Rhagoletis completa

The walnut fruit fly ( Rhagoletis completa ) ( synonym:. Rhagoletis completa suavis ssp ) is a fly from the family of fruit flies ( Tephritidae ).

She is a native of North America pest of walnut plants (and rarely on peach). The Fly is currently spreading out as neozoon in Europe.

Features

The flies are 8 to 10 millimeters long. They have a yellowish to whitish body with brownish stripes. The wings are transparent and with three black bands - one of which has at the wing tip a " V" shape - drawn.

The larvae reach a length of four to six millimeters and have a yellowish colored body with black mouthparts.

Way of life

The larvae of flies develop in the fruits of different walnut family. In North America, inter alia, black walnut, Juglans californica Juglans and hindsii be infested.

In Europe in particular, the common walnut ( Juglans regia ) is overcome.

Rarely, the peaches are infested.

The females of the walnut fruit fly lay eggs than nests beneath the epidermis of immature nuts from where after about 5 days the yellowish larvae hatch and eat for three to five weeks in the flesh of the Walnut ( green dish over the nut). Full grown larvae leave the made ​​-like the walnuts, can fall to the ground and dig a few centimeters deep in the soil, where they pupate and overwinter. The most flies hatch from July to September of next year - some may remain for two or more years in the soil.

Harmful effect

The flesh of the infested nuts begins by the feeding activity of the larvae to rot and turn black - and it takes a soft consistency or even sometimes dries.

The later the infection occurs, the better the nut can develop. However, the flesh can hardly be completely removed, so a consumption is unattractive. In addition, the storability of the nuts is limited.

Distribution in Europe

The walnut fruit has been introduced as neozoon from North America and first detected the end of the 1980s in Switzerland. From there, they spread first to the south (Italy) and South East ( Slovenia and Croatia). 2004, the first attack in Germany was found in the Freiburg im Breisgau - from there the fly spreads out to the north, where they - has reached Hesse and the area around Cologne - following the course of the Rhine. The first infestation was found in France in 2007, the first attack in Austria in 2008.

Combat

In order to combat insecticides can be used, in Europe one has not yet been approved.