Real pine weevil

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Real pine weevil
Pissodes pini a1.jpg

Pine weevil ( Pissodes pini )

Systematics
Class : Insects (Insecta)
Order : Beetle (Coleoptera)
Subordination : Polyphaga
Family : Weevil (Curculionidae)
Genre : Pine weevil ( Pissodes )
Type : Real pine weevil
Scientific name
Pissodes pini
( Linnaeus , 1758)

The real pine weevil ( Pissodes pini ), also known as pine weevil or pine weevil , is a beetle from the family of weevils (Curculionidae). This is a forest pest, which, however, less damage wreaks than, say, the Kiefernkulturrüssler ( P. castaneus ) or Kiefernstangenrüssler ( P. piniphilus ).

Appearance

The real pine weevil reaches a body length of seven to nine millimeters and is dark coffee brown in color. It has a distinctly keeled pronotum , in which the basal corners are almost right-angled. The wing covers show rows of dots with grained longitudinal stripes in between. Two cross bars run over the wing covers, the front one being interrupted several times. The rear one is angled at both ends. As with all other species of the genus Pissodes , the head of the common pine weevil ends in a long extension ( trunk ), on which the antennae arise halfway along.

Distribution area

The original range of the common pine weevil includes Europe, where it can be found in all locations of the forest pine ( Pinus sylvestris ). In the east it is widespread as far as western Siberia . In addition to the Scots pine, it also attacks the neophytic Weymouth pine ( Pinus strobus ) and the Swiss stone pine ( Pinus cembra ).

Damage caused

The female beetles gnaw holes for oviposition where the bark is smooth and not too thick. The branch bases of the lower branch whorls are preferred. The female lays up to twenty eggs in it from April to October. Within four weeks, these eggs develop into larvae, which are light yellow in color and have a light brown head. The larvae migrate in the bast of the tree down the trunk to the roots. About five months after hatching, the larvae penetrate the sapwood, where they pupate in a cave. The young beetles leave their pupa chambers and their host trees through round hideouts.

The damage that both the beetles and the larvae cause by eating their bark is primarily a disruption of the flow of sap in the trees. The main damage done by the common pine weevil is the transmission of fungal spores that damage the trees. In the Swiss stone pine and larch forest , it is one of the secondary pests of the Swiss stone pine ( Pinus cembra ). In this type of high mountain forest, there are regular mass reproductions of the gray larch moth ( Zeiraphera griseana ). Its caterpillars eat the larch bare when it is heavily infested and then switch to the Swiss stone pine. Swiss stone pines react more strongly to this infestation than the European larch ( Larix decidua ); Particularly when they are attacked by secondary pests such as the pine weevil, these trees can die or develop stunted forms.

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