Ips duplicatus (double-spined bark beetle)
- Summary of Invasiveness
- Taxonomic Tree
- Distribution Table
- Risk of Introduction
- Habitat List
- Hosts/Species Affected
- Growth Stages
- List of Symptoms/Signs
- Biology and Ecology
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Plant Trade
- Wood Packaging
- Environmental Impact
- Detection and Inspection
- Similarities to Other Species/Conditions
- Prevention and Control
- Distribution Maps
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PicturesTop of page
IdentityTop of page
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
- IPSXDU (Ips duplicatus)
Summary of InvasivenessTop of page
I. duplicatus is an invasive species in Europe, extending southwards from its natural range in the north of the continent, where it was first described (Olenici et al., 2010). Mass outbreaks of the pest have been observed in the Czech Republic, Slovakia, Poland and Romania (Grodzki, 2003, Turcani et al., 2001; Olenici et al., 2010) and the spread of the beetle in this region of Europe has been observed since the 1990s (Turcani et al., 2001).
In Slovakia, it is considered to be invasive and a quarantine pest (Novotny and Zubrik, 2000).
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Arthropoda
- Subphylum: Uniramia
- Class: Insecta
- Order: Coleoptera
- Family: Scolytidae
- Genus: Ips
- Species: Ips duplicatus
DescriptionTop 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).
DistributionTop of page
The distribution of I. duplicatus has changed. Southern Finland was considered to be the area of common occurrence of I. duplicatus but species abundance has been seriously reduced by the competition of Ips amitinus there. There are opposing trends in the distributions of I. duplicatus in the Scandinavian parts of Europe and Central Europe. In the former, the range and frequency are diminishing. However, the expansion of I. duplicatus in Central Europe (southern Poland, northern Slovakia, north-eastern Czech Republic and Romania) has been recorded since the 1990s. Here the insect had not been recorded earlier or had been found as an exception in faunistic investigations (Pfeffer and Knizek, 1995; Grodzki, 1997; Turcani et al., 2001).
Distribution TableTop of page
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/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|China||Present||CABI/EPPO, 2014; EPPO, 2014|
|-Heilongjiang||Present||Native||Xiao, 1992; CABI/EPPO, 2014; EPPO, 2014|
|-Nei Menggu||Present||Lakatos et al., 2007; CABI/EPPO, 2014; EPPO, 2014|
|Japan||Present||CABI/EPPO, 2014; EPPO, 2014|
|-Honshu||Present||CABI/EPPO, 2014; EPPO, 2014|
|Kazakhstan||Present||CABI/EPPO, 2014; EPPO, 2014|
|Austria||Present||Native||Krehan, 1996; CABI/EPPO, 2014; EPPO, 2014|
|Belarus||Widespread||Native||Fedorov et al., 1998; CABI/EPPO, 2014|
|Belgium||Present, few occurrences||Introduced||Piel et al., 2006; CABI/EPPO, 2014; EPPO, 2014|
|Croatia||Restricted distribution||CABI/EPPO, 2014; EPPO, 2014|
|Czech Republic||Widespread||Native||****||Pfeffer & Knizek, 1995; EPPO, 2011; Holusa et al., 2013; CABI/EPPO, 2014; EPPO, 2014|
|Czechoslovakia (former)||Present||Native||Jelinek, 1993|
|Estonia||Present||Native||Luik, 1986; CABI/EPPO, 2014; EPPO, 2014|
|Finland||Restricted distribution||Native||Selander & Nuorteva, 1980; Valkama et al., 1997; CABI/EPPO, 2014; EPPO, 2014|
|France||Absent, invalid record||EPPO, 2014|
|Germany||Restricted distribution||CABI/EPPO, 2014; EPPO, 2014|
|Greece||Absent, confirmed by survey||EPPO, 2014|
|Hungary||Restricted distribution||CABI/EPPO, 2014; EPPO, 2014|
|Ireland||Absent, confirmed by survey||EPPO, 2014|
|Latvia||Present||CABI/EPPO, 2014; EPPO, 2014|
|Lithuania||Restricted distribution||Native||Gavyalis et al., 1981; CABI/EPPO, 2014; EPPO, 2014|
|Norway||Widespread||Native||Bakke, 1975; CABI/EPPO, 2014; EPPO, 2014|
|Poland||Restricted distribution||Native||Burakowski et al., 1992; Grodzki, 2003; CABI/EPPO, 2014; EPPO, 2014|
|Portugal||Absent, confirmed by survey||EPPO, 2014|
|Romania||Present||Olenici et al., 2010; CABI/EPPO, 2014; EPPO, 2014|
|Russian Federation||Widespread||Native||Pavlovskii, 1955; Kulinich and Orlinskii, 1998; CABI/EPPO, 2014; EPPO, 2014|
|-Central Russia||Present||CABI/EPPO, 2014; EPPO, 2014|
|-Eastern Siberia||Present||Native||Ogibin et al., 1991; EPPO, 2014|
|-Northern Russia||Present||Native||Pavlovskii, 1955; CABI/EPPO, 2014; EPPO, 2014|
|-Russian Far East||Present||CABI/EPPO, 2014; EPPO, 2014|
|-Siberia||Present||Holusa and Grodzki, 2008; CABI/EPPO, 2014|
|-Western Siberia||Present||Native||Pavlovskii, 1955; EPPO, 2014|
|Serbia||Present||CABI/EPPO, 2014; EPPO, 2014|
|Slovakia||Restricted distribution||Native||Invasive||Turcani et al., 2001; CABI/EPPO, 2014; EPPO, 2014|
|Spain||Absent, confirmed by survey||EPPO, 2014|
|Sweden||Widespread||CABI/EPPO, 2014; EPPO, 2014|
|UK||Absent, confirmed by survey||EPPO, 2014|
|Ukraine||Widespread||CABI/EPPO, 2014; EPPO, 2014|
Risk of IntroductionTop of page
I. duplicatus is not considered to be a quarantine pest by EPPO (2003). However, the UK is a protected zone against the introduction of I. duplicatus (Fielding et al., 1994).
Habitat ListTop of page
Hosts/Species AffectedTop 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 StagesTop of page Vegetative growing stage
SymptomsTop of page
Trees that are attacked or infested by I. duplicatus have discoloured crowns. The needles are lighter in colour, form mats and often fall to the ground. They are green and thus visible under the tree. The frass (light-brown sawdust) can be found on the bark, on the basal part of the stems of standing trees. Woodpeckers, in search of developing larvae, often break off the bark of attacked stems.
List of Symptoms/SignsTop of page
|Leaves / abnormal colours|
|Leaves / abnormal leaf fall|
|Leaves / yellowed or dead|
|Stems / gummosis or resinosis|
|Stems / internal feeding|
|Stems / visible frass|
|Whole plant / frass visible|
|Whole plant / internal feeding|
|Whole plant / plant dead; dieback|
Biology and EcologyTop 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 enemiesTop of page
|Natural enemy||Type||Life stages||Specificity||References||Biological control in||Biological control on|
|Chytridiopsis typographi||Pathogen||Holusa et al., 2007|
|Gregarina typographi||Pathogen||Holusa et al., 2007|
Notes on Natural EnemiesTop of page
The complex of parasitoids associated with I. duplicatus is not very rich and probably not well recognized. The dominant natural enemies are the Hymenopterans, mainly Pteromalidae and Braconidae. Seven species were recognized from Poland (Balazy and Michalski, 1962) and three from Siberia, Russia (Kolomiets and Bogdanova, 1980). All of these are also associated with other Ips species, mainly Ips typographus. Thanasimus formicarius and some species of Staphylinidae are predators of major importance. The impact of parasitoids and entomopathogens is variable and depends on local environmental conditions.
Means of Movement and DispersalTop of page
Natural Dispersal (Non-Biotic)
Beetles are able to fly over long distances. Wind and air movements can be additional factors enabling dispersal.
Movement in Trade
I. duplicatus can be transported in wood that has not been debarked and this is thought to be a possible method of enabling the spread of the beetle in Central Europe (Pfeffer and Knizek, 1995).
Plant TradeTop of page
|Plant parts liable to carry the pest in trade/transport||Pest stages||Borne internally||Borne externally||Visibility 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|
|True seeds (inc. grain)|
Wood PackagingTop of page
|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|
ImpactTop 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 ImpactTop 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 InspectionTop 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.
Similarities to Other Species/ConditionsTop of page
I. duplicatus and Ips typographus are similar in all stages of development. I. typographus adults are bigger (4.2-5.5 mm) and thicker than I. duplicatus, and the frontal part of the pronotum is obliquely cut. The rear sides of the elytra are greasy and shiny. The gallery systems of I. typographus are longer, with one to four regular maternal galleries extending from the nuptial chamber.
I. duplicatus and Ips amitinus are also similar in all stages of development. I. amitinus adults are smaller (3.5-4.5 mm) and slimmer than I. duplicatus, and the frontal part of the pronotum is roundly cut. The rear sides of the elytra are shiny. I. amitinus have longer gallery systems, with three to seven irregular maternal galleries extending from the nuptial chamber.
Prevention and ControlTop of page
Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.
The main control method against I. duplicatus is the removal of infested trees before the emergence of a new generation of beetles. If the identification of infested trees is late (advanced development of insects inside the bark), debarking and bark-destroying are effective controls. Standing trap-trees (girdled at the stem base) can be used to attract and localize the attacking beetles, and must be removed after they are fully infested.
Pheromone traps can be used for trapping flying beetles, but they are not an effective control. This method is still in the development phase.
Artificial traps, baited with synthetic pheromones (commercial products exist in several countries), can be used for the detection of species in previously uninfested areas and for the estimation of insect spread (Turcani et al., 2000; Grodzki, 2003).
ReferencesTop of page
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.
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. http://webbut.unitbv.ro/BU2011/Series%20II/BULETIN%20II/Duduman_M.L..pdf
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. http://notulaebotanicae.ro/nbha/article/view/7261
EPPO, 2011. EPPO Reporting Service. EPPO Reporting Service. Paris, France: EPPO. http://archives.eppo.org/EPPOReporting/Reporting_Archives.htm
EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm
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, 2003. Zasieg wystepowania kornika zroslozebnego Ips duplicatus C.R. Sahlberg (Coleoptera: Scolytidae) w obszarach górskich poludniowej Polski. Sylwan, 8:29-36.
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. http://www.cazv.cz
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. http://www.sab.czu.cz
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.
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. http://www.springerlink.com/content/b46r45r22n072476/?p=568bb025ec1d48748afe6445a73c573c&pi=3
Mrkva R, 1995. Nové poznatky o bionomii, ekologii a hubeni lyko?routa severského. Lesnicka Prace, 3-4:5-7.
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.
Pavlovskii EN, 1955. Vrediteli lesa. Spravochnik. Moskva - Leningrad, USSR: Izdatelstvo Akademii Nauk SSSR.
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. http://www.blackwell-synergy.com/servlet/useragent?func=showIssues&code=epp
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. http://www.springerlink.com/link.asp?id=110826
Distribution MapsTop of page
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