From UF/IFAS
In Summary:
A UF/IFAS research team has created the first rapid, non-destructive test capable of detecting disease resistance in palms facing Thielaviopsis trunk rot — a fungus that causes trees to bend, collapse, and die without warning. By using detached leaflets instead of whole trees, scientists can evaluate disease susceptibility in just three days, accelerating treatment testing and breeding efforts. Early findings show that while most palms resist infection, several popular species display variable vulnerability, highlighting the need for continued research across Florida’s iconic landscape palms.
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Ever wonder why some palm varieties flourish while others suddenly bend at the trunk or topple over completely?
From the iconic coconut palm to towering royal palms, these signature features of Florida’s landscapes are facing a silent but serious threat: a fungal disease that can cause trunks to collapse and trees to die.
Related: Florida’s 1,100 natural springs are under threat – a geographer explains how to restore them.
Now, scientists at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) in Davie have developed a groundbreaking tool to detect which palms are at risk -- without harming a single tree.
“Currently, information on disease resistance to fungal pathogens like Thielaviopsis is lacking in palms,” said Braham Dhillon, a molecular plant pathologist at the UF/IFAS Fort Lauderdale Research and Education Center. “Understanding which palm species are resistant to the disease offers a choice to a wide range of stakeholders, including homeowners, homeowner associations, developers, landscape architects, Department of Transportation operations, and other agencies, when deciding what palms they want to plant in their landscape.”
Photo from UF/IFAS
In a recently published UF/IFAS study, researchers unveiled a simple, fast, and non-destructive test to see how different palm species respond to a fungal disease that causes trunk rot, a condition that can make palms buckle and die seemingly overnight and without warning. The disease known as Thielaviopsis trunk rot is caused by a lethal fungus that can infect almost every part of a palm, including roots, trunks, fronds, and flowers. The researchers developed the methodology by testing palms at the U.S. Department of Agriculture’s Agricultural Research Service (USDA-ARS), a 197-acre research hub in Miami.
“This pioneering study represents a significant advancement in our comprehension of palm germplasm collection and its associated disease resistance,” said Sukhwinder Singh, a research leader at USDA-ARS. “By identifying and documenting the disease-resistance traits of these palm species, we are establishing a foundation for more resilient landscapes capable of withstanding the threats posed by major pathogens such as Thielaviopsis.”
This study represents the first large-scale survey of disease resistance in palms and is an important first step in building resilient palm landscapes, said Dhillon.
“Fungi in the group Thielaviopsis are very important pathogens around the globe as these can infect a wide variety of crops such as sugarcane, pineapple, bananas and palms,” said Dhillon. “On palms, these are very sneaky pathogens, as there are no tell-tale symptoms of the infection until a trunk collapses.”
Traditionally, testing palm disease resistance requires using entire plants, a process that is slow, taking about six months to a year to see results, costly, labor-intensive, and deadly for the trees being studied. The new UF/IFAS method changes that by using only detached leaflets. These leaf pieces can be tested in a lab, giving scientists answers within just three days instead of months.
“Being able to use detached leaflets to test resistance is particularly advantageous in long-lived woody species like palms, considering a vast majority of palms in the landscape have a single growing point on top of an unbranched trunk. With detached leaflets, we can test the same palm multiple times against multiple isolates,” he said.
Using the new testing method, the team evaluated 29 palm species from 17 genuses. They discovered that 79% of palms were resistant to infection, while a few species, including Puerto Rico royal palms, coconut palms, and buccaneer palms, showed varying levels of resistance to the disease.
Beyond identifying which palms are at risk, the tool offers a faster way to test potential treatments, such as fungicides or biological controls, before moving to large-scale trials. It would also help identify genetic variation in disease resistance to Thielaviopsis pathogens in palms and guide breeding and conservation efforts to develop more resilient palm varieties. These findings may pave the way for a resilient and prosperous palm industry across the region and he country.
“Even though resistance information on 29 palm species was generated in this study, there is more work to be done,” said Dhillon. “In this study, only five out of the 12 palm species native to Florida were surveyed, and there are many other palm species popular in Florida’s landscape – Canary Island date palms, royal palms, Washingtonia palms, and date palms – that still need to be tested.”
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UF/IFAS scientists developed a groundbreaking test that identifies palm susceptibility to Thielaviopsis trunk rot using detached leaflets rather than whole trees.
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The lethal fungus can infect roots, trunks, fronds, and flowers, often killing palms with no visible warning signs until collapse occurs.
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Traditional resistance testing takes months and destroys the plants; the new method delivers results in three days and allows repeated testing from a single palm.
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In a survey of 29 palm species, 79% showed resistance, while others — including coconut, buccaneer, and Puerto Rico royal palms — demonstrated varying susceptibility.
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The tool can guide landscape choices, help test fungicides and biological treatments, and support breeding programs to create more disease-resistant palms.
ABOUT UF/IFAS
The mission of the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) is to develop knowledge relevant to agricultural, human, and natural resources and to make that knowledge available to sustain and enhance the quality of human life. With more than a dozen research facilities, 67 county Extension offices, and award-winning students and faculty in the UF College of Agricultural and Life Sciences, UF/IFAS brings science-based solutions to the state’s agricultural and natural resources industries and all Florida residents.
For more information, go to ifas.ufl.edu.
