Raspberry beetle
| Raspberry beetle | ||||||||||||
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Raspberry beetle ( Byturus tomentosus ) |
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| Scientific name | ||||||||||||
| Byturus tomentosus | ||||||||||||
| ( De Geer , 1774) |
The raspberry beetle ( Byturus tomentosus , syn .: Dermestes flavescens (Marsham, 1802), Byturus olivaceus (Fournel, 1840), Bytus urbanus and Horticola urbanus (Lindemann, 1865)) is a beetle from the flower eater family (Byturidae). The raspberry beetle is one of the most common pests on raspberries.
description
features
The beetles are 3.2 to 4 mm and some 5 mm long. They have an oval body and are dense and short haired. Young animals are initially light brown. Later they have a brown-gray to gray color. The antennae are eleven-parted and have a three-part club. The eyes are small with the length of the eyes less than half the forehead width between the eyes. The feet are five-limbed; the claw base is provided with a wide tooth. The puncture of the wing covers is very fine and densely distributed. Larvae are 6 to 8 mm long, pale ocher brown with dark brown plates on the dorsal side of each body segment. The larva has three pairs of legs at chest height.
Way of life
In May, when the soil temperatures reach 14 ° C, the beetles hatch out of their hibernation. The females are fertilized around mid-May. The beetles first feed on the buds and young leaves of the raspberry or blackberry . The feeding begins when the flower buds are still closed. The flowers are eaten empty. In June, the beetles can often be found on buds and flowers. They eat pollen there . They lay their eggs on the stamens of open flowers or on unripe fruits. A female lays 30 to 40 eggs individually at the breeding sites. The larvae hatch after six to eight days. The cream-colored larvae then develop in the cones of the fruit and are fully grown by the time the raspberries ripen. They have a brown head and are often referred to as raspberry maggots or raspberry worms , as they first eat the fruit base and then the fruit from the inside. However, it is not a question of maggots , but of larvae. The larva is found in the jagged feeding tunnels that are filled with feces. After 35 to 40 days, the larvae are fully grown. The adult larvae leave the fruit as the raspberry ripens. They drop to the ground, bury themselves and pupate. The finished beetle hatches after five to six weeks, but does not leave its winter quarters until spring. The raspber beetle forms one generation per year. This also applies south of the Alps.
Occurrence and distribution
The raspberry beetle is also found on blackberries and is occasionally found on apples , pears , hawthorns , cherries and plums . However, they also live on weeds and in particular on dandelions. The raspberry beetle is widespread in the Palearctic , you can find it in the north to central Norway and Finland as well as in the north of Sweden . It is also common in the British Isles .
Similar species
A similar species is Byturus ochraceus , which is golden brown in color and slightly larger. It is characterized by larger eyes, the length of which is greater than half the distance between the eyes.
Plant damage
Symptoms
The beetles are pests and leave raspberry and blackberry bushes eating damage to the buds, flowers and young fruits. As a result, the fruits remain in the growth residue, become deformed, become unsightly and unusable for fresh consumption and marketing. The pest is also extremely undesirable in canned food production. Open flowers are attacked by the beetles, eating the stamens and pistils without actually causing damage.
Countermeasures
If it is to be repelled mechanically, the beetles must be collected several times as early as possible to fly and lay eggs. This can be done by tapping and collecting. However, control is often not necessary. A trap with an attractant (raspberry scent) can also be used, which attracts the beetles strongly and in which the beetles drown. Autumn varieties with a yield only in autumn that are not attacked by the raspberry beetle are particularly suitable for organic cultivation. For direct chemical control in the bud stage of the raspberries, pesticides containing the active ingredient group pyrethroids and phosphoric acid esters are effective. The active ingredients diflubenzuron , spinosad , chlorpyriphos , phosalone , etofenoprox and thyocyclam hydrogen oxalate are also infestation-reducing. However, chemical agents are mostly toxic to beneficial insects.
Individual evidence
- ^ Byturus tomentosus (De Geer 1774). Fauna Europaea, accessed May 27, 2007 .
- ↑ a b Catherine Baroffio: Fragrance trap against raspberry beetles . In: Schweizer Bauer , October 28, 2009, p. 15.
- ↑ a b Jiři Zahradnik, Irmgard Jung, Dieter Jung et al .: Käfer Central and Northwestern Europe , Parey Berlin 1985, ISBN 3-490-27118-1 .
- ↑ a b c d e Rolf Fritzsche, Rolf Keilbach, Horst Thiele: The plant, storage and material pests of Central Europe with references to countermeasures . Gustav Fischer Verlag, Jena 1994, p. 165, ISBN 3-3346-0531-0
- ↑ a b c Jimmy Mariéthoz u. a .: Cultivation tips for growing raspberries . In: Handbuch Bereren , Vol. 9 (2007), pp. 52–75.
- ↑ a b c d Gerhard Friedrich, Hans Rode u. a .: Plant protection in integrated fruit growing , Eugen Ulmer Verlag, Stuttgart 1996, p. 404, ISBN 3-8001-5541-9 .
- ↑ a b c Horst Börner, Jens Aumann and Klaus Schlüter: Plant diseases and plant protection , 8th edition, Springer Verlag, Berlin 2009, p. 254, ISBN 978-3-540-49067-8
- ↑ a b Aldo Pollini: La difesa delle piante da frutto. Sintomi, diagnosi, terapia , 4th edition, Edagricole, Bologna 2007, pp. 212-215, ISBN 978-88-506-5246-4 .
