scholarly journals First Report of Pine Wilt Disease Caused by Bursaphelenchus xylophilus on Pinus thunbergii in the Inland City of Zibo, Shandong, China

Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1126-1126 ◽  
Author(s):  
H. Y. Wu ◽  
Q. Q. Tan ◽  
S. X. Jiang
Keyword(s):  
Body Length ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Shandong Province ◽  
Jiangsu Province ◽  
Insect Vector ◽  
Pinewood Nematode ◽  
Pine Wilt ◽  
Stylet Length

The pinewood nematode (PWN) Bursaphelenchus xylophilus (Steiner & Buhrer 1934) Nickle 1970 is the causal agent of pine wilt disease. It is especially damaging in East Asian countries, including Japan, China, and Korea. In China, the nematode has been found in Anhui, Guangdoung, Guizhou, Chongqing, and Zhejiang Provinces since its discovery in Jiangsu Province in 1982 (1). China is confronted with an enormous threat to its pine forests. B. xylophilus is transmitted by the insect vector pine sawyer beetle (Monochamus alternatus). The main host trees are Pinus massoniana, P. thunbergii, and P. densiflora, which are the most common pine trees in China. Shandong Province, located north of Jiangsu Province, is a high-risk area because it was thought to be the northernmost suitable area for the pine wood nematode. P. tabulaeformis, P. densiflora, and P. thunbergii are the principal hosts. In 2010, a pine tree with suspected wilt disease was found in Lushang Forest (36°16′31.11″ N, 118°03′59.79″ E) of P. thunbergii located in Zibo city of Shandong Province. Symptoms were systemic, with almost all leaves brown or yellowish; the tree was nearly dead. Wood samples were collected and nematodes were extracted using a modified Baermann's funnel method. After 12 h, the nematodes were collected from the wood chips, and their morphology was observed with an inverted light microscope (Nikon 90i, Japan). Nematodes had a typical Aphelenchoid-type esophagus and female vulva flap. Females had subcylindrical tails, usually with broadly rounded terminus, some with a short mucro, and flat vulva, whereas males had large paired arcuate spicules with a sharply pointed prominent rostrum, and typical disc-like expansions on distal ends. Standard measurements of these nematodes were as follows: 25 females: body length = 960.9 ± 117.4 (791.5 to 1,265.2) μm, a = 32.1 ± 5.1 (23.7 to 44.5), b = 13.6 ± 1.4 (11.4 to 16.1), c = 28.3 ± 4.6 (21.7 to 42.2), V = 77.8 ± 2.0 (74.2 to 83.9), stylet length = 13.7 ± 1.6 (11.4 to 17.6) μm; 21 males: body length = 785.6 ± 103.2 (609.6 to 1,004.5) μm, a = 33.3 ± 4.4 (26.0 to 40.8), b = 11.9 ± 1.3 (9.0 to 14.6), c = 31.0 ± 2.7 (25.5 to 37.1), stylet length = 13.5 ± 1.9 (11.0 to 17.5) μm, spicule length = 18.8 ± 2.5 (14.9 to 23.9) μm. The morphometrics of this population, apart from body length and “a” value, which are shorter than the Portugal isolate measured by Mota et al. (3), are very much in the same range reported for B. xylophilus. For a more accurate identification, DNA was extracted from individual nematodes using a liquid nitrogen method. The internal transcribed spacers (ITS-1, ITS-2, 5.8S) were amplified by using PCR (2). Nucleotide sequences were compared with the sequences of B. xylophilus in GenBank, accession nos. JN684828 (Portugal), JN684829 (Portugal), JF826219 (Madeira Island) and JQ288086 (Japan). The ITS DNA sequences of the nematode from P. thunbergii were 99% identical to those of B. xylophilus in GenBank. A sequence of this nematode was submitted to the GenBank database and assigned the number KC460340. We have thus confirmed that B. xylophilus is now present north of Changjiang River in Zibo city, Shandong Province. This range expansion, perhaps the result of global warming, will affect both domestic and international quarantine efforts to control the further spread of pinewood nematode. References: (1) X. Y. Cheng et al. Heredity 100:356, 2008. (2) K. Metge and W. Burgermeister. J. Plant Dis. Protect. 113:275, 2006. (3) M. Mota et al. Nematology 1:727, 1999.

scholarly journals Pseudomonas associated with Bursaphelenchus xylophilus, its insect vector and the host tree: A role in pine wilt disease?

2019 ◽  
Vol 49 (6) ◽  
pp. e12564
Author(s):  
Marta Salgueiro Alves ◽  
Anabela Pereira ◽  
Cláudia Vicente ◽  
Manuel Mota ◽  
Isabel Henriques
Keyword(s):  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Host Tree ◽  
Insect Vector ◽  
Pine Wilt

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

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.

scholarly journals The specialization of Esteya vermicola hyphae in infection to Bursaphelenchus xylophilus and its colonization of pine tree

2020 ◽  
Author(s):  
Hai-Hua Wang ◽  
Can Yin ◽  
Jie Gao ◽  
Ran Tao ◽  
Piao-Piao Dai ◽  
...  
Keyword(s):  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Fungal Colonization ◽  
Pinewood Nematode ◽  
Pine Tree ◽  
Pine Wilt ◽  
Pine Trees ◽  
Colonization Patterns ◽  
Esteya Vermicola

AbstractPine wilt disease (PWD) caused by the nematode Bursaphelenchus xylophilus is a serious problem on pines, and there is currently no effective control strategy for this disease. Although the endoparasitic fungus Esteya vermicola showed great effectiveness in controlling pine wilt disease, the colonization patterns of the host pine tree xylem by this fungus are unknown. To investigate the colonization patterns of pine xylem by this fungus, the species Pinus koraiensis grown in a greenhouse was used as an experimental host tree. The fungal colonization of healthy and wilting pine trees by E. vermicola was quantified using PCR with a TaqMan probe, and a green fluorescence protein (GFP) transformant was used for visualization. The results reported a specific infection approach used by E. vermicola to infect B. xylophilus and specialized fungal parasitic cells in PWN infection. In addition, the inoculated blastospores of E. vermicola germinated and grew inside of healthy pine xylem, although the growth rate was slow. Moreover, E. vermicola extended into the pine xylem following spray inoculation of wounded pine seedling stems, and a significant increase in fungal quantity was observed in response to B. xylophilus invasion. An accelerated extension of E. vermicola colonization was shown in PWN-infected wilting pine trees, due to the immigration of fungal-infected PWNs. Our results provide helpful knowledge about the extension rate of this fungus in healthy and wilting PWN-susceptible pine trees in the biological control of PWD and will contribute to the development of a management method for PWD control in the field.Author summaryPine wilt disease, caused by Bursaphelenchus xylophilus, has infected most pine forests in Asian and European forests and led to enormous losses of forest ecosystem and economy. Esteya vermicola is a bio-control fungus against pinewood nematode, showed excellent control efficient to pine wilt disease in both of greenhouse experiments and field tests. Although this bio-control agent was well known for the management of pine wilt disease, the infection mechanism of fungal infection and colonization of host pine tree are less understand. Here, we use GFP-tagged mutant to investigate the fungal infection to pinewood nematode; additionally, the temporal and spatial dynamics of E. vermicola colonize to pine tree were determined by the TaqMan real-time PCR quantification, as well as the response to pinewood nematode invasion. We found a specific infection approach used by E. vermicola to infect B. xylophilus and specialized fungal parasitic cells in PWN infection. In addition, the fungal germination and extension inside of pine tree xylem after inoculation were revealed. In addition, the quantity of E. vermicola increased as response to pinewood nematode invasion was reported. Our study provides two novel technologies for the visualization and detection of E. vermicola for the future investigations of fungal colonization and its parasitism against pinewood nematode, and the mechanisms of the bio-control process.

scholarly journals Characterization of bacterial communities associated with the pinewood nematode insect vector Monochamus alternatus Hope and the host tree Pinus massoniana

2020 ◽  
Author(s):  
Yajie Guo ◽  
Qiannan Lin ◽  
lvyi Chen ◽  
Carballar-Lejarazú Rebeca ◽  
Aishan Zhang ◽  
...  
Keyword(s):  
Pine Wilt Disease ◽  
Wilt Disease ◽  
Insect Vector ◽  
Insect Vectors ◽  
Pinewood Nematode ◽  
Monochamus Alternatus ◽  
Form Complex ◽  
Pine Wilt ◽  
Bacterial Microbiota ◽  
Habitat Niche

Abstract Background: Monochamus alternatus Hope is one of the insect vectors of pinewood nematode (Bursaphelenchus xylophilus), which causes the destructive pine wilt disease. The microorganisms within the ecosystem, comprising plants, their environment, and insect vectors, form complex networks. This study presents a systematic analysis of the bacterial microbiota in the M. alternatus midgut and its habitat niche.Methods: Total DNA was extracted from 20 types of samples (with three replicates each) from M. alternatus and various tissues of healthy and infected P. massoniana (pines). 16S rDNA amplicon sequencing was conducted to determine the composition and diversity of the bacterial microbiota in each sample. Moreover, the relative abundances of bacteria in the midgut of M. alternatus larvae were verified by counting the colony-forming units.Results: Pinewood nematode infection increased the microbial diversity in pines. Bradyrhizobium, Burkholderia, Dyella, Mycobacterium, and Mucilaginibacter were the dominant bacterial genera in the soil and infected pines. These results indicate that the bacterial community in infected pines may be associated with the soil microbiota. Interestingly, the abundance of the genus Gryllotalpicola was highest in the bark of infected pines. The genus Cellulomonas was not found in the midgut of M. alternatus, but it peaked in the phloem of infected pines, followed by the phloem of heathy pines. Moreover, the genus Serratia was not only present in the habitat niche, but it was also enriched in the M. alternatus midgut. The colony-forming unit assays showed that the relative abundance of Serratia sp. peaked in the midgut of instar II larvae (81%).Conclusions: Overall, the results indicate that the bacterial microbiota in the soil and in infected pines are correlated. The Gryllotalpicola sp. and Cellulomonas sp. are potential microbial markers of pine wilt disease. Additionally, Serratia sp. could be an ideal agent for expressing insecticidal protein in the insect midgut by genetic engineering, which represents a new use of microbes to control M. alternatus.

scholarly journals Use of Magnetic Resonance Microscopy for the Nondestructive Observation of Xylem Cavitation Caused by Pine Wilt Disease

2005 ◽  
Vol 95 (7) ◽  
pp. 737-743 ◽  
Author(s):  
Shin Utsuzawa ◽  
Kenji Fukuda ◽  
Daisuke Sakaue
Keyword(s):  
Magnetic Resonance ◽  
Spin Echo ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Pinewood Nematode ◽  
Xylem Cavitation ◽  
Mr Microscopy ◽  
Pine Wilt ◽  
Spin Echo Sequence

The development of xylem cavitation caused by pine wilt disease was visualized nondestructively with a compact magnetic resonance (MR) microscope system. A T1-weighted spin-echo sequence clearly visualized the water-filled xylem of Japanese black pine (Pinus thunbergii) as white zones, whereas cavitated xylem was represented as dark areas. Cavitated areas in the xylem were first observed 6 to 9 days after inoculation with the pinewood nematode (Bursaphelenchus xylophilus), and enlarged gradually over several days. After 11 to 18 days, cavitated areas rapidly increased in size, fused, and reached the cambium. This drastic expansion in cavitation coincided with and appeared to explain the sudden wilting of the seedlings. The development of cavitation observed through MR microscopy corresponded well with previous descriptions of disease progression.

scholarly journals Pine wilt disease: detection of the pinewood nematode (Bursaphelenchus xylophilus) as a tool for a pine breeding programme

2012 ◽  
Vol 42 (6) ◽  
pp. 521-525 ◽  
Author(s):  
B. Ribeiro ◽  
M. Espada ◽  
T. Vu ◽  
F. Nóbrega ◽  
M. Mota ◽  
...  
Keyword(s):  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Breeding Programme ◽  
Disease Detection ◽  
Pinewood Nematode ◽  
Pine Wilt

scholarly journals Insights into the Role of Fungi in Pine Wilt Disease

2021 ◽  
Vol 7 (9) ◽  
pp. 780
Author(s):  
Cláudia S. L. Vicente ◽  
Miguel Soares ◽  
Jorge M. S. Faria ◽  
Ana P. Ramos ◽  
Maria L. Inácio
Keyword(s):  
Complex Disease ◽  
Pine Wilt Disease ◽  
Wilt Disease ◽  
Host Tree ◽  
Fungal Communities ◽  
Insect Vector ◽  
Pinewood Nematode ◽  
Management Actions ◽  
Pine Wilt ◽  
Pinus Spp

Pine wilt disease (PWD) is a complex disease that severely affects the biodiversity and economy of Eurasian coniferous forests. Three factors are described as the main elements of the disease: the pinewood nematode (PWN) Bursaphelenchus xylophilus, the insect-vector Monochamus spp., and the host tree, mainly Pinus spp. Nonetheless, other microbial interactors have also been considered. The study of mycoflora in PWD dates back the late seventies. Culturomic studies have revealed diverse fungal communities associated with all PWD key players, composed frequently of saprophytic fungi (i.e., Aspergillus, Fusarium, Trichoderma) but also of necrotrophic pathogens associated with bark beetles, such as ophiostomatoid or blue-stain fungi. In particular, the ophiostomatoid fungi often recovered from wilted pine trees or insect pupal chambers/tunnels, are considered crucial for nematode multiplication and distribution in the host tree. Naturally occurring mycoflora, reported as possible biocontrol agents of the nematode, are also discussed in this review. This review discloses the contrasting effects of fungal communities in PWD and highlights promising fungal species as sources of PWD biocontrol in the framework of sustainable pest management actions.

scholarly journals Characterization of bacterial communities associated with the pinewood nematode insect vector Monochamus alternatus Hope and the host tree Pinus massoniana

2020 ◽  
Author(s):  
Yajie Guo ◽  
Qiannan Lin ◽  
lvyi Chen ◽  
Carballar-Lejarazú Rebeca ◽  
Aishan Zhang ◽  
...  
Keyword(s):  
Pine Wilt Disease ◽  
Wilt Disease ◽  
Insect Vector ◽  
Insect Vectors ◽  
Pinewood Nematode ◽  
Monochamus Alternatus ◽  
Pine Wilt ◽  
Bacterial Microbiota ◽  
Habitat Niche ◽  
Monochamus Alternatus Hope

Abstract Background Monochamus alternatus Hope is one of the insect vectors of pinewood nematode ( Bursaphelenchus xylophilus ), which causes the destructive pine wilt disease. The microorganisms within the ecosystem, comprising plants, their environment, and insect vectors, form complex networks. This study presents a systematic analysis of the bacterial microbiota in the M. alternatus midgut and its habitat niche. Methods Total DNA was extracted from 20 types of samples (with three replicates each) from M. alternatus and various tissues of healthy and infected P. massoniana (pines). 16S rDNA amplicon sequencing was conducted to determine the composition and diversity of the bacterial microbiota in each sample. Moreover, the relative abundances of bacteria in the midgut of M. alternatus larvae were verified by counting the colony-forming units. Results Pinewood nematode infection increased the microbial diversity in pines. Bradyrhizobium , Burkholderia , Dyella , Mycobacterium , and Mucilaginibacter were the dominant bacterial genera in the soil and infected pines. These results indicate that the bacterial community in infected pines may be associated with the soil microbiota. Interestingly, the abundance of the genus Gryllotalpicola was highest in the bark of infected pines. The genus Cellulomonas was not found in the midgut of M. alternatus , but it peaked in the phloem of infected pines, followed by the phloem of heathy pines. Moreover, the genus Serratia was not only present in the habitat niche, but it was also enriched in the M. alternatus midgut. The colony-forming unit assays showed that the relative abundance of Serratia sp. peaked in the midgut of instar II larvae (81%). Conclusions Overall, the results indicate that the bacterial microbiota in the soil and in infected pines are correlated. The Gryllotalpicola sp. and Cellulomonas sp. are potential microbial markers of pine wilt disease. Additionally, Serratia sp. could be an ideal agent for expressing insecticidal protein in the insect midgut by genetic engineering, which represents a new use of microbes to control M. alternatus .

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