Eight-toothed spruce bark beetle (Ips typographus)
Ips typographus commonly known as Eight-toothed spruce bark beetle or the European spruce bark beetle, large spruce bark beetle and larger eight-toothed spruce bark beetle, is a serious and destructive pest of spruce tree species.
Threat
Ips typographus the most serious and destructive pest of spruce species in its native range which includes Asia and Europe. It is common throughout the entire native range of Picea abies (Norway spruce) in Europe, and also occurs in plantations in Western Europe, outside the natural range of the host. Although mainly a secondary pest attacking weakened or felled trees, its main impacts are through population build-up and mass attack of living trees, which can result in extensive tree mortality. It is a significant quarantine pest risk in areas where spruce is native or planted, e.g. North America, the UK and Ireland, where it has the potential to cause extensive damage if introduced.
Northern Ireland Risk register rating
| Organism | Hosts | NI Risk Rating |
|---|---|---|
| Ips typographus | Picea, Abies, Pinus | 125 |
Susceptible species
Ips typographus prefers weakened or freshly dead trees of the following conifer species: Picea spp., including P. abies (the main host in Europe), P. orientalis, P. yezoensis (Northern Asia), P. sitchensis (plantations in France); Pinus spp.; and Abies spp. Large concentrations of this pest can kill healthy host trees.
Spread
Ips typographus is native to Europe, being found throughout the natural range of Picea abies. It is also found throughout Northern Asia. The beetles are able to fly over long distances. Wind and air movements can be additional factors enabling dispersion up to 43 km. It is absent from the Islands of Great Britain and Ireland, although it has occasionally been intercepted at British ports. One likely source in international trade is wood packaging or bark. The impact on the UK’s spruce forests could be devastating if this pest were to become established in this country. I. typographus is not a quarantine organism in Europe. However, the UK, where Picea abies (Norway spruce) does not naturally occur, is a protected zone against the introduction of this species
Outbreak stage and national plans
A finding of a breeding population of Ips typographus was made in Kent in late 2018. The extent of this outbreak is being investigated, and steps to control the outbreak are being carried out. This is the first finding of the beetle in the UK wider environment. This finding was part of routine surveillance activity. The beetles have been discovered in a woodland setting, the government contingency plan has been initiated and the Forestry Commission has been designated the competent body for the outbreak. Although there is no information to indicate that the beetle has moved further than the originally infested area in South east of England, additional risk informed surveys for the beetle in Northern Ireland will be carried out in early 2019. “
Distribution
Ips typographus is native to Europe, being found throughout the natural range of its main host Picea abies. It is also found throughout Northern Asia. It is absent from the Islands of Great Britain and Ireland and has been recorded in the areas indicated on the figure below.
Symptoms
Trees that are attacked or infested by I. typographus 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. However, under certain circumstances, especially during a mass (rapid) attack, this symptom may be absent.
The frass (light-brown sawdust) can be found on the bark in the basal part of the stems of standing trees. The entrance holes of the beetles are visible on the surface of the bark. Initially these are found in the stem below the crown base. Subsequent attacks occur in the lower parts of the stem, including at human eye-level.
The gallery systems under the bark extend from a nuptial chamber. There are one to four regular, vertically extending maternal galleries and perpendicular wavy larval galleries.
For further information on symptoms including pictures please click here.
Reporting suspect cases
If you think you have spotted the insect or insect damage, please check our symptoms section before reporting it using one of the Further Information contact points below.
Management, grants, treatment
The aim of managing I. typographus is to minimize attacks on living trees. The measures most commonly applied for this purpose are clearing windthrows (trees uprooted or broken by wind), sanitation felling of infested trees and the installation of trapping devices.
Cultural control and sanitary methods
The felling and removal of infested trees from forests is one of the most effective control methods Sanitation felling of infested trees involves the harvesting of windthrown timber (to remove breeding substrates), as well as the sanitation felling of infested standing trees. It is the most widespread measure used to defeat I. typographus. When insect development is further advanced (pupae or young adults inside the bark) the debarking of logs is recommended, followed by the destruction, processing or composting of the bark and insects. Alternatively, the infested logs may be sprayed with or immersed in water, which stops insect development and causes considerable mortality. Spraying infested logs with insecticides, such as pyrethroids, is used locally. Application rates vary according to the legislation in different countries.
Trapping devices
Trap trees, pheromone traps, treated trap trees, standing trap trees and lure-baited fallen wood have been frequently used to capture and reduce numbers of I. typographus. Trap-trees (freshly-felled spruces) are exposed for infestation and then removed or debarked. The effectiveness of these trap-trees or logs can be increased by the use of attached, synthetic pheromone dispensers . Trap trees have been used to capture I. typographus for more than 200 years (Pfeil, 1827), and remains an effective suppression method.
Pheromone trapping and insecticides
The approach used to control I. typographus changed in the 1970s with the discovery and production of an aggregation pheromone for the species. Since the 1970s, traps baited with pheromone lures have been commonly used for monitoring or mass trapping of I. typographus.
Spraying infested logs with insecticides, such as pyrethroids (if not restricted for any reasons), is used locally.
Import & movement restrictions
Although not considered to be a quarantine pest by EPPO, it poses a serious risk to the UK and Ireland, where Picea abies does not naturally occur, but where this and other Picea species are widely planted. Although EPPO considers the risk of spread to these islands as low, both the UK and Ireland have Protected Zones enabling them to impose phytosanitary measures, which are mainly based on requiring absence of bark on any imported host woody material. For the UK, these require:
- that plant material other than fruit or seeds of Picea, Abies, Larix and Pseudotsuga species from non-EU countries is prohibited entry into the UK unless it is bark-free and has undergone heat treatment or some other appropriate treatment;
- conifer wood shall be bark-free; or
- that it shall be accompanied by an official statement (plant passport) confirming that
(a) it originates from an area known to be free from Ips typographus; or
(b) in the case of: wood, that it has been kiln dried to below 20% moisture content, and a mark of ‘Kiln Dried’ or ‘KD’ has been put on the wood or its packaging; and in the case of isolated bark, that it has been subjected to an appropriate treatment against bark beetles.
Further information
Questions and answers
Contact:
Plant Health Inspection Branch
DAERA Northern Ireland
Tel: 0300 200 7847
Email: planthealth@daera-ni.gov.uk