UF/IFAS Team Secures Funds to Expand Avocado Production Into Central Florida, Combat Laurel Wilt Disease
by LOURDES MEDEROS, UF/IFAS
Scientists with the University of Florida have secured a $5 million grant from the U.S. Department of Agriculture National Institute of Food and Agriculture to combat the lethal Laurel wilt disease and the redbay ambrosia beetles responsible for it.
The research aims to improve control and mitigation practices for avocado production in Florida. The grant will also support the testing of new varieties for their tolerance to cold and disease. This initiative is poised to extend avocado cultivation beyond Miami-Dade County, fostering growth and sustainability beyond the Sunshine State’s avocado production industry.
“Laurel wilt is the most devastating disease to avocado trees in the world,” says Jeffrey Rollins, Ph.D., principal investigator and a professor of plant pathology at the UF Institute of Food and Agricultural Sciences, who’s leading the research team. “Trees infested with this pathogen die within four to eight weeks.”
The pathogen is transmitted to trees by four to five ambrosia beetle species and through root grafts of adjacent avocado trees.
Avocado varieties grown in Florida are touted for their nutritional benefits. With more than 50 varieties, each is rich in protein, potassium, iron and vitamins.
“Growers are interested in increasing commercial acreage in Central Florida, thanks to a variety of conditions, one being warmer climates shifting to the north. Currently, avocadoes can be found growing as far north as Polk County,” says Jonathan Crane, Ph.D., a co-principal investigator and a tropical fruit crop specialist at UF/IFAS Tropical Research and Education Center. The grant will support research to expand the market.
Frostproof’s Mitch McLellan, who switched from growing citrus to growing avocados on his land in 2023, says his trees are positively flourishing.
“I expect a bumper crop this year!” he says.
Crane says the South Florida avocado industry has been severely impacted by Laurel wilt with production reduced by about 50%.
McLellan says he hasn’t had any trouble with Laurel wilt in Central Florida.
“So far, I’ve only had spider mites, but they just make the leaves fall off so they are more of an aggravation than anything.”
Laurel wilt was first detected in Florida’s commercial avocado production area of Homestead in 2012. Initially, the disease was spread by one species of the redbay ambrosia beetle, says Crane.
“The pathogen has now spread to 10 ambrosia beetle species five of which we know can transmit the disease,” he says. “That completely complicates everything. There is more at stake because the problem stretches beyond Florida into other avocado-producing states, posing significant risks.”
The disease has destroyed more than 350,000 avocado trees in Florida, says Rollins.
“We are working to avoid what could be an ecological disaster as the beetle also attacks native trees in the Laurel Family as well as avocado trees,” he says.
This significant funding amount will support a trans-disciplinary research team of 12 scientists across the state, leading efforts for the next five years that is aimed at sustaining the Florida avocado industry and expanding avocado production both in South Florida and into Central Florida to accommodate the increased demand.
Meanwhile, UF/IFAS scientists have developed several mitigation efforts and best practices. The new grant will enable UF/IFAS researchers to explore additional innovative pest-management techniques, plant breeding, modeling and genetic solutions to mitigate the impact of this disease.
“The industry is battling the Laurel wilt disease with proven pruning practices to open the groves to increased light and wind, which suppress the ambrosia beetle activity,” says Rollins. “Some growers are injecting fungicide to reduce tree losses, and many growers are replanting lost avocado trees.”
The research team’s goal is to provide growers, investors and the public with the latest proven tools for disease detection, diagnosis and management. Through workshops, community events and bilingual resources, they want to empower stakeholders with science-based solutions while ensuring their concerns are addressed. By integrating research findings into practical strategies, these efforts will help protect the avocado industry and preserve this iconic fruit industry for future generations.
The objective is to understand beyond the dynamics of the disease and biology of the pest in hopes of stopping the beetle in its tracks.
“We are factoring in the need to understand the disease’s movement to better predict its spread,” says Rollins. “As we continue to refine our mitigation practices and share successful strategies, we are also committed to developing new approaches.”
Over the years, Rollins has taken a genetic look at the pathogen for its abilities and strengths that also help uncover weaknesses. “The danger doesn’t stop at Florida’s borders. Laurel wilt is a threat, with its spread already reaching Texas and Kentucky and potentially could devastate California.”
California, home to 90% of avocado production in the United States, is valued at more than $1.6 billion, says Rollins.
“As this disease progresses, its environmental impact grows, attacking native trees and numerous members of the Laurel plant family,” says Crane. “The disease has caused substantial economic losses and has threatened the viability of commercial avocado production.”
By finding cost-effective measures to manage Laurel wilt, researchers seek to ensure the continued sustainability of avocado production that Florida has enjoyed and beyond, he says.
Meanwhile, UF/IFAS researchers have reported an increase in acreage in Central Florida dedicated to avocado cultivation that is in response to the growing demand for avocados in this region.
The development of cold-tolerant avocado varieties as part of the grant’s initiative has the potential for growers in Central Florida to expand their operations.
With its world-class expertise in agricultural research, UF/IFAS researchers are committed to ensuring that Florida avocados thrive and expand despite the challenges posed by Laurel wilt.
“This project represents a significant step forward in safeguarding the state’s agricultural heritage and the livelihoods of those who depend on it,” says Rollins.
