Eastern filbert blight
Fungus
| Type | Fungus |
|---|---|
| Cause | Fungus |
| When | Infection happens in wet weather on new spring growth. |
About
A fungus disease that forms cankers on the branches of European hazelnuts and is a serious threat wherever it occurs. American, beaked and Turkish hazelnuts appear to be immune, and resistant varieties are the best defense (Utah State; Oregon State).
Also called eastern filbert blight, EFB, filbert blight, European filbert blight
How to recognize it
Symptoms
Cankers form on infected branches. On trees with the Gasaway resistance gene they stay fewer and smaller, and some heal over (Oregon State).
Worse when
Long spells of wet weather while new shoots are growing (Utah State), and lots of infected trees nearby, especially in the first spring after planting (Oregon State).
How it spreads
Spores spread during long wet periods and infect new growth (Utah State).
When
Infection happens in wet weather on new spring growth.
Where
A serious disease of European hazelnuts in the East and in parts of Oregon; it had not been reported in Utah when Utah State wrote its guide. New strains found near Woodburn and Silverton, Oregon, can infect some resistant trees (Oregon State).
What to do, gentlest first
Prevention works best; most sprays only protect healthy leaves and can't cure infected ones. Always read and follow the product label.
Plant resistant hazelnuts Prevent
Choose American hazelnuts or resistant varieties and hybrids such as Jefferson, Yamhill, Santiam, Dorris, Wepster, McDonald, Raritan, The Beast or Grand Traverse; avoid very susceptible Ennis and Daviana (Oregon State; Utah State; Nebraska Extension).
Resistant isn't always immune: Grand Traverse can still get some blight, and new strains can infect trees with the Gasaway gene.
Prune out cankers By hand
Cut infected wood off 1 to 3 feet below the visible canker (Utah State). Oregon State advises removing resistant trees that develop cankers.
Protective fungicide sprays Conventional spray
Susceptible European varieties need protective fungicide sprays on new growth in spring (Utah State; Oregon State).
Follow the label.
Plants it affects
Sources
Photo: Photo: Joseph O'Brien, USDA Forest Service / Wikimedia Commons, CC BY 3.0 US (CC BY 3.0 US). Photo resized for the web.
Planting dates and advice are general guidance; check with your local Cooperative Extension office for your area.