WSU Extension

Hortsense

Filbert
 
Disease
Bacterial blight 
Eastern filbert blight 
Powdery mildew 
Insect
Apple mealybug 
Brown marmorated stink bug 
Filbert aphid 
Filbert bud mite 
Filbert leafroller 
Filbertworm 
Lecanium scale 
Omnivorous leaftier 
Tent caterpillars 



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Caption: Powdery mildew fungal structures on filbert leaf
Photo by: R.S. Byther
  
Filbert : Powdery mildew
(revision date: 5/20/2014)


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


Non-Chemical Management
  • 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).
Select non-chemical management options as your first choice!

Chemical Management

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

Images

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