04 NEWSLETTER. September 2014

Landscape

Palm Diseases—Ganoderma

- Hendry County Horticulture News UF

P alm trees symbolize the tropics in the public imagination. Palms swaying in the breeze adorn advertisements for Florida's beaches and resorts. As landscape plants, palms are valued for their unique shape and the intricate texture and form of their leaves and stems. Their variety, beauty, and adaptability have made them some of the most prized landscape plants in the warmer areas of the state. Despite their durability and adaptability, a number of diseases do affect palms in Florida. Serious disease of palms has made its presence known in south Florida, where palms are a dominant part of the landscape. One such lethal and incurable disease is caused by a fungus, ganoderma zonatum, which invades the base or butt of palm trees up to a height of three to four feet above the ground. Ganoderma butt rot affects mature palms. The disease was first discovered in Florida in 1994 and in only a few years it has spread to infect palms throughout the state. At this time, it cannot be said with certainty that there are any palm trees resistant to ganoderma butt rot, but we do know that Queen palms and Coconut palms are very susceptible to the disease. The ganoderma zonatum fungus most often invades a palm tree by

means of a wound at the base of the tree. The fungus then begins to rapidly work its way through the tree’s butt area essentially rotting the wood from the inside. Once the fungus has worked its way through the center of the tree to the surface, it forms a fruiting body called a ‘conk’, a spongy, whitish mushroom -like growth which grows to form a horizontal disc extending out from the bark. Unfortunately, there is currently no effective treatment for ganoderma butt rot. By the time the conk has appeared on the bark, the tree is effectively dead and must be removed. Removal takes extreme care to avoid spreading the fungus airborne to other palms. Tools used and clothing worn must be sterilized all to avoid spreading the disease. Once the diseased palm tree is removed, another palm tree cannot be planted in the same l ocat i on wi thout ext ens i ve sterilization and replacement of the diseased soil. It is important to avoid injuries to the roots and trunks of palms to avert the possibility of creating a wound which may permit spores to infect a palm tree. Periodic observation and quick removal and proper disposal of diseased palms are the major methods of fighting this devastating disease. Direct your gardening questions to Brickman agents at 561-626-7466.

Newsletter

September 2014