Armillaria root rot (Oak root fungus)—Armillaria mellea
Symptoms on trees infected with oak root fungus vary. If the disease develops quickly, leaves tend to
be small and chlorotic and drop early. Shoot growth is poor and shoot dieback is common. Foliage symptoms
may be apparent on only one or two branches if the crown is only partially girdled. The fungus spreads
as white mycelial plaques in the cambium region between the bark and wood.
Identification
Solutions
If less than half of the crown's circumference is girdled, it may be possible to save the tree. In late
spring, remove the soil from around the crown area and cut away all bark and tissue of the crown invaded
by the white leathery fungus. Leave uninfected tissue intact and keep the crown exposed for drying. If
more than half of the crown is infected, the tree should be removed. Before replanting, allow the soil
to dry out. Plant
on mounds with roots close to the soil surface and replant with a resistant species.
Maintaining trees with good fertilization and irrigation programs helps preserve their natural resistance
to this fungus. | 
Tree
infected with Armillaria root rot
White
mycelial growth of Armillaria root rot
|
