Ganoderma Butt Rot

by | Jul 1, 2011 | Uncategorized

Ken Rudisill
Horticulture Agent
Bay County Extension
krru@ufl.edu

Last month, as I was driving to work, I noticed a Pindo Palm that was definitely dying, or should I say, it was dead. I wondered what killed the tree. As I drove by I stopped and I quickly figured it out. The tree had succumbed to Ganoderma butt rot.

Diseased palm on the left, healthy palm on the right. Photo Credits: Dr. M.Elliott,UF/IFAS

Ganoderma butt rot is caused by a fungus (Ganoderma zonatum) that eventually rots the lower portion of the palm. This fungus is not a primary fungus to other plants, just palms.

Stages of conks. Photo Credits: Dr. M. Elliott, UF/IFAS

Even though other palms may show wilt or general decline, the disease can be confirmed by the presents of conks on the trunk. Conks are firm, shelf-like structures that are attached to the lower part 4-5 feet of the palm. They start out as a whitish looking button on the palm then develop a half-moon shape with the straight side attached to the palm.

Confirmation of Ganoderma butt rot can only be made once the conks appear on the trunk, or when the palm is cut down and internal rotting of the trunk is noticed.

The conk produces and releases the fungal spores. The spores become mixed in the soil. The fungus germinates and grows over the roots of the palm. The fungus then enters the woody trunk tissue.  If an infected palm is transplanted, the soil in the transplant site may be contaminated with the fungal spores. It is recommended to remove the conk(s) of an infected palm before you remove the palm. This is to prevent the spreading of the spores. Place a plastic baggie over the conk then break it off the palm. Put the baggie in the trash for disposal in the landfill or incinerator.

There are no cultural or chemical controls for infected palms or preventing the disease.

As soon as the conk(s) are noticed, you should remove the palm. Remove as much of the stump and soil as possible to help prevent the spores from attacking other palms that might be nearby. I had seen a grouping of 20 palms planted in a group where several of the palms were infected. The chances were that all 20 could eventually be infected.

It is not recommended to plant another palm in the same place since the spores can survive in the soil. Other trees such as oaks, pines, maples, can be planted in that area.

John Wells
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