Elm Leaf Beetle Research Articles

Capnodis tenebrionis L.'den izole edilen bakterilerin izolasyonu, karakterizasyonu ve bazı böcek zararlılarına karşı biyolojik mücadele potansiyelleri

Capnodis tenebrionis L. (Coleoptera: Buprestidae) is one of the most destructive pests of stone fruit orchards in several countries, including Türkiye. In the present study, 21 bacterial isolates were isolated from the larvae and adults of C. tenebrionis. The morphological, physiological, biochemical and molecular characteristics of the bacterial isolates were determined. The bacterial flora isolated from C. tenebrionis was as follows: Bacillus cereus, B. mycoides, B. pumilus, Paenibacillus xylanilyticus, B. flexus, B. simplex, Raoultella terrigena, Enterobacter cloacae, Klebsiella oxytoca, B. safensis, B. amyloliquefaciens and B. aryabhattai. The biological control potential of these bacterial isolates against the larvae of several economic pest species, the elm leaf beetle (Pyrrhalta luteola (M.)), the honeycomb moth (Galleria mellonella L.), and the mealworm (Tenebrio molitor Ludwig), was investigated. The isolates of B. cereus showed the highest efficacy against these insect pests.

Plant defensive responses to insect eggs are inducible by general egg-associated elicitors

Egg deposition by herbivorous insects is well known to elicit defensive plant responses. Our study aimed to elucidate the insect and plant species specificity of these responses. To study the insect species specificity, we treated Arabidopsis thaliana with egg extracts and egg-associated secretions of a sawfly (Diprion pini), a beetle (Xanthogaleruca luteola) and a butterfly (Pieris brassicae). All egg extracts elicited salicylic acid (SA) accumulation in the plant, and all secretions induced expression of plant genes known to be responsive to the butterfly eggs, among them Pathogenesis-Related (PR) genes. All secretions contained phosphatidylcholine derivatives, known elicitors of SA accumulation and PR gene expression in Arabidopsis. The sawfly egg extract did not induce plant camalexin levels, while the other extracts did. Our studies on the plant species specificity revealed that Solanum dulcamara and Ulmus minor responded with SA accumulation and cell death to P. brassicae eggs, i.e. responses also known for A. thaliana. However, the butterfly eggs induced neoplasms only in S. dulcamara. Our results provide evidence for general, phosphatidylcholine-based, egg-associated elicitors of plant responses and for conserved plant core responses to eggs, but also point to plant and insect species-specific traits in plant–insect egg interactions.

Microbial associates of the elm leaf beetle: uncovering the absence of resident bacteria and the influence of fungi on insect performance.

Microbial symbionts play crucial roles in the biology of many insects. While bacteria have been the primary focus of research on insect-microbe symbiosis, recent studies suggest that fungal symbionts may be just as important. The elm leaf beetle (ELB, Xanthogaleruca luteola) is a serious pest species of field elm (Ulmus minor). Using culture-dependent and independent methods, we investigated the abundance and species richness of bacteria and fungi throughout various ELB life stages and generations, while concurrently analyzing microbial communities on elm leaves. No persistent bacterial community was found to be associated with the ELB or elm leaves. By contrast, fungi were persistently present in the beetle's feeding life stages and on elm leaves. Fungal community sequencing revealed a predominance of the genera Penicillium and Aspergillus in insects and on leaves. Culture-dependent surveys showed a high prevalence of two fungal colony morphotypes closely related to Penicillium lanosocoeruleum and Aspergillus flavus. Among these, the Penicillium morphotype was significantly more abundant on feeding-damaged compared with intact leaves, suggesting that the fungus thrives in the presence of the ELB. We assessed whether the detected prevalent fungal morphotypes influenced ELB's performance by rearing insects on (i) surface-sterilized leaves, (ii) leaves inoculated with Penicillium spores, and (iii) leaves inoculated with Aspergillus spores. Insects feeding on Penicillium-inoculated leaves gained more biomass and tended to lay larger egg clutches than those consuming surface-sterilized leaves or Aspergillus-inoculated leaves. Our results demonstrate that the ELB does not harbor resident bacteria and that it might benefit from associating with Penicillium fungi.IMPORTANCEOur study provides insights into the still understudied role of microbial symbionts in the biology of the elm leaf beetle (ELB), a major pest of elms. Contrary to expectations, we found no persistent bacterial symbionts associated with the ELB or elm leaves. Our research thus contributes to the growing body of knowledge that not all insects rely on bacterial symbionts. While no persistent bacterial symbionts were detectable in the ELB and elm leaf samples, our analyses revealed the persistent presence of fungi, particularly Penicillium and Aspergillus on both elm leaves and in the feeding ELB stages. Moreover, when ELB were fed with fungus-treated elm leaves, we detected a potentially beneficial effect of Penicillium on the ELB's development and fecundity. Our results highlight the significance of fungal symbionts in the biology of this insect.

Effect of 1,8-cineol on the biology and physiology of elm leaf beetle, Xanthogaleruca luteola (Col.: Chrysomelidae)

Effect of 1,8-cineol on the biology and physiology of elm leaf beetle, Xanthogaleruca luteola (Col.: Chrysomelidae)

Elm tree defences against a specialist herbivore are moderately primed by an infestation in the previous season.

The studies of the long-term effects of insect infestations on plant anti-herbivore defences tend to focus on feeding-induced damage. Infestations by an entire insect generation, including egg depositions as well as the feeding insects, are often neglected. Whilst there is increasing evidence that the presence of insect eggs can intensify plants' anti-herbivore defences against hatching larvae in the short term, little is known about how insect infestations, including insect egg depositions, affect plant defences in the long term. We addressed this knowledge gap by investigating long-term effects of insect infestation on elm's (Ulmus minor Mill. cv. 'Dahlem') defences against subsequent infestation. In greenhouse experiments, elms were exposed to elm leaf beetle (ELB, Xanthogaleruca luteola) infestation (adults, eggs and larvae). Thereafter, the trees cast their leaves under simulated winter conditions and were re-infested with ELB after the regrowth of their leaves under simulated summer conditions. Elm leaf beetles performed moderately worse on previously infested elms with respect to several developmental parameters. The concentrations of the phenylpropanoids kaempferol and quercetin, which are involved in egg-mediated, short-term effects on elm defences, were slightly higher in the ELB-challenged leaves of previously infested trees than in the challenged leaves of naïve trees. The expression of several genes involved in the phenylpropanoid pathway, jasmonic acid signalling, and DNA and histone modifications appeared to be affected by ELB infestation; however, prior infestation did not alter the expression intensities of these genes. The concentrations of several phytohormones were similarly affected in the currently challenged leaves of previously infested trees and naïve trees. Our study shows that prior infestation of elms by a specialised insect leads to moderately improved defences against subsequent infestation in the following growing season. Prior infestation adds a long-term effect to the short-term enhancer effect that plants show in response to egg depositions when defending against hatching larvae.

New Records of Elm Leaf Beetle, Xanthogaleruca luteola, Parasitoids in Colorado, with Notes on Predators

Elm leaf beetle, Xanthogaleruca luteola Müller (Coleoptera: Chrysomelidae), is an invasive pest of elm trees, Ulmus spp. L. Natural enemies are thought to be important in controlling elm leaf beetles, but their natural enemy community is poorly described in many areas of the invaded range. The aim of this research was to identify parasitoids and predators of elm leaf beetle in Colorado, an area with frequent pest outbreaks and where few natural enemies have been described. We present new state records of the egg parasitoid Oomyzus gallerucae Fonscolombe (Hymenoptera: Eulophidae) and the larval-adult parasitoid Erynniopsis antennata Rondani (Diptera: Tachinidae) in Colorado. Parasitism of elm leaf beetle eggs and larvae was <3% during the 2021 sampling season. Both parasitoid species were nearly absent early in the season, and parasitism peaked in late summer. We also identified six species of elm leaf beetle predators, several of which are newly documented to consume elm leaf beetle. Considering the low levels of parasitism and few predators observed in our study, it seems unlikely that natural enemies effectively control elm leaf beetles in Colorado. Additional research is needed to develop effective methods to control this invasive insect pest.

Biological and biochemical effects of lufenuron on Xanthogaleruca luteola (Muller, 1766 ) (Coleoptera: Chrysomelidae)

Xanthogaleruca luteola (Mull., 1766) is the major defoliator pest of elm trees in urban area. In this study the effect of lufenuron on some biochemical and biological characteristics was investigated on X. luteola. The LC30 and LC50 of lufenuron were determined on the second instar larvae as 20.22 and 36.65 mg l-1, respectively. Effects of LC30 and LC50 concentrations of lufenuron on some biological parameters showed that lufenuron caused an increase in larval, pre-pupal and pupal developmental periods. Also, none of the female insects that emerged from the treated larvae did not spawn during their life. The LC50 concentration of lufenuron decreased carbohydrate, lipid and protein content and increased glycogen content. But there was not a significant difference in glycogen, and protein contents following the exposure to LC30 concentration. However, glutathione-s-transferase (GST) and esterase activities were significantly increased at LC50. In conclusion, due to lethal and sublethal effect of lufenuron on biochemical and biological traits of X. luteola, it can be recommended for control this pest in IPM program.

Nanoencapsulation of Acetamiprid by Sodium Alginate and Polyethylene Glycol Enhanced Its Insecticidal Efficiency.

Nanoformulation has been considered one of the newly applied methods in integrated pest management strategies. In this research, a conventional neonicotinoid insecticide acetamiprid was nanoencapsulated via AL (Sodium Alginate) and PEG (Polyethylene Glycol) and tested against the elm leaf beetle Xanthogaleruca luteola. The synthesized particles had spherical-like morphology and nanoscale based on TEM (Transmission Electron Microscopy) and DLS (Dynamic Light Scattering). The encapsulation efficiency and loading percentages of acetamiprid in AL and PEG were 92.58% and 90.15%, and 88.46% and 86.79%, respectively. Leaf discs treated with different formulations by the leaf-dipping method were used for oral toxicity assays. The LC50 values (Lethal Concentration to kill 50% of insect population) of acetamiprid and Al- and PEG-nanoencapsulated formulations on third-instar larvae were 0.68, 0.04, and 0.08 ppm, respectively. Based on the highest relative potency, AL-encapsulated acetamiprid had the most toxicity. The content of energy reserve protein, glucose, and triglyceride and the activity of detoxifying enzymes esterase and glutathione S-transferase of the larvae treated by LC50 values of nanoformulations were also decreased. According to the current findings, the nanoencapsulation of acetamiprid by Al and PEG can increase its insecticidal performance in terms of lethal and sublethal toxicity.

Review of control options for elm leaf beetle, Xanthogaleruca luteola Müller, with a focus on Australia

ABSTRACT Elm leaf beetle (ELB) is a comparatively new invader in south-eastern Australia. ELB can cause considerable defoliation and adversely impact tree health. Here, we conducted a literature review and found a range of control measures. We found two main biological control insects, Oomyzus gallerucae and Erynniopsis antennata, but they rarely adequately control ELB populations or prevent considerable defoliation. We report on more than 20 insecticides used to control ELB, primarily consisting of organophosphates, pyrethroids and neonicotinoids. There is no ideal insecticide as some very effective insecticides have environmental or human health concerns. Products based on azadirachtin or similar compounds seem to generate least concerns and are insect specific, but may have short residues. The choice of insecticidal intervention will be based on issues pertinent to each situation and many pesticide options are available.

Urban environments have species-specific associations with invasive insect herbivores

Abstract Urban forests are critically important for providing ecosystem services to rapidly expanding urban populations, but their health is threatened by invasive insect herbivores. To protect urban forests against invasive insects and support future delivery of ecosystem services, we must first understand the factors that affect insect density across urban landscapes. This study explores how a variety of environmental factors that vary across urban habitats influence density of invasive insects. Specifically, we evaluate how vegetational complexity, distance to buildings, impervious surface, canopy temperature, host availability and density of co-occurring herbivores impact three invasive pests of elm trees: the elm leaf beetle (Xanthogaleruca luteola), the elm flea weevil (Orchestes steppensis) and the elm leafminer (Fenusa ulmi). Insect responses to these factors were species-specific, and all environmental factors were associated with density of at least one pest species except for distance to buildings. Elm leafminer density decreased with higher temperatures and was influenced by an interaction between vegetational complexity and impervious surface. Elm flea weevil density increased with greater host availability, and elm leaf beetle density increased with higher temperatures. Both elm leaf beetle and elm flea weevil density decreased with greater leafminer density, suggesting that insect density is mediated by species interactions. These findings can be used to inform urban pest management and tree care efforts, making urban forests more resilient in an era when globalization and climate change make them particularly vulnerable to attack.

Pyrrhalta luteola (elm leaf beetle)

This datasheet on Pyrrhalta luteola covers Identity, Overview, Distribution, Dispersal, Hosts/Species Affected, Diagnosis, Biology &amp; Ecology, Natural Enemies, Impacts, Prevention/Control, Further Information.

Pyrrhalta luteola (elm leaf beetle)

This datasheet on Pyrrhalta luteola covers Identity, Overview, Distribution, Dispersal, Hosts/Species Affected, Diagnosis, Biology &amp; Ecology, Natural Enemies, Impacts, Prevention/Control, Further Information.

Responses to larval herbivory in the phenylpropanoid pathway of Ulmus minor are boosted by prior insect egg deposition

Main conclusionElms, which have received insect eggs as a ‘warning’ of larval herbivory, enhance their anti-herbivore defences by accumulating salicylic acid and amplifying phenylpropanoid-related transcriptional and metabolic responses to hatching larvae.Plant responses to insect eggs can result in intensified defences against hatching larvae. In annual plants, this egg-mediated effect is known to be associated with changes in leaf phenylpropanoid levels. However, little is known about how trees—long-living, perennial plants—improve their egg-mediated, anti-herbivore defences. The role of phytohormones and the phenylpropanoid pathway in egg-primed anti-herbivore defences of a tree species has until now been left unexplored. Using targeted and untargeted metabolome analyses we studied how the phenylpropanoid pathway of Ulmus minor responds to egg-laying by the elm leaf beetle and subsequent larval feeding. We found that when compared to untreated leaves, kaempferol and quercetin concentrations increased in feeding-damaged leaves with prior egg deposition, but not in feeding-damaged leaves without eggs. PCR analyses revealed that prior insect egg deposition intensified feeding-induced expression of phenylalanine ammonia lyase (PAL), encoding the gateway enzyme of the phenylpropanoid pathway. Salicylic acid (SA) concentrations were higher in egg-treated, feeding-damaged leaves than in egg-free, feeding-damaged leaves, but SA levels did not increase in response to egg deposition alone—in contrast to observations made of Arabidopsis thaliana. Our results indicate that prior egg deposition induces a SA-mediated response in elms to feeding damage. Furthermore, egg deposition boosts phenylpropanoid biosynthesis in subsequently feeding-damaged leaves by enhanced PAL expression, which results in the accumulation of phenylpropanoid derivatives. As such, the elm tree shows similar, yet distinct, responses to insect eggs and larval feeding as the annual model plant A. thaliana.

Insecticidal capacity of Cestrum parqui (Solanaceae) leaf extracts on Xanthogaleruca luteola (Coleoptera: Chrysomelidae) adults

Among a series of exotic pests that have been reported in Chile, Xanthogaleruca luteola (Coleoptera: Chrysomelidae), a defoliating insect of elms (Ulmus spp.), is causing important damage in urban trees in central Chile. The insecticidal capacity of water and ethanol extracts obtained from new and mature leaves of Cestrum parqui (Solanaceae) was evaluated at various concentrations on X. luteola adults in the laboratory. Bioassays with a completely randomized design were used to analyze the effects of each extract. Also, the mean lethal concentration (LC50) was determined for both mature leaf states and solvents. A proximal analysis was done to determine the physical and chemical differences between the maturity stages. Proximal analysis of the powder of both leaf stages revealed differences (P &lt; 0.01) in the content of humidity, ashes, lipids, and proteins, but not in the raw fiber content nor the non-nitrogenous extract. On the third day after exposure, the order of decreasing effectiveness (LC50) ofthe insecticide extracts was: new-ethanol (2.5 % w/v), new-water (3.8 % w/v), mature-ethanol (6.7 % w/v) and mature-water (9.2 % w/v). Our results suggest that C. parqui leaf extracts may have potential use as a bioinsecticide in integrated pest management plans for the control of X. luteola adults, however, tests at a larger scale are necessary to confirm our results.

Ovicidal and Physiological Effects of Essential Oils Extracted from Six Medicinal Plants on the Elm Leaf Beetle, Xanthogaleruca luteola (Mull.)

Plant essential oils may serve as safe alternatives to detrimental synthetic pesticides due to relatively lower side effects on the environment and non-targeted organisms. The current study was conducted to investigate the ovicidal toxicity and physiological disruptions of six medicinal plant essential oils, including Artemisia annua L., Lavandula angustifolia Mill., Origanum vulgare L., Rosmarinus officinalis Spenn., Satureja hortensis L., and Thymus vulgaris L., on elm leaf beetle Xanthogaleruca luteola (Mull.). The LC50 (Lethal Concentration to kill 50% of tested insects) values of 122.8, 287.5, 152.8, 180.6, 315.9, and 1366.2 ppm were recorded for T. vulgaris, L. angustifolia, A. annua, S. hortensis, R. officinalis, and O. vulgare, respectively, 72 h after treatment of 3-day-old eggs of the pest. Significant decreases in the amounts of glucose, protein, and triglyceride macromolecules were also observed after treatment. The application of essential oils derived from T. vulgaris, A. annua, and S. hortensis at 400 ppm revealed 100% ovicidal activity. Accordingly, tested essential oils, particularly the essential oil of T. vulgaris, have been promising potential as biorational insecticides in the management of X. luteola.

Synthesis, crystal structure, cholinesterase inhibitory activity, evaluation of insecticidal activities, and computational studies of new phosphonic acids.

In an attempt to obtain the modified and novel insecticides with low human toxicity, a series of novel mono-, bis-, and tetraphosphonic acid derivatives were designed and characterized by infrared, 1H, 13C, and 31P NMR spectroscopy and X-ray crystallography. The inhibitory effects of the synthesized compounds were evaluated using the in vitro Ellman method on human and insect acetylcholinesterase (AChE). Some of these compounds, which had low human and high insect toxicity, were chosen to assess the killing effects (in vivo) on third larval instar of elm leaf beetle (X. luteola). In vivo and in vitro evidence has revealed that bisphosphonic acids, containing hydrophobic systems, have a good selectivity of insect AChE inhibition. In the present study, docking results showed that bisphosphonic acids had lower binding energy and higher inhibition compared with tetraphosphonic acids due to the type of their topology and the ability of their hydrogen to interact with the catalytic triad (the main active site of the enzyme). Additionally, the QSAR results demonstrated that the major effecting factors on the insecticidal activity of the subject compounds are the hydrophobicity, size, shape, and ability to form a hydrogen bond. The present study can be helpful in the development of new insecticides.

Особенности состояния ильмовых в защитных насаждениях засушливой зоны Нижнего Поволжья

In the Volgograd region, which belongs to low-forest regions, old-growth plantings pre-dominate, in which about 80,0% of the total dendrological composition is accounted for by repre-sentatives of the generic Ulmus complex. In the conditions of urbanization, the pathological pro-cesses and the weakening of woody plants increases. The stable weakened state of the elm trees is typical for squares and roadside plantings (Bsr = 3.28-3.36, respectively). Favorable conditions for maintaining the life optimum of elms are formed in parks, protective forest strips and arbore-tums, where healthy or weakened trees predominate (Bsr = 1,82-1,69-1,87 respectively). Phyl-lophages of different ecological groups are trophically related to the arboreal species of Ulmus. Among leaf-eating pests, Xanthogaleruca luteola Mull is of important economic importance. The pest population varies depending on the ecological conditions of the biotopes and Ulmus species. Keywords: ULMUS, PROTECTIVE FOREST STANDS, CONDITION CATEGORY, MONITORING, ANTHROPOGENIC PRESSURE, PESTS, PEST POPULATION

Pathogenicity of two fungal pathogens on larvae of the elm leaf beetle, Xanthogaleruca luteola Muller (Coleoptera: Chrysomelidae)

BackgroundThe elm leaf beetle (ELB), Xanthogaleruca luteola Muller (Coleoptera: Chrysomelidae), is one of the most important insect pests that cause damage and physiological stress for the trees. In the present research, pathogenicity of both entomopathogenic fungi (EPF), Beauveria bassiana and Metarhizium anisopliae on the 1st, 2nd, and 3rd instar larval of ELB at the concentrations of 105, 106, 107, and 108 conidia per ml, using immersion and spray methods and were evaluated.ResultsThe results showed that LC50 of B. bassiana in immersion and spray methods were 3.88 × 102 and 7.52 × 102 conidia/ml, while LC50 of M. anisopliae in mentioned methods were 7.05 × 102 and 11.85 × 102 conidia/ml, respectively. The highest mortality rate in both EPF was observed in the 1st instar larvae that were significantly different than the control treatment. Moreover, the highest and lowest mortality in both EPF, using immersion and spray methods, were observed at the concentrations of 108 and 105 conidia/ml, respectively. Therefore, susceptibility of 1st and 2nd larval instars was more than 1st instar larvae. Based on the findings of the present study, there was no mortality during the first 24 h, while after 2 days, the mortality was recorded and increased over time in case of both pathogens. Accordingly, B. bassiana and M. anisopliae were pathogenic on larvae of ELB.ConclusionsThe outputs of the study demonstrated that applications of these eco-friendly fungal pathogens with other non-chemical methods are recommended. Of course, under natural conditions, their efficiency may change; thus, more comprehensive studies are necessary.

Coupled gas chromatographic-electroantennographic responses of Xanthogaleruca luteola (Müller) (Coleoptera: Chrysomelidae) to volatile organic compounds from Eucalyptus globulus extract

Xanthogaleruca luteola (Muller) is a monophagous pest species indigenous to Europe, known as elm leaf beetle. During the larval and adult stages, this insect damages elm leaves as it chews small holes in the leaves, causing, even, complete defoliation, leaving only the nervation. Although this species only uses Ulmus spp. as host plants to complete its development, some preliminary results have shown that is attracted to non-host plants such as Eucalyptus globulus Labill. In order to understand the role of volatile organic compounds emitted by E. globulus when the insect is attracted to this non-host plant, dichloromethane extracts of E. globulus were analyzed through gas chromatography-mass spectrometry, and main compounds were identified. Likewise, to evaluate the response of the antennae in X. luteola males and females to the compounds contained in the extract, a gas chromatographic-electroantennographic detection (GC-EAD) was conducted. Only females were observed to respond to α-pinene, eucalyptol, 4-terpineol, α-terpineol, α-terpineol acetate, α-gurjunene, alloaromadendrene, alloaromadendrene, viridiflorene, and globulol compounds. This study is the first step to identify substances mediating the host plant selection of X. luteola.

Erucin modulates digestive enzyme release via crustacean cardioactive peptide in the elm leaf beetle Xanthogaleruca luteola (Coleoptera: Chrysomelidae)

Plant secondary metabolites influence the feeding in insects through several modes of action. In this study, the physiological effects of erucin isothiocyanate were investigated on the elm leaf beetleXanthogaleruca luteola(Müller) (Coleoptera: Chrysomelidae) via impact on crustacean cardioactive peptide (CCAP) and midgut digestive enzymes. Third instar larvae of elm leaf beetle were fed on leaves impregnated with erucin for three days. The results showed that erucin decreasedα-amylase, lipase, and protease release. Western blot analysis and competitive ELISA showed that erucin decreased CCAP content of the midgut, brain, and hemolymph. Moreover, incubation of dissected midgut with CCAP and also its injection into the hemocoel increased digestive enzyme release. It could be concluded that erucin isothiocyanate decreases CCAP content that itself led to a decrease in digestive enzyme release. Also, it suggests that CCAP could be one of the factors, regulating feeding activities in the elm leaf beetle. This report shows that CCAP is both a midgut factor and a neuropeptide that regulates digestive enzyme release in the elm leaf beetle and could be used to study erucin effects in insects.