Bark beetle

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Bark beetle
Grained spruce bark beetle (Cryphalus abietis)

Grained spruce bark beetle ( Cryphalus abietis )

Class : Insects (Insecta)
Order : Beetle (Coleoptera)
Subordination : Polyphaga
Superfamily : Curculionoidea
Family : Weevil (Curculionidae)
Subfamily : Bark beetle
Scientific name
Latreille , 1807
Broodwaves of the printer
Larva of a bark beetle
Book printer in Meyers 1888
Pine marrow beetle

The bark beetles (Scolytinae) are a subfamily of the weevils (Curculionidae). Bark beetles are a species-rich group of beetles , often brown or black in color , of which many species reproduce under the bark or in the wood of trees in self-drilled passages and sometimes cause great economic damage.


As primary consumers or destructors , they play an important role in the material cycle of the forest ecosystem . However, the bark beetles are known to the general public primarily for the severe damage that some species of them can cause in forests after mass reproduction as forest pests .

There are around 6000 species of bark beetle worldwide (as of 2014), and new species are constantly being discovered and described. Around 600 species are native to the Palearctic , between 250 and 300 in Europe and around 110 in Germany.

When German-speaking forestry practitioners speak of “the” bark beetle, they almost always refer to a certain species, the printer ( Ips typographus ).


Bark beetles reach a body length between 0.7 and 12 millimeters (lengths between 1 and 6 millimeters are given for the Central European species, but there are larger species such as the giant bark beetle ( Dendroctonus micans ) with up to 9 mm). The body is ovate to elongated, often heavily sclerotized and hard-armored, usually more or less cylindrical and cylindrical, the ratio of length to width from about 1.2 to 8 to 1. They are black, in various shades of brown to yellowish, rarely somewhat shiny metal. The body surface is usually smooth, often sparsely hairy or scaly. As an exception within the weevils, a trunk (anatomically also called rostrum) in the bark beetles is extremely rudimentary, but mostly completely regressed, which is why they were not counted among the weevils in the past, but rather regarded as an independent family. The head is always more or less inclined downwards (the mouth opening points downwards), usually spherical and narrower than the pronotum , it is often hidden under the protruding pronotum and invisible when looking straight from above. The complex eyes are flat (they do not protrude from the contour of the head), they are rounded to elongated and often kidney-shaped or constricted, sometimes divided into two sections. The antennae are widely separated from one another, pivoted under the eyes or at the base of the mandibles , they are always kneeled (the antenna flagella form an angle with the base member or scapus) with an antenna lobe at the end. On the head capsule, the clypeus and frons are fused together, a labrum is missing. The short, strong mandibles are curved, they end in a point. Many species have a separate pocket at their base in which they transport fungal spores. The stores (lacinia and galea) of the maxilla are fused, the maxillary palpate is tripartite. The pronotum is about as wide as the elytra or slightly narrower, mostly cylindrical and often highly arched, it is relatively short, a good half as long to almost twice as long as it is wide. The scutellum may be clear, but in many species it is sunk and hidden under the wing covers. The elytra are usually cylindrical with straight sides, at the rear end usually abruptly rounded hemispherical, this fall often bears small teeth, which are important in determining the species. As is typical for weevils, four limbs can be seen on the legs, one (the third) is enlarged and hairy on the underside, the fourth has receded into a short, barely visible rudiment. The rails are often serrated on the outside and have a distinct, often hook-like end pin, they are longer than the tarsi and often widened towards the end. Five stermites are visible on the abdomen, as is typical for the weevils, the first two are immovably fused together.

The larvae are maggot-like, legless and usually colored white with a darker, hard sclerotized head capsule. This is usually round, without larval eyes (stemmata). The small, conical antenna consists of only one segment. They have a pair of spiracles on the prothorax and eight, slightly smaller pairs on the first eight of the ten abdominal segments.


Life cycle

Most bark beetles develop in the living tissue of the bark , the bast of trees and other woody plants (for species with a different way of life see below). Many of them begin their development there, but in later stages they switch to the bark, which actually gives them their name, or to the wood. The host plant's attack begins differently depending on the species ; three types can be distinguished: in monogamous species, females begin to set up a breeding path. These are searched for by males, controlled by chemical signals ( pheromones ), and mating occurs on the outside of the bark or within the passage. In polygamous species, there are (a chamber males, Rammelstein chamber called a nesting transfer as the beginning) feed from outside into the bark. Here they are visited one after the other by several females who mate them. Few species are solitary. Here already mated females look for a suitable breeding tree for themselves and start the attack independently.

The mated females then begin to eat a passage within the bark. At its side it deposits its eggs, usually in small, eroded niches, depending on the species on both sides, only on one side or in small groups (clutches). Some species create a larger chamber instead of a narrow tunnel. In all species, the newly hatched larvae then start from this niche and start eating a passage into the nutrient-rich phloem of their host tree. This can be designed very differently: in species that primarily feed directly on the plant matter they eat, they can be ten to fifteen centimeters long; they then extend almost exclusively in the nutrient-rich bast, the wood and the corked outer bark are avoided. These species are called bark breeders by forest entomologists . In contrast, species whose diet is mainly based on self-grown, wood-degrading symbiotic fungi ("ambrosia beetles") usually only create a shorter passage or a chamber in which the larva then grazes the fungal lawn. Since the fungi, unlike the larvae themselves, can also break down lignin and cellulose from wood , such species can also expand their duct systems into the inner wood tissue, called wood breeders by the forts .

Bark beetle larvae go through three to five larval stages before they pupate. After the pupa has rested, which usually only lasts five to ten days, the newly hatched imaginal beetle is in the pupa chamber; it is usually not yet hardened and light in color. In most species, it then continues to eat within the pupa chamber ( maturation feed ). The young beetles then eat an exit hole to the outside through the bark, or they use existing tunnels and holes, in most of the Ambrosia beetles the maternal breeding tunnel. In moderate (temperate) and cold latitudes, the young beetles usually only hatch in the spring or early summer following their development, so they still spend the winter in the host tree. Then they look for a mating partner and a suitable place to lay eggs. To do this, most species carry out dispersion flights , often only over a few hundred meters to a neighboring tree, sometimes over considerable distances, supported by wind and air currents. Some species stop at a suitable tree for further ripening.

Common bark breeders in Central Europe and their preferred tree species:

Frequent wood breeders (xylomycetophage, or ambrosia beetles) in Central Europe and preferred tree species:

Symbiosis with mushrooms, ambrosia beetles

Wood is a very nutrient-poor substrate that lacks numerous nutrients that are essential for herbivores. In order to remedy this deficiency, numerous species of bark beetles have switched to using the decomposition capacity of fungi , with which many species live in a close symbiosis . The cooperation is very different. Many species can live without mushrooms and complete their development, but grow better and faster with their presence. Others are completely dependent on their mushroom partner. In order not to leave anything to chance, these beetles carry the fungus (as mycelium or spores ) with them on their dispersion flights; they have special organs called mycangia or mycetangia for this purpose; special, pocket-shaped indentations at various points on the integument. Various wood-destroying fungi of the genera Ophiostoma and Ceratocystis , "blue-tinged fungi" belonging to the sac fungi of the order Ophiostomatales , as well as a number of closely related anamorphic genera, serve as fungal partners .

The symbiotic mushrooms play a special role in a species-rich group of bark beetles, the ambrosia beetles. The anamorphic mushrooms were named after ambrosia , the food of the Greek gods, after ambrosia , the food of the Greek gods, by their discoverers, who were amazed that some species of bark beetle can obviously grow and thrive in their hollows without eating any significant amounts of wood Genera Ambrosiella and Raffaelea . These mushrooms are no longer able to live independently, they are dependent on their beetle partner to spread; this has been interpreted by various entomologists as an equivalent to agriculture in the animal kingdom. On the other hand, the fungus is the only food source of the beetle larvae and imagines. The same community has independently developed in a very similar form in another group of weevils, the subfamily of the core beetles or Platypodinae , these possibly forming the sister group of the bark beetles. The fungus also has other uses for the beetles, for example by breaking down secondary plant substances formed as a defense of the tree and by closing the resin canals of the conifers through rapid growth .

Ambrosia beetles comprise about 3400 species in ten tribes , which are not closely related to each other, so they do not form a systematic unit, but an ecological group whose way of life must have developed convergent many times , probably at least seven times. They are the only bark beetles that can penetrate the xylem , i.e. the actual wood body within the cambium , so they correspond to the " wood breeders" of forest entomologists. The food base is the conidia of the fungal partner, which lives on wood itself, so the beetle is characterized as "xylomycetophag" (roughly wood-fungal). Since the tree species is only indirectly its food source, individual species often appear in a large number of tree species that are not closely related. Ambrosia beetles have their distribution center in the tropics, but with some species they can be found in temperate latitudes.

Remarkably, a species-rich, presumably monophyletic group of ambrosia beetles has a sex determination system using haplodiploidy . Similar to the better known case of the hymenoptera , unfertilized eggs always turn into males and fertilized ones into females. Typically these species have dwarfed, completely eyeless males that never leave the breeding galleries of their host tree. Mating takes place with sisters (occasionally with dams of the previous generation), so that although sexual reproduction is maintained, a high rate of inbreeding is given.

Food crops

Most species of bark beetles use wood and bark from tree species. Many species that feed on the somewhat more nutrient-rich phloem occur only on a group of related tree species, such as one genus (oligophag), and less even on one tree species (monophag). Most of the wood-eating species are polyphagous, on very different types of wood, and a few even equally on hardwood and coniferous wood. While most species use living trees, there are also bark beetles that specialize in deadwood . Specialists also exist for branches and twigs and roots. Various species, for example from the genus Conophthorus , live in the interior of the cone axis of conifer cones. Few species groups have developed completely different food substrates. A very important agricultural pest is the coffee cherry beetle ( Hypothenemus hampei ) which does not attack the wood of the coffee plants but the fruit. Coccotrypes dactyliperda (and other species of the genus) feeds on the seeds and unripe fruits of date palms . Few species mine in leaves or petioles, some in the roots of herbaceous , non-woody plant species. For example, the clover bark beetle Hylastinus obscurus, which is also widespread in Central Europe, lives in the roots of herbaceous legumes.

Bark beetles of the genus Sampsonius have developed a kleptoparasitic way of life. The adults are not able to create breeding galleries themselves. To do this, they look for those of the genus Dryocoetoides , which are closely related to them . Their faster developing larvae then take over their galleries for their own reproduction.

Species that cause the host tree to die

Among the numerous species of bark beetle, only a few species, mostly attached to conifers, colonize living trees, which they can then cause to die through their infestation, whereas most species are weak parasites (secondary pests) that only colonize dying or sick individuals with greatly reduced resistance can. The total of only around 15 to 20 species tend to mass reproduce ( gradations ) and in years with high population density can cause entire forests to die, each with millions in damage to forestry. Some species from the genus Ips in Eurasia and North America and the genus Dendroctonus , especially in North America, are notorious . The prerequisite for these species is the ability to overcome the defenses of their plant host, e.g. through resin flow and defense chemicals (secondary plant substances) such as terpenoids . In order to be able to attack healthy trees, the species carry out synchronized mass attacks by thousands of individuals on the same tree in order to exhaust its defense. Usually they only succeed in doing this if the tree has already been damaged by other, biotic and abiotic, stress factors such as drought. At the peak of a gradation, some species can also cause massive damage to completely healthy trees through synchronized mass attacks. To synchronize, they use communication through pheromones such as verbenol and myrcene , which are often produced through the chemical conversion of phytochemicals. The advantage for the beetle is that such trees can only compete with other bark beetle species.

In Central Europe, the spruce ( Picea abies ) is the tree species with the highest bark beetle damage. In addition to the natural spruce forests of higher mountain areas, man has created optimal bark beetle biotopes with extensive pure spruce stands. In extreme climatic conditions (long periods of heat or drought, winter with a lot of broken snow), printers and engravers can multiply explosively (years with mass increase are, for example: 1994/95, 1999, 2003/2004, 2018).

A special case is Dutch elm disease, a parasitic fungal disease of all elms in Europe and North America, which is triggered by a fungal disease ( Ophiostoma ulmi and Ophiostoma novo-ulmi ) introduced from East Asia , which is transmitted by bark beetles of the genus Scolytus , in Europe mainly by two species Elm splint beetle , large and small . Infested European elms usually die after a few years. Related fungal diseases that are also transmitted by bark beetles are "Mango sudden decline syndrome" or "Mango sudden death disease" in Mango ( Mangifera indica ). They may also be involved in the spread of Phytophthora ramorum (sudden oak death). In all of these cases, the beetles are only carriers ( vectors ) of the fungus; they themselves only cause negligible damage to the tree.


Spruce monocultures preloaded by wind breaks after bark beetle infestation in the Bavarian Forest National Park .

In Europe, bark beetles caused an average of 2.9 million cubic meters of damaged wood per year between 1950 and 2000, that is 0.7 percent of the European logging volume and around half of the total damage caused by biological pathogens. An analysis of the amount of damaged wood in Europe from 1990 to 2001 showed a similar value with 1.2 percent of the logging. These values are far overshadowed by the damage caused by a single species, the mountain pine beetle (mountain pine beetle, Dendroctonus ponderosae have been caused) in North America, where 11 million hectares of pine forest are from 1990 to 2010 devastated the damaged wood reached 240 million cubic meters.

The main problems of bark beetle infestation are:

  • if the forest is used economically by humans. In the case of large-scale bark beetle infestation, wood prices on the timber market drop dramatically. For forest owners there is great financial damage.
  • Infestation by bark beetles caused by the symbiotic fungi, a discoloration of the wood in the outside area. Due to the higher waste of the saws, this results in a loss of value of at least 30% of the wood price for "healthy" wood.
  • in infestation of edge trees. These protect the forest from wind and storm . Such open spaces make the forest stand more vulnerable. As a result, even more trees have to be felled, or there is more wind break.
  • In some German federal states and in Austria, the forest owner is legally obliged to take measures against the bark beetle to protect the neighboring forest.

Bark beetle control

Attractant trap for bark beetles

In Central Europe, it is mainly the few species of bark beetles that attack conifers that tend to multiply in the forest that are combated. There are mainly two types, the printer ( Ips typographus ) and the engraver ( Pityogenes chalcographus ), especially on the forest tree species spruce. The control is based almost exclusively on measures of the so-called "clean forest management". In addition, wood-breeding species on stored trunk wood are combated. Insecticides are also used here.

The “clean forest management” is based on the fact that the bark beetles that breed bark should be deprived of their nutritional basis in the forest before the incipient foci of infestation develop into mass reproduction. Attempts are made to cut down infested trees that are still standing in a timely manner. Lumbering logs are debarked; It has been shown that peeling off in strips is just as effective as complete debarking, but this method has not yet become established in practice. Material suitable for breeding (harvest residues) remaining in the forest is removed or rendered harmless by mulching, chopping or burning. Under normal conditions, bark beetle populations then remain below the economic damage threshold . Bark beetle infestation should also be counteracted in the long term by means of silvicultural measures by avoiding large monocultures of particularly susceptible species or on locations particularly susceptible to infestation.

Other control methods are based on catching bark beetles on their dispersion flights before they have reached new host trees. Common methods are special attractant traps (pheromone traps) as well as trapping trees and trapping clubs (beating) or piles of trapping wood. These methods achieve roughly comparable performance, but fail at high bark beetle densities; they are then used to determine the infestation density (monitoring).

Switzerland has been using biotechnical methods to combat the bark beetle since 1984.

Fighting bark beetles in the forest using insecticides is legally permissible if specially approved agents are used. However, due to its low effectiveness in connection with high ecological damage, it is used less often than in previous decades. The insecticide treatment of lying, stored logs ( piles ) is still common. Alternative methods are also possible here. These include, for example, wet storage and sealing in plastic films.


The bark beetles were traditionally regarded as an independent family, related to the weevils, leaf beetles and longhorn beetles. Morphological studies on larvae and adults instead suggested a position within the weevils (Curculionidae). This was clearly confirmed by all phylogenomic studies (investigation of the relationships based on the comparison of homologous DNA sequences). Within the weevils, they belong to the derived weevils (in the narrower sense), with kneeling antennae. The first analyzes suggested a close relationship or a sister group relationship to the beetles (Platypodinae), and the Cossoninae , which also bored into wood as larvae, were generally considered to be closely related. More recent analyzes indicate that the beetles are close relatives of the Dryophthorinae subfamily . The similarity of the bark beetles to them (and also to the Cossoninae) is probably based on a convergent evolution through the common way of life in the wood.

The exact position of the bark beetle within the weevil is currently unclear. This is also due to the fact that the monophyly of numerous subfamilies of the extremely species-rich weevils is unexplained and often doubtful. The monophyly of numerous tribes within the subfamily has been confirmed, that of others has not yet been clarified.

The subfamily of bark beetles is divided into the following tribes in the current system from 2009

  1. Scolytini Latreille, 1804
  2. Amphiscolytini Mandelshtam & Beaver, 2003
  3. Bothrosternini Blandford, 1896
  4. Cactopinini Chamberlin, 1939
  5. Carphodicticini Wood, 1971
  6. Coptonotini Chapuis, 1869
  7. Corthylini LeConte, 1876
  8. Cryphalini Lindemann, 1877
  9. Crypturgini LeConte, 1876
  10. Cylindrobrotini Kirejtshuk, Azar, Beaver, Mandelshtam & Nel, 2009
  11. Diamerini Hawthorn, 1909
  12. Dryocoetini Lindemann, 1877
  13. Hexacolini Eichhoff, 1878
  14. Hylastini LeConte, 1876
  15. Hylesinini Erichson, 1836
  16. Hylurgini Gistel, 1848
  17. Hyorrhynchini Hopkins, 1915
  18. Hypoborini Nuesslin, 1911
  19. Ipini Bedel, 1888
  20. Micracidini LeConte, 1876
  21. Phloeosinini Nuesslin, 1912
  22. Phloeotribini Chapuis, 1869
  23. Phrixosomatini Wood, 1978
  24. Polygraphini Chapuis, 1869
  25. Premnobiini Browne, 1962
  26. Scolytoplatypodini Blandford, 1893
  27. Xyleborini LeConte, 1876
  28. Xyloctonini Eichhoff, 1878
  29. Xyloterini LeConte, 1876
Abundance of forms of (tropical) species of the tribe Xyleborini

Here is a generic list with individual species (selection):

Fossil evidence

Fossil evidence of bark beetles has been around since the Middle Cretaceous , roughly 100 million years ago. Initially there were only difficult to interpret fossils from feeding tunnels in petrified wood and compression fossils made of limestone from the famous Florissant fossil deposit (earlier Oligocene), the assignment of which remained uncertain because not all essential features are recognizable, are now made of both Burmese and Lebanese amber well-preserved inclusions have been described. These are remarkable in that they are very similar to the recent species, so that one of the finds has even been placed in a recent genus. The old age of today's bark beetles contrasts with the fact that the weevils themselves belong to the younger beetle families and are not fossilized before the Jurassic . This points to an early radiation of the group, already in the Mesozoic Era. Bark beetles are very species-rich in both Baltic amber and younger Dominican amber , 23 species in seven genera in Baltic amber, five of which are extant.


Individual evidence

  1. a b c d e Bjarte H. Jordal: Scolytinae Latreille, 1806. Chapter 3.7.12 in Richard AB Leschen, Rolf G. Beutel (editors): Handbook of Zoology / Handbuch der Zoologie. Arthropoda, Insecta, Coleoptera, Beetles. Volume 3: Morphology and Systematics (Phytophaga). Walter de Gruyter Berlin / Boston 2014. ISBN 978-3-11-027370-0 .
  2. Jiri Hulcr, Thomas H. Atkinson, Anthony I. Cognato, Bjarte H. Jordal, Duane D. McKenna: Morphology, Taxonomy, and Phylogenetics of Bark Beetles. Chapter 2 in Fernando E. Vega, Richard W. Hofstetter (editors): Bark Beetles: Biology and Ecology of Native and Invasive Species. Elsevier, Amsterdam etc. 2015. ISBN 978-0-12-417156-5 .
  3. Reinhard Schopf & Johannes Enssle: Interesting facts about bark beetles. In NABU Baden-Württemberg (publisher): Technical articles on the planned Black Forest National Park. Stuttgart, February 2013, pp. 34–41.
  4. ^ A b Karl E. Schedl : 91. Family Scolytidae (bark and ambrosia beetles). In: Heinz Freude, Karl Wilhelm Harde, Gustav Adolf Lohse (editor): Die Käfer Mitteleuropas. Volume 10: Bruchidae, Anthribidae, Scolytidae, Platypodidae, Curculionidae. Goecke & Evers, Krefeld 1981. ISBN 3-87263-029-6
  5. a b Kenneth F. Raffa, Jean-Claude Grégoire, B. Staffan Lindgren: Natural History and Ecology of Bark Beetles. Chapter 1 in Fernando E. Vega, Richard W. Hofstetter (editors): Bark Beetles: Biology and Ecology of Native and Invasive Species. Elsevier, Amsterdam etc. 2015. ISBN 978-0-12-417156-5 .
  6. cf. Entry Ambrosia beetle in the spectrum lexicon of biology ,, 1999 Spektrum Akademischer Verlag, Heidelberg.
  7. ^ A b Brian D. Farrell, Andrea S. Sequeira, Brian C. O'Meara, Benjamin B. Normark, Jeffrey H. Chung and Bjarte H. Jordal (2001): The Evolution of Agriculture in Beetles (Curculionidae: Scolytinae and Platypodinae ). Evolution 55 (10): 2011-2027. doi: 10.1111 / j.0014-3820.2001.tb01318.x (open access).
  8. a b Bjarte H. Jordal, Andrea S. Sequeira, Anthony I. Cognato (2011): The age and phylogeny of wood boring weevils and the origin of subsociality. Molecular Phylogenetics and Evolution 59 (3): 708-724. doi: 10.1016 / j.ympev.2011.03.016 .
  9. a b Bjarte H. Jordall, Benjamin B. Normark, Brian D. Farrell (2000): Evolutionary radiation of an inbreeding haplodiploid beetle lineage (Curculionidae, Scolytinae). Biological Journal of the Linnean Society 71: 483-499. doi: 10.1006 / bijl.2000.0457 .
  10. DHR Spennemann (2018): Global distribution of the date stone beetle, Coccotrypes dactyliperda (Coleoptera: Curculionidae, Scolytinae). Journal of Insect Biodiversity and Systematics, 4 (3): 203-226.
  11. BS Lindgren, KF Raffa (2013): Evolution of tree killing in bark beetles (Coleoptera: Curculionidae): trade-offs between the maddening crowds and a sticky situation. Canadian Entomologist 145: 471-495. doi: 10.4039 / tce.2013.27
  12. Bark beetle infestation doubled in 2018. In: Federal Research Institute for Forests, Snow and Landscape , February 6, 2019, accessed on February 6, 2019 .
  13. Karl-Heinz Otto: Never been there before - the extreme mass reproduction of the large eight-toothed spruce bark beetle 2018 , published in GeKo Aktuell 1/2019, publisher: Geographical Commission for Westphalia, Landschaftsverband Westfalen-Lippe (LWL), ISSN 1869-4861. ( PDF file, digitized online )
  14. ^ John Gibbs, Clive Brasier, Joan Webber: Dutch Elm Disease in Britain. Forestry Commission Research Information Note 252, 1994. PDF
  15. Asad Masood & Shafqat Saeed (2012): Bark beetle, Hypocryphalus mangiferae stebbing (Coleoptera: Curculionidae: Scolytinae) is a vector of mango sudden death disease in Pakistan. Pakistan Journal of Botany 44 (2): 813-820.
  16. Mart-Jan Schelhaas, Gert-Jan Nabuurs, Andreas Schuck (2003): Natural disturbances in the European forests in the 19th and 20th centuries. Global Change Biology 9 (11): 1620-1633. doi: 10.1046 / j.1365-2486.2003.00684.x
  17. ^ JC Grégoire & HF Evans: Damage and Control of Bawbilt Organisms. An overview. Chapter 4 in: François Lieutier, Keith R. Day, Andrea Battisti, Jean-Claude Grégoire, Hugh F. Evans (editors): Bark and Wood Boring Insects in Living Trees in Europe, a Synthesis. Springer Verlag, Dordrecht, 2004. ISBN 978-1-4020-2241-8
  18. FAO Food and Agriculture Organization of the United Nations (editor): Global Forest Resources Assessment 2010, Main report (FAO forestry paper 163). FAO, Rome, 2010. ISBN 978-92-5-106654-6 .
  19. Susanne Kaulfuß Susanne (2012): Prevention of insect damage - prevention is better., May 25, 2012.
  20. Lutz-Florian Otto, Bert Schmieder: Information for forest owners on bark beetle infestation, December 9, 2016. (Print version: Otto, L.-F., Schmieder, B. (2016): Waldpost 2016/2017 - newspaper for forest owners in Saxony, publisher Staatsbetrieb Sachsenforst: 13-14.)
  21. a b Gabriela Lobinger and Michael Veicht: Bark beetle control - what is effective, useful, allowed? Bavarian State Ministry for Food, Agriculture and Forests (StMELF), Bavarian State Institute for Forests and Forestry LWF . accessed on August 3, 2019.
  22. ^ Jonas Hagge, Franz Leibl, Jörg Müller, Martin Plechinger, João Gonçalo Soutinho, Simon Thorn (2018): Reconciling pest control, nature conservation, and recreation in coniferous forests. Conservation Letters 2019 (12): e12615. (8 pages) doi: 10.1111 / conl.12615
  23. Threat bark beetle A polemic by Helmut Klein, 2009 (PDF)
  24. Hannes Krehan: The ABC of bark beetle control on spruce ., information for forestry practice. (Print version: BFW practical information 17: 17-18, online July 11, 2016.)
  25. Rainer Hurling & Jan Stetter (2013): Schlitzfalle or Fangholzhaufen? AFZ (Allgemeine Forstzeitung) - der Wald 9/2013: 25-28.
  26. Martin Illi: Pest. In: Historical Lexicon of Switzerland . December 14, 2011 , accessed March 8, 2020 .
  27. Hansjochen Schröter, Jutta Odenthal-Kahabka: Use of insecticides against bark beetles (print version 2005: Hand-out Storm Damage Management . Ed. State Forest Administration Baden-Württemberg and State Forests Rhineland-Palatinate) online February 29, 2012.
  28. Dana Liechti: Forbidden insecticides in the Swiss forest. In: . May 11, 2019, accessed October 1, 2019 .
  29. Sigrid Mugu, Dario Pistone, Bjarte H. Jordal (2018): New molecular markers resolve the phylogenetic position of the enigmatic wood-boring weevils Platypodinae (Coleoptera: Curculionidae). Arthropod Systematics & Phylogeny 76 (1): 45-58.
  30. Dario Pistone, Jostein Gohli, Bjarte H. Jordal (2018): Molecular phylogeny of bark and ambrosia beetles (Curculionidae: Scolytinae) based on 18 molecular markers. Systematic Entomology 43 (2): 387-406. doi: 10.1111 / syen.12281
  31. Miguel A. Alonso-Zarazaga & Christopher HC Lyal (2009): A catalog of family and genus group names in Scolytinae and Platypodinae with nomenclatural remarks (Coleoptera: Curculionidae). Zootaxa 2258: 1-134. doi: 10.11646 / zootaxa.2258.1.1
  32. Anthony I. Cognato & David Grimaldi (2009): 100 million years of morphological conservation in bark beetles (Coleoptera: Curculionidae: Scolytinae). Systematic Entomology 34: 93-100. doi: /10.1111/j.1365-3113.2008.00441.x
  33. Alexander Kirejtshuk, Dany Azar, Roger Beaver, Michail Mandelshtam, André Nel (2009): The most ancient bark beetle known: a new tribe, genus and species from Lebanese amber (Coleoptera, Curculionidae, Scolytinae). Systematic Entomology 34: 101-112. doi: 10.1111 / j.1365-3113.2008.00442.x


Web links

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