


































Energy and Earth Science 
Vol. 5, No. 3, 2022 

www.scholink.org/ojs/index.php/ees 

ISSN 2578-1359 (Print)   ISSN 2578-1367 (Online) 

26 

Original Paper 

Mathematical Modeling and Review of Pine Wilt Disease 

Abdul Ghaffar Khan
1
, Imran

*2,3
, Hayat Zada

2
, Ansar Hussain

2
 & Tariq Mahmood

4
 

1
 Department of Basic Sciences, University of Engineering and Technology, Peshawar, Pakistan 

2
 Government of Khyber Pakhtunkhwa, Agriculture Extension wing, KP, Pakistan 

3
 Department of Agronomy, The University of Agriculture, Peshawar, Pakistan 

4
 Department of Bioinformatics/Agriculture, Hazara University, Mansehra, KP, Pakistan 

*
 Imran, E-mail: imranagrarian@aup.edu.pk 

 

Received: July 21, 2022      Accepted: August 16, 2022     Online Published: September 7, 2022 

doi:10.22158/ees.v5n3p26                    URL: http://dx.doi.org/10.22158/ees.v5n3p26 

 

Abstract 

Pine Wilt Disease (PWD), caused by the pinewood nematode (PWN) Bursaphelenchus xylophilus, 

causes significant losses in coniferous forests in eastern Asia, including Japan, China, and South 

Korea, as well as western Europe, including Portugal. The results of the research papers given at the 

International Symposium on Pine Wilt Disease (IUFRO Working Party Meeting 4.04.03) in Nanjing, 

China, in July 2009 are summarized in this article. The basic themes discussed included pine wilt 

disease (PWD), the pinewood nematode (PWN) Bursaphelenchus xylophilus, and other 

PWN-associated microorganisms that play a significant role in PWD, such as bacteria (e.g., 

Pseudomonas fluorescens). The majority of the papers are based on PWD-PWN research in East Asia 

and Russia. The following are some of the specific topics covered: 1) fundamental concepts of PWD 

development, 2) pathogenicity, 3) host-parasite relationships, including histopathology of diseased 

conifers and the role of toxins from bacteria-nematode ecto-symbionts, 4) PWN life cycle and 

transmission, 5) B. xylophilus dissemination models, 6) associations (with other nematodes), 7) 

diagnostics, 8) quarantine and control of the PWN and 9) biocontrol of the PWN. 

Keywords 

review, a brief survey of research on Pine Wilt Disease 

 

 

 

 

 

 



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1. Introduction 

Pine Wilt Disease (PWD), caused by the pinewood nematode (PWN) Bursaphelenchus xylophilus, 

causes significant losses in coniferous forests in eastern Asia, including Japan, China, and South Korea 

(Zhao, 2008, pp. 264-274) as well as western Europe, including Portugal (Mota & Vieira, 2008). As a 

result, the PWN is one of the most important pests on many countries' quarantine lists around the 

world. 

An International Pinewood Disease Symposium was organised in Nanjing Forestry University on July 

20-23, 2009, under the auspices of the International Union of Forest Study Organizations (IUFRO), as 

a result of the relevance of PWD and ongoing research on the topic. This symposium included over 130 

researchers from 12 nations, who presented their most recent research findings on both the pathogen 

and PWD. We evaluate the most recent research on the issues covered in the symposium, as well as 

other relevant papers, such as surveys being conducted in different countries, PWD pathogenicity, 

PWN taxonomy, and pine wilt control. 

Longhorn beetles of the genus Monochamus vector the PWN’s juvenile transmissive stage. The PWN 

interacts with a variety of wood-inhabiting microorganisms during its life cycle, including fungus on 

which it feeds and reproduces, as well as ecto-symbiotic bacteria from the genus Pseudomonas. PWNs 

eat on plant tissue in living trees and the mycelium of xylobiotic fungi in dead trees, and they live in 

resin channels within the wood. The PWN was introduced into southwestern Europe from East Asia in 

the 1990s, causing significant forest damage (Mota, Braasch, Bravo, Penas, Burgermeister, Metge & 

Sousa, 1999, pp. 727-734). Because of the devastating Pan-European spread of pine wilt disease in 

Portugal, the National Eradication Program to Control the Pinewood Nematode (PROLUNP) was 

established to develop protocols for controlling the PWN, as existing EU measures were ineffective 

(Rodrigues & Sousa, 2009, p. 23; Rodrigues, 2008, pp. 5-14). As a result of global warming, the PWN 

may invade Russia and parts of central and northern Europe. This, combined with the possibility of 

hybridization between the harmful species B. xylophilus and the widely distributed but weakly 

pathogenic B. mucronatus, could result in new pathogenic races, as seen in Japan (Togashi, Kasuga & 

Matsunaga, 2009, pp. 38-39). 

 

2. Fundamental Conceptions of PWD Development 

PWD is thought to be caused by the interaction of three factors, including the presence of: 1) a 

susceptible pine host whose death is a prerequisite for vector beetle oviposition, 2) specific fungi upon 

which the PWNs feed and multiply, and 3) certain mycorhizas, which together promote plant immunity 

and water uptake, both of which decrease host mortality while favouring PWD spread, according to 

various studies (Futai, 1997, pp. 171-181; Futai, 2008, pp. 5-12). Zhao (Zhao & Lin, 2005, pp. 339-345; 

Zhao, 2009, pp. 14-19) believes that a combination of these two factors, namely 1) B. xylophilus 

nematodes and 2) bacteria of the Pseudomonas fluorescens species group (these bacteria are 

ecto-symbyonts on the nematode’s mucous body sheath), is required for PWD development. In an 



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infected tree, as well as on pine callus tissue, nematodes and bacteria boost each other’s multiplication. 

PWN proliferation is stimulated, DNA is destroyed, and pine phloem cells are killed by a protein that is 

similar to the flagellin of P. fluorescens. The mucous body sheath extract reduces the plant’s 

immunological response and promotes Pseudomonas proliferation. When bacteria from B. xylophilus 

species are added to plant tissue cultures, axenic B. mucronatus nematodes (non-pathogenic species of 

the B. xylophilus group) become pathogenic, whereas surface-sterilized Bursaphelenchus nematodes do 

not cause wilt symptoms. Because dying trees attract the beetle that vectors the nematodes and 

associated ecto-symbiotic bacteria, tree death (i.e., death caused by PWD) is an essential condition for 

the PWN-Pseudomonas life cycle to be completed. 

 

3. Pathogenicity 

Only the Japanese strain was harmful to Cedrous deodara in a pathogenicity test with two PWN isolates 

from China and Japan, although both isolates were pathogenic to Pinus thundergii and Pinus 

massoniana (Han, Ben & Zheng, 2009c, p. 57). Pinus k.comoraiensis and Larix olgensis seedlings were 

destroyed by the B. mucronatus isolate (BmRFE) from Pinus koraiensis (Russian Far East), however 

Pinus sylvestris and Pinus densiflora seedlings survived. Furthermore, only the French strain of B. 

mucronatus induced P. sylvestris to wilt out of two B. mucronatus isolates (Kulinich, Zhao & Kozyreva, 

2010, pp. 153-154). Three B. mucronatus isolates from different parts of Russia were studied (Grant 

RFBR 100401644), and it was discovered that B. mucronatus (BmRFE) harboured the most phytotoxic 

bacterium (Zhao, 2009, pp. 14-19). 

The authors investigated (Figure 1) the possibility of invasive species B. xylophilus genetic 

introgression into native populations of B. mucronatus (BM) and its impact on pathogenicity (Togashi, 

Kasuga & Matsunaga, 2009, pp. 38-39). The F1 BM PWN males were backcrossed with virgin females 

from the parent populations of BM and PWN. The findings show that the virgin female is solely 

responsible for cytoplasmic heredity. In addition, investigations have shown that hybrids containing the 

nuclear PWN genome are more likely to be successful. Virulent to P. thunbergii and have a higher 

population in plant tissue, the nuclear BM hybrids outperformed the nuclear BM hybrids, whereas for 

the purposes of this study, cytoplasm heredity was irrelevant Pathogenicity. Two PWN isolates were 

used in different tests. Three inbred lines were used to create the inbred lines. For P. thunbergii, two 

were virulent and two were avirulent. The results revealed that the virulence features of all lines 

differed from each other and from the parent isolates (the gene). AFLP was used to discover 

pathogenicity indicators); On cultures, pathogenic lines had low multiplication rates. Botrytis is a 

fungus (Ichimura, Shinya, Takemoto, Takeuchi & Futai, 2009, p. 55). Pathogenicity is determined by 

the nematode’s ectosymbionts rather than the nematode’s multiplication rate on the fungus. Also, if the 

inoculum consists of PWN cultivated for many generations on Botrytis or if pine seedlings are 

inoculated with transmissive PWN juveniles from beetles, wilt mortality rates are reduced (Li, Wang & 

Moens, 2009a, p. 56). 



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Figure 1. Pine Wilt Disease Model Showing Assessment of Climatic and Ecological Parameters 

Expression under Various Environmental Condition 

 

4. The Histopathology of Conifers and the Significance of Toxins from Bacteria-nematode 

Ectosymbionts in Host-parasite Relationships 

A histological analysis of 1-year P. thunbergii seedlings revealed that the nematode migrates slowly 

and only downward during the early stages of wilt disease development; however, as the population 

grows, nematode movement accelerates and becomes bidirectional (up and down). The cambium, then 

the cortex, phloem, and xylem parenchyma, show necrotic brown colour and tissue deterioration as the 

wilt progresses. In susceptible pine variants, this is followed by an initial increase in the water potential 

of the plant cells, which then decreases and then increases again; however, in susceptible pine varieties, 

all of these activities occur 2 days earlier than in resistant pine species (Su & Ye, 2009, pp. 78-79). The 

quantity of PWNs and bacteria increases throughout PWD growth, particularly P. fluorescens, Pantoea 

sp., and Sphimgomenas pancimobilis (Xie & Zhao, 2009, p. 58). 

PWN and bacteria have been linked in two ways, both of which are related to PWN presence in wood 

samples: Endophytic and true nematode bacterial partners (Actinobacteria and Firmicutes), and 

endophytic bacteria Janthinobacterium agaricidamnosum and Dyella yeojuens (Santos, Proenca, 

Fonseca & Morais, 2009, p. 37). 

 

 



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Such bacterial symbionts are connected to PWNs via a protein and carbohydrate-rich surface coating 

found on all parasitic and invasive stages of the PWN (Shinya, Takeuchi, Hironobu, Ueda & Futai, 

2009, p. 52). The body surface of the worms must first be surface sterilised before examining the 

involvement of such bacteria in PWD pathogenicity. The following is a list of the efficacy of several 

sterilisation solutions, in order of effectiveness: >0.1 percent mercuric chloride >4 percent sodium 

hypochlorite >3 percent hydrogen peroxide The optimal treatment time is 25 minutes at 25 degrees 

Celsius, which produces axenic nematodes. Longer nematode treatment times result in higher nematode 

mortality (Zhang & Zhao, 2009, pp. 59-60). 

Using axenic callus tissue collected from mature P. thunbergii embryos, protocols have been 

established to assess the involvement of PWN and bacterium interactions in PWD formation. Such 

tissue is grown in the dark on a culture medium containing the required hormones. The cell browning 

response does not occur under these conditions (Gao & Zhao, 2009, p. 83). It is possible to test the 

harmful effects of bacterial secretions on pine cells using this approach. As a result, it has been 

demonstrated that a cell-free filtrate obtained from the growth of a P. fluorescens strain isolated from 

PWNs is multi-component, containing proteins and tiny organic compounds. The original non-dialyzed 

filtrate or the mixture of dialyzed components, rather than any single chemical, has the most harmful 

effect on P. thunbergii cell cultures (Xu, Zhao, Liang & Zhao, 2009b, p. 61). The P. fluorescens 

filtrates yielded a flagellin and two cyclic peptides, all of which cause the pine cells’ DNA, nucleus, 

and cytoplasm to degrade, resulting in an increase in cell conductivity (Li, Guo, Zhao & Li, 2009c, p. 

49). The extracellular lignin peroxidase produced by P. fluorescens bacteria isolated from PWNs is 

involved in the biodegradation of lignin. P. thunbergii cell suspensions have been demonstrated to be 

toxic to this enzyme (Kong, Guo, Zhao, & Li, 2009, p. 54). Furthermore, the toxic effect of bacterial 

filtrates has been shown to be genetically determined, with culture filtrates of two Pseudomonas strains 

obtained using artificial mutagens being non-toxic to P. thunbergii cells (Wang, Zhao, Jiang, Ren & 

Zuo, 2009c, p. 53). 

 

5 The Life Cycle of PWN and How It Is Transmitted 

Entomologists and nematologists from Europe and the Far East have recently discovered vital new 

information about the PWN-vector beetle relationship. Previously, only the connections between the 

PWN-Bursaphelenchus xylophilus and its beetle vector Monochamus alternatus in Asia and B. 

xylophilus and its vector M. caronensis in North America had been examined in depth. The beetle 

vector M. galloprovincialis, on the other hand, is quite abundant throughout southern Europe. On Pinus 

pinaster, it is a secondary xylobiont with a one-year life cycle. An investigation of the M. The 

transmission to the galloprovincialis cycle demonstrated that primarily occurs during the maturity of 

the conifer host tree six weeks after the adult beetle emerges) and During beetle oviposition, to a lesser 

extent (Sousa, Bonifacio & Naves, 2009, pp. 42-43). Juveniles in the transmission stage congregate in 

the beetle’s metathorax once they’ve started, they’re in the pupal chambers, there was a relationship 



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with a beetle. The skin of the mature callow beetle is extremely delicate (Naves, Bonifacio & Sousa, 

2009, p. 41). In a study conducted by South Korean academics in 2006, The beetle M. has a symbiotic 

relationship with the beetle M. pine and saltuarius Pinus koraiensis is a species of pine native to Korea. 

M. was found to be the winner. Saltuarius Beetles are vectors of PWN transmissive juveniles. 

Bursaphelenchus mucronatus and Bursaphelenchus mucronatus (European type) Han and colleagues 

(Han, Koh, Han, Chung & Shin, 2009b, p. 81). B. xylophilus is attracted to wood that has already been 

afflicted with nematodes, according to research on PWN migration. The fungal infection When 

compared to other fungus, Botrytis cinerea, which is used to raise PWN in the lab, is the most 

appealing. while the non-fractioned extract’s attraction impact is bigger than any of its fractions (Pan & 

Long, 2009, p. 71). PWN transfer from roots to a 7-year-old pine (2009). seedlings have been observed 

and confirmed by PWNs are found in the roots of native forest plants (Yil-Sung, Hyang-Mi & 

Hei-Soon, 2009, p. 80). 

 

6. Models of Bursaphelenchus Xylophilus Dispersal 

At the Nanjing Symposium, several talks focused on simulation modelling of PWN’s past spread and 

loss forecasts from PWD. For the evolution of the genus Bursaphelenchus, Ryss (2009) devised an 

allopatric model. According to the model, 1) the genus B. xylophilus arose in the north of the 

paleocontinent Pangea, 2) the B. xylophilus species group arose in East Asia, and 3) B. xylophilus 

arose in the American continent and was later returned to the initial area of its species group, namely 

East Asia, via an anthropogenic mode. The order Aphelenchida as a whole is thought to have originated 

in the Gondwana paleocontinent (as evidenced by the locations of the most basic taxa within the order), 

and that the aphelenchids then travelled north in Pangea. Anhydrobiotic and entomophilic stages 

evolved into various lines of aphelenchids throughout the historic spread to the north. PWN distribution 

models in China (Wang, 2009a, pp. 45-46) are based on PWN occurrence records, particularly in 

economically important regions in the Yangtze and Pearl river drainage zones. The latter leads to the 

conclusion that PWD diffusion in China is primarily due to internal and international trade. For forest 

plantations in a group of Chinese provinces, mathematical prognostic models on PWN distribution 

were constructed. Elevation, annual precipitation, precipitation seasonality, annual temperature range, 

tree height, and crown diameter are all used in these models (Li, Ju & Wu, 2009b, p. 47; Shi, Luo, Wu, 

Yai, Chen & Jiang, 2009, p. 44). 

 

 

 

 

 

 

 



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7. Associations 

A survey of the pines Pinus massoniana, Pinus thunbergii, Pinus elliottii, Pinus densifl ora, and Pinus 

armendii revealed that the PWN B. xylophilus co-inhabits with 10 other nematode species for the 

dominant species: B. mucronatus, B. aberrans, B. hofmanni, B. sp., Aphelenchoides macronucle (Negi 

& Ye, 2009, p. 84). The Aphelenchoides nematodes from the Japanese black pine, P. thunbergii, are 

characterised as a new species with molecular and morphological differences from A. macronucleatus 

(Cheng, Hao & Lin, 2009, p. 35). The occurrence of morphologically and taxonomically identical 

aphelenchid species and genera highlights the need for molecular diagnostics for PWN. 

 

8. Diagnostics 

Compared morphological and molecular data to determine Bursaphelenchus species identity, 

establishing 13 species groups based on six morphological characteristics and creating an illustrated 

tabular key using the most important morphological characteristics such as the number of lateral fields 

incisures, male caudal papillae patterns, and male spicule shapes. Seventy-three of the nominal 

Bursaphelenchus species were successfully categorised, whereas twenty-four were not. For 39 species, 

a phylogenetic SSU r-DNA tree is provided (Braasch, Gu & Burgermeister, 2009, p. 73). 

Other presentations in Nanjing focused on the PWN’s molecular diagnostics. In South Korea, 15 

Bursaphelenchus isolates were analysed using PCRITS and D2D3 rDNA (sequencing and RFLP), 

resulting in the identification of Bursaphelenchus xylophilus, B. mucronatus (European subspecies on 

Pinus koraiensis and Asiatic subspecies on Pinus thunbergii), P. tusciae, P. lini, P. Because of the 

unique zipcode that hybridises on the carrier with oligonucleotides-primers and thus eliminates the 

accumulation of inhibitors of the PCR process (Ge, Li, Liu & Chen, 2009, p. 32) developed a padlock 

probe and HRCA technique to identify PWNs; the technique detection sensitivity was 10 times higher 

than that of conventional PCR. Because of its simplicity, a new diagnostic approach based on 

isothermal specific amplification of PWN DNA taken directly from tiny wood chips (Aikawa, Kanzaki 

& Kikuchi, 2009, p. 34) is anticipated to become common in the future. Another presentation at the 

Nanjing meeting focused on another easy express approach for identifying the early stages of the PWN 

by revealing cellulase activity using a colour reagent. The premise for this approach is that dead wood 

containing B. mucronatus turns white, and real-time fluorescent molecular diagnostics (ATF-PCR 

ITS-2) are employed to validate PWN identification (Wang, 2009b, pp. 25-26). 

 

9. Control and Quarantine of the PWN 

Quarantine methods contain a set of detection and control strategies for PWN, as well as approaches 

for specialist timber treatment. PWD is a standard process used in quarantine work. Epidemiological 

surveys, PWN diagnostics, and beetle plotting traps, vertical wood traps, and the disposal of dying 

animal’s branches on damaged trees or dead and dying trees, nematode-infested lumber fumigation, 

and biological control command (Huang, Tang, Chen, Kang, He & Yang, 2009, p. 67). Using aerial 



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photography is also a viable option. Near-infrared colour film photography enables for PWD-affected 

plants can be identified by their leaves. discolouration. The original recognises the latter. Infected trees 

can be recognised using GIS software. using a palmtop computer with a built-in camera Receiver for 

GPS (Nakamura, Takehana, Itagaki, Tashiro, Ohta & Nakakita, 2009, p. 33). 

The European Union’s (EU) action plan for PWD calls for the creation of a three-kilometer-wide 

clear-cut zone encircled by a six-kilometer quarantine zone surrounding the affected area. Only after 

rigorous treatment and control can logs from the quarantine zone be transported out of the zone. In 

addition, the quarantine zone must be maintained for a period of 15 years following the last PWN 

report (Hannunen, Tomminen, Poutt & Kukkonen, 2009, p. 77). Cutting, burning, or fumigation of 

wood, limits on transporting wood from infested areas, and a mandatory 3-year control in areas where 

the PWN has been identified before the territory can be proclaimed a “clean area” are all part of South 

Korea’s post-PWD management plans after detection (Hannunen, Tomminen, Poutt & Kukkonen, 2009, 

p. 77). Heat treatment, methylbromide fumigation, and removal and burning of infected trees are the 

three forms of quarantine treatments used in the EU. Because to methyl bromide limits (due to 

environmental concerns), three alternative chemicals are now recommended: the fumigant sulphur 

fluoride, the trunk-injection drugs Milbemectin, and Emamectine benzoate (Shin, Moon & Han, 2009, 

p. 22). For wood goods and wood packaging material destined for international trade, the International 

Plant Protection Convention (IPPC) mandates a 30-minute heat treatment at 56°C (wood core 

temperature) (Trindade & Cerejeira, 2009, p. 85). Because both conventional and real-time PCR rely 

on the detection of DNA, they are unable to distinguish between dead and live PWNs. As a result, a 

new reverse transcriptase PCR assay based on the utilisation of the heat shock protein 70 A mRNA as a 

viability marker has been created to evaluate the heat treatment efficiency. This marker degrades 

rapidly in dead PWNs in comparison to stable DNA (Allen, 2009, p. 24). 

 

10. The PWN’s Biocontrol 

The vector beetles, PWNs, or their ectosymbiotic bacteria can all be targets for biocontrol. The PWN 

vector Monochamus alternatus has been infected with a pathogenic strain of the entomophilic fungus 

Metarhizium, which was originally obtained from the ichneumon Scleroderma. Mass release of the 

fungus carried on laboratory reared Scleroderma provides effective biocontrol in areas with severe 

PWD (Xu, Pan, Liu & Han, 2009a, p. 66). Under field conditions in China the release of \sScleroderma 

guani (natural enemy of Monochamus \sbeetles) near PWD-affected trees leads to a 20 percent 

parasitism rate of the vector beetle M. alternatus (Tang, Kang, Liang, Chen, Huang, Chen, Chen, Yang 

& He, 2009, p. 68). The regular release of radiation-treated Monochamus alternatus males into 

PWN-infested forests can effectively reduce the number of beetles; for example, after six years of 

regular release, the results are comparable to those obtained using chemical control against 

Monochamus, but at a much lower cost (Zhang, Ma, Wen, Qu & Hou, 2009, p. 69). 



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In addition, wood-rotting fungus and certain plant compounds can be employed to combat the PWN. A 

search was conducted in China for a fungus that effectively decomposes the stumps of PWD-killed 

Pinus massoniana trees. One stipulation for such fungi is that they cannot be used as food by the PWN. 

For testing, a strain of the fungus Laetiporus sulphureus was chosen (Wang, Chen, Li, Piao, Shin & 

Chung, 2009b, p. 82). The fraction with the highest antinematode activity was isolated by high-speed 

countercurrent chromatography (HSCCC) from five strains of the actinomycete Streptomyces with 

nematicide filtrates (Jiang, Zhao, Wang & Zuo, 2009, p. 65). In South Korea, the hypomycete Esteya 

vermicola is the first endoparasitic fungus recovered from fungus-infected PWN. The fungus’s sticky 

lunate conidia connect to the nematode cuticle during its life cycle, and the mycelia penetrate and eat 

the nematode’s body. During the next infection cycle, Esteya vermicola produces fresh conidia, which 

infect intact nematodes. Several aggressive Esteya strains were isolated, all of which killed PWN 

isolates in 4 to 5 days (Wang, Fang, Wang & Sung, 2009a, p. 64). Using a commercial biocontrol agent 

containing Esteya strains against the PWN and several application methods (suspension spraying, trunk 

injection into trees, and applying infected nematodes onto trees), researchers found that E. vermicola 

could help pine trees survive PWN infection in greenhouse and field tests (Sung, Fang, Wang & Wang, 

2009, p. 63). To manage PWD in Portugal, oil components from several aromatic plants were studied, 

and four of 27 oils were identified as anti-PWN. At 1 mg mL, their nematicidal activity was Thymbra 

capitata > Thymus caespititius > Satureja montana and > Cymbopogum citratus in order of efficiency. 

Carvacrol and geranial were discovered to be nematicidal compounds (Vieira, Barbosa, Lima, Dias, 

Tinoco, Pedro, Figueiredo, Barrosa & Mota, 2009, p. 76). The strong nematicidal activity of 

Cynanchum komarovii extracts has been determined in China, and the activity has been linked to 

succinate dehydrogenase inhibition in the PWN (Yang & Liu, 2009, p. 70). 

The strong efficacy of oxolinic acid against five bacterial strains isolated from the PWN has been 

identified in laboratory experiments employing six antibiotics. After injecting 3-mg oxolinic acid into 

3-year-old seedlings, pine wilt symptoms in P. densiflora decreased by 70%. A mixture of oxolinic acid 

and the nematicidal agent abamectin showed better disease control of PWD in field experiments with 

20-year-old pines than either oxolinic acid or abamectin alone (Kim, Kwon, Choi, Choi, Jang, Park, 

Sung, Kang, Moon & Lee, 2009, p. 75). 

PWD control has been proposed in Hunan Province, China, using local P. densiflora seedlings. 

The second generation of resistant and susceptible pine clones hybrids that survived the experiments 

show increased resistance to PWN and a significant reduction in PWN-induced mortality. 

The International Symposium in Nanjing outlined the essential concepts of parasite-caused conifer wilt, 

including newly collected knowledge on the function of symbionts and PWN vectors in the disease’s 

pathogenesis and transmission. Biocontrol and contemporary quarantine tactics are examples of new 

technology tools in diagnostics and pest control.  

 

 



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11. Conclusion 

We have successfully developed a numerical scheme known as (NSFDM) for the consider model. 

Through the mentioned method, we have computed the solution of the proposed model for different 

values of n, m. Hence (NSFDM) will excellently use in future for dealing non complicated problems. 

Pine Wilt Disease (PWD), caused by the pinewood nematode (PWN) Bursaphelenchus xylophilus, 

causes significant losses in coniferous forests in eastern Asia, including Japan, China, and South Korea, 

as well as western Europe, including Portugal. The results of the research papers given at the 

International Symposium on Pine Wilt Disease (IUFRO Working Party Meeting 4.04.03) in Nanjing, 

China, in July 2009 are summarized in this article. The basic themes discussed included Pine Wilt 

Disease (PWD), the pinewood nematode (PWN) Bursaphelenchus xylophilus, and other 

PWN-associated microorganisms that play a significant role in PWD, such as bacteria (e.g., 

Pseudomonas fluorescens). The majority of the papers are based on PWD-PWN research in East Asia 

and Russia. The following are some of the specific topics covered: 1) fundamental concepts of PWD 

development, 2) pathogenicity, 3) host-parasite relationships, including histopathology of diseased 

conifers and the role of toxins from bacteria-nematode ecto-symbionts, 4) PWN life cycle and 

transmission, 5) B. xylophilus dissemination models, 6) associations (with other nematodes), 7) 

diagnostics, 8) quarantine and control of the PWN and 9) biocontrol of the PWN. 

 

Author contribution 

Mr. Abdul Ghaffar Khan, conducted this experiment, collected the data, analyze the data and wrote the 

manuscript, while Dr. Imran and Ansar Hussain revised and reviewed the manuscript. Dr. Tariq 

Mahmood, and Dr. Hayat Zada identified disease and pathogens of the pine wilt study under various 

climatic conditions. 

 

Conflict of interest 

The authors declared that they have no any interest of conflict in publishing these findings. 

 

 

 

 

 

 

 

 

 

 

 



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loop-mediated isothermal amplifi cation. International Symposium on Pine Wilt Disease (p. 34). 

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Allen, E. (2009). Significance of PWN (Bursaphelenchus xylophilus) in international phytosanitary 

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