Oak root fungus (Armillaria
root rot)—Armillaria mellea
Vines affected by Armillaria root rot decline in vigor, the leaves turn yellow in early summer, and
cane growth becomes weaker before the vine eventually collapses. Areas of diseased vines may gradually
increase in size each year if left untreated. The crown and root tissue becomes rotted. Underneath the
bark are creamy white plaques or fans of fungus mycelium with a distinct mushroom odor.
If less than half of the crown's circumference is girdled, it may be possible to save the vine. In late
spring, remove the soil from around the crown and cut away all bark and tissue that is 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 vine should be removed. Before replanting, allow the soil to
dry out and replant with a resistant species. Maintaining vines with good fertilization and irrigation programs helps preserve their natural resistance to this fungus.
symptoms of oak root fungus
mycelial growth of Armillaria root rot