|Name: Ips typographus |
|Pest Authorities: (Linnaeus)|
| Taxonomic Position: Insecta: Coleoptera: Scolytidae|
|Sub-specific Taxon: |
|Pest Type: Insect|
European spruce bark beetle (English)
Gran scolyte de l'epicea (French)
Grosser 8 - zähniger Fichtenborkenkäfer (German)
Le typographe de l'epicea (French)
Bostrichus octodentalis Paykull
Dermestes typographus Linneaus
|RISK RATING SUMMARY|
|Numerical Score: 9|
|Relative Risk Rating: Very High Risk|
| Uncertainty in this assessment results from: Uncertainty in this assessment stems from the fact that the ability of Ips typographus to compete with aggressive, indigenous bark beetles that attack spruces in North America, including the spruce beetle, Dendroctonus rufipennis, and several species of Ips, is unknown. |
|RISK RATING DETAILS|
|Establishment Potential Is High Risk
|The relevant criteria chosen for this organism are: |
- Suitable climatic conditions and suitable host material coincide
with ports of entry or major destinations.
- Organism has active, directed host searching capability or is vectored by an
organism with directed, host searching capability.
- Organism has high inoculum potential or high likelihood of
reproducing after entry.
|Justification: Suitable climatic conditions and hosts (Picea spp.) occur at ports of entry in Canada and the northern part of the U.S. that would allow for its establishment. This insect has an active and directed capacity for seeking out suitable hosts and has a high probability of being able to reproduce should it enter via the northern portions of North America. Moreover, Ips typographus has a demonstrated ability to adapt to new hosts by infesting the North American Picea sitchensis when it was introduced into the United Kingdom. A supplementary set of risk maps for the U.S. is available at: Risk maps |
| Spread Potential Is High Risk
|The relevant criteria chosen for this organism are: |
- Organism is capable of dispersing more than several km per year
through its own movement or by abiotic factors (such as wind, water or vectors).
- Organism has demonstrated the ability for redistribution through human-assisted transport.
- Organism has a high reproductive potential
- Potential hosts have contiguous distribution.
- Newly established populations may go undetected for many years due to cryptic nature, concealed activity, slow development of damage symptoms, or misdiagnosis.
|Justification: Ips typographus adults are strong fliers and capable of traveling several km in search of suitable host material. They are also subject to dispersal by winds. Immature stages (eggs, larvae and pupae) are subject to redistribution by human assisted means, especially via wood products (unprocessed logs or lumber, crating, pallets and dunnage containing bark strips). Between 1985 and 2000, I. typographus was intercepted 286 times in association with packing material entering the United States (Haack 2001). Ports with recent interceptions include Erie, PA (1993), Camden, NJ (1994) and Burns Harbor, IN (1995). This insect has a relatively high reproductive potential and because of its cryptic nature of breeding under the bark of host trees and its similarity to several indigenous species of Ips, infestations could go undetected for several years. |
This insect is probably capable of successfully invading any of the spruces indigenous to North America. The boreal forests of Canada, the northernmost states of the U.S. (e.g. Alaska, Maine, Minnesota) are virtually a continuous forest of spruce, which could provide a large volume of suitable host type to allow rapid spread of this insect.
The cryptic nature of this insect, its similarity to indigenous species and the abundance of suitable host would make eradication efforts logistically difficult, if not impossible.
| Economic Potential Is High Risk
|The relevant criteria chosen for this organism are: |
- Organism attacks hosts or products with significant commercial value (such as for timber, pulp, or wood products.
- Organism directly causes tree mortality or predisposes host to mortality by other organisms.
- Damage by organism causes a decrease in value of the host affected, for instance, by lowering its market price, increasing cost
of production, maintenance, or mitigation, or reducing value of property where it is located.
- Organism may cause loss of markets (domestic or foreign) due to
presence and quarantine significant status.
- Organism has demonstrated ability to develop more virulent strains or damaging biotypes.
- No effective control measure exists.
- Organism has potential to be a more efficient vector of a native or introduced pest.
|Justification: Ips typographus is considered Europe’s most destructive bark beetle and records of outbreaks date from the eighteenth century. Outbreaks have developed in drought stressed trees, windthrow and logging slash. An outbreak in Germany at the end of World War II resulted in a loss of 30 million cubic meters of spruce. More recently an outbreak in Norway and Sweden between 1970 and 1982 following an episode of high winds resulted in a loss of 7 million cubic meters of spruce (Speight and Wainhouse 1989). |
An economic analysis for possible introduction of I. typographus was made as part of a pest risk assessment for importation of larch from the Soviet Far East (USDA Forest Service 1991). This analysis considered forest resources only in the Pacific Northwest of the United States and estimated the best case and worst-case scenarios to range between $201 million and $1.5 billion in losses in Washington and Oregon alone should this insect be introduced. Damage in North America would, by no means, be restricted to Washington and Oregon.
|Environmental Potential Is High Risk
|The relevant criteria chosen for this organism are: |
- Organism is expected to cause significant direct environmental effects, such as extensive ecological disruption or large scale reduction of biodiversity.
- Introduction of the organism would likely result in control/eradication programs that may have potential adverse environmental affects.
|Justification: Establishment of Ips typographus would result in the presence of another aggressive bark beetle in North America’s spruce forests. However, its ability to cause become a major damaging agent is dependent on its capacity to compete successfully with indigenous bark beetles such as the spruce beetle, Dendroctonus rufipennis, and several species of spruce infesting Ips. These bark beetles increase in numbers in response to the same factors favored by I. typographus (e.g. windthrow, freshly cut logs, stressed trees). |
Many spruces, including Norway spruce, Picea abies, are important ornamental trees in northern North America. As urban trees, they have even greater value than the wood they contain. The introduction of Ips typographus could threaten this urban resource and lead to greater usage of pesticides by homeowners.
| In its natural range, Ips typographus attacks several species of spruce, Picea spp. Known spruce hosts are Picea abies, Picea jezoensis, Picea orientalis and Picea obovata. Other members of the Pinaceae are also attacked including fir, Abies spp., pines, Pinus spp. and larches, Larix spp. According to one report, the preferred hosts of Ips typographus in the Caucasus Region of Europe are pines (Krivolutskaya 1983). Picea jezoensis, native to Asia, is attacked by a subspecies, I. typographus (Linnaeus) f. japonicus Niijima (Yamaoka et al. 1997). |
The North American Sitka spruce, Picea sitchensis, which is widely planted in portions of the British Isles, is also attacked (Browne 1968) but thus far has not been subject to major outbreaks (Sean Murphy, personal communication, 1999).
This insect is widely distributed in Asia including China (Heilongjang, Sechuan and Jilin Provinces), Japan, Korea, Turkey and Asian Russia (Siberia, Kamchatka, Sakhalin Islands) (Wood and Bright 1992, Bright and Skidmore 2002).
Found over most of Europe including Estonia, Finland, France, Germany, Greece, Republic of Georgia, Latvia, Lithuania, Luxembourg, Norway, Poland, Portugal, Romania, European Russia, Spain, Sweden, Swizerland, Italy (including Sardinia), Czech Republic, Bulgaria, and the former Yugoslav Republics (Wood and Bright 1992, Bright and Skidmore 2002).
This insect is introduced into the United Kingdom (North Wales) (Bright and Skidmore 2002).
| The genus Ips is a large genus of bark beetles (about 60 species) indigenous to conifer forests of Asia, Europe and North America. Twenty-five species are known from North American pines and spruces and several are regarded as important pests (Drooz 1985, Furniss and Carolin 1977, Cibrián Tovar et al. 1995, Wood 1982). |
Ips typographus overwinters in the adult stage, generally in the duff near the tree where it developed (Christiansen and Bakke 1988). A few individuals remain beneath the bark during the winter, especially in the southern part of the insect's range (Christiansen and Bakke 1988). Adults finish maturation in the spring prior to their dispersal flight (Forsse and Solbreck 1985). These flights are initiated in response to air temperatures of 20 C, which can occur from April to June in Europe, depending on latitude and altitude (Bakke et al. 1977).
A complex system of chemical communication governs the host selection process. Male beetles find suitable hosts, probably in response to tree odors, and then initiate attacks. The males produce pheromones, which aggregate both sexes to the host material. Once the host material is fully colonized, the beetles produce anti-aggregant chemicals, which lead to cessation of further attacks . Male beetles are the principal producers of these chemicals, which are derived from host monoterpenes (Vite et al. 1972).
Males excavate a nuptial chamber beneath the bark and eventually mate with one to four females. These females in turn construct egg galleries in the phloem, which radiate out from the nuptial chamber (Christiansen and Bakke 1988). Gallery length varies with gallery density, but 10-12 cm is an average length. Blue-stain fungi are normally transferred with the beetle and grow into the wood around the gallery (Chararas 1962, Christiansen and Bakke 1988). Parent females also may leave the successfully colonized host and establish another brood in other trees or logs (Christiansen and Bakke 1988).
The number of generations per year is dependent upon temperature. In the northern portion of its range, Ips typographus has one generation a year (Christiansen and Bakke 1988), but can complete two generations per year further south. In the northern part of its range, adults emerge from July to October, depending on time of brood establishment, microclimate and weather (Christiansen and Bakke 1988). Further south in Europe, Duelli and others (1986) described two peak flight periods: May/June for the overwintering populations and July/August for the summer generation. The second generation may emerge in November, but more typically, adults hibernate in the brood tree or forest litter and emerge the following spring (Christiansen and Bakke 1988).
The European spruce beetle readily infests down host material, which contains fresh cambium. Windstorms frequently provide the breeding material for subsequent outbreaks of I. typographus, which can kill large numbers of trees. (Christiansen and Bakke 1988).
|Economic Impact: Many examples of large-scale, devastating outbreaks of Ips typographus are reported throughout Eurasia (Christiansen and Bakke 1988). Recent outbreaks in central Europe and Scandinavia have resulted in trees being killed over large areas with losses totaling several million cubic meters of wood (Eidmann 1992, Worrell 1983). A seven-year epidemic following World War II killed 30 million cubic meters of Norway spruce in Germany (Schwerdtfeger 1957). Some outbreaks in German and Norwegian forests have lasted for 30-50 years (Christiansen and Bakke 1988). In Norway, an outbreak in the 1970s, which killed 5 million cubic meters of spruce, led to a substantial reduction of the country's gross national product (Christiansen and Bakke 1988). High losses occur each year in Russia and other countries of the former USSR and outbreaks have occurred in Italy (Lozzia 1993), Poland, and the Czech Republic (Pfeffer and Skuhravy 1995). |
The species in the genus Picea are fairly closely related (J. Alden 1999, personal communication) with little genetic differentiation occurring within the genus (Wright 1955). Picea jezoensis, native to Asia and a known host of Ips typographus, for example, is taxonomically similar to several North American species of Picea, including Sitka spruce, P. sitchensis and Engelmann spruce, P. engelmannii. Moreover, P. jezoensis is able to hybridize with the North American white spruce, P. glauca (Wright 1955). This suggests that Ips typographus would have liitle or no problem adapting to North American spruces for host material.
The spruce bark beetle serves as a vector for a number of fungi. One of these, Ophiostoma polonicum Siem., is highly virulent and capable of killing its hosts by itself (Horntvedt et al. 1983). Other fungi are also associated with this insect (Furniss et al. 1990). Yamaoka and others (1997) list nine species of Ophiostomatales fungi associated with Ips typographus in Norway and Japan. Blue-stain fungi are normally transferred with the beetle and grow into the wood around the gallery (Chararas 1962).
|Environmental Impact: Ips typographus is capable of killing large numbers of trees during outbreaks. This causes major ecological disruptions resulting in change of tree species composition to non-host trees and increaed fuel for high intensity wildfires. |
|Control: Management of Ips typographus relies on many of the same techniques that are applied to native species of North American bark beetles. The approaches involve either the manipulation of habitat or direct reduction of beetle populations. One of these approaches is the avoidance of population buildups by limiting the amount of host material available to the bark beetle. Prompt salvage or debarking of windthrown material may help to limit population growth, but may be impractical when large areas are involved. Direct controls have included the use of attractant and repellent pheromones to either trap out beetles or reduce attacks on suitable host material. Insecticides have been used in direct control, but have a number of limitations in their application. It is important to note that outbreaks of I. typographus and other bark beetles continue to occur both in Eurasia and North America, but outbreaks do not start in stands that have been managed using appropriate tactics of salvage and sanitation. |
|DETECTION AND IDENTIFICATION|
|Symptoms: The most conspicuous indication of attack by Ips typographus is that the foliage of infested trees fades from green to yellow to reddish brown. Breeding attacks are characterized by the presence of reddish-brown boring dust on the bark surface of trees, freshly cut logs, or windthrow. If relatively vigorous trees are attacked, pitch tubes are found in bark crevasses. The gallery pattern in the cambial region of infested trees consists of a nuptial chamber and two to five longitudinal egg galleries. Breeding attacks are accompanied by blue stain in the woody tissue (Abgrall and Soutrenon 1991). |
Round exit holes can be seen are visible on the bark surface of trees where this insect has completed its life cycle and adults have emerged.
|Morphology: Ips typographus averages 4 to 5.5 mm in length and is dark brown in color. The adults are typical bark beetles of the subfamily Ipinae of the family Scolytidae. The head is covered by a thoracic shield and is not visible when viewed dorsally. The declivity is concave, with each side having armed by a four distinct spines (Grüne 1979). |
Eggs are pearly white in color. The larvae are white, legless, ‘C’ shaped grubs with an amber colored head capsule. Mature larvae are about 5 mm long. The pupae are white, mummy-like, and have some adult features, including wings that are folded behind the abdomen.
| Testing Methods for Identification: Species identification of bark beetles (Family Scolytidae) must be made from the adult stage. Identification of insects, suspected of being exotic species of Ips, should be done by a qualified insect taxonomist with expertise in the family Scolytidae. |
|MEANS OF MOVEMENT AND DISPERSAL |
The spruce bark beetle has demonstrated strong dispersal capability (Botterweg 1982). In an extreme case Ips typographus adults were captured on a baited log 43 km from the nearest spruce forest (Nilssen 1984). In another case, beetles were found in the stomach of trout in lakes 35 km from the nearest spruce forest (Nilssen 1978). Laboratory experiments have also shown that adult Ips spp. can fly continuously for several hours. In the field, however, flight has only been observed to take place over limited distances and then usually downwind.
Long distance dispersal by human assisted means is via unprocessed spruce logs or packing material, pallets and dunnage containing bark strips that could harbor immature stages of Ips typographus.
|Abgrail, J.F.; Soutrenon, A. 1991. La forêt et ses ennemis. Paris, France: Centre National du Machinisme Agricole du Genie Rural des Eaux et des Forets (CEMAGREF). |
|Bakke, A.; Austara, O.; Pettersen, H. 1977. Seasonal flight activity and attack pattern of Ips typographus in Norway under epidemic conditions. Meddelelser fra Norsk Institutt for Skogforskning 33: 253-268. |
|Balachowsky, A. 1949. Coleoptera, Scolytides. Faune de France. 50. P. Lechevalier, Paris, France. |
|Botterweg, P.F. 1982. Dispersal and flight behavior of the spruce bark beetle Ips typographus in relation to sex size and fat content. Zeitschrift für Angewandte Entomologie 94(5): 466-489. |
|Bright, D.E.; Skidmore, R.E. 2002. A catalog of Scolytidae and Platypodidae (Coleoptera), Supplement 2 (1995-2000). Ottawa: National Research Council (NRC) Press, 523 pp. |
|Browne, F.G. 1968. Pests and diseases of forest plantation trees - An annotated list of the principal species occurring in the British Commonwealth. Oxford, UK: Clarendon Press, 1330 pp. |
|Chararas, C. 1962. A biological study of the scolytids of coniferous trees. Encyclopedie Entomologique 38. P. Lechevalier, Paris, France. |
|Christiansen, E.; Bakke, A. 1988. The spruce bark beetle of Eurasia. In: Berryman, A.A., ed. Dynamics of forest insect populations: Patterns, causes, implications. New York: Plenum Press: 479-503. |
|Cibrián Tovar, D.; Méndez Monteil , J.T.; Campos Bolaños, R.; Yates, H.O. III, Flores Lara, J. 1995. Forest insects of Mexico North American Forestry Commission, FAO, Publication 6, 453 pp. |
|Drooz, A.T. 1985. Insects of eastern forests USDA Forest Service, Miscellaneous Publication 1426, 608 pp. |
|Duelli, P.; Studer, M.; Naef, W. 1986. The flight of bark beetles outside of forest areas. Journal of Applied Entomology 102(2): 139-148. |
|Eidmann, H.H. 1992. Impact of bark beetles on forests and forestry in Sweden. Journal of Applied Entomology 114(2): 193-200. |
|Forsse, E.; Solbreck, C. 1985. Migration in the bark beetle Ips typographus L.: Duration, timing and height of flight. Zeitschrift für Angewandte Entomologie 100: 47-57. |
|Furniss, M.M.; Solheim, H.; Christiansen, E. 1990. Transmission of blue-stain fungi by Ips typographus Coleoptera: Scolytidae in Norway spruce. Annals of the Entomological Society of America 83(4): 712-716. |
|Furniss, R. L.; Carolin, V.M. 1977. Western forest insects. USDA Forest Service, Miscellaneous Publication 1339, 654 pp. |
|Grüne, S. 1979. Brief illustrated key to European bark beetles. M. & H. Schaper, Hannover, Germany. |
|Haack, R.A. 2001. Intercepted Scolytidae at U.S. ports of entry: 1985-2000. Integrated Pest Management Reviews 6(3) 253-282.
|Horntvedt, R.; Christiansen, E.; Solheim, H.; Wang, S. 1983. Artificial inoculation with Ips typographus associated blue-stain can kill healthy Norway spruce trees. Meddelelser fra Norsk Institutt Skogforskning 38(4): 1-20. |
|Krivolutskaya, G.O. 1983. Ecological and geographical characteristics of the northern Asian barkbeetle fauna (Coleoptera, Scolytidae). Entomological Review 62(2): 52-67. |
|Lozzia, G.C. 1993. Outbreaks of Ips typographus in spruce stands of northern Italy. Bollettino di Zoologia Agraria e di Bachicoltura. 25: 173-182. |
|Niemela, P.; Mattson, W.J. 1996. Invasion of North American forests by European phytophagous insects. Biosience 46(10): 741-753. |
|Nilssen, A. C. 1978. Development of a bark fauna in plantation of spruce (Picea abies (L.) Karst.) in North Norway. Astarte 11: 151-169. |
|Nilssen, A.C. 1984. Long range aerial dispersal of bark beetles and bark weevils Coleoptera Scolytidae and Curculionidae in northern Finland. Ann. Entomol. Fenn. 50(2): 37-42. |
|Pfeffer, A.; Skuhravy, V. 1995. [The bark beetle Ips typographus and problems associated with it in the Czech Republic]. Anzeiger für Schädlingskunde, Pflanzenschutz, Umweltschutz 68, 151-152. |
|Schwerdtfeger, F. 1957. Die Waldkrankheiten, 2nd edition. Hamburg: Paul Parey. |
|Speight, M.R.; Wainhouse, D. 1989. Ecology and management of forest insects. Oxford, UK: Clarendon Press, 374 pp. |
|USDA Forest Service. 1991. Pest risk assessment on the importation of larch from Siberia and the Soviet Far East. Miscellaneous Publication No. 1495. Washington, DC: United States Department of Agriculture, Forest Service. 262 p. |
|Vite, J.P.; Bakke, A.; Renwick, J.A.A. 1972. Pheromones in Ips (Coleoptera: Scolytidae): Occurrence and production. Canadian Entomologist 104: 1967-1975. |
|Wood, S.L. 1982. The bark and ambrosia beetles of North and Central America (Coleoptera: Scolytidae), a taxonomic monograph. Great Basin Naturalist Memoirs 6, 1359 pp. |
|Wood, S.L.; Bright, D.E. 1992. A catalog of Scolytidae and Platypodidae (Coleoptera). Part 2: Taxonomic Index. Great Basin Naturalist Memoir 13, 1553 pp. |
|Worrell, R. 1983. Damage by the spruce bark beetle in South Norway, 1970-1980: A survey and factors affecting its occurrence. Meddelelser fra Norsk Institutt for Skogforskning 38(6): 1-34. |
|Wright, J.W. 1955. Species crossability in spruce in relation to distribution and taxonomy. Forest Science 1(4): 319-349. |
|Yamaoka, Y.; Wingfield, M.J.; Takahashi, I.; Solheim, H. 1997. Ophiostomatoid fungi associated with the spruce beetle Ips typographus f. japonicus in Japan. Mycological Research 101: 1215-1227. |
| Name and Address of the First Author: |
Central Oregon Insect and Disease Area Office
USDA Forest Service
1645 Highway 20 East