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Polygraphus proximus (Coleoptera: Scolytidae)

Sakhalin-fir bark beetle

 

Adult beetleWhy: Polygraphus proximus is a bark beetle, mainly feeding on firs (Abies spp.) which has been introduced from the Far East of Russia into the Western part of Siberia and European Russia. Currently, the pest has invaded Moscow and Leningrad regions in European Russia, and several areas in Siberia (Kemerov and Tomsk regions, Krasnoyarsk Territory – covering an area of approximately 30 000 ha). In Siberia, it has caused significant damage and tree mortality in forests of Siberian fir (A. sibirica). Because P. proximus may represent a major threat to European and Siberian fir species, the EPPO Panel on Quarantine Pests for Forestry recommended that P. proximus should be included in the EPPO Alert List.

Polygraphus proximus adult- Courtesy: Evgeni Akulov (RU)
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Where: Polygraphus proximus is indigenous to Asia. It is commonly found in the Far East of Russia (including the Kuril Islands), Korea Democratic Peoples’ Republic, Japan and the North-East of China. The native area of P. proximus more or less coincides with the distribution range of the Far Eastern species of Abies.
EPPO region: Russia - Central Russia (introduced - Leningrad region in 1999, Moscow region in 2006), Eastern Siberia (introduced – Krasnoyarsk), Far East (native - Khabarovsk, Primorye, Sakhalin including the Kuril islands (Iturup, Kunashir, Shikotan)), Western Siberia (introduced – Altay, Kemerovo in the mid 1990s, Tomsk in 2009).
Asia: China (North-East), Japan (Hokkaido, Honshu, Kyushu, Shikoku), Korea Democratic Peoples’ Republic, Russia (Far East).

On which plants: In Asia, the major hosts of P. proximus are Far Eastern firs: Abies nephrolepis, A. holophylla, A. mariesii, А. firma and A. sachalinensis, but it can develop in other species of Abies. In Russia, it was found in A. sibirica and A. balsamea. In its native area, other recorded hosts are pine trees (Pinus spp., including P. koraiensis), larches (Larix spp.), hemlocks (Tsuga spp.), spruces (Picea abies and P. ajanensis).  For the moment, there is no data on the host status of other Abies species grown in the EPPO region (e.g. A. alba). More information would also be needed on the damage this pest may cause to other conifers recorded as hosts.

DamageDamage: P. proximus is a bivoltine species that produces subcortical galleries. In its natural habitats, this bark beetle does not cause tree mortality, unless trees are weakened by other biotic or abiotic factors. Its biological characteristics in new habitats in Europe are yet unknown, but in invaded areas in Siberia tree mortality has been observed. The crowns of newly infested fir trees initially look healthy, but trunks are fully covered by drops and streams of oleoresin exuded from beetle entry holes. On infested firs, the crown turns light brown-red and finally yellow when the trees die. Affected firs usually die 1-2 years after infestation. After tree death, needles and bark start to fall off and typical bark beetle galleries can easily be seen. Under the bark each nest consists of two to three female galleries up to 8 cm long, horizontally oriented. Larval galleries are vertically oriented along the tree trunk and reach 7 cm in length.
In Siberia and European Russia, P. proximus is a primary pest, which can cause significant economic losses to forests. In addition to direct damage, P. proximus like other bark beetles,is associated with blue stain fungi which can cause wood discoloration and necrosis of vascular tissues. In Japan, two new Ophiostoma species were isolated from P. proximus and infested Abies trees: Ophiostoma aoshimae sp. nov. and Ophiostoma rectangulosporium sp. nov. In Russia, the presence of Ophiostoma aoshimae was recently reported on A. sibirica, probably transferred by P. proximus from its natural range into Siberian forests. Further research is needed to better understand the relationships between P. proximus and blue-stain fungi, and to evaluate the pathogenicity of these fungi in areas where the insect has been introduced.

Dissemination: Because P. proximus may be hidden in the wood and therefore difficult to detect, it may be easily transported with conifer wood and wood products moving in trade. P. proximus could be transported as larvae, pupae or adults in round wood and wooden material with bark attached. The pest has been detected in traded wood (internal movement) by the Russian NPPO. As the adults can fly, they can ensure the pest spread over short distances, but no data is available on flying distances. The pest may also be carried as a hitchhiker on planting material.

Pathway: Wood and bark, wood products, plants for planting of host plants of P. proximus from countries where the pest occurs.

Possible risks: Abies species and other conifers are economically important forest and amenity trees in the EPPO region. Before 2009, there was no documented information on P. proximus in Siberia and it was generally believed that it could not develop on A. sibirica. The observation of two large outbreaks in Siberia (now covering 30 000 ha) in the taiga forest have clearly demonstrated that P. proximus could enter into new areas and damage species other than those reported in its native range. Although the pathway of introduction of P. proximus is not known, it is supposed that it has been introduced into Siberia during the mid-1990s with wood from the Far East. The possibility that P. proximus may transfer pathogenic fungi (e.g. Ophiostoma spp.) to living trees also adds to the risk. The aggressive and invasive behaviour observed in the forests of European Russia and Siberia indicate that P. proximus has the potential to becomea serious pest of firs and possibly other conifers in the EPPO region and that it is desirable to prevent its further spread.

Sources                 
Akulov EN, Kulinich OA, Ponomarev VL (2011) Polygraphus proximus – new invasive pest of Russian coniferous forests. Zashita i Karantin Rastenii no 7, p 34-35.
Baranchikov Y, Pashenova N, Petko V (2012) United they stand: invasive association of four-eyed fir bark beetle and ophiostomal fungus destroy fir taiga forest in Siberia. Abstract of a paper presented at the 3rd meeting of IUFRO Working Unit 7.03.12 ‘Alien invasive species and international trade’ (Tokyo, JP, 2012-06-10/16).
http://hyoka.nenv.k.u-tokyo.ac.jp/alien2012/alien_abst/o04.pdf (abst.)
http://hyoka.nenv.k.u-tokyo.ac.jp/alien2012/alien_report/O04_Baranchikov.pdf

Chilakhsaeva EA (2008) First record of Polygraphus proximus (Coleoptera: Scolytidae) in Moscow province. Bulletin of the Moscow Society of Naturalists 113(6), 39-42.
Chilahsaeva EA (2010) Genus Polygraphus Erichson, 1836 (Coleoptera, Scolytidae): species of Moscow region fauna survey. Bulletin of the Moscow Society of Naturalists 115(3), 48-50.
Gninenko YI, Cheelakhsaeva EA, Klukin MS (2010) New risk for European forests - ussuryjsky bark beetle Polygraphus proximus. Proceedings of the first Serbian forestry Congress - Future with Forests (Belgrade, SR, 2010-11-11/13), pp 171–172.
Ohtaka N, Masuya H, Kaneko S, Yamaoka Y (2006) Two new Ophiostoma species lacking conidial states isolated from bark beetles and bark beetle-infested Abies species in Japan. Canadian Journal of Botany 84(2), 282-293.
Pashenova NV, Baranchikov YN, Petko VM (2011) Invasive Ophiostomataceae fungi from the holes caused by Polygraphus proximus. Zashita i Karantin Rastenii no. 6, 31-32.
Tokuda M, Shoubu M, Yamaguchi D, Yukawa J (2008) Defoliation and dieback of Abies firma (Pinaceae) trees caused by Parendaeus abietinus (Coleoptera: Curculionidae) and Polygraphus proximus (Coleoptera: Scolytidae) on Mount Unzen, Japan. Applied Entomology and Zoology 43(1), p. 1-10.
INTERNET:
Baranchikov Y, Akulov E, Astapenko S (2010) Bark beetle Polygraphus proximus: a new aggressive far eastern invader on Abies species in Siberia and European Russia. USDA Research Forum on Invasive Species GTR-NRS-P-75 http://www.treesearch.fs.fed.us/pubs/37559
Chilahsaeva EA (2011) List of bark beetles (Scolytidae) of some regions of the European part of Russia. Polygraphus proximus Blandford, 1894 (Scolytidae) http://www.zin.ru/Animalia/Coleoptera/eng/polpro__.htm
Linnakoski R (2011) Bark beetle-associated fungi in Fennoscandia with special emphasis on species of Ophiostoma and Grosmannia. Dissertationes Forestales 119, 74 pp. Available at: http://www.metla.fi/dissertationes/df119.pdf

EPPO RS 2011/216, 2013/087

Panel review date 2013-03
Entry date 2011-10

 

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