Chestnut borer
| Chestnut borer | ||||||||||||
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Chestnut borer ( Curculio elephas ) |
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| Scientific name | ||||||||||||
| Curculio elephas | ||||||||||||
| ( Gyllenhaal , 1836) |
The chestnut borer ( Curculio elephas ) is a southern European weevil that attacks sweet chestnuts ( Castanea sativa ) and various oaks ( Quercus ).
features
The chestnut borer is about six to ten millimeters long without a trunk and gray-reddish-gold in color, the legs and antennae are brownish -red . The upper wings ( elytra ) are longitudinally striped. The trunk of the female is the same length as the body, that of the male is about half as long.
The whitish larvae are 12 to 15 millimeters long in the last, fourth larval stage. Your head capsule is brown. They don't have legs.
Occurrence
The chestnut borer occurs in southern Europe .
Way of life
The adult beetles appear on the surface from mid-August. The females each lay a single egg on a young fruit of the sweet chestnut or oak . A female lays up to 40 eggs. When the ripe fruits fall off, the larvae eat a hole around five millimeters in diameter in the fruit shell and retreat into the ground. The larvae overwinter in the ground in a cocoon at a depth of 10 to 60 centimeters and only pupate around June of the following year. Most larvae pupate after the first winter, but in 25 to 40% this diapause lasts two to four years. As a result, the chestnut borer has a population dynamic that is difficult to calculate.
Importance as a pest
If there is a strong infestation in sweet chestnut stands, the sweet chestnut borer can cause severe fruit damage. An infected chestnut appears healthy on the outside as long as the larva is still inside. However, the fruit is inedible due to the feeding passages and the excrement. Since infected chestnuts show no symptoms, they are also sold. The infestation with "worms" is only noticed by the consumer.
An effective containment measure is to quickly collect the fruit after it has fallen, before the larvae eat themselves, and then destroy the fruit that has been identified as infected.
swell
Ecker et al. a .: Sweet chestnut. Forest tree and fruit trees . Zoppelberg Buchverlag, Ehrenhausen 2006, p. 66f. (without ISBN)
Individual evidence
- ↑ a b Stephan Hahn: The chestnuts. Food source and threatened natural resource . Books on Demand, 2004, p. 218. ISBN 3-8334-2192-4
further reading
- Edmund Reitter : Fauna Germanica - The beetles of the German Empire. Volume 5, KG Lutz, Stuttgart 1916
- Edmund Reitter: Fauna Germanica - The beetles of the German Empire. 5 volumes, Stuttgart KG Lutz 1908–1916, digital library volume 134, Directmedia Publishing GmbH, Berlin 2006, ISBN 3-89853-534-7
Web links
- Curculio (Curculio) elephas at Fauna Europaea