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The present study highlights, for the first time, the chemical composition of secondary metabolites (lipophilic and hydrophilic compounds) present in the phloem tissues of infected mature Pinus pinaster Ait. trees (on average 74 years old), which may be potentially determinant in the development of the pine wood nematode (PWN) Bursaphelenchus xylophilus. The levels of secondary metabolites in the phloem of infected trees were fairly constant along the height of the trees (an average of 30% dry phloem), but slightly lower compared with total extractives content in the phloem of mature healthy P. pinaster trees (30.0 vs. 39.9%). The hydrophilic fraction represented 91% of the total soluble compounds (27.3% of phloem mass) and it was mainly composed of phenolic compounds and reducing sugars (44.8% and 58.8% of the ethanol-water extracts). The lipophilic fraction (2.7% of phloem mass), was dominated by tricyclic diterpenic compounds (54.2–63.2% of the total lipophilic extracts) and fatty acids. Differences in the relative concentrations of individual compounds were observed compared to healthy pines, suggesting a response to the biotic stress imposed by nematode damage by an increased content of diterpenic resin acids, specifically dehydroabietic and abietic acids, and of total unsaturated fatty acids with a predominance of 9-octadecenoic acid. [ABSTRACT FROM AUTHOR]

In our previous screening of the transcriptome of the causal agent of the devastating pine wilt disease, pine wood nematode (PWN, Bursaphelenchus xylophilus), after treatment with the nematicide fomepizole, Surfeit locus gene sft-4, which encodes a regulatory factor, was found to be downregulated. In situ hybridization results showed that the sft-4 was continuously expressed from egg to adult and was especially high in the reproductive system. Here in a study of the effect of RNA interference (RNAi) of sft-4 and recombinant SFT-4 on PWN activity, treatment with sft-4 dsRNA inhibited feeding, reproduction, oviposition and egg hatching of PWN with the greatest inhibition on reproduction and oviposition, whereas recombinant SFT-4 had the opposite effect. In addition, RNAi of sft-4 changed the female–male ratio and lifespan of PWN. In bioassays of PWNs, with RNAi of sft-4 on seedlings and 2-year-old Pinus thunbergii trees, none of the treated plants developed symptoms during the monitoring period, indicating that virulence of PWNs was either significantly weakened. These results indicate that the influence of sft-4 on PWN pathogenicity may be mainly through regulating reproductive function of PWN and its lifespan. [ABSTRACT FROM AUTHOR]

The pinewood nematode (PWN) Bursaphelenchus xylophilus is a forestry quarantine pest and causes an extremely dangerous forest disease that is spreading worldwide. Due to the complex pathogenic factors of pine wood nematode disease, the pathogenesis is still unknown. B. xylophilus ultimately invades a host and causes death. However, little is known about the defence-regulating process of host pine after infection by B. xylophilus at the molecular level. Therefore, we wanted to understand how Pinus massoniana regulates its response to invasion by B. xylophilus. P. massoniana were artificially inoculated with B. xylophilus solution, while those without B. xylophilus solution were used as controls. P. massoniana inoculated with B. xylophilus solution for 0 h, 6 h, 24 h, and 120 h was subjected to high-throughput sequencing to obtain transcriptome data. At various time points (0 h, 6 h, 24 h, 120 h), gene transcription was measured in P. massoniana inoculated with PWN. At different time points, P. massoniana gene transcription differed significantly, with a response to early invasion by PWN. According to Gene Ontology (GO) classification and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, P. massoniana response to PWN invasion involves a wide range of genes, including plant hormone signal transformation, flavonoid biosynthesis, amino sugar and nucleoside sugar metabolism, and MAPK signalling pathways. Among them, inoculation for 120 hours had the greatest impact on differential genes. Subsequently, weighted gene coexpression network analysis (WGCNA) was used to analyse transcriptional regulation of P. massoniana after PWN infection. The results showed that the core gene module of P. massoniana responding to PWN was "MEmagenta", enriched in oxidative phosphorylation, amino sugar and nucleotide sugar metabolism, and the MAPK signalling pathway. MYB family transcription factors with the highest number of changes between infected and healthy pine trees accounted for 20.4% of the total differentially expressed transcription factors. To conclude, this study contributes to our understanding of the molecular mechanism of initial PWN infection of P. massoniana. Moreover, it provides some important background information on PWN pathogenic mechanisms. [ABSTRACT FROM AUTHOR]

Background: Bursaphelenchus xylophilus is a pathogenic nematode that causes pine wilt disease (PWD). To prevent the rapid spread of this pathogen, developing a method for rapid and accurate detection of B. xylophilus is required. Methods and results: In this study, we produced a B. xylophilus peroxiredoxin (BxPrx), which is a protein that is overexpressed in B. xylophilus. Using recombinant BxPrx as an antigen, we generated and selected a novel antibody that binds to BxPrx via phage display and biopanning. We subcloned the anti-BxPrx single-chain variable fragment-encoding phagemid DNA to mammalian expression vector. We transfected the plasmid into mammalian cells and produced a highly sensitive recombinant antibody that enabled nanogram order detection of BxPrx. Conclusion: The sequence of anti-BxPrx antibody as well as the rapid immunoassay system described here can be applied for rapid and accurate diagnosis of PWD. [ABSTRACT FROM AUTHOR]

AS the major causative agent of pine wilt disease, pine wood nematode, Bursaphelenchus xylophilus can result in rapid and massive deaths of pine forest, and even severe economy burdens globally. Botanical nematicides are the promising alternatives of the synthetic commercial nematicides which are causing more and more concerns such as drug resistance, threats to biodiversity and environmental pollution. In this review, we summarized the main nematicidal plant secondary metabolites against pine wood nematode including alkaloids, terpenoids, coumarins, flavonoids and glycosides. The chemical structures of the typical nematicidal phytochemicals with their activity index against pine wood nematode were illustrated, and the structure–activity relation and the action mode of the nematicidal phytochemicals were discussed, which will support future works on discovery of novel potent natural nematicides and the derivatives of natural products with higher nematicidal activity against pine wood nematode. [ABSTRACT FROM AUTHOR]

Bursaphelenchus xylophilus, causal agent of pine wilt disease, causes extensive damage worldwide. Strategies are needed to inhibit population growth or block the spread of the invasive nematode to control pine wilt disease. The gene daf-8 plays crucial roles in larval development and dauer formation in Caenorhabditis elegans, but little is known about its orthologue in B. xylophilus. In the present molecular characterization and functional analysis of daf-8 in B. xylophilus (Bx-daf-8), RT-qPCR showed that the expression of Bx-daf-8 gradually increased during the embryonic stage, peaked in the second-stage juvenile (J2), then dramatically dropped in the J3, and remained at that low level for the rest of its life. Bx-daf-8-transgenic C. elegans was employed to mimic the spatiotemporal expression of Bx-daf-8, which was expressed close to the pharynx during early embryogenesis and weakly throughout the whole body during late embryogenesis. It was observed in head neurons and tail ganglions throughout all postembryonic stages. B. xylophilus embryos were severely abnormal, and hatching rate decreased sharply after Bx-daf-8 knockdown. daf-16-1 and da-f16-2, downstream genes in the IIS pathway, also dropped sharply after Bx-daf-8 knockdown. We propose that TGFβ may crosstalk with the IIS pathway upstream of Bx-daf-16 and that daf-8 may act as a master regulator of daf-16 in B. xylophilus. However, knockdown of Bx-daf-8 did not lead to constitutive developmental arrest at the dauer larval stage, indicating that dauer entry in B. xylophilus might be controlled by several genes and is more complicated than in C. elegans. Bx-daf-8 alone did not control the dauer entry in B. xylophilus, but it was indispensable for embryogenesis, providing a potential target for suppressing population growth of B. xylophilus. [ABSTRACT FROM AUTHOR]

Pine wilt disease was first discovered in Dongtang town, Liaoning Province, China, in 2017. Monochamus saltuarius Gebler is a new vector of pinewood nematode and the only known vector in Liaoning Province. The biology of this pest has not been reported thus far; therefore, it is necessary to study its life history. During 2018 and 2019, we collected 138 and 491 adult M. saltuarius beetles, respectively, to analyze their eclosion from larva to adult stage. In mid-March, overwintering larvae began to feed (on xylem) and seek nutrition in preparation for pupation and eclosion. The adults began to appear in mid-April, and the population reached its peak in late May. The life span of the adults was 28–76 days. After approximately 1 week of supplemental nutrition (feeding on twigs), adults began to mate and lay eggs. The egg stage of M. saltuarius lasted 4–8 days. The larvae in Dongtang town have 4 instars and overwinter in tunnels as 3rd–4th instars. The 1st-instar stage lasted 3–9 days, the 2nd-instar stage lasted 11–23 days, the 3rd-instar stage lasted 30–130 days, and the 4th-instar stage lasted 44–180 days. The pupal stage lasted 7–12 days, and the life span of the adults was 28–76 days. In this study we systematically monitored the life history of M. saltuarius for the first time. Our objective was to lay a foundation for improving control of this pinewood nematode vector. [ABSTRACT FROM AUTHOR]

Pine wilt disease, caused by Bursaphelenchus xylophilus and Bursaphelenchus mucnatus, is a serious quarantined disease. Arboreal nematode-trapping fungi of Pinus spp. are effective predators on nematodes and have strong host adaptability. The development of these fungal resources may be an effective way to control pine wood nematodes. We collected 515 samples of pine wilt disease from the areas of Ninghai City (Zhejiang province), Shuangbai County (Yunnan province), and Daxing'anling (Heilongjiang province), China. Through isolation, culture and identification, 6 species of nematode-trapping fungi (Arthrobotrys cladodesr, A. oligospora, A. musiformis, A. dendroides, Dactylellina ellipsospora, Monacrosporium thaumasium) were identified for predation against B. xylophilus, and 9 species (Arthrobotrys dactyloides, A. cladodesr A. oligospora A. dendroides, Dactylellina ellipsospora, Dactylella asthenopaga, D. leptospora, Arthrobotrys superba, Monacrosporium drechseri) were identified for predation against B. mucnatus. This study provides information in the classification of arboreal predator nematodes and provides an important basis for future biological control of pine wood nematodes. [ABSTRACT FROM AUTHOR]

Genes homologous to members of the MRP gene family in Caenorhabditis elegans are important in drug resistance. To further explore the molecular mechanism of drug resistance in pine wood nematode (Bursaphelenchus xylophilus), we used bioinformatics approaches to analyze genomic data for B. xylophilus and identified Bx-MRP genes. We predicted the structure and function of the genes and encoded proteins. Using bioinformatics programs to predict and analyze various properties of the predicted proteins, including hydrophobicity, transmembrane regions, phosphorylation sites, and topologically isomeric structures, of these Bx-MRP genes, we determined that they function in transmembrane transport. From the results of RT-qPCR, the Bx-MRP family members confer significant differential resistance to different drug treatments. After treatment with different concentrations of emamectin benzoate, avermectin and matrine, the expression of each gene increased with increasing drug concentrations, indicating that the family members play a positive role in the regulation of multidrug resistance. [ABSTRACT FROM AUTHOR]

Background: Bursaphelenchus xylophilus, commonly known as the pine wood nematode (PWN), is one of the most destructive nematode species. It causes pine wilt, a slow progressive disease that results in economic loss worldwide. Objective: Here, we review the nematode detection methods, including morphological, molecular, chemical, and protein-based methods, and assess how the nematode's distribution, virulence, incidence, and severity may be attenuated. Results: Pathogenicity of the pine wood nematode is determined via its morphological and molecular characteristics. Many studies have used nucleic acid PCR amplification as a molecular-based technique, but there are often problems with DNA isolation. Currently, molecular-, chemical-, and protein-based analysis methods are used to diagnose emerging pine wilt diseases. Conclusion: It is important to quickly diagnose and treat symptomatic trees, but the asymptomatic trees also require quick diagnosis and removal. For this reason, morphological- and DNA-based methods should be combined with chemical- and protein-based approaches for quick and efficient detection. [ABSTRACT FROM AUTHOR]

Bursaphelenchus xylophilus is an economically important pathogen that has caused serious damage to pine forests. Fatty acid and retinol-binding proteins (FARs) are nematode-specific proteins. One FAR gene, Bx-FAR-1, was identified from the transcriptome of B. xylophilus as a putative effector. It was upregulated in both highly and weakly virulent isolates in early infection stages. Transient expression assays showed that Bx-FAR-1 inhibited BAX- and INF1-induced cell death in Nicotiana benthamiana when secreted into the intracellular site. Bx-FAR-1 was expressed in the glandular tissues, intestines, and seminal vesicles of nematodes by in situ hybridization. Silencing Bx-FAR-1 via in vitro RNA interference attenuated the reproductive ability and pathogenicity of B. xylophilus as well as increased the expression of the pathogenesis-related gene 6 and JA biosynthesis gene LOX-5 (lipoxygenase-5) in pine trees. These results suggest that Bx-FAR-1 suppresses the plant immune response in the N. benthamiana intracellular site and may contribute to the pathogenicity of B. xylophilus in the early infection stages. [ABSTRACT FROM AUTHOR]

Competitive displacement is not only the most extreme outcome of interspecific competition, but also an important strategy for invasive species to be successful invaders. Pinewood nematode, Bursaphelenchus xylophilus, the causal agent for pine wilt disease and global quarantine pest, usually displaces Bursaphelenchus mucronatus, a native sympatric sibling species, during its invasion process. Despite this prevalent outcome, the driving forces behind this displacement remain elusive. Ascarosides, an evolutionarily conserved family of nematode pheromones, are versatile in structure and function. We hypothesize these nematode pheromones play a role in species displacement. To investigate this hypothesis, we compared the ascarosides composition of B. xylophilus and B. mucronatus by LC–MS/MS followed by bioassays to test the responses of two nematodes to both crude and synthetic ascarosides. We found that asc-C5 (ascr#9) was the most abundant component and that there were no differences in pheromone composition between the two nematode species. B. xylophilus had faster growth rates under competition conditions. Furthermore, low concentrations of both crude and synthetic ascarosides [asc-C5, asc-C6 (ascr#12) and their mixture] enhanced female fecundity and body length growth in B. xylophilus but not in B. mucronatus. In contrast, body length of B. mucronatus was suppressed by a crude extract of its own ascarosides as well as by synthetic ascarosides (asc-C5, asc-C6 and their mixture). Our results strongly suggest that ascarosides play a role in the competitive displacement between two nematode species, which could explain the phenomena observed in B. xylophilus-invaded forests where B. mucronatus widely existed prior to B. xylophilus invasion. [ABSTRACT FROM AUTHOR]

Alternatives to methyl bromide fumigation are needed for the phytosanitary treatment of log exports. Among the potential alternative, fumigants are phosphine, and sulfuryl fluoride, which are already in use for other commodities and are labeled for use on wood products. Ethanedinitrile is being used for log treatment in Australia and its registration for that purpose is being sought in other countries. These alternative fumigants were tested against the pinewood nematode, in a range of artificially infested wood samples with high moisture content and, in some cases, the bark layer intact on the surface exposed to the fumigant. Phosphine and sulfuryl fluoride successfully eliminated pinewood nematodes on pine wood chips but neither was completely effective on pine blocks with intact bark. Ethanedinitrile was effective on pine chips, blocks and logs at all the doses tested: 40–100 mgL−1 for 24 h at 20 °C. Ethanedinitrile appears to be a promising alternative to methyl bromide for the fumigation of pine logs. Further testing at lower temperatures and doses, and with commercial-scale log loads, is recommended. [ABSTRACT FROM AUTHOR]

Fluopyram, an excellent nematicide, has better water solubility than abamectin; this feature is important for its systemic transport in trees as a trunk-injection agent. To identify the potential of fluopyram as a trunk-injection agent against Bursaphelenchus xylophilus, its toxicity to different developmental stages and effects on the egg hatching and reproduction of B. xylophilus were studied. Fluopyram exhibited significant nematicidal activity similar to that of abamectin, with LC50 values of 0.945, 1.69 and 3.23 mg L− 1 for second-stage juveniles (J2), third-stage juveniles (J3) and fourth-stage juveniles/adults (J4/adults), respectively. The hatching rate at a fluopyram concentration of 3 mg L− 1 was 20.78%, significantly lower than that in the control group (90.48%) at 24 h. In addition, the reproduction of B. xylophilus at a concentration of 2.21 mg L− 1 decreased significantly, similar to the effect of abamectin at 1.42 mg L− 1. In a hydroponic experiment, fluopyram treatment decreased the number of B. xylophilus at a concentration of 64 mg L− 1. Fluopyram exhibited a greater inhibitory effect than abamectin. Overall, fluopyram has significant nematicidal activity against B. xylophilus and shows potential to be a new trunk-injection agent. [ABSTRACT FROM AUTHOR]

Esteya vermicola is an endophytic fungus of pine wood nematode(s) (PWN) Bursaphelenchus xylophilus and a promising biocontrol agent. However, until now, only the lunate spores of E. vermicola have been demonstrated to be highly effective against pine wilt disease. In the present study, blastospores of E. vermicola were successfully used as a biocontrol agent through injection into large pine trees in Aewol-eup, Jeju, South Korea. When pine trees were injected with a 6–8 mL blastospore suspension of E. vermicola (108 mL−1) 1 month before inoculating them with PWN, 73.77% of the trees remained alive after one year. When injected with blastospores of E. vermicola 2 and 4 weeks after PWN infection, 40% of the trees were saved. As a control, the pine trees inoculated with PWN only all died. Moreover, a hypothesis of the mechanism of biocontrol within the pine tree was proposed based on the population density of PWN over time along with the presence of E. vermicola in the pine tree. The hypothesis involved a cycle that included the growth of E. vermicola without PWN infection, attraction and adhesion to PWN, movement and death of infected PWN, production of a second generation of lunate spores, and attraction of other migratory PWN. [ABSTRACT FROM AUTHOR]

Pine wilt disease (PWD) is a devastating disease affecting the growth of Pinus massoniana, often leading to withering and death. To reveal the changes involved during disease progression, we investigated the mRNA expression profile of P. massoniana infested by Bursaphelenchus xylophilus. The infestation resulted in the downregulation of genes involved in interactions with pathogenic pathways such as disease resistance gene, CC-NBS-LRR resistance-like protein, and the gene encoding a putative nematode resistance protein. Increased infestation pressure (number of nematodes inoculated) caused a continuous decline in the gene expression of stem samples. An infestation of P. massoniana also resulted in a pathway enrichment of genes involved in phenylpropanoid metabolism and flavonoid biosynthesis, which in turn reduced the levels of total phenols and total flavonoids. A downregulation of auxin responsive family protein was observed in infested samples, which resulted in a suppression of plant growth. Thus, upon B. xylophilus infestation, a downregulation of genes associated with the recognition of pathogens, PWD resistance, and growth regulation was observed in P. massoniana, together with a decrease in the levels of phytoalexin-like secondary substances, all of which resulted in withering and ultimately death of P. massoniana. [ABSTRACT FROM AUTHOR]

Pine wilt disease (PWD) affects forests globally and is caused by the pinewood nematode (PWN) Bursaphelenchus xylophilus. It has been proposed that PWD development has a strong association with air temperature. Because symptom development is related to the number of PWNs and they are poikilothermic animals whose development and multiplication are affected by temperature; it appears that temperature conditions affect the PWN multiplication rate, which leads to difference in disease progression. However, limited information is available about the temperatures inside pine trees, and the understanding of how temperature affects PWN multiplication and PWD progression remains incomplete. Therefore, in the present study, we evaluated the temperature, number of PWNs, and external symptoms of PWD in Pinus thunbergii seedlings infected with PWNs at air temperatures of 20 °C, 25 °C, and 30 °C over time. We found that the seedling temperatures were slightly higher than the air temperature under each temperature condition and that the effective accumulated temperature calculated using a base temperature of 10 °C was related to the number of PWNs and symptom development in all temperature test groups. However, at 20 °C, there were very few PWNs in some seedlings and none of the seedlings showed partial or full wilting. These findings suggest that PWD progression is greatly affected by ambient temperature and facilitated by increase in PWN populations with effective accumulated temperature especially in the range of 25 °C–30 °C. [ABSTRACT FROM AUTHOR]

Pinewood nematode [Bursaphelenchus xylophilus (Steiner & Buhrer, 1934)] is considered a significant threat to European forests. Functional monitoring of its vector, the longhorn beetle Monochamus galloprovincialis (Olivier, 1795), represents an efficient method of pinewood nematode detection and needs to be adopted across European countries. Hence, the effectiveness of M. galloprovincialis trapping under different attractants and trap heights above the ground was investigated at four forest study sites in the Czech Republic in 2015–2016. Additionally, the effects of the calendar week and meteorological variables were assessed. In total, 24 Teflon-coated cross-vane traps (Crosstrap® traps) captured 1524 M. galloprovincialis individuals and 36,896 nontarget insects. Traps placed in the canopy (18–24 m above the ground) captured sevenfold more M. galloprovincialis individuals than those installed 2 m above the ground, and the Spanish attractant Galloprotect Pack® resulted in three times more catches than the Austrian attractant Gallopro Pinowit®. The highest maximum daily temperature during trap exposure was also an important factor, with most catches occurring above 27 °C. The results showed that Teflon-coated cross-vane traps with Galloprotect Pack® attractant are efficient tools for M. galloprovincialis monitoring in Central European forests when installed in the tree canopy. Additionally, we suggest using traps with larger sieve mesh sizes at the bottom to enable the escape of small nontarget taxa. During the 2-year study, the pinewood nematode was not found. However, 38 specimens of M. galloprovincialis were shown to be vectors of Bursaphelenchus mucronatus (Mamiya & Enda, 1979) dauers. [ABSTRACT FROM AUTHOR]

Pine wood nematode (PWN), Bursaphelenchus xylophilus, causes pine wilt disease (PWD) in Pinus species given suitable climatic conditions. A model was run for Germany to assess the potential that Pinus sylvestris trees succumb to pine wilt once B. xylophilus has been introduced. The following climate scenarios have been modelled: current climatic conditions, an exceptional hot year (2003) and two future climatic conditions with target year 2050 for low (B1) and middle (A1B) emission scenarios based on the IPCC classification. Additional parameters included in the model were nematode inoculum, time of infestation and tree physiological conditions (healthy ors stressed). Under the current climatic conditions, P. sylvestris would not develop PWD assuming that trees are healthy. However, water-stressed trees in the river Rhine area south-west of Germany may succumb to PWD in the current climate. Climatic conditions like those experienced in 2003 would support the expression of PWD in healthy trees in the south of Germany and in almost the whole of Germany if the trees are stressed. Predicted future temperature increases up to 2050 under both emission scenarios will lead to more stress, placing extensive areas of Germany at risk of PWD, including the north-eastern part where Pinus sylvestris is the dominant tree species. [ABSTRACT FROM AUTHOR]

To accelerate the breeding and selection of Pinus densiflora Siebold and Zucc. resistance to pine wilt disease, a micropropagation system was established and nematode resistance evaluated in vitro. Cotyledon-hypocotyl explants from 28-day-old seedlings were first cultured on Gresshoff and Doy medium supplemented with 4.0 mg L−1 6-benzyladenine and 0.2 mg L−1 α-naphthaleneacetic acid (NAA) to stimulate the formation of buds. Induced buds were subsequently subcultured on Gupta and Durzan medium supplemented with 0.1% (w/v) activated charcoal for elongation. Stem sections derived from shoots were used as explants for the further multiplication. Roots were formed from shoots transferred to woody plant medium containing 0.2 mg L−1 NAA for 4 weeks. The nematode resistance test showed that symptoms in micropropagated shoots after infection with pine wood nematode (PWN) were similar to those in plants infected in the field. The wilting rate varied from 20 to 100% among different clones 18 days after inoculation. The most susceptible clone was Clone 6-4 with a 100% wilting rate, while Clone 8-4 showed a relatively high resistance with a 20% wilting rate. The number of nematodes recovered from Clone 8-4 shoots was significantly lower (P = 0.05) than from Clones 5-10 and 16-4. This work contributes to the breeding of PWN resistance in P. densiflora. [ABSTRACT FROM AUTHOR]

Bursaphelenchus xylophilus is the pathogen that causes pine wilt disease, which has greatly damaged forests and ecosystems in countries of East Asia and Europe. Bursaphelenchus mucronatus is closely related to B. xylophilus in morphology and host plant specificity. A long-running debate has existed regarding whether these two species can successfully produce hybrid offspring. In the present study, we performed in the laboratory, hybridization of two B. xylophilus nematode isolates from China and Japan and three B. mucronatus isolates from China, Japan and France. Nematode isolates of B. xylophilus were successfully crossed with B. mucronatus isolates, and the rate of hybridization was relatively high; however, some hybrid offspring died. Successful hybridization occurred between B. xylophilus and B. mucronatus isolates from China, and 22 generations of hybrids were produced. All F1 hybrids could be backcrossed with their parents and produce offspring. Variation in mucro length among the hybrid offspring and their parents was observed. The hybrid offspring and their parents were inoculated into 3-months-old black pine (Pinus tunbergii) seedlings. Weaker pathogenicity of hybrid offspring was observed compared with that of their parents, and significantly fewer offspring nematodes than parents were reisolated from pines. Therefore, the offspring of B. xylophilus and B. mucronatus may exist in the forest and could influence disease epidemics. [ABSTRACT FROM AUTHOR]

Understanding the coevolution of pathogens and their associated mycoflora depend upon a proper elucidation of the basis of their chemical communication. In the case of pine wilt disease, the mutual interactions between cerambycid beetles, invasive pathogenic nematodes, (Bursaphelenchus xylophilus) and their symbiotic ophiostomatoid fungi provide a unique opportunity to understand the role of small molecules in mediating their chemical communication. Nematodes produce ascarosides, a highly conserved family of small molecules that serve essential functions in nematode biology and ecology. Here we demonstrated that the associated fungi, one of the key natural food resources of pine wood nematodes, can detect and respond to these ascarosides. We found that ascarosides significantly increase the growth of L. pini-densiflorae and Sporothrix sp. 1, which are native fungal species in China that form a symbiotic relationship with pinewood nematodes. Hyphal mass of L. pini-densiflorae increased when treated with asc-C5 compared to other ophiostomatoid species. Field results demonstrated that in forests where higher numbers of PWN were isolated from beetle galleries, L. pini-densiflorae had been prevalent; the same results were confirmed in laboratory studies. Furthermore, when treated with asc-C5, L. pini-densiflorae responded by increasing its production of spores, which leads to a higher likelihood of dispersal by insect vectors, hence explaining the dominance of L. pini-densiflorae over S. sp. 1 in the Tianwang and Nanlu Mountains within the Northern Forestry Centre of China. These findings provide an emphatic representation of coevolution of pine wood nematode and its associated fungi. Our results lay a broader foundation for a better understanding of inter-kingdom mutualisms and the chemical signals that mediate their establishment. [ABSTRACT FROM AUTHOR]

Pine trees have economically and ecologically important roles. However, since the beginning of the twentieth century, a large number of trees have been seriously damaged by pine wilt disease (PWD). Although many studies have been conducted into blocking the spread of PWD, relatively few studies have been performed to examine the transcriptional responses of pine trees to the pine wood nematode (PWN). Here, we performed de novo assembly and analysis of the Pinus densiflora transcriptome by next-generation sequencing (NGS), to identify transcriptional responses that are related to the PWD infection. We identified that 586 of 71,003 assembled unigenes were differentially expressed after PWD infection. Gene ontology analysis showed that biological process terms related to defense responses (response to oxygen containing compound, response to jasmonic acid, response to biotic stimulus, cinnamic acid biosynthetic process, etc.) were significantly enriched in the DEGs after PWD infection. Our results suggested that jasmonic acid signaling is important in controlling defense response against PWD infection and is finely tuned by coordinated expression of positive and negative regulators. These findings contribute to our understanding of the transcriptional responses of P. densiflora to PWN, and could facilitate the development of biomarkers for diagnosis of PWD. [ABSTRACT FROM AUTHOR]

We reconstructed the phylogeography of European populations of Monochamus galloprovincialis (Coleoptera, Cerambycidae), the European vector of the pinewood nematode, Bursaphelenchus xylophilus. This study investigated the Quaternary history of M. galloprovincialis and tested whether environmental parameters and/or host tree species influenced the genetic structure of M. galloprovincialis populations. Twelve polymorphic microsatellite loci and a Bayesian analysis were applied to 1098 individuals of M. galloprovincialis from 45 European locations. The continental populations formed five main genetic clusters, typical of postglacial recolonization routes observed for temperate biota associated with pine trees. The distribution of clusters formed boundaries along mountain ranges, indicating a potential role of elevation as a large-scale barrier to dispersal for this species. The correlation between environmental parameters and the distribution of genetic clusters of M. galloprovincialis was investigated using a partial redundancy analysis and showed an effect of precipitation rather than host tree species. From an applied perspective, these results suggest that climatic conditions and elevation may constitute barriers to the dispersal of M. galloprovincialis and the associated PWN. [ABSTRACT FROM AUTHOR]

Pine wilt disease (PWD) results from the interaction of three elements: the pathogenic nematode, Bursaphelenchus xylophilus; the insect-vector, Monochamus sp.; and the host tree, mostly Pinus species. Bacteria isolated from B. xylophilus may be a fourth element in this complex disease. However, the precise role of bacteria in this interaction is unclear as both plant-beneficial and as plant-pathogenic bacteria may be associated with PWD. Using whole genome sequencing and phenotypic characterization, we were able to investigate in more detail the genetic repertoire of Serratia marcescens PWN146, a bacterium associated with B. xylophilus. We show clear evidence that S. marcescens PWN146 is able to withstand and colonize the plant environment, without having any deleterious effects towards a susceptible host ( Pinus thunbergii), B. xylophilus nor to the nematode model C. elegans. This bacterium is able to tolerate growth in presence of xenobiotic/organic compounds, and use phenylacetic acid as carbon source. Furthermore, we present a detailed list of S. marcescens PWN146 potentials to interfere with plant metabolism via hormonal pathways and/or nutritional acquisition, and to be competitive against other bacteria and/or fungi in terms of resource acquisition or production of antimicrobial compounds. Further investigation is required to understand the role of bacteria in PWD. We have now reinforced the theory that B. xylophilus-associated bacteria may have a plant origin. [ABSTRACT FROM AUTHOR]

The pine wood nematode (PWN) Bursaphelenchus xylophilus is the causal agent of pine wilt disease (PWD), a xylem restricting disease of pine trees. PWN, a native of North America where it very rarely kills native pine trees, has spread internationally killing host trees in China, Japan, Korea, Taiwan and Portugal, with isolated incursions into Spain. Based on the locations where tree mortality has been recorded, it appears that pine trees growing in hot, dry conditions are more susceptible to pine wilt disease. This paper describes the ETpN model, an evapo-transpiration model (previously developed by Forest Research), which has been modified to incorporate the presence of PWN inside a tree and which predicts the regions of Europe that are likely to succumb to PWD. ETpN acts independently of the vector beetle ( Monochamus spp.), predicting the likelihood of PWD on the assumption that a tree in a particular region has already been infested by the pine wood nematode. Different regions across Europe are included to investigate and demonstrate how different climates affect PWD incidence significantly. Simplified, 'lite' and latency models have been developed to allow a non-specialist user to determine respectively the risk of PWD at a particular location and the likelihood of delays (latency) in expression of wilt symptoms. [ABSTRACT FROM AUTHOR]

Identifying the invasion routes and determining the origin of new outbreaks of invasive species are of crucial importance if we are to understand the invasion process, improve or establish regulatory measures and, potentially, limit the damage. We focused here on the invasion of Europe by the pinewood nematode (PWN), Bursaphelenchus xylophilus (Steiner & Buhrer, 1934; Nickle 1970; Nematoda: Aphelenchoididae), a major pest of forest ecosystems, native to North America and already invasive in Asia since the beginning of the twentieth century. We evaluated the genetic diversity and structure of worldwide field PWN samples by classical and Bayesian population genetics methods to determine the source of the European invasive populations and the number of introduction events in Europe. We found (1) a very strong spatial genetic structure in native PWN populations, (2) a very low level of polymorphism in each of the invaded areas and (3) contrasted results concerning the origin of European invasive populations. Our findings provide evidence for: (1) a large effect of genetic drift on the biological cycle of the PWN, due to intense demographic bottlenecks during tree infections, not compensated for by effective dispersal of its vector; (2) a single introduction event for each of the invaded areas in Japan and Europe and a small effective size for the introduced populations and (3) a mainland Portuguese origin for PWN populations from Madeira. However, more sophisticated methods of invasion route inference and broader sampling are required to conclusively determine the origin of the European outbreak. [ABSTRACT FROM AUTHOR]

The pine wood nematode ( Bursaphelenchus xylophilus) belongs to economically most important quarantine plant parasitic nematodes in Asia and Europe. As wood transported within the international trade plays major role in B. xylophilus spreading into new areas, attention should be given to wood treatment. With methyl bromide ban in the EU in 2000 new chemicals should be investigated. This work describes results obtained from model fumigation of hollow wooden blocks containing B. xylophilus nematodes in sawdust with gaseous hydrogen cyanide (HCN). Data considering HCN concentration in gas chamber and treated wooden blocks are also presented; HCN concentrations inside wooden blocks were recounted to ct product values which show irregular sorption of HCN by the wood. Total B. xylophilus mortality was observed in the variants treated with the initial HCN concentration of 12.30 g m and exposure times from 8 to 20 h, 18.21 g m and exposure times of 2, 4, 6, 10 and 16 to 20 h, 21.71 g m and exposure times of 12, 18 and 20 h and 24.12 g m and exposure times of 2, 6, 12 and 18 h. Results show overall good efficiency of HCN treatment on B. xylophilus mortality, however, research on naturally infested wood should be desirable. [ABSTRACT FROM AUTHOR]

Pine wilt disease is caused by the pine wood nematode [ Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle]. In East Asia, an important vector of the nematode is Monochamus alternatus Hope. We determined the tolerance and reproductive ability of sawyer beetles and the nematode to altitude and temperature at elevations between 850 and 1,450 m on Mt. Fuji in Japan. The number of emergent adults decreased markedly along the altitudinal gradient, but the beetle could still reproduce at 1,050 m (8.2 °C annual mean temperature). Beetles with a 2-year life cycle increased rapidly in number with increasing altitude. The pine wood nematode survived through winter at all altitudes tested (850-1,450 m). The beetle population decreased between 950 (9.1 °C) and 1,150 m (8.3 °C). Therefore, the beetle population seems to be stable at 850 m (10.2 °C) and lower altitudes (higher temperatures) but cannot be maintained from 950 (9.1 °C) to 1,150 m (8.3 °C) without constant immigration of beetles from lower altitudes. The beetles could not reproduce at altitudes above 1,150 m (lower than 8.2 °C). From the mean and effective cumulative temperatures, we concluded that the beetle (and its population) can endure temperatures lower than those previously reported. Pine wilt disease also occurred at lower temperatures and higher altitudes than expected. We have summarized the principal strategies for controlling the disease at high altitudes based on these results. [ABSTRACT FROM AUTHOR]

Pine wilt disease, caused by the nematode Bursaphelenchus xylophilus, is responsible for devastation of pine forests worldwide. Until now, there are no effective ways of dealing with this serious threat. The use of 1-aminocyclopropane-1-carboxylate (ACC) deaminase (encoded by the acdS gene)-producing plant growth-promoting bacteria has been shown to be a useful strategy to reduce the damage due to biotic and abiotic stresses. Pinus pinaster seedlings inoculated with the ACC deaminase-producing bacterium Pseudomonas putida strain UW4 showed an increased root and shoot development and reduction of B. xylophilus induced symptoms. In contrast, a P. putida UW4 acdS mutant was unable to promote pine seedling growth or to decrease B. xylophilus induced symptoms. This is the first report on the use of ACC deaminase-producing bacteria as a potential biological control agent for a tree disease, thus suggesting that the inoculation of pine seedlings grown in a tree nursery might constitute a novel strategy to obtain B. xylophilus resistant pine trees. [ABSTRACT FROM AUTHOR]

Plant parasitic nematodes are the most destructive group of plant pathogens worldwide and their control is extremely challenging. Plant Essential oils (EOs) and their constituents have a great potential in nematode control since they can be developed for use as nematicides themselves or can serve as model compounds for the development of derivatives with enhanced activity. This study reviews the plant EOs evaluated as potential nematicides and their toxic effects against pinewood nematode ( Bursaphelenchus xylophilus) and root-knot nematodes ( Meloidogyne spp.). Additionally, the nematicidal activity to M. javanica of several EOs from Spanish aromatic plants and their components is described. [ABSTRACT FROM AUTHOR]

Pine wilt disease (PWD) is caused by the pinewood nematode (PWN), Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle, and is transmitted by cerambycid beetles. In some pine trees infected with the PWNs in Japan, foliage changes from green to brown in summer to autumn of a nematode infection year (summer- autumn-killed trees) and the others in the following spring of a nematode infection year (spring-killed trees). The vector beetles require 1 or 2 years for development in cool summer areas and 1 year in warm summer areas. To evaluate the effects of the spring-killed trees and vectors with a long developmental time on the PWD epidemics, we presented simple mechanistic mathematical models. The models showed that it was possible for spring-killed trees to cause PWD epidemics when the transmission rate was high, and the efficacy of spring-killed trees as infection source was similar to that of summer- autumn-killed trees. Spring-killed trees and vector beetles with a developmental time of 2 years harbored in summer- autumn-killed trees delayed epidemic timing by 3-10 years or actually suppressed epidemics. [ABSTRACT FROM AUTHOR]

The content of NO and HO as well as the activities of nitric oxide synthase (NOS)-like and nitrate reductase (NR) were monitored in the needles of Pinus thunbergii infected by Bursaphelenchus xylophilus. The results showed that the content of NO increased significantly only 8 h after the invasion of B. xylophilus, while HO increased 12 h after invasion. NO donor SNP could promote and NO scavenger cPTIO could prevent the production of NO and HO. The content of NO changed earlier than that of HO. In addition, the symptoms appeared 9, 5 and 12 days, respectively, after the inoculation with B. xylophilus, SNP pre-treatment and cPTIO pre-treatment followed by B. xylophilus infection. After B. xylophilus infection, the content of NO in P. thunbergii changed fiercely more earlier than the appearance of external symptoms, which indicated that the content of NO was related with the appearance and the development of the symptoms. The treatment with l-NNA (NOS inhibitor) inhibited the content of NO significantly, whereas, NaWO (NR inhibitor) had no effect. The further analysis of NOS revealed that NO changed in consistent with cNOS activity. To sum up, NO, as the upstream signal molecule of HO, was involved in the pine early response to the invasion of B. xylophilus and influenced the accumulation of the content of HO. Moreover, NOS-like rather than NR was responsible for the endogenous NO generation, which was modulated by cNOS during the interaction between P. thunbergii and B. xylophilus. Key message NO is involved in early response of P. thunbergii to the invasion of B. xylophilus and NOS is the key enzyme responsible for NO generation in P. thunbergii. [ABSTRACT FROM AUTHOR]

Bursaphelenchus xylophilus, the pinewood nematode (PWN) and causal agent of Pine Wilt Disease (PWD), was detected for the first time, in 1999, in Portugal, and in Europe. Despite the efforts of the Portuguese National Forestry and Quarantine Authorities, the disease has spread to new forest areas in the centre of mainland Portugal, in 2008, and to the island of Madeira, in 2009. More recently, two foci of PWD were reported from Spain. The free circulation of non-treated wood and wood products, as part of global trade, may explain this phenomenon, which constitutes a threat to other European forestlands. This review gathers the most recent up-to-date information about PWD in Europe, as well as in other countries, presenting integrative management procedures for detection and control, and the scientific knowledge generated over the last decade, to understand the complex biological system behind the disease. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare the response to infestation by the pine wood nematode (PWN) Bursaphelenchus xylophilus between Pinus pinaster and P. pinea at an initial stage of the disease, 3 h after inoculation. The PWN is the causal agent of pine wilt disease and is destroying pine forests all over the world. In Portugal its main host is the maritime pine, P. pinaster, and its vector is the longhorn beetle Monochamus galloprovincialis. Interestingly, this disease does not seem to affect the species P. pinea and several factors could be behind this difference in susceptibility. With regards to the effects of the disease at a transcriptional level, the suppression subtractive hybridization (SSH) technique was utilized to identify Expressed Sequence Tags (EST) in P. pinaster and P. pinea when inoculated with PWN. EST were isolated, cloned, sequenced and identified using BlastN and BlastX, and indicated that at an initial stage of the disease there is activation of a tree defence response at a molecular level, mainly related to oxidative stress, production of lignin and ethylene and post-transcriptional regulation of nucleic acids. 58% of the isolated sequences are not yet described, which shows the lack of genomic information currently available for pine. [ABSTRACT FROM AUTHOR]

In this study, we report on the bacterial community associated with the pinewood nematode Bursaphelenchus xylophilus from symptomatic pine wilted trees, as well as from long-term preserved B. xylophilus laboratory collection specimens, emphasizing the close bacteria-nematode associations that may contribute to pine wilt disease development. [ABSTRACT FROM AUTHOR]

Pinewood nematode is native to North America and has been a deadly exotic pest infecting pine forests in Japan since the 1900s. It was first recorded in 1982 in subtropical China and has since aggressively spread to 113 counties and 14 provinces. As of 2007 the disease has infected over one million hectares of pine forests and 44 million pine trees in China 1982-2007. Besides inspection and quarantine, the main policy to control this disease is to eradicate the infected pines, which is costly and only partially effective. We investigated the community structure of four Pinus massoniana plantations with similar age and site conditions that were infested by pinewood nematode at different times (0, 4, 8, and 12 years), with the community structure in a zonal evergreen broad-leaved forest nearby. Our results demonstrate that the pinewood nematode infection accelerated the succession from the native pine plantations with higher economical values to the zonal evergreen broad-leaved forests which provide more ecological services. The conversion of pine plantations to natural forests is an urgent challenge facing China today. Thus, the infestation of pinewood nematode provides a unique opportunity for the conversion of the pine-dominated plantations and forests into broad-leaved forests and we therefore suggest that the government should invest its limited resources based on an appropriate trade-off between economic loss and ecological gain. [ABSTRACT FROM AUTHOR]

Pseudomonas fluorescens GcM5-1A was isolated from the pine wood nematode (PWN), Bursaphelenchus xylophilus, obtained from wilted Japanese black pine, Pinus thumbergii, in China. In this paper, a genomic library of the GcM5-1A strain was constructed and a toxin–producing clone was isolated by bioassay. Nucleotide sequence analysis revealed an open reading frame of 1,290 bp encoding a protein of 429 amino acids with N-terminal putative signal peptide of 36 amino acids, which shared a similarity of 83, 82 and 80% identity with hypothetical protein PFLU2919 from P. fluorescens SBW25, Dyp-type peroxidase family protein from P. fluorescens Pf-5 and Tat-translocated enzyme from P. fluorescens Pf0-1, respectively. The gene encoding a full-length protein or without the putative signal peptide was cloned and expressed as a soluble protein in E. coli. The recombinant protein was purified to electrophoretic homogeneity by affinity chromatography using a Ni2+ matrix column. Its relative molecular weight was estimated to be 48.5 kDa by SDS-PAGE for full-length protein, and 45.0 kDa for the recombinant protein without putative signal peptide. Bioassay results showed that the recombinant protein with or without the putative signal peptide was toxic to both suspension cells and P. thunbergii seedlings. HPLC analysis demonstrated that components in branch extracts of P. thunbergii were significantly changed after addition of the recombinant full-length protein and hydrogen peroxide, which indicated that it is probably a peroxidase. This study offers information that can be used to determine the mechanism of pine wilt disease caused by the PWN. [ABSTRACT FROM AUTHOR]

The pine sawyer beetle, Monochamus galloprovincialis, is a pest of pine trees in Europe and North Africa. Previously considered a secondary pest of stressed and dying trees, it is now receiving considerable attention as a vector of the pine wood nematode, Bursaphelenchus xylophilus, the causal agent of a lethal wilting disease in susceptible species of pines. Adult beetles are attracted to traps baited with a kairomone blend consisting of a host volatile, α-pinene, and two bark beetle pheromone components, ipsenol and 2-methyl-3-buten-2-ol. More recently it has been shown that mature male M. galloprovincialis produce a pheromone that attracts mature females in a laboratory bioassay. Here, volatiles were collected from mature male and female M. galloprovincialis, and a compound produced specifically by mature males was identified as 2-undecyloxy-1-ethanol from its gas chromatographic retention times, its mass spectrum, and by comparison with synthetic standards. The naturally-derived and synthetic compounds elicited electroantennographic responses from both females and males. Sealed polyethylene vials and polyethylene sachets were shown to be effective dispensers with zero-order release, the latter giving a higher release rate than the former. In two field tests, multiple-funnel traps baited with synthetic 2-undecyloxy-1-ethanol caught both female and male M. galloprovincialis, with higher catches at the higher release rate. This compound also synergized the attractiveness of the kairomone blend, the combined mixture catching 80–140% more beetles than the sum of the catches to each bait separately and luring up to two beetles/trap/d in a moderate-density population. We conclude that 2-undecyloxy-1-ethanol is a male-produced aggregation pheromone of M. galloprovincialis. This is the first example of a sex-specific compound in the cerambycid subfamily Lamiinae with significant behavioral activity in the field at a range sufficient to make it a useful trap bait. The possible roles of this pheromone in the chemical ecology of M. galloprovincialis and its potential use in pine wilt disease management are discussed. [ABSTRACT FROM AUTHOR]

Monochamus galloprovincialis Olivier (Coleoptera: Cerambycidae) is one of the vectors of the pinewood nematode Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle (Nematoda: Parasitaphelenchidae), the causal agent of pine wilt in susceptible pine trees. It is therefore important to study both the biological and ecological characteristics of the beetle. In this study reproductive potentials of female beetles reared on two pine species were investigated under laboratory conditions and compared using fertility tables constructed for beetles reared on each tree species. Beetle population parameters were compared between tree species. The intrinsic rate of increase and associated population parameters of beetles reared on Pinus sylvestris L. were consistently higher than those reared on P. nigra Arnold. This result suggests that P. sylvestris has a significantly greater positive effect on the reproductive potential of M. galloprovincialis populations than does P. nigra. [ABSTRACT FROM AUTHOR]

Pine wood nematode (PWN, Bursaphelenchus xylophilus), originating from North America, causes destructive pine wilt disease. Different pine forest ecosystems have different resistances to B. xylophilus, and after its invasion, the resilience and restoration direction of different ecosystems also varies. In this study, an interpretative structural model was applied for analyzing the response of pine forest ecosystem to PWN disturbance. The result showed that a five-degree multi-stage hierarchical system affected the response of the pine forest ecosystem to PWN disturbance, in which direct affecting factors are resistance and resilience. Furthermore, the analysis to the 2nd, 3rd and 4th degree factors showed that not only does distribution pattern of plant species and pine’s ecological features affect the resistance of pine forests’ ecosystem, but removal of attacked trees and other measures also influence the resistance through indirectly affecting the damage degree of Monochamus alternatus and distribution pattern of plant species. As for resilience, it is influenced directly by soil factors, hydrology, surrounding species provenance and biological characteristics of the second and jointly dominant species, and the climate factors can also have a direct or indirect effect on it by affecting the above factors. Among the fifth elements, the elevation, gradient and slope direction, topographical factors, diversity of geographical location and improvement of prevention technology all influence the response of pine forest ecosystem to PWN disturbance. [ABSTRACT FROM AUTHOR]

Pine wood nematode (PWN), Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle is an important invasive alien species in forests of China and has become one of the most destructive forest diseases. In order to improve the resistance and resilience of pine forest ecosystems against B. xylophilus invasion and make the pine forest ecosystem more timely responsive to PWN invasion, we made some recommendations based on five years of intensive observations. We advocate a set of management measures with the theme “Prevention is priority, but integrated with curative techniques and ecological resilience” on the pine forest ecosystem invaded by B. xylophilus; details of accurate measures are proposed. The aim is to discover the underlying problems of present pine forest ecosystems and to take, correspondingly, administrative measures and strategies, which will encourage the pine forest ecosystem to develop in a benign way. [ABSTRACT FROM AUTHOR]

Our research focused on Pinus massoniana information extracted from remote sensing images based on the knowledge detection and decision tree algorithm and established a spatial pattern model, combining quantitative theoretical ecology with remote sensing (RS) and geometric information system (GIS) techniques. Applying information extraction methods and a spatial pattern model, we studied P. massoniana spatial patterns changes before and after the invasion by pine wood nematode ( Bursaphelenchus xylophilus) in Fuyang and Zhoushan counties, Zhejiang Province, east China. The P. massoniana spatial patterns are clustering, whether the invasion happened or not. But the degree of clustering is different. Our results show good agreement with field data. Applying the results, we analyzed the relationship between spatial patterns and the invasion level. Then we drew the elementary conclusion that there are two kinds of patterns for pine wood nematode to spread: continuous and discontinuous diffusion. This approach can help monitor and evaluate the changes in ecological systems. [ABSTRACT FROM AUTHOR]

The invasion of Bursaphelenchus xylophilus (pine wood nematode, PWN) carried by Monochamus alternatus predominately attacks Masson pine ( Pinus massoniana) forests and causes great economic losses in China. In this study, we assessed whether the effect of the invasion of PWN is different between island and inland forests. Arthropods were sampled in Fuyang (inland) and Zhoushan (island) counties in Zhejiang Province with sweep netting and light traps at four plots. During two field periods (May to June 2004 and September to October 2005) a total of 21,916 insects, representing 384 species belonging to 99 families and 15 orders, were collected in the sample plots from the island, whereas, from the inland forest a total of 29,262 insects, representing 308 species belonging to 96 families and 13 orders, were found. A hierarchical cluster analysis (HCA) and one-way ANOVA, based on the composition of different arthropod guilds, were performed. The results showed that there was no significant difference in the composition of arthropod communities at the family level between inland and island. But these two habitats had a significant effect on the composition of species, individuals, sub-communities and energy class levels. Statistically, the composition of the two orders, Lepidoptera and Diptera, in the two habitats were significantly different. [ABSTRACT FROM AUTHOR]

A polymerase chain reaction-restriction fragment length polymorphism analysis was used to discriminate isolates of Bursaphelenchus xylophilus and B. mucronatus. The amplifications of B. xylophilus isolates yielded one fragment of approximately 890 bp and that of B. mucronatus was about 930 bp. Digestion of amplified products of each nematode isolate with five restriction endonucleases revealed the following results: 1) Dra I digestion of the internal transcribed spacer (ITS) products of B. xylophilus populations yielded two fragments of 510 and 380 bp. Dra I could not digest the ITS products of B. mucronatus populations; 2) Sal I could not digest the ITS products of all B. xylophilus populations, but it could digest those of B. mucronatus populations into two fragments, which were 720 and 220 bp; 3) digested products of four B. xylophilus populations by Msp I yielded two fragments of 530 and 360 bp, except GZ02, which could not be digested. B. mucronatus populations yielded three fragments: 340, 290, and 180 bp; 4) all populations of B. xylophilus and B. mucronatus could not be digested by Apa I; 5) digestion of the ITS products of B. xylophilus and B. mucronatus yielded two fragments of 520 and 370 bp, and 530 and 400 bp respectively. The restriction endonucleases Dra I and Sal I could be used to identify B. xylophilus and B. mucronatus. Because the results of digestion of B. xylophilus and B. mucronatus were markedly different, they were very easy to be identified and applied; Msp I and Xho I were not suitable for identification of B. xylophilus and B. mucronatus and Apa I could not identify and distinguish between B. xylophilus and B. mucronatus. [ABSTRACT FROM AUTHOR]

Since the beginning of the 20th century, pine trees in Japan have been seriously damaged by the pine wilt disease. This disease is caused by the pine wood nematode, Bursaphelenchus xylophilus, which is transmitted by the Japanese pine sawyer, Monochamus alternatus. The control of disease depends to a large extent on chemicals, but the public is now demanding environmentally friendly control methods. The virulence of B. xylophilus varies very widely. Pre-inoculation of young pine trees in a nursery with avirulent B. xylophilus has induced systemic resistance of trees against a subsequent inoculation with virulent B. xylophilus. This induced resistance was considered a hopeful means for developing a biological control for the disease. The induced resistance by the avirulent nematodes was also expressed in mature pine trees in a forest where the disease was naturally epidemic. However, the effects of induced resistance were not satisfactory for practical biological control. Since the inoculation with higher concentrations of the avirulent B. xylophilus induced the resistance more effectively, the pre-inoculation method will need to be improved to develop the biological control. The induced resistance of pine trees by avirulent B. xylophilus should be one of the candidate biological control methods against pine wilt disease. This induced resistance also provides an experimental system to clarify physiological interactions between the nematodes and pine trees. [ABSTRACT FROM AUTHOR]

Nematicidal activity of aloperine, cytisine, N-methylcytisine, and matrine was bioassayed by the agar medium method and the cotton ball method. The corresponding results from the two methods showed that the nematicidal activity of aloperine was the strongest. Its activity, expressed as log (1/ID50) was also the strongest (8.67) in comparison with the previously reported nematicidal activity of seven other quinolizidine alkaloids bioassayed by the same method. We hypothesize that the nematicidal activity of quinolizidine alkaloids is determined primarily by the types of functional group pairs and types of functional group in their molecular structures. Based on this hypothesis, alkaloids with strong nematicidal activity can be predicted on the basis of their structure. [ABSTRACT FROM AUTHOR]

Monochamus galloprovincialis (Coleoptera, Cerambycidae) is the vector of the Pine Wood Nematode ( Bursaphelenchus xylophilus) in Europe. This nematode is the agent of the Pine Wilt Disease (PWD), a syndrome causing important damages in Eurasian pine forests. We report here the development of 12 polymorphic microsatellites loci specific to this species. We observed a moderate allelic richness over all loci. The number of allele per locus ranked from 2 to 8, with an average of 3.75. These markers will help to characterize the effect of the spread of an invader on the genetic structure of a native vector species. [ABSTRACT FROM AUTHOR]

Pine wilt is a serious and fatal disease in pine forests. It is caused by the pine wood nematode, Bursaphelenchus xylophilus, transmitted by the Japanese saw beetle Monochamus alternatus. Control of this disease depends on reducing its vector population. The public is demanding environmentally friendly control methods and biological control has become increasingly seen as an important, safe and effective approach. Through our investigations both in the field and by breeding in our laboratory, a new predator of M. alternatus, Tetrigus lewisi (Coleoptera: Elateridae), was found for the first time in China. Given our continuous observations, we are assured that the predatory behavior of the elater can be separated into four parts, i.e., foraging and sensing, killing, eating and excretion. They always took several hours to eat the preys that have been killed momentarily. We finally found that most of the elaters preferably attacked in the stomach and abdomen of the larva of M. alternatus. [ABSTRACT FROM AUTHOR]