Filbert: Powdery mildew

categories: Filbert Filbert Diseases Tree Fruits

revision date: 2022-12-05 12:00

Powdery mildew fungal structures on filbert leaf.
Powdery mildew fungal structures on filbert leaf
Photo by: R.S. Byther

Biology

Powdery mildew is a fungal disease found on leaves and succulent shoots of hazelnut. A characteristic powdery white growth occurs on the underside of leaves and sometimes also covers shoot tips. Young growth may be distorted, particularly later in the season. Small, dark fungal structures may be seen in the white mats. The disease often appears late in the growing season. It typically causes little damage. Powdery mildew development is favored by a combination of warm days, cool nights, and humid weather. The fungus can overwinter on the plant and on infected plant debris.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

  • Space plantings and prune to provide good air circulation.
  • Plant in full sun.
  • Remove and destroy infected debris beneath trees.
  • Prune out and destroy severely infected shoots when noticed (if practical).

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

  • In general, powdery mildew is not serious and does not warrant special control measures.