If no control measures are taken walnuts will be damaged, but the nuts inside may be salvageable. For those homeowners who wish to use pesticides to control the husk fly, malathion spray is recommended. A malathion spray application in August will reduce infestations. A second application three weeks later may be needed if the infestation is severe. Consult the malathion label for dosage and instructions.
Good coverage is vital to successful control.
For people who have one or two large walnut trees, McNeilan recommends calling a commercial tree sprayer. Home-type spray equipment may not give good coverage on large trees.