Changes in Major Insect Pests of Pine Forests in Korea Over the Last 50 Years

Understanding the occurrence patterns of forest pests is fundamental for effective forest management from both economic and ecological perspectives. Here, we review the history of the occurrence patterns and causes of outbreaks and declines of pests in Korean pine forests over the last 50 years. During this period, the major pests of pine forests in Korea have shifted from pine caterpillar (Dendrolimus spectabilis Butler) to the pine needle gall midge (PNGM, Thecodiplosis japonensis (Uchida and Inouye)) and finally to pine wilt disease (PWD) caused by the pine wood nematode (Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle). Outbreaks of pine caterpillar, a native species in Korea, have been recorded as far back as 900 years, and it was the most relevant forest pest in Korea until the 1970s. The decline of its importance has been attributed to reforestation and higher levels of subsequent natural enemy activity. The PNGM is an invasive species, first discovered in Korea in 1929, that became widely distributed by 1992 and the major forest pest in the 1980s and 1990s. A suite of parasitic wasps attacking the PNGM contributed at least partially to the decline of PNGM densities. Following the decline of the PNGM, damage from PWD has increased since 2003. These shifts in major forest pests might be related to changes in forest composition and interactions among forest pests. Therefore, a new management strategy for controlling forest pests is required to mitigate the decline of pine forests in Korea.

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Pine chemical volatiles promote dauer recovery of a pine parasitic nematode, Bursaphelenchus xylophilus

Parasitology ◽

10.1017/s0031182019001264 ◽

2019 ◽

Vol 147 (1) ◽

pp. 50-57 ◽

Cited By ~ 2

Author(s):

Wei Zhang ◽

Yongxia Li ◽

Long Pan ◽

Xuan Wang ◽

Yuqian Feng ◽

...

Keyword(s):

Parasitic Nematode ◽

Pine Wilt Disease ◽

Bursaphelenchus Xylophilus ◽

Wilt Disease ◽

Pine Forests ◽

Pinewood Nematode ◽

Dispersal Stage ◽

Pine Trees ◽

The Common ◽

Gradient Effects

AbstractPinewood nematode, Bursaphelenchus xylophilus, a pine parasitic nematode, poses a serious threat to its host pine forests globally. When dispersal-stage larvae 4 (dauer, DL4) of B. xylophilus enters the new pine, it moults into propagative adult (dauer recovery) and reproduces quickly to kill the host pine. Here, we found pine chemical volatiles, rather than the common dauer recovery factors of nematodes (e.g. suitable temperatures, nutrient availability or density), promote B. xylophilus dauer recovery. The results showed that volatilization of chemicals in host pines could attract DL4 and promote DL4 recovery. To identify which chemicals promote this process, we determined the stimulated activity of the main volatiles of pines including six monoterpenes and two sesquiterpenes. Results showed that all the six monoterpenes promoted dauer recovery, especially β-pinene and β-myrcene, but the two sesquiterpenes have no effect on the transformation. Furthermore, β-pinene performed gradient effects on dauer recovery. We hypothesized that when DL4 infect pine trees, the pine volatiles released from the feeding wounds are used as chemical signals for DL4 transformation to adult to reproduce and rapidly kill the pines. Our study identified the B. xylophilus dauer recovery chemical signal and may contribute to preventing pine wilt disease.

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Genetic Structure of Populations of the Pinewood Nematode Bursaphelenchus xylophilus, the Pathogen of Pine Wilt Disease, Between and Within Pine Forests

Phytopathology ◽

10.1094/phyto-97-3-0304 ◽

2007 ◽

Vol 97 (3) ◽

pp. 304-310 ◽

Cited By ~ 15

Author(s):

Zhihua Zhou ◽

Daisuke Sakaue ◽

Bingyun Wu ◽

Taizo Hogetsu

Keyword(s):

Genetic Diversity ◽

Genetic Structure ◽

Genetic Difference ◽

Pine Wilt Disease ◽

Bursaphelenchus Xylophilus ◽

Pine Forests ◽

Pinewood Nematode ◽

High Genetic Diversity ◽

Low Genetic Diversity ◽

Individual Trees

We analyzed the genetic structure of Bursaphelenchus xylophilus populations within individual trees (subpopulations) in three distant pine forests (Tanashi, Tsukuba, and Chiba in Japan) based on the polymorphism of four microsatellite (SSR) markers. Most of the nematodes from subpopulations in Tanashi showed the same genotype over 2 years, indicating that nematodes of that genotype dominated there for years. In contrast, 16 and 15 genotypes were identified in nematode populations from Tsukuba and Chiba, respectively. Despite the high genetic diversity within the Tsukuba and Chiba populations, extremely low genetic diversity was observed within the subpopulations. The genetic difference between the Tsukuba and Chiba populations was significantly smaller than that between Tanashi and either Tsukuba or Chiba. Observed heterozygosity was significantly less than expected based on Hardy-Weinberg equilibrium. These findings are best explained by a founder effect, geographic isolation between populations, explosive nematode multiplication from a small number within individual trees, and the Wahlund effect.

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The Impact of Pine Wood Nematode Infection on the Host Fungal Community

Microorganisms ◽

10.3390/microorganisms9050896 ◽

2021 ◽

Vol 9 (5) ◽

pp. 896

Author(s):

Yi Liu ◽

Zhao-Lei Qu ◽

Bing Liu ◽

Yang Ma ◽

Jie Xu ◽

...

Keyword(s):

Fungal Community ◽

High Throughput Sequencing ◽

Pine Wilt Disease ◽

Bursaphelenchus Xylophilus ◽

Wilt Disease ◽

Pine Forests ◽

Pinewood Nematode ◽

Functional Prediction ◽

Linear Discriminant ◽

The Impact

Pine wilt disease (PWD), caused by pinewood nematode (PWN) Bursaphelenchus xylophilus, is globally one of the most destructive diseases of pine forests, especially in China. However, little is known about the effect of PWD on the host microbiome. In this study, the fungal community and functional structures in the needles, roots, and soil of and around Pinus thunbergii naturally infected by PWN were investigated by using high-throughput sequencing coupled with the functional prediction (FUNGuild). The results showed that fungal richness, diversity, and evenness in the needles of diseased trees were significantly lower than those of healthy ones (p < 0.05), whereas no differences were found in the roots and soil. Principal coordinate analysis (PCoA) showed that the fungal community and functional structures significantly differed only in the needles of diseased and healthy trees, but not in the soil and roots. Functionally, the saprotrophs had a higher abundance in the needles of diseased trees, whereas symbiotrophs abundance was higher in the needles of healthy trees (linear discriminant analysis (LDA) > 2.0, p < 0.05). These results indicated that PWN infection primarily affected the fungal community and functional structures in the needles of P. thunbergii, but not the roots and soil.

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The influence of Canadian research on semiochemical-based management of forest insect pests in Canada

The Canadian Entomologist ◽

10.4039/tce.2015.17 ◽

2015 ◽

Vol 148 (S1) ◽

pp. S170-S209 ◽

Cited By ~ 8

Author(s):

Maya L. Evenden ◽

Peter J. Silk

Keyword(s):

Pest Management ◽

Chemical Ecology ◽

Insect Pests ◽

Research Effort ◽

Forest Pest ◽

Forest Insect ◽

Forest Pests ◽

Forest Pest Management ◽

And Control ◽

Canadian Research

AbstractInsects use semiochemicals to mediate important behaviours such as mating, oviposition, and foraging for resources. Chemical ecology research aims to identify these message-bearing chemicals and develop synthetic copies of semiochemicals for use in integrated pest management (IPM). There has been, and continues to be, an extensive research effort to understand the chemical ecology of various insects considered to be pests of forests in Canada. Canadian chemical ecology research has had an impact on IPM of forest insect pests in Canada and around the world. Canadian researchers have been involved in the identification of semiochemicals used by forest insects and the development and implementation of semiochemical-based management tactics for forest pest management. Semiochemicals have been incorporated into forest pest management for a variety of insect taxa primarily as tools to monitor and control forest insect pests in Canada. The goals of the current review are to: (1) highlight research conducted on semiochemical-based management of forest pests in Canada; (2) discuss the current and potential uses of semiochemicals in IPM of forest pests in Canada; and (3) evaluate potential areas for increased research and implementation of semiochemicals into the management of forest pests in Canada.

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Some Mites of the Genus Proctolaelaps Berlese (Acarina: Blattisociidae) Associated with Forest Insect Pests

The Canadian Entomologist ◽

10.4039/ent9715-1 ◽

1965 ◽

Vol 97 (1) ◽

pp. 15-32 ◽

Cited By ~ 24

Author(s):

Evert E. Lindquist ◽

Preston E. Hunter

Keyword(s):

United States ◽

New Species ◽

Food Habits ◽

Species Complex ◽

Insect Pests ◽

Southeastern United States ◽

Pine Forests ◽

Forest Insect ◽

Forest Pests ◽

Three New Species

AbstractSix species of Proctolaelaps, found associated with insect pests of pine forests in the southeastern United States, are described and illustrated. These are: P. bickleyi (Bram), P. fiseri Samšinák, P. hystrix (Vitzthum), and three new species, P. dendroctoni, P. dioryctriae, and P. hystricoides. Newly recorded for North America are P. fiseri, P. hystrix, and P. ulmi Hirschmann; distributions for the last two species include British Columbia. Garmania striata Westerboer is synonymized under P. bickleyi; the problem of the lewisi species complex, which includes P. bickleyi, P. lewisi (Garman and McGregor), and P. utahensis (Chant), is noted.Although the food habits of these and related mites are mostly unstudied, tentative observations indicate that some species are commensals and others are predators of their insect associates. Investigation of such mites and their relationships with forest pests is urged.

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Efficacy of some insecticide modules against major insect pests and spider population of rice, Oryza sativa L.

ENTOMON ◽

10.33307/entomon.v43i4.405 ◽

2018 ◽

Vol 43 (4) ◽

pp. 257-262

Author(s):

Atanu Seni ◽

Bhimasen Naik

Keyword(s):

Oryza Sativa ◽

Grain Yield ◽

Untreated Control ◽

Insect Pests ◽

Oryza Sativa L ◽

Gall Midge ◽

Stem Borer ◽

The Other ◽

The Third ◽

Treated Plot

Experiments were carried out to assess some insecticide modules against major insect pests of rice. Each module consists of a basal application of carbofuran 3G @ 1 kg a.i ha-1 at 20 DAT and Rynaxypyr 20 SC @ 30 g a.i ha-1 at 45 DAT except untreated control. All modules differ with each other only in third treatment which was applied in 65 DAT. The third treatment includes: Imidacloprid 17.8 SL @ 27 g a.i ha-1, Pymetrozine 50 WG @ 150 g a.i ha-1, Triflumezopyrim 106 SC @ 27 g a.i ha-1, Buprofezin 25 SC @ 250 g a.i ha-1; Glamore (Imidacloprid 40+Ethiprole 40% w/w) 80 WG @ 100 g a.i. ha-1, Thiacloprid 24 SC @ 60 g a.i ha-1, Azadirachtin 0.03 EC @ 8 g a.i ha-1, Dinotefuran 20 SG@ 40 g a.i ha-1 and untreated control. All the treated plots recorded significantly lower percent of dead heart, white ear- head caused by stem borer and silver shoot caused by gall midge. Module with Pymetrozine 50 WG @ 150 g a.i ha-1 treated plot recorded significantly higher per cent reduction of plant hoppers (>80% over untreated control) and produced higher grain yield (50.75 qha-1) than the other modules. Among the different treated modules the maximum number of spiders was found in Azadirachtin 0.03 EC @ 8 g a.i ha-1 treated module plot followed by other treatments.

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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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Enhanced accumulation of pinosylvin stilbenes and related gene expression in Pinus strobus after infection of pine wood nematode

Tree Physiology ◽

10.1093/treephys/tpab053 ◽

2021 ◽

Author(s):

Hwan-Su Hwang ◽

Jung Yeon Han ◽

Yong Eui Choi

Keyword(s):

Transcription Factors ◽

Defense Mechanisms ◽

De Novo ◽

Pinus Strobus ◽

Pine Wilt Disease ◽

Monomethyl Ether ◽

Bursaphelenchus Xylophilus ◽

Nematicidal Activity ◽

Dependent Manner ◽

Pine Wood

Abstract Pine wood nematodes (PWNs: Bursaphelenchus xylophilus) infect pine trees and cause serious pine wilt disease. Eastern white pine (Pinus strobus) has resistance to PWN. However, the detailed defense mechanisms of P. strobus against PWN are not well known. When P. strobus plants were infected with PWNs, the accumulation of stilbenoids, dihydropinosylvin monomethyl ether (DPME) and pinosylvin monomethyl ether (PME), were increased remarkably. DPME and PME had the high nematicidal activity. Interestingly, the nematicidal activity of the two compounds was resulted in a developmental stage-dependent manner. PME was more toxic to adult PWNs than juveniles, whereas DPME was found more toxic to juvenile PWNs than the adults. The genes involved in PME and DPME biosynthesis such as phenylalanine ammonia-lyase (PAL), 4-coumarate-CoA ligase (4CL), pinosylvin synthase (STS), and pinosylvin O-methyltransferase (PMT) were isolated using de novo sequencing of the transcriptome in P. strobus. In addition, transcription factors (bHLH, MYB and WRKY) related to stilbene biosynthesis were isolated. qPCR analyses of the selected genes (PAL, 4CL, STS, and PMT) including transcription factors (bHLH, MYB and WRKY) revealed that the expression level of the selected genes highly enhanced after PWN infection. Our results suggest that pinosylvin-type stilbenoid biosynthesis is highly responsive to PWN infection and plays an important role in PWN resistance of P. strobus trees.

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Chitosan increases Pinus pinaster tolerance to the pinewood nematode (Bursaphelenchus xylophilus) by promoting plant antioxidative metabolism

Scientific Reports ◽

10.1038/s41598-021-83445-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Marta Nunes da Silva ◽

Carla S. Santos ◽

Ana Cruz ◽

Adrián López-Villamor ◽

Marta W. Vasconcelos

Keyword(s):

Phenolic Compounds ◽

Pinus Pinaster ◽

Plant Defence ◽

Pine Wilt Disease ◽

Bursaphelenchus Xylophilus ◽

Nematode Population ◽

Post Inoculation ◽

Pinewood Nematode ◽

Plant Tolerance ◽

The Moment

AbstractThe pine wilt disease (PWD), for which no effective treatment is available at the moment, is a constant threat to Pinus spp. plantations worldwide, being responsible for significant economic and environmental losses every year. It has been demonstrated that elicitation with chitosan increases plant tolerance to the pinewood nematode (PWN) Bursaphelenchus xylophilus, the causal agent of the PWD, but the biochemical and genetic aspects underlying this response have not been explored. To understand the influence of chitosan in Pinus pinaster tolerance against PWN, a low-molecular-weight (327 kDa) chitosan was applied to mock- and PWN-inoculated plants. Nematode population, malondialdehyde (MDA), catalase, carotenoids, anthocyanins, phenolic compounds, lignin and gene expression related to oxidative stress (thioredoxin 1, TRX) and plant defence (defensin, DEF, and a-farnesene synthase, AFS), were analysed at 1, 7, 14, 21 and 28 days post-inoculation (dpi). At 28 dpi, PWN-infected plants elicited with chitosan showed a sixfold lower nematode population when compared to non-elicited plants. Higher levels of MDA, catalase, carotenoids, anthocyanins, phenolic compounds, and lignin were detected in chitosan-elicited plants following infection. The expression levels of DEF gene were higher in elicited plants, while TRX and AFS expression was lower, possibly due to the disease containment-effect of chitosan. Combined, we conclude that chitosan induces pine defences against PWD via modulation of metabolic and transcriptomic mechanisms related with plant antioxidant system.

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In Silico Screening of Agonist and Antagonist Natural Compounds from Reported Essential Oils against Bursaphelenchus xylophilus

Chemistry Proceedings ◽

10.3390/ecsoc-24-08386 ◽

2020 ◽

Vol 3 (1) ◽

pp. 31

Author(s):

Jorge M. S. Faria ◽

Ana Margarida Rodrigues ◽

Pedro Barbosa ◽

Manuel Mota

Keyword(s):

Essential Oils ◽

Pine Wilt Disease ◽

Natural Compounds ◽

Bursaphelenchus Xylophilus ◽

Pinewood Nematode ◽

Highly Active ◽

Bibliographic Data ◽

Agonist And Antagonist ◽

Containment Strategy ◽

Detailed Chemical

Chemical control has been the most effective and reliable containment strategy in integrated pest management of pine wilt disease (PWD), caused by the pinewood nematode (PWN), Bursaphelenchus xylophilus. Yet, large spectrum nematicides can be dangerous to human health and the environment. Essential oils (EOs) are safer sustainable alternatives, being composed of highly active natural compounds. A survey of bibliographic data on the detailed chemical composition and activity of the EOs used against the PWN allowed pinpointing monoterpenes as the main source of structures with agonist or antagonist properties. Transversal EO data treatment can identify potential highly active anti-PWN compounds.

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