Beech wool scale insect
| Beech wool scale insect | ||||||||||||
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Beech scale insects ( Cryptococcus fagisuga ) |
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| Scientific name | ||||||||||||
| Cryptococcus fagisuga | ||||||||||||
| Lindinger , 1936 |
The Buchenwollschildlaus ( Cryptococcus fagisuga ) is a kind from the family of Eriococcidae that the scale insects counts. The type originally lived on in Europe domestic European beech ( Fagus sylvatica ). It sits - often colony-wise - especially on thin bark on exposed roots or branches. They dig into the tree with their long proboscis and feed on the phloem sap .
Under unfavorable conditions for the common beech or with simultaneous fungal attack, the beech wool scale louse can become a "pest". The common beech is less susceptible than the American beech ( Fagus grandifolia ).
description
No males are known of the species so far (as of 2010). The females reproduce parthenogenetically , i. i.e., without fertilization. They are hemispherical, have a diameter of 0.75 to 1 millimeter, are legless, wingless, yellow and carry flakes / tufts of white wax wool on their backs.
From June to October the females lay up to 50 unfertilized eggs, from which lively larvae develop that still have legs. These larvae can be spread by the wind and colonize suitable places on beeches. They tap the flow of sap from the trees, also with a noticeably long trunk. In the spring of the second year these larvae develop into the "mother lice". These have no legs and only tiny antennae stubs.
Damage to infested trees
Heavily infested beeches look from a distance as if they were painted white due to the wax wool of the beech wool scale insect. The tissue of the trees that has been pierced by the sucking process can be stimulated to the formation of new cells and, in the event of severe infestation, can grow into cancerous growths four to twelve years later. This often leads to so-called mucus flow and infections by the fungi Nectria coccinea var. Faginata and Nectria galligena , bacteria and other insects. Such combinations can significantly weaken even large beech trees. In extreme cases, the bark and bast die off and detach from the wood, causing the tree to die.
distribution
The original distribution area of the beech wool scale in Europe corresponds to the distribution of the common beech and thus extends from southern Sweden to Turkey . Around 1890 the beech wool scale insect was introduced with plants to Nova Scotia in southeastern Canada . There it is one of the neozoa and attacks the American beech.
By 1980 it had spread to the New England states, New York, and eastern Pennsylvania . In 1981 the species was first found in the Monongahela National Forest in West Virginia . In 1984 it was found in the Holden Arboretum in Lake County ( Ohio ), in the following years - in low frequencies - in other parts of Ohio.
literature
- Georg Benz and Markus Zuber: The most important forest insects in Switzerland and neighboring countries . Verlag der Fachvereine, Zurich 1993, ISBN 3-7281-2053-7 .
- Heiko Bellmann , Klaus Honomichl : Biology and ecology of the insects. A pocket dictionary . Founded by Werner Jacobs and Maximilian Renner. 4th edition. Spectrum Academic Publishing House - Elsevier GmbH, Heidelberg 2007, ISBN 978-3-8274-1769-5 .
- Wolfgang Schwenke et al. (Ed.): The forest pests of Europe. A manual in 5 volumes . Volume 1: worms , snails , arachnids , millipedes and hemimetabolic insects . Parey, Hamburg et al. 1972, ISBN 3-490-11016-1 .
- Fritz Schwerdtfeger : The forest diseases. Textbook of forest pathology and forest protection . 4th revised edition. Parey, Hamburg et al. 1981, ISBN 3-490-09116-7 .
- Bernhard Klausnitzer , Konrad Senglaub (eds.). Excursion fauna of Germany . Founded by Erwin Stresemann . Volume 2: Hans-Joachim Hannemann: Invertebrates: Insects . 10th revised edition. Spectrum Academic Publishing House - Elsevier GmbH, Heidelberg et al. 2005, ISBN 3-8274-1698-1 .
- ME Mielke, DB Houston, DR Houston: First Report of Cryptococcus fagisuga, Initiator of Beech Bark Disease, in Virginia and Ohio . The American Phytopathological Society, St. Paul MN 1985, doi : 10.1094 / PD-69-905g .
- Ashley B. Morris, RL Small, MB Cruzan: Investigating the Relationship Between Cryptococcus fagisuga and Fagus grandifolia in Great Smoky Mountains National Park . In: Southeastern Naturalist . 1, H. 4, 2007, ISSN 1528-7092 , pp. 415-424.
