Dogwood: Armillaria root rot

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

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

Non-chemical Management

Select non-chemical management options as your first choice!

• 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.

Chemical Management

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

• None recommended

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