Filbert Leafroller
Archips rosanus
2 host plants
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Filbert leafroller larvae roll leaves together with silk and feed on the enclosed tissue in spring and early summer. You will see rolled leaves with holes chewed through them; damage is most obvious in new foliage. Though unsightly, leaf rolling does not significantly impact tree health or nut production in most cases.
Prune out rolled leaves and remove them to interrupt the pest life cycle if populations are light. Bacillus thuringiensis (Bt) applied to foliage in spring targets young caterpillars effectively. Allow natural parasitoids to establish; they provide good control over time. Most filberts tolerate moderate leaf rolling without harm. No chemical control is justified in home gardens given the minor impact.
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Cultural Controls
- Pick out and destroy rolled leaves and nests with caterpillars, when practical.
- Pinch rolled leaves to kill caterpillars.
- Encourage natural enemies of caterpillars including birds, parasitic wasps and flies, and predacious beetles.
- Avoid use of broad-spectrum insecticides which kill beneficial insects.