunctata consistently generated weak but reproducible amplification signals across replicates. Sanger sequencing excluded contamination, confirming low-level non-target amplification in complex biological matrices. Although the signals were faint, ambiguous results in quarantine settings may trigger shipment detention, confirmatory laboratory testing, or temporary trade restrictions, thereby increasing inspection workload, delaying clearance, and generating avoidable compliance costs. These findings indicate that trade-mediated species assemblages can compromise assay performance beyond expectations derived from conventional taxonomy-based specificity testing. To reduce interpretive uncertainty and associated regulatory burden, we propose a tiered diagnostic workflow combining rapid on-site isothermal screening with specificity-oriented SYBR Green qPCR confirmation. This strategy enhances diagnostic reliability while preserving operational efficiency in applied biosecurity surveillance. Full article

Ips typographus is one of the most destructive bark beetles affecting conifer forests in Europe, where climatic disturbances and the movement of infested wood can rapidly shift populations from endemic levels to severe outbreaks. Early detection through border inspections and forest monitoring is essential to prevent new introductions and limit the spread of established populations. Here, we developed and validated a probe-based TaqMan qPCR assay, targeting the mitochondrial COI barcode region, for the rapid and species-specific detection of I. typographus from both insect material and environmental DNA recovered from frass and exit-hole wood chips. Validation followed EPPO PM7/98(5) guidelines, assessing analytical specificity, sensitivity, repeatability, reproducibility, and inter-laboratory transferability. High analytical specificity was demonstrated against a broad panel of non-target species, and reliable amplification was obtained across different tested matrices. The method showed strong analytical sensitivity, with limits of detection of 0.32 pg/µL for adult-derived DNA and 1.6 pg/µL for artificial frass. Repeatability, reproducibility, and inter-laboratory blind testing further confirmed the diagnostic reliability of the method. This validated qPCR assay provides a rapid and sensitive molecular tool for the early detection of I. typographus, supporting border inspection and phytosanitary diagnostic laboratories in forest biosecurity activities. Full article

Forest pests and diseases are some of the major disturbances affecting the stability of forest ecosystems. Accurate identification of insect-infested trees is therefore crucial for assessing forest health and implementing precision forestry management. This study focuses on stand-level detection of cypress trees (Cupressus funebris Endl.) that were affected by the cypress bark beetle (Phloeosinus aubei Perris), and the framework enables individual tree segmentation, insect-infested tree detection, and stand infestation assessment. Firstly, individual trees were extracted from Light Detection and Ranging (LiDAR) point cloud data using the layer-stacking seed point algorithm. Based on the segmented tree crowns, four vegetation indices (Visible Atmospherically Resistant Index (VARI), Visible-band Difference Vegetation Index (VDVI), Red-Green Index (RGI), and Color Index of Vegetation Extraction (CIVE)) were calculated from Unmanned Aerial Vehicle (UAV) RGB imagery. Insect-infested cypress trees were extracted through threshold segmentation. Through visual interpretation, the optimal vegetation index was determined and the infestation rate at the stand level was calculated. Based on the above framework, a total of 1368 trees were identified in the cypress stand, with a segmentation Precision of 82.51%, a Recall of 80.00%, and an F1-score of 81.24%. RGI achieved the best performance (Precision = 100.00%, Recall = 86.96%, F1-score = 93.02%) and identified 20 infested trees, accounting for 1.46% of the cypress stand. Supplementary experiments further confirm the superiority of the RGI index and the μ ± 2σ thresholding method. These results demonstrate that the proposed method enables rapid detection of the infested cypress trees, effective monitoring of stand health and infestation severity, thereby supporting informed decision-making in pest control and forest management. Full article

Outbreaks of Ips hauseri, a major bark beetle pest in Central Asian Picea schrenkiana forests, have intensified under climate warming and prolonged droughts. However, the reproductive behavior and gallery construction strategies of this species remain poorly understood, limiting our ability to predict its population dynamics. Here, we dissected 219 galleries from infested spruce trees in Hami, Xinjiang, during an outbreak period (2024–2025). We identified 11 distinct gallery morphologies, with harem size (number of females per male) ranging from one to seven. Gallery length was positively correlated with egg production. Reproductive output peaked at a harem size of five, beyond which both gallery dimensions and fecundity declined. Host tree diameter at breast height (DBH) significantly influenced gallery complexity, with larger trees supporting more maternal galleries. Upward-oriented galleries were longer and contained more eggs than downward ones. Intraspecific competition, mediated by gallery adjacency and spatial orientation, strongly affected offspring development. Our results demonstrate that I. hauseri exhibits flexible gallery architecture and reproductive adjustments in response to resource availability and competition—a behavioral plasticity that likely contributes to its outbreak potential. Monitoring gallery morphology and harem size could enhance early detection and population forecasting for this increasingly damaging forest pest. Full article

Southern pine beetle infestations impact ecosystems throughout the southeastern US. Our understanding of hydrologic and biogeochemical impacts on ecosystem structure and function is largely guided by severe outbreaks occurring in the western US. A simulated mortality experiment was conducted on loblolly pine trees via girdling with and without blue-stain fungi inoculation to mimic a small-scale infestation. We measured whole-tree water use, canopy-derived hydrologic and biogeochemical fluxes, soil moisture, and soil respiration for two years following treatments to quantify the impacts of tree mortality on water, carbon, and nitrogen cycles. In the second year of our study, a significant drought occurred, subjecting study trees to a secondary stressor. We found that compared to control trees, girdled trees exhibited reduced water uptake within 6 months and succumbed to mortality within 18 months. We found that by the time trees reached the gray phase of attack, stemflow was 1.7-times lower in girdled trees compared to control trees. Stemflow from girdled trees had up to 7.2-times higher concentrations of ammonium and 2.8-times higher concentrations of total nitrogen. Although stemflow carbon concentrations were indistinguishable between treatments, total carbon flux in stemflow was 2.0-times greater in non-girdled trees (p = 0.030). Finally, even though soil moisture and respiration were not different between treatments, it was not possible to isolate the response of these to mortality versus drought. Our results present the connection between bark beetle outbreaks and the initial impacts on forest biogeochemistry. Changes in the distribution of canopy-derived water inputs, coupled with altered carbon and nitrogen fluxes, serve as hot spots around bark beetle-killed trees. Further research is necessary to understand whether these isolated hot spots may prime the system, alter microbial and invertebrate communities, and lead to changes in decomposition processes at larger scales. Full article

Bark beetle infestations and other natural disturbances have increasingly affected Norway spruce (Picea abies (L.) Karst.) forests across Europe resulting in devaluation and decreased applicability of woody biomass of such trees. The aim of this research was to investigate the extractive content of bark beetle-attacked and dead wind-damaged Norway spruce trees relative to healthy trees, in order to assess their potential for extractives recovery. After harvesting, three discs were dissected along the stem height of each tree, and samples of sapwood, heartwood, knots, and bark were collected. Sequential extraction of the samples was performed using cyclohexane and acetone–water mixture in an accelerated solvent extractor. Lipophilic and hydrophilic extractives were determined gravimetrically, while total phenols and proanthocyanidins were measured by UV–Vis spectrophotometry. Results showed that knotwood contained the highest amounts of hydrophilic extractives and total phenols among investigated tissues. Knots of healthy trees contained the highest amount of hydrophilic extractives (52.4% w w⁻¹), while knots of dead wind-damaged trees contained significantly higher content of total phenols (8.8% w w⁻¹). The total phenols in bark beetle-attacked and healthy trees were 7.1% w w⁻¹ and 7.2% w w⁻¹, respectively. The sapwood and heartwood of dead wind-damaged trees had higher content of hydrophilic extractives (3.4% and 2.3% w w⁻¹) than healthy and bark beetle-attacked trees. Bark from healthy trees contained more total phenols (2.7% w w⁻¹) than bark of bark beetle-attacked trees, while proanthocyanidin contents in bark were comparable among three groups of trees. Our findings revealed that woody biomass from bark beetle-attacked and dead wind-damaged Norway spruce trees contains significant levels of phenolics, indicating high potential for extracting valuable compounds in biorefineries. Full article

Recent intensive research on the cypress bark beetle, Phloeosinus aubei was prompted because of its invasion of Central Europe that caused serious damage to scale-leaved conifer ornamental trees. This dynamic also increased the risk of accidental introduction into North America. In contrast to other historically well-studied bark beetles infesting spruce, pine or broad-leaf trees, intense study of the pheromones and host plant kairomones of bark beetles associated with cupressaceous trees has only begun in the past decade. This highly specialized clade is represented by the genus Phloeosinus. The pressing need for semiochemical-baited traps demands the identification of behavior-modifying compounds. This challenge involves unraveling the various stimuli interacting in the complex communication system to reveal the composition of signal bouquets and the absolute configuration of their components capable of evoking behavior responses. In this short overview we describe the recent research results on host-finding and intraspecific chemical communication of P. aubei, with a short outlook on the species of this genus. Full article

Phloeosinus cupressi Hopkins is an invasive bark beetle that poses a serious threat to Cupressus trees, with potential ecological and economic impacts globally. Native to North America, it has spread to Australia and New Zealand, and climate change may further alter its range. Global trade increases the risk of spread, highlighting the need for predictive modeling in management. In this study, we employed CLIMEX and random forest (RF) models to project the potential global distribution of P. cupressi, incorporating host distribution data for Cupressus. Climatic suitability is concentrated in temperate, subtropical, and Mediterranean zones, including Europe, the U.S., South America, China, Australia, and New Zealand, totaling 10,165.22 × 10⁴ km². Coldest-quarter precipitation (bio19) and annual temperature range (bio7) were identified as the most influential variables. Under RCP6.0 scenarios, suitable areas are projected to expand northward, increasing by ~18%. Regional shifts include contraction in southern Europe and South China, expansion in southern Argentina, southeastern Australia, and coastal New Zealand. Temperature sensitivity is expected to exceed precipitation, enhancing colonization. Due to global Cupressus trade, quarantine and monitoring should focus on high-risk regions. Our findings support early detection, long-term monitoring, and control measures for managing P. cupressi under climate change. Full article

Over the last decade, bark beetle outbreaks have significantly impacted forests in Central Europe, causing extensive loss of forest cover. We evaluated the impact of partial deforestation in three mountain forest catchments in the Jeseníky Mountains, comparing them with the unaffected Červík catchment (Beskydy Mountains) and the severely affected Pekelský stream catchment (Czech-Moravian Highlands). Atmospheric deposition in the catchments was similar, with total element input driven primarily by precipitation volumes rather than ion concentrations. We did not observe the hypothesized increase in DOC and nitrogen export, although nitrate outflow was slightly higher than atmospheric input in two cases. Significant export of calcium, magnesium, and bicarbonates was driven mainly by the geology of the individual catchments. The limited impact of bark beetle outbreaks on DOC dynamics can be attributed to the relatively low proportion of clear-cut areas and the rapid development of ground vegetation on impacted sites. Full article

Forests provide a wide range of ecosystem services, and their importance in supporting human well-being is widely recognized. As goods and benefits from forests are exhaustible, it is therefore essential to gather sound data for their monitoring and management. Remote sensing has gained increasing importance in collecting data on forests, driven by the growing demand for regularly updated environmental data. However, remote sensing modeling of vegetation requires reference data to be collected in the field. This article presents a dataset on tree crown cover—both total and by species—of 528 georeferenced forest plots located in the Eastern Alps, Italy, an area affected by extensive wind and snow damage and subsequent widespread damage caused by bark beetles. The characteristic species of the forest types in the dataset are widely distributed over the Eurasian continent, making the dataset potentially useful to many users and researchers studying forest biodiversity or remote sensing applications to monitor forest cover changes. Data were collected within a still ongoing project aimed at detecting crown cover changes in small forest patches. Full article

Over the last few decades, the frequency of outbreaks of Ips acuminatus has rapidly increased in Latvia. These beetles are commonly associated with blue-stain fungi, which increase tree mortality and decrease the timber quality of affected trees. The aims of this study were: (i) to identify fungi associated with I. acuminatus in Latvia and (ii) to determine the influence of different factors (such as locality, month of beetle capture, beetle sex) on the diversity of associated fungi. From a total of 590 analysed I. acuminatus beetles, 564 resulted in fungal growth and yielded 1247 fungal isolates, representing 36 fungal taxa. Among the fungi isolated, the most common were Akanthomyces muscarius, followed by Penicillium spp., Mucor spp., Cladosporium cladosporioides, Leptographium cucullatum, Ophiostoma minus, and Graphilbum acuminatum. No significant differences in fungal diversity between different locations and between male and female I. acuminatus were observed. However, significant seasonal differences were observed between months in which I. acuminatus beetles were captured and fungal communities isolated from them. More research is needed on the potential of the entomopathogenic fungi isolated in this study for the biological control of I. acuminatus. Also, the pathogenicity of isolated Ophiostomatoid fungi and their ability to cause blue-stain in Pinus sylvestris timber could be further evaluated. Full article

This study investigated the diversity, distribution, and seasonal abundance of ambrosia and pine bark beetles (PBBs) in the Florida Panhandle, focusing on Leon and Gadsden Counties between July 2022 and October 2023. A total of 1657 specimens representing 24 species and 18 genera were captured using baited Lindgren funnel traps. Dominant species varied by location: Xyleborinus saxesenii, Cnestus mutilatus, and Xylosandrus crassiusculus were most abundant in Leon County, while Xylosandrus amputatus prevailed in Gadsden County. Three new county records were documented, including Xylosandrus amputatus and Ambrosiodmus lewisi for Leon County, and Cyclorhipidion distinguendum for Gadsden County. Additionally, three ambrosia beetle species within Platypodinae Euplatypus compositus, Myoplatypus flavicornis, and Euplatypus compositus were recorded across both counties. Seasonal patterns showed pronounced activity peaks during spring and early fall, corresponding with warmer and more humid conditions that support beetle reproduction and host colonization. Climatic analysis revealed that moisture-related variables, particularly relative humidity and precipitation, were the strongest predictors of beetle abundance, reflecting the ecological dependence of ambrosia beetles on fungal symbionts. Greater species richness observed in Leon County suggests that favorable microclimatic and habitat conditions enhance colonization dynamics. The documentation of new county records highlights the influence of shifting trade pathways, human movement, and environmental change on species introductions. The findings underscore the need for continuous surveillance and refined detection systems integrating ethanol-based lures and species-specific pheromones. As climate change continues to modify forest ecosystems, these results provide essential guidance for developing proactive monitoring and management strategies to protect forest health, biodiversity, and timber resources in the Florida Panhandle. Full article

This study aims to develop a novel high-efficiency lure for Tomicus yunnanensis Existing bark beetle attractants often rely on single or fixed-ratio blends of host volatiles and their oxidation products, which struggle to mimic the dynamic release process of insect semiochemicals in nature. To address this, we established a dynamic reaction system based on the catalytic oxidation of α-pinene: ① background control (no catalyst, no heating), ② thermal oxidation system (no catalyst, 40 °C), and ③ catalytic oxidation system (with a titanium–copper modified chabazite-type zeolite catalyst, 40 °C). Behavioral screening using a Y-tube olfactometer revealed a clear gradient in attraction effectiveness among the three systems: catalytic oxidation > thermal oxidation > background control. The products from the catalytic oxidation system at 2 h of reaction showed the highest efficacy, achieving an attraction rate of 61%, which was significantly superior to the α-pinene control. These results indicate that generating dynamically proportioned volatile mixtures through catalytic oxidation can significantly enhance the attraction of T. yunnanensis Further analysis by gas chromatography–mass spectrometry (GC-MS) demonstrated that the catalyst efficiently promoted the directional conversion of α-pinene into key bioactive compounds such as verbenol, myrtenal, and myrtenone, thereby substantially improving behavioral activity. After field validation, this dynamically released attractant could potentially be developed into a real-time field-release lure system for monitoring adult emergence and large-scale trapping, providing a feasible new technological pathway for the precise and sustained management of bark beetle pests. Full article

Understanding how forests recover after severe disturbances is essential for developing effective management strategies that promote stable forest regeneration. Disturbances are particularly significant in transition zones such as treelines, which are highly sensitive to climate change. In the subalpine treeline ecotone of Zao Mountains (northeastern Japan), a severe double-pest infestation devastated the Abies mariesii forest, triggering a treeline retreat of nearly 400 m. Prior to the infestation, the stand density was estimated at 3135 (based on the sum of standing living and dead standing trees and fallen trees detected in the orthomosaics generated for the year 2019). Of these, 3023 were standing trees (of which 2787 were dead). By 2025, the number of standing trees had declined to 2472 (18.2% reduction), a significant development for Abies seedlings, which appeared to establish in decaying fallen logs. In order to evaluate whether this disturbance has permanent or temporary effects, high-resolution unmanned aerial vehicle (UAV) imagery was collected annually over the study area, resulting in six orthomosaics from 2019 to 2025 (2020 data unavailable) for continuous and precise forest monitoring. Analysis of the monitored area revealed that in the 6.9 ha study site, entirely covered by 1.2–1.3 m tall sasa vegetation (Sasa kurilensis), the number of new young trees increased from 60 (2019) to 119 in 2025. These younger trees were mainly located near surviving mature trees. Sasa vegetation did not exert a negative effect on regeneration but instead appeared to function as a strong wind protection, facilitating Abies seedling growth. In conclusion, fallen logs and sasa vegetation appeared to have a positive effect on fir regeneration as suggested by the increasing number of young trees observed over time. The bark beetle outbreak functioned as a forest stand-replacing disturbance, where the subalpine fir forest at the treeline is expected to regenerate naturally within the coming decades. Full article

Forest structure, including trees, deadwood and tree-related microhabitats, is a key determinant of forest biodiversity. Their relative contribution in shaping local (alpha) biodiversity and its variation (beta) between sites remains unclear. We assessed how forest characteristics shape alpha and beta diversity of beetle communities in mixed silver fir–beech forests within the Vallombrosa Nature Reserve (Tuscany, Italy). We sampled 47 circular plots recording single-tree attributes, deadwood volume and decay stage, and the occurrence of tree-related microhabitats. Beetle assemblages were surveyed using window flight traps, yielding over 11,000 individuals belonging to 187 species, 20% of those known from central-southern Italian forests, 58% of which were listed in the Italian Red List of Saproxylic Beetles and 10% of which were threatened. Statistical models (GLMs and GDMs) revealed that alpha diversity was driven by fine-scale features, including tree species composition, microhabitats (cavities, bark, epiphytes) and deadwood diversity. In contrast, beta diversity was shaped by stand structure and inter-stand heterogeneity. Our results highlight the need for conservation strategies that simultaneously maintain tree-level heterogeneity and secure variation across the landscape. Management should therefore combine retention of microhabitats and diverse deadwood substrates with promotion of structurally diverse, mixed stands to sustain beetle diversity at multiple spatial scales. Full article