Filbert: Bacterial blight
categories: Filbert Filbert Diseases Tree Fruits
revision date: 2022-12-05 12:00
Photo by: Unknown
Biology
Bacterial blight of filbert may attack buds, leaves, twigs, branches, and the trunk. Infected buds may be killed before leafing out. Leaves initially develop pale green, water-soaked spots, which later turn reddish-brown. Current-season shoots show dark green, water-soaked spots on the bark. These later turn reddish-brown and can girdle the stem, causing dieback above the lesion. Leaves often remain attached to dead shoots. One- and two-year-old twigs are also attacked. Infections may spread into main branches or trunks, where cankers may girdle and kill trees. The infected tissues may show a bacterial ooze in the spring, when most new infections occur. Bacterial blight is more severe on trees that have been damaged by frost, sunscald, or other problems.
Management Options
Use Integrated Pest Management (IPM) for successful plant problem management.
Non-chemical Management
Select non-chemical management options as your first choice!
- Plant disease-free stock.
- Plant resistant varieties such as ‘Hall’s Giant’.
- Avoid highly susceptible varieties such as ‘Barcelona’.
- Provide proper culture. Healthy trees are more resistant to disease.
- Prune out and destroy infected tissues, making cuts 2′-3′ below infected branches. Disinfect pruning tools between cuts to avoid spreading bacteria to healthy tissues.
- Prevent injury to trees including sunscald and frost damage, if possible.
Chemical Management
IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.
- Apply in late August or early September.
- In seasons of heavy rainfall, apply again when 3⁄4 of the leaves have dropped.
- Homeowners should not make foliar applications to trees over 10 ft. tall.
- Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.
Approved Pesticides
Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.