ODESSA, Fla. — Through a tiny office window behind William Kennedy Burchenal’s desk, a row of sickly orange trees could be seen standing in the bright Florida sun. Their limbs were withered and leaves deformed; the wood looked like rot.
They were thriving once, but that was before a citrus disease that scientists compare to HIV struck, crippling hundreds of trees and forcing the family to let part of the grove decline, close its juice blending business, and put the entire operation up for sale.
‘‘I’ve spent the last two years slowly dismantling my father’s dream,’’ Burchenal said of Cee Bee’s Citrus, established by his father, Bill, who died in 2016. ‘‘And it feels like crap.’’
There are so many dead and dying Florida groves like Cee Bee’s that some economists have administered last rites to the state’s $9 billion citrus industry.
Ninety percent of the state’s groves are infected by a bacterium called huang long bing, which, like oranges, originated in China. The pathogen often prevents raw green fruit from ripening, a symptom called citrus greening. Even when the fruit does ripen, it sometimes drops to the ground before it can be picked. Under Florida law, citrus that falls from a tree untouched cannot be sold.
As the state prepares for the November to May harvest, thousands of growers have already quit, leaving ‘‘ghost groves’’ in their wake. More than 7,000 farmers grew citrus in 2004; since then, nearly 5,000 have dropped out.
About two-thirds of the factories that processed fruit to juice have shut down. The number of packing operations — which make oranges, tangerines, and grapefruit look polished for picky buyers — has nosedived from nearly 80 to 26. And 34,000 jobs were eliminated in the 10 years up to 2016, according to a University of Florida study.
The loss of so many farmers and citrus cultivation could be the death the state’s second-largest industry behind tourism, and one that produces more than 80 percent of the country’s orange juice, some economists say.
Florida’s Department of Citrus called huang long bing — which means yellow dragon sickness — ‘‘one of the most destructive foreign plant diseases imaginable’’ and acknowledged that it ‘‘has decimated the state’s iconic industry.’’
The outlook is so bad that researchers at a compound of laboratories 30 miles south of Disney World in rural Lake Alfred are frantically trying to develop new root stocks to create trees that can better tolerate disease and genetically engineer new types of oranges to replace traditional varieties that are more vulnerable.
‘‘We’re in a race right now to save the Florida citrus industry,’’ said Michael Rogers, the director of the University of Florida’s Citrus Research and Education Center.
HLB, short for huang long bing, is spread by yet another invasive species — a tiny insect called a citrus psyllid, which sucks the bacteria into its gut as it feeds on citrus leaves. The insect then infects the next healthy leaf on which it feeds.
Citrus psyllids reproduce so rapidly that they develop a resistance to insecticides within a year. Spraying to control them while trying to revive trees has driven up farming costs. Growers are spending $663 more per acre than they did the year before the discovery of the bacterium, a 54 percent increase.
A study by researchers at the University of Florida and Virginia Tech shows that climate change will allow the psyllid to spread to states north of Florida as their temperatures rise.
According to the report, the pest thrives in temperatures between 60 and 90 degrees Fahrenheit. That is bad news for growers in Florida, whose temperatures hover in that range year-round. It means the bug is here to stay.
‘‘Much of the Florida citrus groves are already pretty inundated,’’ said Leah R. Johnson, an assistant professor of statistics at Virginia Tech and coauthor of the study. ‘‘It’s going to be hard because we didn’t catch it early enough.’’
Despite the grim news, the state citrus department struck an upbeat tone recently, saying an increase in the amount of fruit boxed in the past two years was a sign that the industry was rebounding. Sales jumped from a low of 40 million boxes two seasons ago to 70 million last season.
Citrus growers ‘‘are resilient and optimistic about the future,’’ Shelley Rossetter, a spokeswoman for the Florida Department of Citrus, said in July. ‘‘Florida will continue to be a major producer of citrus for years to come.’’
Two of the nation’s largest orange juice distributors — PepsiCo, the owner of Tropicana, and Coca-Cola, the owner of Minute Maid — were similarly optimistic, even though citrus production has dropped by half and revenue loss is approaching $5 billion.
If Florida’s citrus industry were to fail, the companies could buy citrus products from other parts of the world, such as Costa Rica and Brazil. But both say they support the Florida industry.
Tropicana partnered with the University of Florida to create disease-tolerant orange varieties in experimental groves. Minute Maid has invested billions to plant new trees and partnered with Bayer’s crop science division to develop an anti-bacterial agent to fight HLB.
‘‘Without advanced tools to control citrus greening, the citrus industry in Florida could be out of business within 10 to 15 years,’’ Adrian Percy, the former head of Bayer’s research division, told a digital magazine in 2017.
But those tools are now available at the lab in Lake Alfred, Rogers said.
When the effort started nearly 15 years ago, the scientists quickly learned how fearsome HLB was.
Their work resulted in a key finding: The disease attacks citrus tree roots, robbing them of their ability to absorb the nutrients the trees need to survive.
Tripti Vashisth, an assistant professor of horticultural science at the University of Florida, said each fruit on a tree relies on nutrients drawn from the roots. To ration the dwindling food, the trees drop the fruit.
‘‘Its own survival is more important, right?’’ Vashisth said. ‘‘Maybe it thinks, I can produce more food next year. Let me survive this year.’’
Vashisth and her team developed a technique by which farmers spoon-feed smaller amounts of fertilizer to sick trees every two weeks, as opposed to massive amounts three times per year, so allowing roots to better absorb the nutrients.
In another part of the lab, researchers working under Jude Grosser, a professor of plant cell genetics, took an only-the-strong-survive approach to root-building. They analyzed which roots succumbed to the pathogen and replaced them with roots that were more tolerant. But the replacement couldn’t be just any root; it also had to produce a sweeter fruit for the market.
New fruit could soon replace the two vintage orange varieties — the Hamlin and the Valencia, a juice mixture that most Americans have gulped for decades.
But the National Academies of Sciences, Engineering and Medicine still maintains a downbeat outlook. A breakthrough discovery for managing HLB in the near future is unlikely, it said in a study last year.