Raspberry beetle

Raspberry beetle ( Byturus tomentosus )

The raspberry beetle ( Byturus tomentosus ) is a beetle of the family of flowers eater ( Byturidae ). Synonyms for scientific names are Dermestes flavescens ( Marsham, 1802), Byturus olivaceus ( Fournel, 1840), Bytus urbanus and Horticola urbanus ( Lindemann, 1865). The raspberry beetle is one of the most common pests of raspberries.

• 2.1 symptoms
• 2.2 Countermeasures

Description

Features

The beetles, 3.2 to 4 mm and 5 mm long part. You have an oval body shape and are densely hairy and short. Young animals are initially light brown. Later, they have a brown -gray to gray color. The sensors are elfgliedrig and have a tripartite lobe. The eyes are small, the eye length is less than half the face width between the eyes. The feet are five-membered; the jaw base is equipped with a wide tooth. The puncturing of the elytra is distributed very fine and dense. Larvae are 6-8 mm long, pale ocher-brown with dark brown patches on the back side of each body segment. The larva has three pairs of legs in the chest.

Way of life

In May when soil temperatures reach 14 ° C, the beetles emerge from their winter hiding places. The fertilization of the females will take about mid-May. The beetles eat first on buds and young leaves of raspberry or blackberry. The feeding begins when the flower buds are still closed. The flowers are eaten there yet. In June, the beetles are often found on buds and flowers. They eat there pollen. They lay their eggs on the stamens of open flowers or immature fruit. A female lays 30 to 40 eggs singly on the breeding grounds. After six to eight days, the larvae hatch. The cream-colored larvae then develop in the journals of the fruit and are currently the raspberry ripeness grown. They have a brown head and are often referred to as maggots raspberry or raspberry worms, as they only eat the fruit of the ground, and then the fruit from the inside. But it is not maggots but larvae. The larva is found in the jagged feeding programs, which are filled with feces. After 35 to 40 days, the larvae are fully grown. The fully grown larvae leave the fruit during ripening of raspberry. They can fall to the ground, dig in and pupate. After five to six weeks slips the finished beetle, which, however, leaves its winter quarters until the spring. The Himberkäfer is one generation per year. This applies also to the south of the Alps.

Occurrence and distribution

The raspberry beetle is also found in blackberries and is occasionally also found in apple, pear, hawthorn, cherry and plum. However, they also live on weeds and in particular on dandelion. The raspberry beetle is widespread in the Palaearctic region, it is found in the north into middle Norway and Finland and northern Sweden. In the British Isles it is also frequently found.

Similar Species

A similar type is Byturus aestivus which is golden brown in color and slightly larger. It is characterized by larger eyes, whose length is greater than half the distance between the eyes.

Plant damage

Symptoms

The beetles are pests and leave on raspberry and blackberry bushes feeding damage of buds, flowers and young fruits. So that the vegetables remain stunted growth, deformed, become unsightly and unusable for fresh consumption and marketing. Also in the canning of the pest is extremely undesirable. Open flowers are attacked by the beetles, the stamens and pistils are eaten without really damage occurs.

Countermeasures

Should be mechanically blocked, the bugs need to be collected as early as possible to the flight and oviposition several times. This can be done by tapping and collecting. Often, however, no control is required. This can also be used with a trap attractant ( raspberry scent) that attract beetles strong and drown in the beetles. Autumn varieties with yield until the autumn that are not infected by raspberry beetles, are particularly suitable for organic farming. For direct chemical control in the bud stage of raspberries are plant protection products containing the active group pyrethroids and phosphoric acid esters effectively. The active ingredients diflubenzuron, spinosad, chlorpyriphos, Phosalone, Etofenoprox and Thyocyclam - hydrogen oxalate are reducing infestation. However, chemical agents are usually toxic to beneficial insects.