Description
    The walnut husk fly and the walnut husk maggot both occur commonly throughout central United States.

    The walnut husk fly and the husk maggot look alike. They are light brown in color and have two transparent wings with dark cross bars. They are smaller than the house fly. The larvae of both species are legless and pale yellow in color. Full grown larvae are up to 1/2 inch long.

Injury
    The walnut husk fly and the walnut husk maggot breed and lay eggs in the husks of nearly mature walnut fruits in early autumn. The larvae burrow into and feed on the husk, producing black, slimy husks that stain and stick to the shell. The maggots can sometimes be seen crawling in the husks.

    Husk maggots and husk flies do not penetrate into the nut, so the taste and color of the nutmeat are not affected. However, the slimy nature of the husks reduces their value to commercial nutmeat producers because the husk is difficult to remove. The infested husks also make the nuts unattractive and undesirable to the private walnut grower.

Control
    Pick up and remove infested walnuts from the plantation as soon as possible after they fall from the trees. Contact your county extension agent for recommended controls.