This audio is generated automatically. Please let me know if you have any comments.
Oranges are a core part of Florida’s identity. Drive across the state and you’ll see the fruit prominently displayed on locals’ license plates. But after years of disease and natural disasters exacerbated by climate change, Florida’s iconic orange groves could become a thing of the past.
For years, growers have been trying to solve a long-standing problem caused by a devastating disease known as citrus greening. The bacterial infection, spread by tiny insects, has killed scores of trees, degraded millions of acres of forest, and reduced Florida’s total citrus production by 74 percent.
In recent years, natural disasters have exacerbated the problem, increasing the importance of finding treatments for citrus greening. Last October, Hurricane Milton wreaked havoc, hitting 70% of Florida’s most productive acreage. At the same time, orange growers were recovering from previous hurricanes and disease threats.
“When you think about the battles we’ve had with greening and the impact of storms that take years for tree crops to recover, it’s just difficult for growers to get their bearings,” said CEO Matt Joyner. It is part of Florida Citrus Mutual, an industry trade group representing Florida citrus growers.
The U.S. Department of Agriculture announced on December 10 that Florida’s orange harvest is expected to be the lowest in 100 years, following Milton’s. This is a huge reversal from early 2024, when the Department of Agriculture expected production to be 11% higher than the previous year.
Even as growers race to save what’s left of Florida’s orange groves, many are optimistic the state’s citrus industry can still recover. Especially if researchers can find a solution to combat citrus greening. Growers have been without a cure for many years, but promising research over the past two years could potentially change that.
“Twenty years of fighting citrus greening has taken a toll on our industry,” Joyner said. “The good news is that there have been several breakthroughs in extensive research over the past 18 to 24 months.”
Competition to treat citrus greening
In the United States, citrus greening was discovered in Florida in 2005, and has since spread to Georgia, Alabama, California, Louisiana, South Carolina, and Texas. The disease, which Joyner calls “the most difficult disease known to citrus worldwide,” is spread by a tiny insect called the Asian citrus psyllid.
Once infected, the tree dies slowly over two to three years. Affected trees may still produce some fruit, but yields are greatly reduced and the citrus produced is often discolored, bitter, and lopsided.
In 2023, scientists from the USDA Agricultural Research Service shared a potential treatment for disease by strengthening trees’ natural immune systems. Gene-edited plants that produce receptor proteins can recognize pathogens and then activate the tree’s own immune response.
Commons’ tactic has been to treat orange trees with antibiotics and protect young trees with mesh bags. This will only slightly extend its life rather than eliminate the problem. Meanwhile, USDA has invested more than $400 million to address citrus greening, including more than $57 million through the Citrus Disease Research and Extension Program since 2014 to find long-term solutions.
Although the potential treatment is still being tested, the department said gene-edited trees could offer growers the opportunity to prevent citrus greening without pesticides or remove affected trees from orchards.
Meanwhile, many growers and researchers have focused their efforts on plant growth regulators as a way to improve tree health and prevent production losses. Chemicals such as gibberellic acid and 2,4-D have been found to support healthier trees by reducing fruit drop and increasing production.
Early studies with growers have shown that trees treated with plant growth regulators retain more fruit despite natural disasters. Treated trees are also more likely to preserve fruit even in sub-zero temperatures, opening up more possibilities for citrus resilience in the face of a variety of challenges.
“We’ve deployed some tools commercially that we didn’t have before,” Joyner said. “Many of the indicators we were looking for in the fight against greening are actually showing positive signs.”
Is it too late to save Florida’s oranges?
A new solution to citrus greening is a small ray of optimism in a difficult situation for growers, whose conditions are made worse by increasingly powerful hurricanes and other weather events.
Milton was dealt a blow in 2022 by Hurricane Ian, which tore fruit from trees and flooded orchards as growers began to get back on their feet. All growers can do is prevent damage from natural disasters, making it even more important to find solutions to citrus greening and make trees more climate-resilient.
“If there’s a hurricane hurtling toward the state and we have almost 300,000 acres of tree crops and that storm hits, we can’t really protect them from that,” Joyner said. But ongoing efforts to prevent greening and restore tree health can put trees back in a better position if they are hit by another storm.
Nonetheless, there are significant obstacles to tackling this devastating disease. This is especially true in Florida, where the disease is found in every county with a commercial citrus operation. Maria Victoria Coll Aráoz, an Argentine scientist leading research into cheaper technologies to prevent citrus greening, has been told to “get out of Florida”, saying it is too late to save the industry.
“Florida has kind of lost its way,” Coll Aráoz said. “Most people in the industry tell you that.”
Coll Aráoz’s research focuses on push-pull pest management, a strategy that uses stimuli to repel pests from crops and attract them to other areas where they can be controlled. The team studied the use of curry plants as “trap crops” to attract the psyllids that cause greening.
So far, curry plants combined with pest-fighting plant hormones have yielded promising results. Using this method, the presence of insect vectors was reduced by 91% and psyllid egg laying was reduced by a whopping 100%.
Despite the potential breakthrough, Coll Aráoz said funds to spread his solution are limited. It’s unclear whether she will be able to continue the promising experiment until 2025.
But as growers find themselves at a loss for what to do with the constant hits on production, more people are willing to take part in experiments like Coll Aráoz. This could help increase demand for new research and accelerate efforts to find solutions before the next big storm or weather event.
“It’s hard to see so much fruit on the ground and to see our trees knocked down by big storms,” Joyner said. Just as we are seeing bright signs of recovery,” Joyner said. “But we remain optimistic. We now have the tools to help this industry continue to recover and rebuild.”
