First Report of Bursaphelenchus mucronatus kolymensis Associated with Pinus sylvestris in Serbia

Bursaphelenchus mucronatus kolymensis (Korentchenko) Braasch et al. (1), also referred to as the European type of B. mucronatus, is morphologically very similar to the pine wood nematode (PWN) B. xylophilus (Steiner & Buhrer) Nickle, the causal agent of pine wilt disease. The main morphological difference between the two species is the shape of the female tail mucro (3); however, some populations of PWN vary in mucro shape, which can lead to misidentification. Since PWN was found and identified for the first time in Portugal in 1999 (4), concern about the spread of PWN to pines and other conifers all over Europe has increased. Therefore, the PWN survey in every European country is essential. In 2011, the Serbian Ministry of Agriculture, Forestry and Water Management implemented phytosanitary measures for detection of PWN in the territory of the Republic of Serbia. In September 2013, wood samples were collected from a 40-year-old wilted Pinus sylvestris located on Divcibare Mountain, western Serbia. Nematodes were extracted by a modified Baermann funnel method. Nematode specimens (10 females and 10 males) were characterized by an Aphelenchoid-type esophagus, female vulva flap, mucro on the end of female tail, and males with paired arcuate spicules. Morphological identification matched that of B. mucronatus kolymensis (1). The specific morphometric evidence for this European type subspecies of B. mucronatus was sub-cylindrical female tail with mucro 3 to 4 μm long, digitate, well offset from tail (5). Species identification was confirmed by PCR-RFLP of the rDNA ITS region using one female and one male nematode separately (2). The sizes of restricted DNA fragments as determined with agarose gel and capillary electrophoresis were in compliance with reported data in the literature (2,4) and support the identification of the nematode as B. mucronatus kolymensis. To our knowledge, this is the first report of any species belonging to Bursaphelenchus genus in Serbia. The presence of B. mucronatus kolymensis in Serbia indicates the possibility of establishment and spread of PWN. Therefore, the measures taken in case of PWN occurrence should be prepared and training foresters to identify pine wilt disease symptoms should be encouraged in Serbia. References: (1) H. Braasch et al. J. Nematode Morphol. Syst. 14:77, 2011. (2) W. Burgermeister et al. Nematology 11:649, 2009. (3) Y. Mamiya and N. Enda. Nematologica 25:353, 1979. (4) M. M. Mota et al. Nematology 1:727, 1999. (5) M. M. Mota and P. Vieira. Page 146 in: Pine Wilt Disease: A Worldwide Threat to Forest Ecosystems. Springer Science and Business Media, 2008.

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First Report of Bursaphelenchus pinophilus on Korean pine (Pinus koraiensis)

Plant Disease ◽

10.1094/pdis-93-12-1354c ◽

2009 ◽

Vol 93 (12) ◽

pp. 1354-1354 ◽

Cited By ~ 4

Author(s):

H. Han ◽

Y.-J. Chung ◽

S.-C. Shin

Keyword(s):

Morphological Characteristics ◽

Pine Wilt Disease ◽

Its Region ◽

Wilt Disease ◽

Pinus Koraiensis ◽

Molecular Diagnostic ◽

Accurate Identification ◽

Causal Organism ◽

First Report ◽

Pine Wilt

The genus Bursaphelenchus Fuchs, 1937 contains approximately 90 species (3) that are morphologically similar. Pine wood nematode, Bursaphelenchus xylophilus (4) Nickle, 1970, is the causal organism of pine wilt disease and accurate identification is essential for diagnosis of the disease. In Korea, pine wilt disease was first reported in 1988 and devastated 6,800 ha of pine forest through 2008. For a survey of trees with pine wilt disease, wood samples were taken randomly from dead Pinus koraiensis in Namyangju, Gyeonggi Province in Korea. The extracted nematodes from dead trees were maintained in culture on Botrytis cinerea and morphological characteristics were observed with an inverted light microscope (Leica DE/DMI 3000B). Identification of Bursaphelenchus spp. based on morphological characteristics is difficult, especially for identification of juveniles that carry few morphological features for species identification. The internal transcribed spacer (ITS) region in ribosomal DNA provides useful molecular diagnostic markers for this genus (1). The nematodes were provisionally identified as Bursaphelenchus pinophilus based on the characteristic long and arcuate body shape, male spicule with distinctive rostrum and small cucullus, female vulval flap, and mucronate conical tail. Other Bursaphelenchus spp. with vulval flaps and spicules with cucullus are B. xylophius, B. mucronatus, B. abruptus, and B. pinophilus. For molecular diagnosis, DNA was extracted from more than 30 individual nematodes with a DNeasy Kit (Qiagen, Valencia, CA) and ITS regions 1, 2, and 5.8S in rDNA were amplified by PCR (US/PTC-0220; Bio Rad, Hercules, CA). The ITS-restriction fragment length polymorphism pattern was consistent with that of B. pinophilus (2). The ITS rDNA sequence of B. pinophilus from Korean pines had a 98% sequence homology to that of B. pinophilus in GenBank (Accession No. AM160664). The pathogenicity of B. pinophilus has not been determined. To our knowledge, this is the first report of B. pinophilus on P. koraiensis, but it was previously reported from Poland, Germany, and Portugal on P. sylvestris and P. pinaster (1). References: (1) H. Braasch. EPPO Bull. 31:127, 2001. (2) W. Burgermeister et al. Russ. J. Nematol. 13:29, 2005. (3) R. Sriwati et al. Nematology 10:1, 2008. (4) G. Steiner and E. M. Buhrer. J. Agric. Res. 48:946, 1934.

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Prevention of Pine Wilt of Scots Pine (Pinus sylvestris) with Systemic Abamectin Injections

Arboriculture & Urban Forestry ◽

10.48044/jauf.2006.025 ◽

2006 ◽

Vol 32 (5) ◽

pp. 195-201

Author(s):

Randall James ◽

Ned Tisserat ◽

Tim Todd

Keyword(s):

Pinus Sylvestris ◽

Scots Pine ◽

Pine Wilt Disease ◽

Bursaphelenchus Xylophilus ◽

Wilt Disease ◽

Pinewood Nematode ◽

Commercial Formulation ◽

Breast Height ◽

Pine Wilt ◽

Trunk Injection

We examined the efficacy of the insecticide/nematicide abamectin to prevent pine wilt disease caused by the pinewood nematode (Bursaphelenchus xylophilus) in Scots pine (Pinus sylvestris). Pinewood nematode movement was inhibited (>80% death or paralysis) following a 48 hr exposure to abamectin concentrations as low as 0.1 μL a.i. per L (100 ppb). A commercial formulation of abamectin (Avid™) was injected into Scots pine using a pressurized systemic trunk injection tube (STIT) technique. Fifteen to 30 mL (0.45 to 0.90 fl oz) of Avid per STIT could be injected into the trees in less than 1 hr. Trees were successfully injected throughout February, March, and April at temperatures above 4.4°C (40°F). Survival after 1 year of 10 cm diameter (4 in) at breast height (dbh) Scots pines injected with Avid and subsequently inoculated with pinewood nematode was higher (75%) than in pines injected with water (42%). Similarly, survival after 3 years of large Scots pines (30 to 60 cm [12 to 24 in] dbh)] injected with Avid and exposed to a natural epidemic of pine wilt was higher (96%) than in noninjected pines (33%) or those injected with water (71%). These results indicate that preventive injections of Scots pine with Avid are effective in protecting against pine wilt disease.

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Bursaphelenchus xylophilus: An Important Pathogenic Factor of Pine Wilt Disease and Its Relationship With Bursaphelenchus mucronatus

Plant Disease ◽

10.1094/pdis-02-21-0396-re ◽

2021 ◽

Author(s):

Yu-Long Li ◽

Chang-Ji Fan ◽

Xiao-Hui Jiang ◽

Xing-Yi Tian ◽

Zheng-Min Han

Keyword(s):

Pine Wilt Disease ◽

Bursaphelenchus Xylophilus ◽

Wilt Disease ◽

Natural Hybridization ◽

Hybrid Population ◽

Future Studies ◽

Pine Wilt ◽

Bursaphelenchus Mucronatus ◽

Pathogenic Variation

Pine wilt disease is the most devastating pine disease caused by Bursaphelenchus xylophilus. Bursaphelenchus mucronatus is morphologically similar to B. xylophilus and geographically overlaps in its distribution. Although interspecific hybridization of the two nematodes has been performed in vitro, the dynamic regularity of hybrid formation and its risk in forests has not been well evaluated. In this study, a hybrid of B. xylophilus and Bursaphelenchus mucronatus mucronatus was identified in the laboratory and fields by molecular markers. The heterozygosity of ITS-5.8S loci for identification was unstable in the hybrid population, and the allele inherited from B. m. mucronatus was lost over several generations. We also provided evidence that hybrids existed in some new epidemic areas, while old epidemic areas were usually dominated by B. xylophilus. Hybrids could be generated when B. m. mucronatus was invaded by B. xylophilus, and the pathogenicity of the hybrids was similar to that of B. xylophilus. These findings may improve the understanding of the natural hybridization between B. xylophilus and B. m. mucronatus and pathogenic variation in pine wilt disease, providing new insights for future studies on disease detection, transmission, and quarantine.

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First Report of Bursaphelenchus xylophilus Causing Pine Wilt Disease on Pinus radiata in Spain

Plant Disease ◽

10.1094/pdis-03-15-0252-pdn ◽

2015 ◽

Vol 99 (10) ◽

pp. 1449-1449 ◽

Cited By ~ 19

Author(s):

P. Zamora ◽

V. Rodríguez ◽

F. Renedo ◽

A. V. Sanz ◽

J. C. Domínguez ◽

...

Keyword(s):

Pinus Radiata ◽

Pine Wilt Disease ◽

Bursaphelenchus Xylophilus ◽

Wilt Disease ◽

First Report ◽

Pine Wilt

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First Report of Pine Wilt Disease on Pinus koraiensis in Korea

Plant Disease ◽

10.1094/pdis-92-8-1251a ◽

2008 ◽

Vol 92 (8) ◽

pp. 1251-1251 ◽

Cited By ~ 12

Author(s):

H. Han ◽

Y.-J. Chung ◽

S.-C. Shin

Keyword(s):

Dna Sequences ◽

Pinus Densiflora ◽

Pine Wilt Disease ◽

Wilt Disease ◽

Internal Transcribed Spacers ◽

Pinus Koraiensis ◽

Korean Pine ◽

Accurate Identification ◽

First Report ◽

Pine Wilt

Pine wilt disease is one of the most important forest tree diseases, especially in the East Asian countries of Japan, China, and Korea. The causal agent, Bursaphelenchus xylophilus (3), is transmitted by the insect vectors, pine sawyer beetles (Monochamus spp.). The vectors mainly attack coniferous trees and the infected trees die within several weeks. In Korea, pine wilt disease was first reported in Busan City in 1988, and now, the damaged area covers 7,820 ha and more than 60 cities in Korea. The main host trees are Pinus densiflora and P. thunbergii, which are the most common pines distributed in Korea. In 2006, however, we found pine wilt disease in a forest of P. koraiensis located in Gwangju City in Gyeonggi Province. Symptoms were systemic and leaves turned brown or yellowish. Wood samples were collected from the affected trees, and nematodes were extracted by a modified Baermann's funnel method. After 24 h, nematodes were collected from wood chips, and morphology was observed with an inverted light microscope (Leica DE/DMI 3000B, Wetzlar, Germany). Morphology was characterized by a typical Aphelenchoid-type esophagus, head constriction, female vulva flap, female tail, and a male spicule shape similar to B. xylophilus. For more accurate identification, DNA was extracted from individual nematodes with a DNeasy Kit (Qiagen, Valencia, CA). The internal transcribed spacers (ITS) 1 and 2 and 5.8S regions were amplified by PCR (1). Sequenced nucleotide information was compared with the sequences of B. xylophilus already reported in GenBank (Accession Nos. AB294736, AB277208, AM 157747, AY 347913, and BXU92464). ITS DNA sequences of the nematode from Korean pine was >99% identical to B. xylophilus in GenBank. The B. xylophilus from Korean pine tree was also successfully cultured in Botrytis cinerea medium and pathogenicity was tested from June to October 2007. More than 95% mortality was observed with the inoculation of 20 replicate 15-year-old trees of P. koraiensis and P. densiflora with 15,000 nematodes per tree. Therefore, we confirmed that pine wilt disease occurred in P. koraiensis in Korea. P. koraiensis is an endemic species in Korea and distribution is limited to the northern Korean Peninsula and some locations in Russia. It has been shown that P. koraiensis is susceptible to the pine wood nematode by an inoculation test in Japan (2); however, to our knowledge, this is the first report of pine wilt disease on P. koraiensis under field conditions in Korea. References: (1) W. K. Burgermeister et al. Russ. J. Nematol. 13:29, 2005. (2) K. Futai and T. Furuno. Bull. Kyoto Univ. For. 51:3, 1979. (3) G. Steiner and E. M. Buhrer. J. Agr. Res. 48:946, 1934.

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Suppressive effects of Bursaphelenchus mucronatus on pine wilt disease development and mortality of B. xylophilus-inoculated pine seedlings

Nematology ◽

10.1163/15685411-00002760 ◽

2014 ◽

Vol 16 (2) ◽

pp. 219-227 ◽

Cited By ~ 1

Author(s):

Si-Mi Liao ◽

Satomi Kasuga ◽

Katsumi Togashi

Keyword(s):

Pine Wilt Disease ◽

Nematode Species ◽

Bursaphelenchus Xylophilus ◽

Wilt Disease ◽

Reproductive Interference ◽

Dependent Manner ◽

Nematode Density ◽

Pine Wilt ◽

Bursaphelenchus Mucronatus ◽

Pine Trees

Bursaphelenchus xylophilus causes pine wilt disease in Pinus trees whereas B. mucronatus has no or little virulence to the trees. Interspecific crossing experiments conducted so far suggest reproductive interference between the two nematode species. Theory predicts that one of the two competing species populations quickly displaces the other through reproductive interference in a frequency-dependent manner. Thus, it is anticipated that B. mucronatus suppresses the virulence of B. xylophilus against pine trees when B. mucronatus heavily outnumber B. xylophilus. To determine the suppressive effects of B. mucronatus, the two nematode species were inoculated simultaneously on 30 3-year-old Pinus thunbergii seedlings at three combinations of different numbers, and B. xylophilus alone was inoculated on 30 other seedlings at the corresponding numbers in early August. Seedlings were observed at intervals of 4 or 6 weeks and two stem sections were sampled from each seedling to determine the density and species composition of nematode populations after death or in December. Inoculation of B. mucronatus significantly retarded the speed of foliage discolouration from 0.170 ± 0.024 week−1 to 0.061 ± 0.017 week−1 and significantly prolonged the survival time of seedlings. Bursaphelenchus mucronatus significantly reduced the nematode density from 1799.7 ± 305.0 to 521.0 ± 148.4 (g dried seedling stem)−1. Analysis of rDNA genotype showed 1846 B xylophilus, no B. mucronatus and one hybrid.

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Effects of cavitation on the development of pine wilt disease caused by Bursaphelenchus xylophilus.

Japanese Journal of Phytopathology ◽

10.3186/jjphytopath.54.606 ◽

1988 ◽

Vol 54 (5) ◽

pp. 606-615 ◽

Cited By ~ 34

Author(s):

Keiko KURODA ◽

Toshihiro YAMADA ◽

Kazuhiko MINEO ◽

Hirotada TAMURA

Keyword(s):

Pine Wilt Disease ◽

Bursaphelenchus Xylophilus ◽

Wilt Disease ◽

Pine Wilt

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Early detection of pine wilt disease in Pinus tabuliformis in North China using a field portable spectrometer and UAV-based hyperspectral imagery

Forest Ecosystems ◽

10.1186/s40663-021-00328-6 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Run Yu ◽

Lili Ren ◽

Youqing Luo

Keyword(s):

Early Stage ◽

Vegetation Indices ◽

Pine Wilt Disease ◽

Wilt Disease ◽

Pinus Tabulaeformis ◽

Pine Tree ◽

Preventative Measures ◽

Pine Wilt ◽

Pine Trees ◽

Airborne Vehicle

Abstract Background Pine wilt disease (PWD) is a major ecological concern in China that has caused severe damage to millions of Chinese pines (Pinus tabulaeformis). To control the spread of PWD, it is necessary to develop an effective approach to detect its presence in the early stage of infection. One potential solution is the use of Unmanned Airborne Vehicle (UAV) based hyperspectral images (HIs). UAV-based HIs have high spatial and spectral resolution and can gather data rapidly, potentially enabling the effective monitoring of large forests. Despite this, few studies examine the feasibility of HI data use in assessing the stage and severity of PWD infection in Chinese pine. Method To fill this gap, we used a Random Forest (RF) algorithm to estimate the stage of PWD infection of trees sampled using UAV-based HI data and ground-based data (data directly collected from trees in the field). We compared relative accuracy of each of these data collection methods. We built our RF model using vegetation indices (VIs), red edge parameters (REPs), moisture indices (MIs), and their combination. Results We report several key results. For ground data, the model that combined all parameters (OA: 80.17%, Kappa: 0.73) performed better than VIs (OA: 75.21%, Kappa: 0.66), REPs (OA: 79.34%, Kappa: 0.67), and MIs (OA: 74.38%, Kappa: 0.65) in predicting the PWD stage of individual pine tree infection. REPs had the highest accuracy (OA: 80.33%, Kappa: 0.58) in distinguishing trees at the early stage of PWD from healthy trees. UAV-based HI data yielded similar results: the model combined VIs, REPs and MIs (OA: 74.38%, Kappa: 0.66) exhibited the highest accuracy in estimating the PWD stage of sampled trees, and REPs performed best in distinguishing healthy trees from trees at early stage of PWD (OA: 71.67%, Kappa: 0.40). Conclusion Overall, our results confirm the validity of using HI data to identify pine trees infected with PWD in its early stage, although its accuracy must be improved before widespread use is practical. We also show UAV-based data PWD classifications are less accurate but comparable to those of ground-based data. We believe that these results can be used to improve preventative measures in the control of PWD.

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Dynamical aspects of pine wilt disease and control measures

Chaos Solitons & Fractals ◽

10.1016/j.chaos.2021.110764 ◽

2021 ◽

Vol 145 ◽

pp. 110764

Author(s):

Takasar Hussain ◽

Adnan Aslam ◽

Muhammad Ozair ◽

Fatima Tasneem ◽

J.F. Gómez-Aguilar

Keyword(s):

Pine Wilt Disease ◽

Wilt Disease ◽

Control Measures ◽

Pine Wilt ◽

And Control

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Spatiotemporal Pattern of Pine Wilt Disease in the Yangtze River Basin

Forests ◽

10.3390/f12060731 ◽

2021 ◽

Vol 12 (6) ◽

pp. 731

Author(s):

Zhuoqing Hao ◽

Jixia Huang ◽

Yantao Zhou ◽

Guofei Fang

Keyword(s):

River Basin ◽

Yangtze River ◽

Yangtze River Basin ◽

Pine Wilt Disease ◽

Wilt Disease ◽

Spatiotemporal Pattern ◽

Pinewood Nematode ◽

The Yangtze River ◽

Pine Wilt ◽

The Yangtze River Basin

The Yangtze River Basin is among the river basins with the strongest strategic support and developmental power in China. As an invasive species, the pinewood nematode (PWN) Bursaphelenchus xylophilus has introduced a serious obstacle to the high-quality development of the economic and ecological synchronization of the Yangtze River Basin. This study analyses the occurrence and spread of pine wilt disease (PWD) with the aim of effectively managing and controlling the spread of PWD in the Yangtze River Basin. In this study, statistical data of PWD-affected areas in the Yangtze River Basin are used to analyse the occurrence and spread of PWD in the study area using spatiotemporal visualization analysis and spatiotemporal scanning statistics technology. From 2000 to 2018, PWD in the study area showed an “increasing-decreasing-increasing” trend, and PWD increased explosively in 2018. The spatial spread of PWD showed a “jumping propagation-multi-point outbreak-point to surface spread” pattern, moving west along the river. Important clusters were concentrated in the Jiangsu-Zhejiang area from 2000 to 2015, forming a cluster including Jiangsu and Zhejiang. Then, from 2015–2018, important clusters were concentrated in Chongqing. According to the spatiotemporal scanning results, PWD showed high aggregation in the four regions of Zhejiang, Chongqing, Hubei, and Jiangxi from 2000 to 2018. In the future, management systems for the prevention and treatment of PWD, including ecological restoration programs, will require more attention.

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