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Ips duplicatus (double-spined bark beetle)


  • Last modified
  • 11 October 2017
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Preferred Scientific Name
  • Ips duplicatus
  • Preferred Common Name
  • double-spined bark beetle
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Metazoa
  •     Phylum: Arthropoda
  •       Subphylum: Uniramia
  •         Class: Insecta

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Lateral view of an adult.
CaptionLateral view of an adult.
CopyrightMieczyslaw Kosibowicz
Lateral view of an adult.
AdultLateral view of an adult.Mieczyslaw Kosibowicz
Eggs in egg niches.
CaptionEggs in egg niches.
CopyrightWojciech Grodzki
Eggs in egg niches.
EggsEggs in egg niches.Wojciech Grodzki
Larvae and pupae inside the breeding site.
TitleLarvae and pupae
CaptionLarvae and pupae inside the breeding site.
CopyrightWojciech Grodzki
Larvae and pupae inside the breeding site.
Larvae and pupaeLarvae and pupae inside the breeding site.Wojciech Grodzki
Initial phase of infestation: adults boring the maternal galleries.
TitleAdult beetles boring
CaptionInitial phase of infestation: adults boring the maternal galleries.
CopyrightWojciech Grodzki
Initial phase of infestation: adults boring the maternal galleries.
Adult beetles boringInitial phase of infestation: adults boring the maternal galleries.Wojciech Grodzki
The completed maternal and larval galleries of a heavy infestation.
TitleHeavy infestation
CaptionThe completed maternal and larval galleries of a heavy infestation.
CopyrightWojciech Grodzki
The completed maternal and larval galleries of a heavy infestation.
Heavy infestationThe completed maternal and larval galleries of a heavy infestation.Wojciech Grodzki


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Preferred Scientific Name

  • Ips duplicatus (Sahlberg, 1836)

Preferred Common Name

  • double-spined bark beetle

Other Scientific Names

  • Bostrychus duplicatus Sahlberg, 1836
  • Tomicus duplicatus (Sahlberg, 1836)
  • Tomicus infucatus Eichhoff, 1878
  • Tomicus judeichi (Kirsch, 1870)

International Common Names

  • Russian: koroed-dvoinik

Local Common Names

  • Czech Republic: lýkozrout severský
  • Finland: pieni kirjanpainaja
  • Germany: Borkenkaefer, Nordischer Fichten-; nordischer Fichtenborkenkäfer
  • Norway: dobbelt-tannet barkbille
  • Poland: kornik zroslozebny
  • Slovakia: lýkozrut severský

EPPO code

  • IPSXDU (Ips duplicatus)

Taxonomic Tree

Top of page
  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Arthropoda
  •             Subphylum: Uniramia
  •                 Class: Insecta
  •                     Order: Coleoptera
  •                         Family: Scolytidae
  •                             Genus: Ips
  •                                 Species: Ips duplicatus


Top of page Adult

The adults are small (2.8-4 mm long), cylindrical, dark-brown, shiny and hairy. The antennae are clavate. The frontal part of the pronotum is roundly cut, dentate and squamate, and the hind part is stippled. There are rows of depressed points on the glossy elytra, with spaces in between them. The posterior edges of the elytra form a characteristic collar shape, with dents on both sides. There are four teeth on these edges, and the second and third teeth are joined. The rear side of the elytral declivity is greasy and shiny (when the insect is viewed from the rear).


The eggs are whitish-grey, ovate and small (0.7 mm long). They are individually laid in niches along both sides of the maternal gallery (average of 60 eggs per female).


The larvae and adults are similar in size. The larvae are 4.5-5.5 mm long, white, cylindrical and legless, with small, brown, chitinous heads and brown mandibles.


The pupae have many free segments (pupa libera). They are white and similar in size to the adults (up to 5 mm).

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes


ChinaPresentCABI/EPPO, 2014; EPPO, 2014
-HeilongjiangPresentNativeXiao, 1992; CABI/EPPO, 2014; EPPO, 2014
-JilinPresentNativeXiao, 1992
-Nei MengguPresentLakatos et al., 2007; CABI/EPPO, 2014; EPPO, 2014
JapanPresentCABI/EPPO, 2014; EPPO, 2014
-HonshuPresentCABI/EPPO, 2014; EPPO, 2014
KazakhstanPresentCABI/EPPO, 2014; EPPO, 2014


AustriaPresentNativeKrehan, 1996; CABI/EPPO, 2014; EPPO, 2014
BelarusWidespreadNativeFedorov et al., 1998; CABI/EPPO, 2014
BelgiumPresent, few occurrencesIntroducedPiel et al., 2006; CABI/EPPO, 2014; EPPO, 2014
BulgariaWidespreadEPPO, 2014
CroatiaRestricted distributionCABI/EPPO, 2014; EPPO, 2014
Czech RepublicWidespreadNative****Pfeffer & Knizek, 1995; EPPO, 2011; Holusa et al., 2013; CABI/EPPO, 2014; EPPO, 2014
Czechoslovakia (former)PresentNativeJelinek, 1993
EstoniaPresentNativeLuik, 1986; CABI/EPPO, 2014; EPPO, 2014
FinlandRestricted distributionNativeSelander & Nuorteva, 1980; Valkama et al., 1997; CABI/EPPO, 2014; EPPO, 2014
FranceAbsent, invalid recordEPPO, 2014
GermanyRestricted distributionCABI/EPPO, 2014; EPPO, 2014
GreeceAbsent, confirmed by surveyEPPO, 2014
HungaryRestricted distributionCABI/EPPO, 2014; EPPO, 2014
IrelandAbsent, confirmed by surveyEPPO, 2014
LatviaPresentCABI/EPPO, 2014; EPPO, 2014
LithuaniaRestricted distributionNativeGavyalis et al., 1981; CABI/EPPO, 2014; EPPO, 2014
NorwayWidespreadNativeBakke, 1975; CABI/EPPO, 2014; EPPO, 2014
PolandRestricted distributionNativeBurakowski et al., 1992; Grodzki, 2003; CABI/EPPO, 2014; EPPO, 2014
PortugalAbsent, confirmed by surveyEPPO, 2014
RomaniaPresentOlenici et al., 2010; CABI/EPPO, 2014; EPPO, 2014
Russian FederationWidespreadNativePavlovskii, 1955; Kulinich and Orlinskii, 1998; CABI/EPPO, 2014; EPPO, 2014
-Central RussiaPresentCABI/EPPO, 2014; EPPO, 2014
-Eastern SiberiaPresentNativeOgibin et al., 1991; EPPO, 2014
-Northern RussiaPresentNativePavlovskii, 1955; CABI/EPPO, 2014; EPPO, 2014
-Russian Far EastPresentCABI/EPPO, 2014; EPPO, 2014
-SiberiaPresentHolusa and Grodzki, 2008; CABI/EPPO, 2014
-Western SiberiaPresentNativePavlovskii, 1955; EPPO, 2014
SerbiaPresentCABI/EPPO, 2014; EPPO, 2014
SlovakiaRestricted distributionNative Invasive Turcani et al., 2001; CABI/EPPO, 2014; EPPO, 2014
SpainAbsent, confirmed by surveyEPPO, 2014
SwedenWidespreadCABI/EPPO, 2014; EPPO, 2014
UKAbsent, confirmed by surveyEPPO, 2014
UkraineWidespreadCABI/EPPO, 2014; EPPO, 2014

Hosts/Species Affected

Top of page I. duplicatus mainly inhabits spruces. Picea obovata (Siberian spruce) is the main host tree of I. duplicatus in the European and Siberian taiga. In Sakhalin, Russia, the main host tree is Picea jezoensis (ezo spruce), in China it is Picea koraiensis (Korean spruce) and in Europe it is Picea abies (Norway spruce). However, infestations have also been observed on Pinus sylvestris (Scotch pine) and Pinus cembra (arolla pinetree). In Siberia, Russia, infestations were observed on Pinus cembra var. sibirica (Pfeffer and Knizek, 1995) and Larix spp. (larches) (Pavlovskii, 1955).

Growth Stages

Top of page Vegetative growing stage

List of Symptoms/Signs

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  • abnormal colours
  • abnormal leaf fall
  • yellowed or dead


  • gummosis or resinosis
  • internal feeding
  • visible frass

Whole plant

  • frass visible
  • internal feeding
  • plant dead; dieback

Biology and Ecology

Top of page I. duplicatus is primarily adapted to the conditions of the Siberian taiga, Russia. It is adapted to the low temperatures and very short vegetation periods, and thus displays peculiarities in its biology and ecology in European conditions.

Swarming in the spring begins in April, and is short and intense. The beetles often attack trees that are dispersed within the stands, and initiate attacks in the zone just below and inside the crown. In endemic conditions, only this zone is attacked and the lower parts of the stem are usually infested by Ips typographus. However, in epidemic conditions, the zone attacked by I. duplicatus may be much larger and reach the middle and basal parts of the stems.

The males are responsible for host-tree selection. The females are attracted by male pheromones containing ipsdienol and E-myrcenol (Bakke, 1975; Byers et al., 1990). One male can attract one to five females, but usually they attract two to four. Each female bores a maternal gallery and lays an average of 60 eggs in niches on both sides of the gallery. After approximately 1 to 2 weeks the eggs hatch and the larvae begin to bore galleries that are approximately 5 cm long. The larval stage usually lasts 2 to 4 weeks, depending on the thermal conditions. Pupation takes approximately 1 week and the beetles require additional feeding time for maturation. Feeding takes approximately 2 weeks after which time the beetles are ready to produce a new brood. The development of one generation usually takes approximately 6 to 8 weeks in Central European conditions. The beetles can establish sister generations after the establishment of the main generations.

I. duplicatus usually has two generations per year. In the severe conditions of northern Europe only one generation can occur, but in Central Europe, during extremely warm and long summers, three generations can occur (Mrkva, 1995). Variability in the number of generations results from species adaptation to the conditions of the northern parts of the European continent.

The beetles attack standing trees only, and trees and logs lying on the ground are not infested.

I. duplicatus can co-occur with some bark beetle species and these are mainly I. typographus, Ips amitinus and Pityogenes chalcographus. However, I. typographus and I. amitinus may be competitors for I. duplicatus (Schlyter and Anderbrant, 1993; Pfeffer and Knizek, 1995; Grodzki, 1997).

I. duplicatus overwinters as an adult in the litter, soil or bark but not in the breeding sites.

Natural enemies

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Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Beauveria bassiana Pathogen Eggs/Pupae
Chytridiopsis typographi Pathogen Holusa et al., 2007
Coeloides bostrychorum Parasite Larvae
Dendrosoter middendorffii Parasite Larvae
Gregarina typographi Pathogen Holusa et al., 2007
Rhopalicus brevicornis Parasite Larvae
Rhopalicus tutela Parasite Larvae
Roptrocerus xylophagorum Parasite Larvae
Thanasimus formicarius Predator Eggs/Larvae
Tomicobia seitneri Parasite Adults

Plant Trade

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Plant parts liable to carry the pest in trade/transportPest stagesBorne internallyBorne externallyVisibility of pest or symptoms
Bark adults; pupae Yes Pest or symptoms usually visible to the naked eye
Stems (above ground)/Shoots/Trunks/Branches adults; eggs; larvae; pupae Yes Pest or symptoms usually visible to the naked eye
Plant parts not known to carry the pest in trade/transport
Fruits (inc. pods)
Growing medium accompanying plants
Seedlings/Micropropagated plants
True seeds (inc. grain)

Wood Packaging

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Wood Packaging not known to carry the pest in trade/transport
Loose wood packing material
Processed or treated wood
Solid wood packing material with bark
Solid wood packing material without bark


Top of page The outbreak of I. duplicatus, recorded in southern Poland and north-eastern Czech Republic in the 1990s, resulted in considerable losses of Norway spruce (Picea abies) stands, due to the premature mortality or sanitary felling of the trees (Grodzki, 1997; Holusa, 2001).

Environmental Impact

Top of page The mortality of spruces can result in changes in the species composition of forests with spruce as an admixture, or in the decline of pure spruce stands, especially those that have been artificially introduced.

Detection and Inspection

Top of page The discoloration of infested trees, due to the abnormal colour of the needles, is clearly visible. Another obvious symptom of infestation is the bark that has been broken off by woodpeckers.

The frass on the bark surface and in the tree base is easy to find during periods of good weather. However, it disappears after rainfall.

The nuptial chambers, maternal galleries, eggs, larvae and pupae (depending on the extent of insect development) are easy to find under the bark.

Attacked trees are often dispersed inside the stands and sometimes on the stand edges. These trees are often grouped but individually attacked trees also occur.

Initial attacks are usually localized in the upper part of standing trees, especially just below or in the crown zone. The symptoms of early infestations are not very evident; the discoloration of foliage and broken bark (removed by woodpeckers) are more obvious.


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Bakke A, 1975. Aggregation pheromone in the bark beetle Ips duplicatus (Sahlberg). Norwegian Journal of Entomology, 22(1):67-69

Balazy S; Michalski J, 1962. Pasozyty korników (Coleoptera, Scolytidae) z rzedu blonkówek (Hymenoptera) wystepujace w Polsce. Prace Kom. Nauk Rol. i Kom. Nauk Les. PTPN, XIII(1):71-141.

Burakowski B; Mroczkowski M; Stefanska J, 1992. Volume 18, Part XXIII. Beetles - Coleoptera. Curculionoidea apart from Curculionidae. Katalog Fauny Polski, 23(18):324 pp.; many ref.

Byers JA; Schlyter F; Birgersson G; Francke W, 1990. E-Myrcenol in Ips duplicatus: an aggregation pheromone component new for bark beetles. Experientia, 46(11-12):1209-1211

CABI/EPPO, 2014. Ips duplicatus. [Distribution map]. Distribution Maps of Plant Pests, No.June. Wallingford, UK: CABI, Map 782.

Duduman ML; Isaia G; Olenici N, 2011. Ips duplicatus (Sahlberg) (Coleoptera: Curculionidae, Scolytinae) distribution in Romania: preliminary results. Bulletin of the Transilvania University of Brasov, Series II - Forestry, Wood Industry, Agricultural Food Engineering, 4(53 Part 2):19-26.

Duduman M-L; Olenici N; Isaia G, 2012. Research carried out in Romania on the northern bark beetle (Ips duplicatus, Coleoptera: Curculionidae, Scolytinae). In: Proceedings of the Biennial International Symposium Forest and Sustainable Development, Brasov, 19-20 October, 2012. Brasov, Romania: Transilvania University Press, 9-14.

Duduman ML; Vasian I, 2012. Effects of volatile emissions of Picea abies fresh debris on Ips duplicatus response to characteristic synthetic pheromone. Notulae Botanicae, Horti Agrobotanici, Cluj-Napoca, 40(1):308-313.

EPPO, 2011. EPPO Reporting Service. EPPO Reporting Service. Paris, France: EPPO.

EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization.

Fedorov NI; Sarnatskii VV; Rikhter Ie; Raptunovich ES; Kovbasa NP; Rogovoi AP; Puchilo AV, 1998. Specific features of the mass dying of spruce trees in forests of Belarus. Lesovedenie, No. 6:12-23; 16 ref.

Fielding N; Evans B; Burgess R; Evans H, 1994. Protected Zone surveys in Great Britain for Ips typographus, I. amitinus, I. duplicatus and Dendroctonus micans. Research Information Note - Forestry Authority Research Division Farnham, UK, No. 253:6 pp.

Gavyalis VM; Yakaitis BYu, 1981. The attraction of various species of bark-beetles with methylbutenol, cis-verbenol, ipsdienol and mixtures of these pheromones. Khemoretseptsiya Nasekomykh, No. 6:115-120

Grodzki W, 1997. Possibilities of the control of double-spined bark beetle Ips duplicatus C. R. Sahlb. populations in southern Poland. Sylwan, 141(11):25-36; 32 ref.

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Holusa J, 2001. Is dying of spruce forests in Silesia a result of drought, fungi or bark beetles?. Journal of Forest Science, 47(Special Issue 2):100.

Holusa J; Grodzki W, 2008. Occurrence of Ips duplicatus (Coleoptera: Curculionidae, Scolytinae) on pines (Pinus sp.) in the Czech Republic and southern Poland - short communication. Journal of Forest Science, 54(5):234-236.

Holusa J; Lukásová K; Trombik J, 2013. The first record of Ips duplicatus (Coleoptera: Curculionidae, Scolytinae) infestations in central European inner mountains. Scientia Agriculturae Bohemica, 44(2):97-101.

Holusa J; Weiser J; Drapela K, 2007. Pathogens of Ips duplicatus (Coleoptera: Scolytidae) in three areas in Central Europe. Acta Protozoologica, 46(2):157-167.

Jelinek J, 1993. Check-list of Czechoslovak Insects IV (Coleoptera). In: Picka J, ed. Occasional Papers on Systematic Entomology. Prague, Czech Republic: Folia Heyrovskyana, Supplementum 1.

Kolomiets NG; Bogdanova DA, 1980. Parazity i chishchniki ksilofagov Sibiri. Novosibirsk, USSR: Izdatelstvo "Nauka", Sibirskoe Otdelenie.

Krehan H, 1996. Bark beetle infestation in Austria in 1995. Forstschutz Aktuell, No. 17/18:3-4.

Kulinich OA; Orlinskii PD, 1998. Distribution of conifer beetles (Scolytidae, Curculionidae, Cerambycidae) and wood nematodes (Bursaphelenchus spp.) in European and Asian Russia. Bulletin OEPP, 28(1/2):39-52; 42 ref.

Lakatos F; Grodzki W; Zhang QH; Stauffer C, 2007. Genetic comparison of Ips duplicatus (Sahlberg, 1836) (Coleoptera: Curculionidae, Scolytinae) populations from Europe and Asia. Journal of Forest Research, 12(5):345-349.

Luik A, 1986. Temperature as the principal exogenous regulator of winter dormancy in xylophages. Metsanduslikud Uurimused, Estonian SSR, 21:98-102

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Novotny J; Zubrik M, 2000. Biotickí skodcovia lesov Slovenska. Bratislava, Slovakia: Lesnicka sekcia Ministerstva pôdohospodarstva SR.

Ogibin BN; Lobanova AV; Maslov AD; Matusevich LS; Tsankov G, 1991. Protecting coniferous roundwood against insect pests in the Komi SSR. Izvestiya Vysshikh Uchebnykh Zavedenii, Lesnoi Zhurnal, No. 5:16-19; 8 ref.

Olenici N; Duduman M-L; Olenici V; Bouriaud O; Tomescu R; Rotariu C, 2010. The first outbreak of Ips duplicatus (Coleoptera, Curculionidae, Scolytinae) in Romania. In: Proceedings of the 10th IUFRO Workshop of WP 7.03.10 "Methodology of Forest Insect and Disease Survey in Central Europe", September 20-23, 2010, Freiburg, Germany [ed. by Delb, H. \Pontuali]. Freiburg and Baden-Württemberg, Germany: Fakultät für Forst- und Umweltwissenschaften der Albert-Ludwigs-Universität and Forstliche Versuchs- und Forschungsanstalt (FVA), 135-140.

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Piel F; Gregoire JC; Knizek M, 2006. New occurrence of Ips duplicatus Sahlberg in Herstal (Liege, Belgium). Bulletin OEPP/EPPO Bulletin, 36(3):529-530.

Weiser J; Holusa J; Zizka Z, 2006. Larssoniella duplicati sp. nov. (Microsporidia, Unikaryonidae), a newly described pathogen infecting the double-spined spruce bark beetle, Ips duplicatus (Coleoptera, Scolytidae) in the Czech Republic. Journal of Pest Science, 79(3):127-135.

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