WSU Extension

Hortsense

Dogwood
 
Disease
Anthracnose 
Armillaria root rot 
Collar rot 
Leaf scorch and leaf roll 
Powdery mildew 
Insect
Brown soft scale 
Lecanium scale 
Oystershell scale 



print version| pdf version| email url    
Caption: Armillaria root rot infecting trunk
Photo by: C.R. Foss
  
Dogwood : Armillaria root rot
(revision date: 4/28/2014)


Biology
Armillaria root rot is a fungal disease transmitted between plants by root contact. Armillaria is often found in newly cleared soils or ones which have been flooded. Symptoms typically include production of smaller-than-normal leaves, leaf yellowing, leaf drop, and dieback of branches. Symptoms may appear on part or all of the plant. White thread-like masses of the fungus may be found beneath the bark near the crown of infected trees, and/or as shoestring-like rhizomorphs, which are dark strands of the fungus growing on or just beneath the soil surface. Honey-colored mushrooms often grow near the base of infected trees in the fall. Infected trees may also exhibit a dark black line in the infected area encircling the base of the plant.
Management Options


Non-Chemical Management
  • Remove and destroy infected plants, including roots.
  • Air-dry soil from infected site before replanting.
  • Plant only resistant plants in infected areas.
  • Proper irrigation reduces the likelihood of Armillaria infection.
  • Leave newly cleared ground fallow for one year or longer.
Select non-chemical management options as your first choice!

Chemical Management

None recommended

Images

+ Show larger images

 
Caption: Armillaria root rot infecting trunk
Photo by: C.R. Foss
Caption: Armillaria root rot infecting trunk
Photo by: R.S. Byther
Caption: Armillaria rhizomorphs
Photo by: R.S. Byther