Magnolia Tree Fungus

Healthy magnolia

According to Debbie Shaughnessy and Bob Polomski, horticulturalists at Clemson University, there are 80 species of magnolias. A popular decorative tree in the southern United States, magnolias are relatively pest-free but may be affected by a number of fungi.

Artist's Conk

Tree fungus

Artist's conk, or Ganoderma applanatum, is a fungus that attacks a variety of ornamental trees, including the magnolia. It generally invades through wounds in the tree. The woody shelf-like fungus can grow up to 30 inches wide.

Varnish Fungus Rot

Varnish fungus rot, or Ganoderma lucidum, has a shelf-like appearance similar to artist's conk, but features a shiny upper layer with ring-like bands of reddish browns and cream. It can kill a host tree within three to five years.

Oyster Mushroom

The oyster mushroom, or Pleurotus ostreatus, is prized by chefs, but is an enemy of magnolias. The mushrooms appear in tender crowded flushes which return annually.

Common Split Gill

The common split gill, or Schizophyllum commune, attacks dead parts of living magnolias. The fungi are heavily gilled and scalloped at the borders. They appear whitish when young and darken with age. Sunburn and drought are risk factors for magnolias.

Parchment Fungus

Parchment fungus, or Stereum sp., appears as flat, roundish, papery growths on the surface of dead branches but does not attack living wood.

Prevention

Because chemical treatment of large trees is generally not feasible, the best defense against fungal infection is prevention. Avoid damaging the bark of trees with mowers and trimmers. Remove dead branches before they break away, exposing the cambial layer beneath the bark of the trunk, and water trees during periods of extreme heat or drought.

References

• Clemson Extension: Magnolia
• University of California: Wood Decay Fungi in Landscape Trees