Walnut husk fly - Plant Pests

Walnut husk fly, this fruit fly of a few mm in size has only recently appeared in Europe.

recognize walnut husk fly — Walnut husk fly, photo: Karel van de Pol

Walnut husk fly (Rhagoletis completa) is a fly from the family of fruit flies (Tephritidae). This fruit fly of a few mm in size has only recently appeared in Europe. It is an invasive species from North America where this fruit fly damages walnut crops. The larvae of the fruit fly bore into the husks and live off the ripening walnuts. These discolor, then mucus formation occurs. Fungi also develop on the affected walnuts.
The mature larvae crawl out of the husks to pupate in the soil.

Where to find

Walnut (Juglans)

Control

Difficult to control; once the larvae are in the husks, the damage is irreversible. Destroy the early fallen and affected nuts. Chemical pesticides are used in professional walnut cultivation (North America).

Prevention

Occasionally releasing a clump of chickens among the nutstree helps reduce the number of fruit flies. Chickens eat the mature larvae from the husks.