White Fungus on a Ficus

Leaf Blight

• Leaf blight is caused by the fungus Pellicularia kolerga. This condition begins as a yellow, water-soaked patch on the leaves. Over time these patches spread and the upper surface of the leaf turns silvery white. The underside becomes brown and develops a thin web of fungus. Eventually, the leaf turns entirely brown and shrivels up. This condition is best dealt with by planting in sterilized soil and avoiding wet conditions, but you can remove infected leaves to protect the rest of the plant.

Mushroom Root Rot

• This member of the Armilleria genus attacks the roots of ficus trees. The plant may appear to decline slowly or weaken suddenly. Dead areas appear on the main stem and bigger roots, with white fungus visible under the peeling dead bark. Mushroom root rot is spread by infected soil and tends to appear after major stress incidents such as freeze damage or drought. It can also be encouraged by poor drainage. According to Texas A&M University, replanting the tree in sterile soil is the best remedy.

Sclerotium Blight

• Sclerotium rolfsii fungus causes a yellowish-white mat of material to develop at the base of the ficus. This growth usually contains hard yellow or brown bodies and slowly weakens the plant. Using sterilized soil and keeping infected material -- such as old leaves and grass -- away from the ficus help prevent this disease, but infected plants usually require destruction.

Shelf Fungus

• White shelf or bracket fungi may appear on the trunks and branches of trees that have already suffered damage. These fungi indicate that the wood below them is already dead and rotting. Freeze injury or other sources of damage may encourage this kind of growth. Because the infected wood has already died, the only remedy is to remove the plant.

Mushrooms

• Cream to pale yellow mushrooms sometimes appear in the soil around a potted ficus. These usually spread by wind blown spores or infected soil, but they are unlikely to harm the ficus itself. According to Iowa State University, these mushrooms are somewhat toxic and you should remove them if pets or children are nearby. They are otherwise harmless.

Considerations

• Fuzzy white protrusions on the surface of a ficus plant may not be fungus. Several types of sap-sucking scale insects can be mistaken for fungal infestations. Just like blights and rots, they can weaken a tree or vine, but you cannot remove them using most fungicides or normal cultural methods. North Dakota State University recommends treating suspected scale insects with a combination fungicide-miticide-insecticide spray to ensure removal.