Walnut husk fly control - Ask Extension
Since the larvae live in the ground, it seems like timing a spray would be difficult. Could one put plastic sheet under the tree to keep them from co...
Knowledgebase
Walnut husk fly control #872478
Asked June 10, 2024, 5:02 PM EDT
Since the larvae live in the ground, it seems like timing a spray would be difficult. Could one put plastic sheet under the tree to keep them from coming out? I'm really sad about my crop being dam.
Benton County Oregon
Expert Response
The damage starts in the tree, not when the walnuts drop to the ground. The female flies attack the nuts and lay their eggs on them and larvae develop in husks. Commercial growers target the adult flies with sprays to prevent egg laying. The timing is not difficult, traps and a phenology models helps predict when the females are laying. A tarp could potentially be used to prevent the larvae from entering the soil to pupate, lessening pressure for the following year. See section on sanitation under link below.
https://pnwhandbooks.org/insect/nut/walnut/walnut-walnut-husk-fly
https://pnwhandbooks.org/insect/nut/walnut/walnut-walnut-husk-fly
