Lethal bronzing palm disease — Sebastian, Florida

Lethal bronzing is a fatal palm disease caused by a phytoplasma, and UF/IFAS lists Indian River County, where Sebastian sits, among the Florida counties with confirmed cases.

UF/IFAS PP163 describes the pathogen as a phytoplasma, an unculturable bacterium that has no cell wall, classified as Candidatus Phytoplasma aculeata. It lives only in the sap-carrying phloem of the palm and is not known to survive outside its host, whether plant or insect. The practical meaning for a Sebastian yard is that it cannot be mechanically transmitted by pruning tools or infected roots touching new roots; it moves only in the mouth of a feeding insect.

The county list puts Sebastian inside the affected zone. PP163 reports the phytoplasma has been isolated from palms in 36 different counties, and its table of confirmed counties includes Indian River alongside neighboring Brevard, St. Lucie and Okeechobee. UF/IFAS does not publish counts by county or city, so the number of infected palms in Sebastian is not public; the confirmation is county wide, from the Sebastian Highlands to Vero Beach and the barrier island.

It is not the same disease as lethal yellowing, though both are phytoplasmas. UF/IFAS PP146 records lethal yellowing in Indian River County since 2012 and notes it does not attack the native sabal, while lethal bronzing does, which is why bronzing worries Sebastian more.

Lethal bronzing was first identified in late 2006 in Hillsborough County near Tampa, reached the cabbage palm by 2008, and has since been confirmed from Jacksonville to the Keys, including Indian River County.

PP163 traces the outbreak that later reached Indian River County. In late 2006, a novel phytoplasma disease was identified in Hillsborough County, Florida, in the Tampa area, in edible, wild and Canary Island date palms and in queen palm. In 2008, the phytoplasma was found in the cabbage palm. The first name, Texas Phoenix Palm Decline, came from a matching pathogen on Canary Island date palms around Corpus Christi, Texas, in the early 2000s, and the disease was renamed once it turned up in Louisiana and Mexico and in palms outside the date palm genus.

UF/IFAS Gardening Solutions summarizes the reach: from Jacksonville to the Keys, the disease has spread to more than 30 of Florida's 67 counties since 2006. PP163 states it remains most prevalent in central Florida and is spreading north and south, and its latest revision added Escambia, Franklin, Marion, Nassau and Volusia counties. For Sebastian, on the line between central and south Florida, that pattern means pressure from both directions along the Indian River Lagoon.

Most palms in Sebastian yards can get lethal bronzing, since UF/IFAS lists 21 hosts including the sabal, queen, coconut, Christmas, pygmy date, pindo, Bismarck and Canary Island date palms.

The full host table in PP163 also includes the edible and wild date palms, Chinese fan palm, needle palm and Chinese windmill palm. PP163 cautions that as the disease becomes more established and spreads south into areas with higher palm diversity, the host range could expand. The sabal is the host that matters most in Sebastian because of its numbers. UF/IFAS Gardening Solutions puts it plainly: the state tree is under threat from one of the most lethal palm diseases in Florida.

The signs come in order on a Sebastian palm. PP163 states that if fruit is present, the first symptom is generally premature fruit drop, and if only flower stalks are present they turn necrotic. Discoloration then starts on the oldest, lowest leaves and climbs the canopy, ending when the spear leaf collapses, meaning the bud has died. Gardening Solutions describes the leaf color as a bronze-like brown and contrasts it with the grayish tone of a normal old frond. The latent period between infection and symptoms appears to be about four to five months, and the decline from first symptoms to spear collapse takes about two to three months.

Pruning hides the earliest signs. PP163 notes that if the inflorescences are trimmed, fruit drop and flower necrosis are no longer reliable indicators, a common situation on Sebastian sabals whose flower stalks are cut for neatness.

The insect that spreads lethal bronzing breeds in lawn grass, and UF/IFAS states that in Florida's urban landscape its preferred nymph host is St. Augustinegrass, the most common lawn in Sebastian.

UF/IFAS IN704 identifies the American palm cixiid, Haplaxius crudus, as the putative vector of lethal bronzing in Florida. Adults are approximately 2.5 to 3 mm (0.1 in) long and feed on palm leaves, while the nymphs develop on grasses and sedges. In Florida the preferred host in the urban landscape is St. Augustinegrass, which puts the nursery for the vector in the lawns around nearly every Sebastian palm.

Only a few insects in a Sebastian lawn carry the pathogen. IN704 reports that less than 1% of Haplaxius crudus carry the phytoplasma in the wild, but their abundance is enough to cause persistent disease pressure in the urban landscape. Infected palms draw more of them: a yearlong UF study published in Insects in 2020 found the cumulative number of H. crudus was 4.5 times greater on phytoplasma-infected relative to non-infected palms, one reason a sick palm left standing raises the risk for its neighbors.

Research relevant to Sebastian has shifted toward the insect. In an August 10, 2021 UF/IFAS release, researchers stated that current management relies on tree removal and antibiotics, neither of which are sustainable, and that managing the insect will be the way to control the disease. The UF/IFAS Fort Lauderdale palm phytoplasma diagnostic clinic processes yellow sticky traps to show whether the insect is present and carrying the disease, a service listed in IN704.

A Sebastian palm that shows symptoms and tests positive for lethal bronzing is removed promptly, and nearby healthy palms are tested and can be injected with oxytetracycline every three to four months.

PP163 is direct about it: once a palm shows symptoms and tests positive, it should be removed immediately, because the label rate of oxytetracycline-hydrochloride is not sufficient to reverse symptoms and the longer the palm stands, the higher the chance of further spread. Healthy-looking palms nearby can test positive too and should also come down, while palms that test negative can receive preventive injections every three to four months for at least two years. Gardening Solutions advises contacting the county Extension office first. In Indian River County that is UF/IFAS Extension Indian River County, reachable at (772) 226-4330, and the IRC Master Gardener Program runs a Wednesday morning plant clinic at the North IRC Library, 1001 Sebastian Blvd.

City rules still apply to a dying sabal. The City of Sebastian tree protection brochure dated April 7, 2023 treats a sabal with 6 feet or more of clear trunk as a specimen tree that needs a $25 removal permit and an inspection. The same brochure cites the 2019 state law, CS/HB 1159, that bars local permits for removing a dangerous residential tree documented by a certified arborist or licensed landscape architect. Replacement palms for Sebastian yards can be chosen from species absent from the PP163 host table; nursery stock is listed among trees and palms on Digital Towns Market. Digital Towns Market is our marketplace.

Last verified: October 10, 2026, against UF/IFAS EDIS and City of Sebastian sources.