Wood-boring Insects Research Articles

Cossula duplex Dyar & Schaus, 1937 (Lepidoptera: Cossidae): a wood borer of Caryocar brasiliense Cambess in the Brazilian Savanna

ABSTRACT Over the past years, there have been several observations of pequi trees (Caryocar brasiliense Cambess.) being infested with a large wood boring insect that compromises the structural integrity and health of the trees. However, the economic losses caused by this damage were attributed to an unidentified cossid. The present study aims to identify the species causing this damage in the Brazilian Savanna by monitoring trees exhibiting damage with the goal of capturing emerging adults. In total, 12 adults were collected, preserved and identified by comparison of the genitalia. All specimens (male and female) were identified as Cossula duplex Dyar & Schaus, 1937. This species was previously not recorded from Brazilian Savannah regions and is reported for the first time from the Brazilian states of Minas Gerais and Goias. Further studies are needed to evaluate the association of this species to the mortality of C. brasiliense, an economically important and endangered species of the Brazilian Savannah.

A Method for Classifying Wood-Boring Insects for Pest Control Based on Deep Learning Using Boring Vibration Signals with Environment Noise

Wood-boring pests are difficult to monitor due to their concealed lifestyle. To effectively control these wood-boring pests, it is first necessary to efficiently and accurately detect their presence and identify their species, which requires addressing the limitations of traditional monitoring methods. This paper proposes a deep learning-based model called BorerNet, which incorporates an attention mechanism to accurately identify wood-boring pests using the limited vibration signals generated by feeding larvae. Acoustic sensors can be used to collect boring vibration signals from the larvae of the emerald ash borer (EAB), Agrilus planipennis Fairmaire, 1888 (Coleoptera: Buprestidae), and the small carpenter moth (SCM), Streltzoviella insularis Staudinger, 1892 (Lepidoptera: Cossidae). After preprocessing steps such as clipping and segmentation, Mel-frequency cepstral coefficients (MFCCs) are extracted as inputs for the BorerNet model, with noisy signals from real environments used as the test set. BorerNet learns from the input features and outputs identification results. The research findings demonstrate that BorerNet achieves an identification accuracy of 96.67% and exhibits strong robustness and generalization capabilities. Compared to traditional methods, this approach offers significant advantages in terms of automation, recognition efficiency, and cost-effectiveness. It enables the early detection and treatment of pest infestations and allows for the development of targeted control strategies for different pests. This introduces innovative technology into the field of tree health monitoring, enhancing the ability to detect wood-boring pests early and making a substantial contribution to forestry-related research and practical applications.

Detection of Active Infestation by Wood-Boring Insects via Acoustic Emission using the IADS (Insect Activity Detection System)

The preservation of wooden art and cultural artifacts is severely threatened by the infestation of wood-boring insects. Distinguishing between active and inactive infestations in practice poses a significant challenge, often leading to unnecessary treatments or delayed actions. This article focuses on the examination of the Insect Activity Detection System (IADS), an innovative AE measurement device for the detection of feeding noises of wood-boring larvae. Starting with an overview of the theoretical framework, the results of practical experiments are shown. Finally, we will present some possible applications of IADS in the conservation of art and cultural heritage.

Fusarium species associated with Euwallacea xanthopus in South Africa, including two novel species

ABSTRACT Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) are small wood-boring insects that live in an obligate symbiosis with fungi, which serve as their primary food source. Beetles residing in the genus Euwallacea have evolved a unique association with a clade of Fusarium that falls within the aptly named Ambrosia Fusarium Clade (AFC). The discovery of the invasive polyphagous shot hole borer, E. fornicatus, in South Africa, has heightened awareness of ambrosia beetles and their symbionts in the country. In this study, we investigated the Fusarium symbionts of three species of Euwallacea in South Africa, with a specific focus on those associated with E. xanthopus. Isolations of Fusarium strains from both living and dissected beetles yielded nearly 100 isolates. Using multigene phylogenetic analyses, these isolates were identified as six different Fusarium species. Fusarium hypothenemi and F. euwallaceae have previously been reported from South Africa. Fusarium pseudensiforme and Fusarium AF-6 are new records for the country. The remaining two species are new to science and are described here as F. rufum sp. nov. and F. floriferum sp. nov. Targeted fungal isolation from specific beetle body parts revealed that the AFC species collected were typically associated with the dissected beetle heads and helped us identify the likely nutritional symbiont of E. xanthopus. This study highlights the understudied diversity of fungal associates of ambrosia beetles present in South Africa.

Tradeoffs in longleaf pine conservation: Prescribed fire management increases exotic ambrosia beetle abundance in pine-hardwood forests

Exotic woodboring insects, including some ambrosia beetles (Coleoptera: Curculionidae, Scolytinae, and Platypodidae), are threatening native forests worldwide. Longleaf pine (Pinus palustris Mill.) forest is an endangered habitat in the southeastern United States. One of the most important actions necessary for its conservation is prescribed fire, which maintains its savanna structure. However, prescribed fire is a forest disturbance, possibly creating new niches for colonization by exotic insects. The interaction between prescribed fire and exotic ambrosia species is understudied, especially in highly fire-dependent ecosystems. We carried out a two-year experiment in mixed longleaf pine forests in Alabama, USA. We compared ambrosia beetle communities in recently burned and unburned sites. We found that more than 66 % of total individuals in longleaf pine forests, regardless of fire management, were exotic species. Moreover, exotic ambrosia beetles were more abundant in burned stands, whereas native species showed no difference between burned or unburned stands. Fire management influenced stand species composition for native but not exotic ambrosia beetles. These results indicate that trade-offs exist in managing fire-dependent ecosystems, especially in the Anthropocene era, which is associated with rampant biological invasions. Fire is important to preserve the longleaf pine habitat, but it simultaneously acts as a disturbance, increasing the population density of those exotic species taking advantage of the presence of stressed or dying trees.

An additional record of Ibalia Latreille, 1802 (Hymenoptera: Cynipoidea: Ibaliidae) from Korea with a revised key to Korean species

The Ibaliidae family, a small group within the Cynipoidea (Hymenoptera: Apocrita), includes fewer than 20 known species from the Northern Hemisphere. Ibaliids are parasitoids of wood-boring insect larvae and some are utilized as biological control agents for siricid woodwasps. In Korea, four species from two subgenera of Ibalia Thomson are recorded, with only one species, Ibalia (Ibalia) leucospoides leucospoides (Hochenwarth), previously documented. Recent taxonomic studies on Korean Ibaliidae have revealed that I. (I.) aprilina Kerrich, previously known only from Japan, is now recorded in Korea for the first time. This paper re-describes I. (I.) aprilina Kerrich with detailed illustrations of its diagnostic features and provides an updated key to the five Korean species of the genus Ibalia, including I. (I.) aprilina.

Non-Invasive Assessment of the Internal Condition of Urban Trees Infested by Two Cerambycid Beetles, Aromia bungii and Massicus raddei, Using Sonic Tomography

The introduction of wood-boring insects to non-native areas can pose a significant threat to global forest ecosystems. Aromia bungii and Massicus raddei, native to Asia including Korea but potentially important in urban forestry worldwide, are severe trunk borers that have recently infested host trees in urban landscapes of Korea. The signs of external injury can help identify cerambycid-infested trees. However, assessing the internal condition of trees without causing damage is challenging, which hinders the management of infested trees that are still alive. This study evaluated the potential use of sonic tomography to assess injury characteristics in the woody parts of trees, such as Prunus × yedoensis and Quercus palustris infested by A. bungii and M. raddei, respectively. Among the 45 investigated trees, the number of holes on external parts was recorded by visual examination. Sonic tomography images revealed decayed areas, allowing for a comparison of internal damage between infested and non-infested trees. The internal status of trees infested by the two cerambycid beetles differed from that of healthy trees. While some healthy trees exhibited minimal internal damage, those that were not infested by beetles showed decayed areas, potentially caused by non-biological factors such as frozen cracks. In conclusion, sonic tomography equipment can potentially be used for non-invasive assessment of internal injuries caused by wood-boring insects in urban trees.

PdPLR1 effectively enhances resistance of Populus deltoides ‘shalinyang’ to Anoplophora glabripennis by positive regulation of lignan synthesis

Anoplophora glabripennis (ALB) is one of the most devastating wood boring insects of poplars. Populus deltoides ‘Shalinyang (PdS), a new poplar variety, shows strong resistance to ALB infestation. However, the molecular mechanism of insect resistance in PdS is unclear. Here, we found that lignan content was much higher in PdS phloem after ALB infestation than in healthy trees, and that adding lignan to artificial diet significantly reduced: larval weight; digestive enzyme activity (cellulase [CL], polygalacturonase [PG]); detoxification enzyme activity (carboxylesterase [CarE], glutathione S-transferase [GSH-ST]); and defense enzyme activity (Catalase [CAT]). We further identified the lignan biosynthesis-related PdPLR1 gene (Pinoresinol-lariciresinol reductase, PLR) based on transcriptome analysis, and it was significantly up-regulated in the PdS phloem attacked by ALB. Overexpression of PdPLR1 in Arabidopsis increased th lignan content. In contrast, silencing PdPLR1 in PdS significantly decreased expression levels of PdPLR1 and lignan content by 82.45% and 56.85%. However, silencing PdPLR1 increased the number of adults ovipositions and eggs hatching. The activity of CL, PG, CarE, GSH-ST and CAT and the biomass of larvae fed on phloem of PdS with silenced PdPLR1 were significantly higher than in the control. Taken together, up regulation of PdPLR1 enhanced PdS resistance to ALB by regulating lignan synthesis. Our findings provide in-depth insights into the molecular mechanisms of PdS-ALB interactions, which lay the foundation for understanding of defense in poplars to pest infection.

Virulence and Pathological Characteristics of a New Metarhizium anisopliae Strain against Asian Long-Horn Beetle Anoplophora glabripennis Larvae

The Asian long-horn beetle (ALB) is a serious wood-boring insect. Continuous isolation of different fungal strains is vital for using fungi for the control of ALB. The virulence and pathological characteristics of a new Metarhizium anisopliae strain DES3 isolated from the desert afforestation stands against the larvae of ALB were assessed in this study. The corrected mortality reached 100% at the conidial concentration of 109 and 108 conidia/mL, and 91.11 ± 4.44% at 107 conidia/mL. Similarly, the LC/LT showed high virulence as well. Meanwhile, the virulence of a commercial M. anisopliae strain against the ALB larvae was evaluated. The corrected mortality was only 33.33% at 109 conidia/mL, and less than 10% at 108 conidia/mL. The pathological characteristics after infection by the M. anisopliae strain DES3 were evident, mainly embodied in the rupture of the adipose tissue, muscle tissue, and midgut. But there was no obvious change after infection by the commercial M. anisopliae strain. In conclusion, these results establish that the M. anisopliae strain DES3 has high virulence in a dosage-dependent manner against ALB larvae, indicating the potential of fungal strain DES3 to be developed as biopesticide for biocontrol of A. glabripennis.

Predicted range expansion of Prostephanus truncatus (Coleoptera: Bostrichidae) under projected climate change scenarios.

The larger grain borer (Prostephanus truncatus [Horn] [Coleoptera: Bostrichidae]) is a wood-boring insect native to Central America and adapted to stored maize and cassava. It was accidentally introduced to Tanzania and became a pest across central Africa. Unlike many grain pests, P. truncatus populations can establish and move within forests. Consequently, novel infestations can occur without human influence. The objectives of our study were to (i) develop an updated current suitability projection for P. truncatus, (ii) assess its potential future distribution under different climate change scenarios, and (iii) identify climate variables that best inform the model. We used WALLACE and MaxEnt to predict potential global distribution by incorporating bioclimatic variables and occurrence records. Future models were projected for 2050 and 2070 with Representative Concentration Pathways (RCPs) 2.6 (low change) and 8.5 (high change). Distribution was most limited by high precipitation and cold temperatures. Globally, highly suitable areas (> 75%) primarily occurred along coastal and equatorial regions with novel areas in northern South America, India, southeastern Asia, Indonesia, and the Philippines, totaling 7% under current conditions. Highly suitable areas at RCPs 2.6 and 8.5 are estimated to increase to 12% and 15%, respectively, by 2050 and increase to 19% in 2070 under RCP 8.5. Centroids of highly suitable areas show distribution centers moving more inshore and away from the equator. Notably, the result is a range expansion, not a shift. Results can be used to decrease biosecurity risks through more spatially explicit and timely surveillance programs for targeting the exclusion of this pest.

Ecological Niche Studies on Hylurgus ligniperda and Its Co-Host Stem-Boring Insects

Hylurgus ligniperda (Fabricius), a significant quarantine pest, has recently invaded China, marking a new spread outside its known global distribution. This study aims to clarify the invasion and colonization mechanisms of H. ligniperda in Shandong Province, a primary colonization site. This study employed sampling surveys and analysis of damaged wood, discovering that the wood-boring insects sharing the same host as H. ligniperda mainly include Cryphalus sp., Arhopalus rusticus, and Shirahoshizo sp. Through ecological niche theory, the study analyzed the ecological niche relationships between H. ligniperda and these three wood-boring insects, from the perspectives of temporal and spatial resource utilization. The results reveal that these insects could cause damage to P. thunbergii trees at different health levels, with H. ligniperda being the most destructive. The ecological niches of insect populations varied significantly by tree vigor and height. Cryphalus sp. occupied the entire trunk, whereas A. rusticus and Shirahoshizo sp. were concentrated in the lower-middle trunk and the root section up to a depth of 1 m. Notably, H. ligniperda primarily targeted tree roots. Due to the differences in spatial distribution, there was no intense competition between H. ligniperda and other wood-boring insects. With a decline in the health of the host tree, Cryphalus sp. ascended the trunk, whereas H. ligniperda spread deeper into the roots and A. rusticus moved towards the base of the trunk and the top of the roots. Shirahoshizo sp. showed a less defined distribution pattern. Therefore, H. ligniperda was more dominant during the later stage of damage. The position occupied by each insect on the trunk was relatively stable, and the ecological niche overlap value with H. ligniperda was low in terms of temporal resources. Therefore, H. ligniperda and other stem-boring pests exhibit coexisting populations mainly through the allocation and utilization of spatial resources, eventually promoting the successful colonization of H. ligniperda.

A Time-Frequency Domain Mixed Attention-Based Approach for Classifying Wood-Boring Insect Feeding Vibration Signals Using a Deep Learning Model.

Wood borers, such as the emerald ash borer and holcocerus insularis staudinger, pose a significant threat to forest ecosystems, causing damage to trees and impacting biodiversity. This paper proposes a neural network for detecting and classifying wood borers based on their feeding vibration signals. We utilize piezoelectric ceramic sensors to collect drilling vibration signals and introduce a novel convolutional neural network (CNN) architecture named Residual Mixed Domain Attention Module Network (RMAMNet).The RMAMNet employs both channel-domain attention and time-domain attention mechanisms to enhance the network's capability to learn meaningful features. The proposed system outperforms established networks, such as ResNet and VGG, achieving a recognition accuracy of 95.34% and an F1 score of 0.95. Our findings demonstrate that RMAMNet significantly improves the accuracy of wood borer classification, indicating its potential for effective pest monitoring and classification tasks. This study provides a new perspective and technical support for the automatic detection, classification, and early warning of wood-boring pests in forestry.

Optimal allocation of resources among general and species-specific tools for plant pest biosecurity surveillance.

This paper proposes a surveillance model for plant pests that can optimally allocate resources among survey tools with varying properties. While some survey tools are highly specific for the detection of a single pest species, others are more generalized. There is considerable variation in the cost and sensitivity of these tools, but there are no guidelines or frameworks for identifying which tools are most cost-effective when used in surveillance programs that target the detection of newly invaded populations. To address this gap, we applied our model to design a trapping surveillance program in New Zealand for bark- and wood-boring insects, some of the most serious forest pests worldwide. Our findings show that exclusively utilizing generalized traps (GTs) proves to be highly cost-effective across a wide range of scenarios, particularly when they are capable of capturing all pest species. Implementing surveillance programs that only employ specialized traps (ST) is cost-effective only when these traps can detect highly damaging pests. However, even in such cases, they significantly lag in cost-effectiveness compared to GT-only programs due to their restricted coverage. When both GTs and STs are used in an integrated surveillance program, the total expected cost (TEC) generally diminishes when compared to programs relying on a single type of trap. However, this relative reduction in TEC is only marginally larger than that achieved with GT-only programs, as long as highly damaging species can be detected by GTs. The proportion of STs among the optimal required traps fluctuates based on several factors, including the relative pricing of GTs and STs, pest arrival rates, potential damage, and, more prominently, the coverage capacity of GTs. Our analysis suggests that deploying GTs extensively across landscapes appears to be more cost-effective in areas with either very high or very low levels of relative risk density, potential damage, and arrival rate. Finally, STs are less likely to be required when the pests that are detected by those tools have a higher likelihood of successful eradication because delaying detection becomes less costly for these species.

Assessing the Prevalence of Wood-Boring Insects in Green Spaces of Herat City, Afghanistan

Assessing the Prevalence of Wood-Boring Insects in Green Spaces of Herat City, Afghanistan

Chemical Composition and FTIR Analysis of Acetylated Turkey Oak and Pannonia Poplar Wood

In this research, acetylation was applied under industrial conditions to improve the properties of Turkey oak and Pannonia poplar wood. Both species are potential “climate winners” in Hungary, yet they are currently underused due their low durability and poor dimensional stability. The acetylation modification process may be a suitable method to improve their properties. In order to verify the effectiveness of the process, comparative chemical analyses (cellulose, hemicelluloses, lignin, extractives, ash, buffering capacity, and pH) of the untreated and acetylated heartwood and sapwood were carried out for both species for the first time. Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy was also used to support the evaluation of the chemical analyses. The weight percent gain was 11.54% for poplar and 0.94% for Turkey oak, indicating poor treatment efficiency for the latter. The cellulose, hemicelluloses, and lignin contents changed significantly in poplar, with the highest change (+81%) induced by acetylating the hemicelluloses. Only the alpha-cellulose content decreased significantly in Turkey oak, presumably due to the degradation of the non-crystalline part of the cellulose. Acetylation may improve the resistance of Pannonia poplar against moisture, weather, decay, and wood-boring insects, but the process parameters need to be optimized in order to prevent degradation and discoloration in poplar. Turkey oak was found to be less suitable for acetylation due to its low permeability and tendency to crack.

Early Detection of Potential Infestation by Capnodis tenebrionis (L.) (Coleoptera: Buprestidae), in Stone and Pome Fruit Orchards, Using Multispectral Data from a UAV

Wood-boring insect pests pose a significant threat to orchards, potentially leading to tree mortality. In the initial stages of infestation, no visible symptoms are apparent, but as infestations progress, rapid and widespread symptoms emerge, resulting in accelerated tree decline. Therefore, the timely detection of early wood-boring insect symptoms is critical for effective pest control, necessitating advanced methods such as remote sensing. In this study, remote sensing is utilized to identify the early symptoms of peach flatheaded root borer (PFRB) infestation in trees. A multispectral sensor attached to a UAV captures aerial imagery data from stone fruit and pome fruit orchards. These data undergo processing in photogrammetric and GIS programs, where NDVI, NDRE, and the tree crown area are computed. On-site observations confirm PFRB infestations. Various machine-learning models, including logistic regression (LR), artificial neural network (NN), random forest (RF), and extreme gradient boosting (XGBoost), are compared using mean NDVI values, mean NDRE values, crown area, mean temperature, and mean relative humidity. Mean NDVI values emerge as the most crucial factor for predicting PFRB infestation across all machine-learning models. The XGBoost model proves the most effective, achieving an accuracy of 0.85, with marginal variations from the other tested models.

Field trials of pheromone blends of longhorned beetles in South Korea

Longhorned beetles (Coleoptera: Cerambycidae) are a diverse family of wood-boring insects that provide valuable ecosystem services but also cause significant damage to forests and crops. South Korea is a crucial region for studying Cerambycidae due to the presence of invasive and endemic pests. In this study, we tested four blends of known cerambycid pheromones and a control (isopropanol) as attractants for longhorned beetles in two sites in central Korea and two sites in Jeju Island in southern Korea from April to August 2022. A total of 309 individuals from 17 species were caught, with five species being significantly attracted to a particular pheromone blend. The attraction of species whose pheromones are not known to specific blends provides promising leads that can be used to expedite identification of the actual pheromones for these species. Our results also provide further confirmation that pheromone components are often widely shared among related cerambycid taxa on different continents.

A Study of Adult Olfactory Proteins of Primitive Ghost Moth, Endoclita signifer (Lepidoptera, Hepialidae).

Endoclita signifer is a prominent wood-boring insect species in eucalyptus plantations in Guangxi, China, causing significant ecological and economic damage. A novel approach to controlling the challenging wood-boring pest involves disrupting the olfactory communication between insects and the volatile compounds emitted by plants. To identify the olfactory proteins contributing to host selection based on 11 GC-EAD-active volatiles from eucalyptus leaves and to discover the highly expressed olfactory proteins, we conducted a study on the antennal transcriptomes of adult E. signifer and screened key olfactory proteins in the antennae. We identified a total of 69 olfactory proteins. When compared to the larval transcriptomes, the antennal transcriptome of adult E. signifer revealed the presence of 17 new odorant-binding proteins (OBPs), including 2 pheromone-binding proteins (PBPs), 7 previously unreported chemosensory proteins (CSPs), 17 new odorant receptors (ORs), 4 new gustatory receptors (GRs), 11 novel ionotropic receptors (IRs), and 2 sensory neuron membrane proteins (SNMPs). Through the phylogenetic tree of OBPs and ORs, we identified EsigPBP2 and EsigPBP3 as two of the three PBPs, designated EsigOR13 as EsigOrco, and recognized EsigOR10 and EsigOR22 as the newly discovered EsigPRs in E. signifer. In the adult antennae, the expression levels of EsigGOBP14, EsigGOBP13, EsigOBP14, EsigOBP17, EsigCSP14, and EsigOR16 were notably high, indicating that these proteins could be pivotal in binding to plant volatiles.

Çam Kütüklerindeki Monochamus galloprovincialis (Cerambycidae) Populasyonlarına Karşı Steinernema carpocapsae (Steinernematidae)’nin Biyolojik Mücadelede Kullanılması

Aim of study: Pine wilt disease (PWD) is a serious threat to the susceptible pine forests. It is caused by Bursaphelenchus xylophilus (Nematoda: Parasitaphelenchidae) (Steiner and Buhrer 1934), Nickle 1970 and transmitted by Monochamus Dejean beetles. In the recent study, we assessed the effects of entomopathogenic nematode, Steinernema carpocapsae (Nematoda: Steinernematidae) against Monochamus galloprovincialis larvae in Anatolian black pine and Scots pine logs. 
 Area of the study: The experiments were conducted in Duzce University, Faculty of Forestry and in a pine forest at Duzce University campus area. 
 Material and methods: The mean number of eggs per pine logs, and the productivity of S. carpocapsae in M. galloprovincialis larvae were compared under laboratory conditions. The nematode experiments were conducted using oviposited pine logs in the field.
 Main results: The females of M. galloprovincialis oviposited more eggs on Scots pine compared to black pine logs. Both in black pine and in Scots pine, the survival rates of M. galloprovincialis after nematode application was significantly lower than control. 
 Highlihts: As a result of the study, S. carpocapsae can be an efficient biological control agent of this wood-boring insect.

Two new species of Xorides Latreille (Hymenoptera, Ichneumonidae) from China, with notes on biology and a key to species known from China

Two species of Xorides Latreille, 1809 are reported parasitizing wood-boring insects in trunks and relatively larger twigs of Juglans mandshurica Maxim. in Kuandian Manzu Autonomous County, Liaoning, in the Palaearctic part of China. Two new species are described: X. juglanse Sheng, Broad & Sun sp. nov. and X. kuandianense Sheng, Broad & Sun sp. nov. One species, X. sapporensis (Uchida, 1928), was associated with wood-borers in J. mandshurica Maxim. for the first time. A key to the 46 species of Xorides Latreille known from China is provided.