Search Results (58)

In this paper, we present the results of field investigations on the suitability of three types of trunk traps (‘Commercial 1’, ‘Commercial 2’, and ‘Prototype’) for capturing spongy moth (Lymantria dispar) larvae in two areas with different climates and forest ecosystems. In areas of NE Slovenia, which were characterized by Pannonian climate and regular rainfall during the research period (2022–2024), the ‘Commercial 2’ trap was the most suitable for the capture of old larvae. In a forest with 20–30 m tall trees with the dominant species Quercus robur, Carpinus betulus, and Pinus sylvestris, it proved easy to set ‘Commercial 2’ on trunks and change their parts upon inspection for captures. ‘Commercial 1’ traps proved to be less suitable, since their bags quickly were filled with water during downpours and consequently fell out of the traps. ‘Prototype’ traps proved to be the most suitable in an area with a Mediterranean climate (Greece), where the trees (Quercus spp.) were smaller (3–4 m) and both younger and older larvae could more easily come into contact with the sticky surface of the inner part of the trap, of which longer-lasting effectiveness was possible in a drier climate. For the mass trapping of larvae in urban areas with a more humid climate, we therefore suggest the use of ‘Commercial 2’ traps, and in areas with a drier climate, the use of ‘Prototype’ traps. Full article

This study investigated the bioactivity of common ash (Fraxinus excelsior L.) and manna ash (Fraxinus ornus L.) leaf extracts, both in the crude form and incorporated into a biopolymer matrix, against spongy moth (Lymantria dispar L.) larvae. Chemical analysis revealed that both species were abundant in polyphenolic compounds, with common ash containing significant quantities of p-hydroxycinnamic acid derivatives and verbascoside, while manna ash was rich in coumarins, particularly aesculetin and aesculin. This study evaluated the feeding deterrent activity, contact and digestive toxicity, effects on larval nutritional indices, and larval development. Chitosan–gelatin-based biopolymer matrices containing the leaf extracts exhibited strong feeding deterrent activity at all tested concentrations, while crude leaf extracts showed moderate deterrence. The biopolymer matrices influenced spongy moth behavior only after digestion, resulting in reduced consumption and growth, as well as a prolonged duration of the third larval instar. No contact toxicity was observed for the biopolymer matrices. Incorporating leaf extracts into the chitosan–gelatin biopolymer matrix significantly enhanced their bioactivity against spongy moth larvae compared with crude leaf extracts. The results suggest that biopolymer matrices containing common ash and manna ash leaf extracts are promising environmentally friendly bioproducts for forest insect control, offering an innovative approach to managing spongy moth populations and protecting forest ecosystems. Full article

The bioactivity of the Ailanthus altissima crude leaf extract (CLE) and a leaf extract incorporated into a biopolymer matrix (BPM) was tested against Lymantria dispar larvae. The crude leaf extracts and those incorporated into a chitosan–gelatin polymer matrix were examined in choice and non-choice assays at 0.01, 0.05, 0.5, and 1% concentrations for feeding deterrent activity, contact, and digestive toxicity. The CLE exhibited moderate deterrent activity at all concentrations, whereas the BPM showed a very strong deterrent effect at 0.5% and 1% and a strong effect at 0.1% and 0.01%. No significant differences in digestive or contact toxicity were observed between the CLE and BPM groups and the control groups. The BPM also influenced larval behavior after digestion, decreasing consumption and growth and increasing development time. The higher bioactivity of the CLE compared to the control group is attributed to its high content of total phenols, flavonoids, and tannins, whereas the enhanced bioactivity of the BPM is due to its incorporation into the biopolymer matrix. Given its very strong deterrent activity, and absence of contact and digestive toxicity, the BPM can be recommended as a potential environmentally friendly bioproduct for forest pest control after field evaluation. Full article

The European spongy moth, Lymantria dispar dispar (L.) (Lepidoptera: Erebidae), originating from Eurasia, is found in Europe, Africa, and North America. Its polyphagous larvae infest deciduous and coniferous trees, causing severe damage during mass outbreak years. Thus, it is listed as one of the top 100 invasive alien species worldwide. The management and containment of this pest vary significantly between Europe and North America, with North America exhibiting a more robust response regarding the containment of the outbreaks. This study evaluates the current state of the European Union (EU-27) forests’ legal, political and cooperative protection frameworks concerning L. dispar dispar. We identified active and potential new stakeholders to assess the level of national and international collaboration in forest protection. We conducted a SWOT analysis to propose new strategies and solutions, aiming for enhanced cooperation in protecting EU forests from L. dispar dispar outbreaks. Our findings highlight the potential of new monitoring and reporting technologies and the importance of increased social and political awareness through social media and public campaigns. These measures would enable more centralized and coordinated efforts among member states. A few of the most significant results in each category of SWOT analysis are as follows: for strengths, a well-established network of EU and national stakeholders exists; for opportunities, emerging innovative technologies, such as IoT, AI, and 5G, are transforming our approach to forest protection; for weaknesses, there is a lack of informed choices regarding proactive measures to contain the outbreak due to a lack of centralized EU coordination and the inefficiencies of national state policies. Finally, the numerous threats to the well-being of EU forests competing for the attention of institutions and relevant stakeholders is by far one of the most important parameters regarding the threats to the EU’s forest protection. The study advocates for a unified, technologically advanced approach to manage and mitigate L. dispar dispar impacts in European forests, emphasizing the need for strengthened international cooperation and the strategic implementation of innovative solutions. Full article

Dendrolimus superans (Lepidoptera: Lasiocampidae) and Lymantria dispar (Lepidoptera: Lymantriidae) are two important forest defoliators in northeast China, with the former being a specialist on Larix spp. and the latter being a generalist feeding on >500 species of plants. The morphology and ultrastructure of antennal sensilla of both male and female D. superans and L. dispar were examined using scanning electron microscopy (SEM). In both sexes of D. superans, the following five types of antennal sensilla were found: sensilla trichoidea, s. chaetica, s. coeloconica, s. gemmiformia, and s. basiconica. In males of L. dispar, six types of antennal sensilla: sensilla trichoidea, s. chaetica, s. coeloconica, s. basiconica, s. styloconica, and s. auricillica, were identified. In addition to the six types found in males, a seventh type of sensilla, s. squamiform, was only detected on L. dispar female antennae. For s. chaetica of D. superans, a unique ultrastructure of sub-branches that have one branch, two branches, and three branches was observed on their tips, which has not yet been reported on other insects. s. styloconica, s. auricillica, and s. squamiform, not found in the specialist D. superans, may be related to the euryphagy of L. dispar. Potential functionalities of these sensilla were discussed with reference to moth feeding habits, and their morphology, distribution, and ultrastructures on both species. Full article

Spongy moth (Lymantria dispar Linnaeus 1758) populations have the potential to reach outbreak levels, causing disruptions to forest ecosystems across Eurasia and North America. Continuous monitoring of the size and health of the spongy moth population in the egg stage is important for managing population outbreaks. Current methods include counting eggs within egg masses using manual methods. This study introduces an innovative solution aimed at optimizing the prediction of biotic disturbances and preventing the potential risks associated with spongy moth population outbreaks. The challenges and constraints related to the process of hair removal from spongy moth eggs have been effectively addressed through the development of a device powered by a torque-generating unit. This study aims to (1) introduce a novel device designed for the removal of hairs from spongy moth (L. dispar) eggs; (2) introduce a new hair removal procedure; and (3) empirically demonstrate the benefits of the introduced innovations. The introduced device and the procedure enable a significantly expedited diagnosis of the potential for a population outbreak in the current year, with the potential for widespread utilization. This invention enhances our understanding of predicting biotic disorders and facilitates the rapid assessment of the risk of their occurrence. Full article

Increasing temperatures, prolonged drought, the increased severity and intensity of storms, and other effects of climate change are being felt globally, and long-lived forest tree species may struggle in their current ranges. Oaks (Quercus spp.) have evolved a range of adaptations to dry and hot conditions and are believed to be a “climate change winner” by increasing their suitable habitat. However, a mixture of life history traits and increasing susceptibility to herbivores and xylovores as well as secondary pathogen infections still put oaks at risk of decline. Oak species found in the Midwestern, Great Lakes, and Northeastern United States and Canada are important keystone species with high ecological and economical importance. They are also vulnerable to existing, new, and emerging threats that have the potential to cause mortality across entire stands quickly. Current examples of insect threats include the Lymantria dispar (spongy moth), Agrilus bilineatus (twolined chestnut borer), and Nitidulidae (sap beetles) as disease vectors. Examples of emerging insects of concern include Cynipidae (oak gall wasps) and Enaphalodes rufulus (red oak borer). This study describes these insects, explains their mechanisms of action and the effects on oaks, and explores mitigation strategies for each. Full article

Lymantria xylina Swinhoe (Lepidoptera: Erebidae) is a potentially invasive pest, similar to Lymantria dispar asiatica Vnukovskij and Lymantria dispar japonica Motschulsky (Lepidoptera: Erebidae). To evaluate its potential for spread and flight distance related to egg deposition on vessels at ports, we employed a flight mill to assess the flight capabilities of its adults under varying conditions. Our findings revealed that females primarily flew short distances and ceased flying after 3:00 AM, whereas males covered much longer distances throughout the day. Sex, age, and flight duration significantly influenced flight ability. Females exhibited weaker flight capability than males, and their ability declined with increasing age or flight duration. Notably, 1-day-old moths displayed the strongest flight ability, with average flight distances of up to 3.975 km for females and 8.441 km for males. By the fifth day, females no longer flew, and males experienced reduced flight ability. After continuous hanging for 16 h, females lost most of their flight capacity, while males remained capable of flight even after 32 h. Additionally, female flight ability decreased significantly after mating, possibly due to factors such as egg-carrying capacity, weight, and load ratio. This study provides a foundation for assessing the risk of long-distance dispersal of L. xylina via ocean-going freighters, considering female moths’ phototactic flight and oviposition. Full article

This paper addresses the problem of constructing a mathematical model of population density dynamics and the dynamics of forest areas damaged by spongy moth (Lymantria dispar L.) outbreaks in the United States, Europe, Russia, and Japan. The key variable of the model is either the pest population density or the area of forests damaged by spongy moths during a season. This variable can be considered proportional to the total current pest abundance in the study area. For the purposes of modeling, data from a number of different authors was used (see bibliography), as well as data from surveys conducted at the egg or caterpillar stage. The complexity of modeling the dynamics of L. dispar abundance is largely due to the fact that, when studying the dynamics of spongy moth population density, the values of external factors such as parasites, predators, and the amount of available food are often unknown. A simple model was proposed using only two types of data: population density and monthly weather characteristics. Our analysis demonstrated that, even in the absence of knowledge regarding the characteristics of ecosystem components interacting with the spongy moth population (parasites, predators, and the state of forage trees), it is possible to introduce models that characterize the regulatory processes in the population in terms of (i) the presence of negative and positive feedbacks in the system and (ii) the influence of external weather factors. The system under investigation was described as an autoregressive system, whereby the current state of the population is dependent on its state in previous years. The order of autoregression in the system was estimated using the order of the maximum significant partial autocorrelation function. It was found that the regulation of spongy moth population density was characterized by the presence of two feedback loops: positive feedback between the current population density and the population density in the previous season and negative feedback between the current population density and the population density two years ago. To evaluate the model, its stability margin was calculated and found to be directly proportional to the positive feedback coefficient and inversely proportional to the negative feedback coefficient. The model was demonstrated to explain up to 90% of the observed variance of real data. Although the model coefficients for different local populations (North America, Europe, and Asia) differ, the general form of the equation describing both direct data on population densities and indirect data on pest dynamics characterized by areas of stand damage is consistent. Consequently, the form of the ADL model is general, irrespective of the location of the local population. Full article

Plants and insects coevolved as an evolutionarily successful and enduring association. The molecular arms race led to evolutionary novelties regarding unique mechanisms of defence and detoxification in plants and insects. While insects adopt mechanisms to conquer host defence, trees develop well-orchestrated and species-specific defence strategies against insect herbivory. However, current knowledge on the molecular underpinnings of fine-tuned tree defence responses against different herbivore insects is still restricted. In the current study, using a multi-omics approach, we unveiled the defence response of Populus tremula against aphids (Chaitophorus populialbae) and spongy moths (Lymantria dispar) herbivory. Comparative differential gene expression (DGE) analyses revealed that around 272 and 1203 transcripts were differentially regulated in P. tremula after moth and aphid herbivory compared to uninfested controls. Interestingly, 5716 transcripts were differentially regulated in P. tremula between aphids and moth infestation. Further investigation showed that defence-related stress hormones and their lipid precursors, transcription factors, and signalling molecules were over-expressed, whereas the growth-related counterparts were suppressed in P. tremula after aphid and moth herbivory. Metabolomics analysis documented that around 37% of all significantly abundant metabolites were associated with biochemical pathways related to tree growth and defence. However, the metabolic profiles of aphid and moth-fed trees were quite distinct, indicating species-specific response optimization. After identifying the suitable reference genes in P. tremula, the omics data were further validated using RT-qPCR. Nevertheless, our findings documented species-specific fine-tuning of the defence response of P. tremula, showing conservation on resource allocation for defence overgrowth under aphid and moth herbivory. Such findings can be exploited to enhance our current understanding of molecular orchestration of tree responses against herbivory and aid in developing insect pest resistance P. tremula varieties. Full article

The main biochemical traits were estimated in poplar leaves under biotic attack (aphids and spongy moth infestation). Changes in the abundance of bioactive compounds in genetically uniform individuals of European aspen (Populus tremula), such as proline, polyphenolic compounds, chlorophylls a and b, and volatile compounds, were determined between leaves damaged by sucking insects (aphid—Chaitophorus nassonowi) and chewing insects (spongy moth—Lymantria dispar) compared to uninfected leaves. Among the nine analyzed phenolic compounds, only catechin and procyanidin showed significant differences between the control leaves and leaves affected by spongy moths or aphids. GC-TOF-MS volatile metabolome analysis showed the clear separation of the control versus aphids-infested and moth-infested leaves. In total, the compounds that proved to have the highest explanatory power for aphid-infested leaves were 3-hexenal and 5-methyl-2-furanone, and for moth-infested leaves, trans-α-farnesene and 4-cyanocyclohexane. The aphid-infested leaves contained around half the amount of chlorophylls and twice the amount of proline compared to uninfected leaves, and these results evidenced that aphids influence plant physiology more than chewing insects. Full article

Spongy moth (Lymantria dispar dispar) has caused considerable damage to oak trees across eastern deciduous forests. Forest management, post-outbreak, is resource intensive and typically focused on ecosystem restoration or resource loss mitigation. Some local forest managers and government partners are exploring developing technologies such as Unpiloted Aerial Systems (UASs, UAVs, or drones) to enhance their ability to gather reliable fine-scale information. However, with limited resources and the complexity of investing in hardware, software, and technical expertise, the decision to adopt UAS technologies has raised questions on their effectiveness. The objective of this study was to evaluate the abilities of two UAS surveying approaches for classifying the health of individual oak trees following a spongy moth outbreak. Combinations of two UAS multispectral sensors and two Structure from Motion (SfM)-based software are compared. The results indicate that the overall classification accuracy differed by as much as 3.8% between the hardware and software configurations. Additionally, the class-specific accuracy for ’Declining Oaks‘ differed by 5–10% (producer’s and user’s accuracies). The processing experience between open-source and commercial SfM software was also documented and demonstrated a 25-to-75-fold increase in processing duration. These results point out major considerations of time and software accessibility when selecting between hardware and software options for fine-scale forest mapping. Based on these findings, future stakeholders can decide between cost, practicality, technical complexity, and effectiveness. Full article

“Calling behaviour” is a stereotyped rhythmic motor pattern displayed by female moths, by which they emit the sex pheromone to attract of conspecific males. Calling occurs through a squeezing mechanism based on the turtleneck-like folding and unfolding of the ovipositor cuticle during its telescopic extensions and retractions. This mechanism is under the control of the terminal abdominal ganglion (TAG). By combining anatomical and electrophysiological approaches, here we studied the morpho-functional organisation of the abdominal muscles and the activity of motoneurons from TAG nerve N4-N6 as correlated to the ovipositor movements during calling in the female spongy moth Lymantria dispar. Our results show that the three abdominal segments S7, S8 and S9 (ovipositor) are highly specialized structures containing cuticular appendages, hinges, apodemes and several large muscles, innervated by N4 and especially by N5. N6 mainly innervates the oviductal tract. We also identified a number of motor units from N4 and N5, the spike activity of which is correlated with the ovipositor movements during calling. In conclusion, the release of sex pheromones in the female spongy moth is obtained by extensions and retractions of the ovipositor operated by a coordinated motor program, which is mainly sustained by the activity of a few motor units under the control of TAG nerves N4 and N5. Full article

The Bacillus thuringiensis serovar thuringiensis strain 800/15 has been actively used as an agent in biopreparations with high insecticidal activity against the larvae of the Colorado potato beetle Leptinotarsa decemlineata and gypsy moth Lymantria dispar. In the current study, we present the first draft genome of the 800/15 strain coupled with a comparative genomic analysis of its closest reference strains. The raw sequence data were obtained by Illumina technology on the HiSeq X platform and de novo assembled with the SPAdes v3.15.4 software. The genome reached 6,524,663 bp. in size and carried 6771 coding sequences, 3 of which represented loci encoding insecticidal toxins, namely, Spp1Aa1, Cry1Ab9, and Cry1Ba8 active against the orders Lepidoptera, Blattodea, Hemiptera, Diptera, and Coleoptera. We also revealed the biosynthetic gene clusters responsible for the synthesis of secondary metabolites, including fengycin, bacillibactin, and petrobactin with predicted antibacterial, fungicidal, and growth-promoting properties. Further comparative genomics suggested the strain is not enriched with genes linked with biological activities implying that agriculturally important properties rely more on the composition of loci rather than their abundance. The obtained genomic sequence of the strain with the experimental metadata could facilitate the computational prediction of bacterial isolates’ potency from genomic data. Full article

Recently, we found that the spongy moth Lymantria dispar L. is susceptible to infection by a Dendrolimus sibiricus cytoplasmic polyhedrosis virus (DsCPV-1). In the present study, we evaluated the pathogenicity of DsCPV-1 against L. dispar larvae and its impact on surviving insects after the infection. Offspring of virally challenged insects were tested for susceptibility to a stress factor (starvation). In addition, we used light microscopy and quantitative polymerase chain reaction (qPCR) to test the ability of DsCPV-1 to be transmitted vertically. We found insect mortality of the L. dispar parents following the infection was positively associated with DsCPV-1 dose. DsCPV-1 was lethal to second-instar L. dispar larvae with a 50% lethal dose (LD₅₀) of 1687 occlusion bodies per larva. No vertical transmission of DsCPV-1 to offspring larvae was detected, while the majority of insect deaths among offspring larvae were caused by microsporidia (Vairimorpha lymantriae), which was harbored by the parents. The offspring of virally challenged parents exhibited a higher number of detected microsporidia compared to the control. Our findings suggest that the application of DsCPV-1 is effective in controlling pests in terms of transgenerational impact following virus exposure. Full article