After much scientific chopping with a machete, I believe this tree was dying from lethal yellowing.
There are weevils that lay eggs in the center of palm trees, then the developing larvae tunnel the tree to death. In this case, there were no weevils. The symptoms also look to me like the dreaded lethal yellowing.
Lethal yellowing is a disease of palms which swept through South Florida decades ago and took out many of the iconic palms lining roads and parks.
According to Infogalactic:
“There is a direct connection between green lawns and the spread of lethal yellowing in Florida. Even so-called ‘resistant cultivars’ such as the Malayan Dwarf or the Maypan hybrid between that dwarf and the Panama Tall were never claimed to have a 100% immunity.The nymphs of the planthoppers develop on roots of grasses, hence the areas of grass in the vicinity of palm trees is connected with the spread of this phytoplasma disease. The problem arose as a direct result of using coconut and date palms for ornamental and landscaping purposes in lawns, golf courses and gardens together with these grasses. When these two important food palms were grown in traditional ways (without grasses) in plantations and along the shores, the palm groves weren’t noticeably affected by lethal yellowing. There is no evidence that disease can be spread when instruments used to cut an infected palm are then used to cut or trim a healthy one. Seed transmission has never been demonstrated, although the phytoplasma can be found in coconut seednuts, but phytosanitary quarantine procedures that prevent movement of coconut seed, seedlings and mature palms out of an LY epidemic area should be applied to grasses and other plants that may be carrying infected vectors.”
See – there’s another reason not to keep your yard nice!
The symptoms exhibited by this unfortunately coconut palm mesh with what I read at UF about lethal yellowing disease:
“As foliage discoloration advances up through the crown (canopy), the spear (youngest) leaf collapses and hangs down in the crown. This indicates the apical meristem (bud or growing point of the palm) has died.
For most palm species, including coconuts, death of the apical meristem usually occurs when one-half to two-thirds of the crown has become yellow or brown. However, for Phoenix species and Borassus flabellifer, spear leaf collapse and death of the apical meristem occurs when one-third or less of the crown has become discolored (Figure 15). For Adonidia and Veitchia, the spear is usually unaffected until after all other leaves have died.
Once this spear leaf breaks off or falls from the crown, it is not readily apparent that the apical meristem (bud) has died.
Eventually, the entire crown of the palm withers and topples, leaving a bare trunk standing. Infected palms usually die within 3 to 5 months after the first appearance of symptoms.”
Yep. That’s what happens.
How I Plan to Deal with Lethal Yellowing
Unfortunately, there’s not a foolproof cure for the disease. UF admits as much, even in giving a treatment plan:
“Chemical control of LY is achieved by application of the antibiotic oxytetracycline HCl (often referred to as OTC) administered to palms by liquid injection into the trunk
As a therapeutic measure, systemic treatment on a 4-month treatment schedule should begin as early in symptom expression as possible. Symptomatic palms with >25% discolored leaves should be removed, since they are unlikely to respond to OTC treatment. For susceptible Phoenix species, if the apical meristem (bud) is already dead, the palm will not respond to OTC treatment.
The antibiotic can also be used preventively to protect palms when LY is known to occur in the area. The amount recommended depends on the size of the treated palm. Always follow directions for use on the label.
The one question often asked regarding OTC injections concerns the length of time one must continue to inject. Unfortunately, there is no definitive answer. The antibiotic does not necessarily kill the phytoplasma but simply reduces or suppresses the phytoplasma population in the palm to a level that is no longer harmful, allowing resumption of normal growth of the palm. If injections are stopped, it is possible the phytoplasma will begin to increase once again and symptoms will reappear on the palm. Alternatively, if the disease is still active in the area, the unprotected palm could be re-infected with the phytoplasma.
Disease management via control of planthopper populations is insufficient to justify repeated insecticide applications in landscapes. Planthoppers are flying insects, and they also can be blown around by wind.
Use of host palm resistance represents the most practical long-term solution for LY control.”
There are varieties here in Central America that are being tested for lethal yellowing resistance.
For now, I am cutting down infected specimens…
…and I am planting more coconuts around this property. Coconuts out in the wild and on the beaches don’t seem to be dying all that much, even as the ones around houses are.
Hollywood Blvd in Hollywood, Florida, used to be lined with Jamaican King palm trees – a large, beautiful coconut palm.
Lethal yellowing killed many of them and then, in 1989, the news went out that the trees would be replaced with a hybrid royal palm:
“On Wednesday, city commissioners agreed to spend $247,000 to plant 233 Maypan palms on the beach and 30 royal palms on Hollywood Boulevard.
“If we`re going to have a Hollywood, we`ve got to have royal palms on Hollywood Boulevard,“ City Commissioner John Williams said.
Hundreds of Jamaican tall coconut palms already are planted on the beach, and about 200 royal palms line Hollywood Boulevard from Young Circle to the Intracoastal Waterway.
But some of the existing trees have been harmed by fungus and lethal yellowing disease, as well as improper pruning by city employees, said Jerry Behrmann, who owns Key Lime Landscape Nursery and was hired to plant the new palms.
Behrmann said he expected to begin the beach plantings within two weeks, but was not sure how soon the trees would be planted on the boulevard.
The Maypans, a hybrid created to resist lethal yellowing, will stand about 20 feet high, or about 10 feet shorter than the Jamaican talls on the beach. The new royal palms, about 20 feet tall, will be dwarfed by the old 60- to 70-foot palms that dot the boulevard.”
The Boulevard is beautiful now thanks to those palms, but I can imagine how much more tropical it would have looked with those towering coconut palms.
All gone, thanks to lethal yellowing.
“Blight comes at you fast,” as the insurance company says, right?