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By Mark Govan, Host “Florida Gardening” on 970WFLA Live on Sunday’s 7-9am
Tampa Bay is ground zero for a new Palm Tree Killer. Here is what you need to know to protect your investment
We all love palm trees for their stately beauty, and many of us have purchased them over the years only to have some freeze due to cold temperatures, while others have slowly declined from nutritional deficiencies. Now we have another problem. Tampa Bay Florida has now become ground zero for a problem that could mean the death of our beloved palms. This disease is called Lethal Bronzing. Lethal Bronzing is almost always a death sentence for our palms and is now spreading throughout the state. Is there any hope for our palms? Yes, but the treatment is not inexpensive, and you must begin now if you are going to protect your trees. If you have pricey palms in your landscape or if you manage a large commercial property, then you need to read this article and act soon. Let’s get started.
Lethal Bronzing is a bacterial disease called a phytoplasma. This, not a new problem as has been represented by the local media and in fact, has been around for many years. The former name of this disease was Texas Phoenix Palm Decline or TPPD. Because this disease primarily attacked Phoenix palms, it was named for them. I first heard about this disease well over ten years ago while I was working with the Pinellas County Commercial Horticultural Board and Loren Westenberger of Westenberger Tree Service. Loren had trained our group on the identification, control, and how to inject palms to protect them from this fatal disease and if memory serves me, his company had over five-hundred trees under contract at that time.
Symptoms of Lethal Bronzing include the premature death of the palms flower spikes and any fruit produced by your tree. You will also notice the older fronds tend to turn a dark-brown to reddish-brown or gray. These visual signs can be very hard to diagnose as many of these symptoms can appear as nutritional deficiencies. Another problem we should note is that because this disease not only affects Phoenix palms, you have a much wider range of symptoms to look for. Palm tree species affected by this disease include the Sabal, Queen, Pygmy Island Date Palms, Phoenix Palms, Christmas Palms, and the Chinese Fan Palm. The further this disease spreads in a tree, the fronds may show varying coloration due to the tree being infected. The cause of the frond discoloration is due to the damage of the palm’s vascular system by sap-sucking insects. The exact insect that transmits this phytoplasma has not yet been positively identified at the time of writing this article. Although the symptoms may help you to identify this disease, you really need to take a core sample to determine if the tree is infected.
If you suspect your tree may be infected, then you will need to send a sample of the core to a testing lab in order to confirm the presence of this disease. I highly recommend you hire a professional pest control operator to perform this tissue extraction. If you plan on doing this yourself, then you will need a cordless drill with a six-inch-long 5/16th-inch drill bit. Use a propane torch to sterilize the drill bit prior to boring into the base of the palm. Once sterilized, use a squirt bottle to cool off the drill bit. Next, drill down at the base of the palm and use gloves and a Ziplock bag that has been properly documented to collect the tree shavings. Gloves need to be used to ensure the sample is not contaminated. You will need enough wood shavings to fill a small film case in the Ziplock bag. After collecting your sample, you should plug the drill hole with a wooden golf tee. Insert the golf tee into the hole and use a hammer to set the tee in place. The samples collected should be free of debris like old boots of palms. Samples should be sent overnight to the UF testing lab in Gainesville, FL along with the seventy-five-dollar testing fee.
Some homeowners will be reluctant to pay the testing and collection fees charged by professionals when they could just go ahead and treat their tree for less money. Most people just want the treatment performed, but this could be a waste of resources if the tree does not have the disease. Unfortunately, the only way to know for sure if your tree is infected is to take the sample and pay the fees. Remember, if several palm trees are in the same vicinity of the suspected tree, then you will need to treat all susceptible trees. If your tree was very costly, then you will probably pay the fee. The key here is to protect the trees you have before they can contract this deadly disease. Treatment of your tree will need to be performed once every four months to keep your tree(s) from developing this disease.
The product we use to treat your palms is called Oxytetracycline or OTC. My company also applies a minor nutritional element package at the time of treatment to help the tree recover from any deficiencies it may have. This is very important in keeping your trees healthy. Commercial properties and Resort Facilities need to pay close attention to this disease and should have their susceptible trees preventively treated every four months. Treating them before a problem occurs can save you money versus having to replace the trees.
Palms can be a wonderful addition to any landscape, but they do require preventative care and routine nutritional feedings to keep them healthy and vigorous. Be vigilant in protecting your investment and monitor your trees monthly for any change in appearance. Mother Nature will continually pressure us with additional problems to overcome, but I will try to guide you through these challenges. Enjoy your palm trees and remember, without plants, we would not be here.