From our Landscape Architect
"Palm Diseases to Watch Out For" by Janielle Guzinski
We love our palm trees here in Galveston. Usually palms are very hardy and resistant plants, but sometimes it seems like one just goes downhill in the blink of an eye. When this happens, it can be the result of a disease. Unfortunately for the palms, since they only have one growing point at the top of the tree, once that goes, the entire palm is gone. I'm going to give you a quick rundown on some palm diseases that may affect our palms here on Galveston Island.
Texas Phoenix Palm Decline (TPPD)
This is a fast-acting disease that affects Canary Island dates, true/edible dates, sylvestri dates, cabbage palms, and queen palms. It is caused by a phytoplasma that is spread by insects. These insects carry the disease and when they go to suck the sap out of the palm, they infect it. The first symptom is premature fruit drop followed by the leaves turning reddish-brown and dying. This discoloration in the leaves starts at the older leaves at the tip of the frond.
It is incurable, although it can be managed through injections of liquid antibiotic to the trunk as long as the center leaves have not died yet. I would only recommend this in special cases because it is expensive and not a true cure but only a treatment.
Fusarium Wilt of Canary Island Date Palms
This disease has been found on Tiki Island, so we know it is in the area. This disease is most commonly spread by infected pruning tools. However, it is also found in the soil. So if you lose a palm to this disease, you cannot replant a new Canary Island date in that spot because it will also succumb. This disease kills in a lopsided way. The leaves on one side of the palm will start to die. It will quickly spread until it reaches the center of the palm, killing it. There are fairly obvious brown streaks on the stem of the palm leaf as it starts to die.
It is caused by a fungus, but most fungicides are ineffective at treating it. Because it is soil borne as well as transmitted by pruning tools, it is a good idea to dispose of any dead palms in such a way that the soil or infected leaves are not used as mulch on another property. The best way to stop the spread of the disease is to disinfect pruning tools and dispose of dead material properly.
Lethal Yellowing (LYD)
This is another disease caused by a phytoplasma. It affects a variety of palms including Chinese fan palms and many date palm species. It is spread by an insect like TPPD and has similar symptoms. Symptoms start with premature fruit drop and continue with yellowing or browning of leaves. The discoloration of the leaves continues moving from bottom leaves up to the central growing point. Once it kills that center, the palm is dead.
This disease is also incurable, but can be treated with antibiotic injections like TPPD. There is some debate as to whether or not some of the large die-offs in the valley were a result of LYD or of TPPD.
If you think your palm might be diseased, you can bring us a frond to look at to try and visually identify the disease. However, the most definitive diagnosis is by submitting a frond to the extension office in LaMarque. Let's all work together and try and keep our palms alive and our little island disease free.
Galveston County Extension Office ~ 4102 Main Street LaMarque, Texas ~ (281)534-3413