Citrus Greening Forces Florida Growers To Trust A Controversial Savior

The Plague That Could Wipe Out Orange Juice

By the spring of 2006, Maury Boyd had grown used to dealing with catastrophe. At 13, he had started working for McKinnon Corporation, his stepfather's family's citrus company comprised of thousands of acres of orange groves in Florida. In the 50 years since then, he'd helped the groves recover from freezes, hurricanes and a disease known as citrus canker -- all of which could easily have destroyed the business.

Yet even Boyd, now the president of the company, got scared when scientists from the Florida Department of Agriculture told him that his trees were infected with huanglongbing -- more commonly known as HLB or "citrus greening."

HLB is the most serious disease a citrus tree can contract. Within 18 months of infection, a tree's leaves develop telltale yellow splotches. Its fruit starts to turn green at the wrong end and taste so bitter that it's almost inedible. Limbs fall off. Roots decay. As little as four or five years later, the tree withers into a brown skeleton and dies. There is no cure.

Greening spreads rapidly through and between groves of any citrus fruit -- limes, grapefruit and, most notably for Florida, oranges. By the time it reached Boyd, just six months after it was first discovered in Florida on a pomelo tree on a farm outside Miami, it had already devastated the commercial citrus industries in Thailand, Vietnam, Saudi Arabia, the Philippines, Reunion Island, Indonesia and southern China. The only widely accepted solution was to remove infected trees and quarantine infected areas.

huanglongbingA grapefruit on a tree in Fort Pierce, Florida shows the signs of HLB. (Photo by Joe Raedle/Getty Images)

Forty percent of the trees in some of Boyd's groves were already symptomatic, and Boyd knew that many more could be silent carriers of the disease. He did the math and realized that removing every infected tree would drive the McKinnon Corporation out of the citrus industry after a century growing oranges.

"The tipping point had arrived before we were even diagnosed," Boyd said, in the gravelly drawl he picked up at military school in Virginia.

Thousands of farmers across Florida were facing the same dilemma. Some decided to sell their groves to real estate developers. Others who tried to hang on watched helplessly as their trees stopped producing fruit and died. Many in the industry feared that the disease would soon accomplish what cold snaps, tropical storms and other diseases could not: destroy the Florida citrus industry -- taking orange juice, that rite of the American morning, along with it.

"There aren’t any citrus industries in the world that have encountered this disease and come up with a management system that allows them to continue to produce citrus in the presence of the disease long-term," said Harold Browning, one of the leading experts on HLB and the COO of the Citrus Research and Development Foundation in Lake Alfred, Fla.

"If you’re a pessimist," he continued, "You’ll say no one else has done it, so there’s a likelihood that HLB will take out the industry."


Like the black plague, huanglongbing came to the West from Asia.

There are actually two different types of the disease -- an African strain and an Asian one, each of which is caused by a different type of bacteria in the genus Candidatus liberibacter. American citrus trees have caught the Asian kind, which is spread from tree to tree in the saliva of aphid-sized insects called Asian citrus psyllids.

asian citrus psyllidThe tiny Asian citrus psyllid spreads HLB from tree to tree. (Photo by Joe Raedle/Getty Images)

Once the bacteria enter the tree, they attack the innermost layer of its bark, known as the "phloem," which is to trees what blood vessels are to humans. This attack prevents the tree from effectively transporting water, nutrients and minerals between the roots in the ground and the leaves and fruit at the top, driving the tree into decline.

HLB was first clearly identified as an infectious disease, rather than a symptom of nutrient deficiencies, by a Chinese scientist named Lin Kung Hsiang. After earning a Ph.D. in agricultural sciences at Cornell in February 1941, he returned to his home country to conduct a study of citrus trees. He discovered that the groves in southeast China had been ravaged by a mysterious syndrome that local farmers called "huanglongbing," or "yellow dragon disease," after the yellowed tree shoots that are a characteristic sign of the disease. The farmers told Lin that they had known about the disease since the 1870s, but that it had only become a serious problem around 1936.

In 1956, Lin wrote a landmark treatise on HLB. But because he published it in communist China, his efforts went largely unnoticed by scientists in Europe and the Americas.

The disease continued to spread, becoming endemic in China, southeast Asia, the Indian subcontinent and southern Africa in the decades following the publication of Lin’s paper. By the end of the 20th century, it had killed over 100 million citrus trees across the globe.

But it still hadn't hit Florida, or Brazil's São Paulo State, which together produce more than 80 percent of the world's orange juice. When Asian citrus psyllids (or “jumping plant lice”) were first spotted in São Paulo State in the 1940s and in Florida in 1998, western scientists assured growers that none of the psyllids had tested positive for the HLB bacteria, so the risk of infection was slight.

Then citrus growers began to notice troubling symptoms. The glossy emeralds of their trees' leaves began to dull into mottled yellows. Some of their oranges and grapefruits started to turn green and bitter. In March 2004 and August 2005, scientists in São Paulo State and Florida, respectively, confirmed what some citrus growers already suspected: Greening had landed in the two biggest citrus-producing regions in the world.

Soon, HLB was epidemic in both regions. By February 2009, less than three years after the first positive HLB test on a citrus tree in Florida, the disease had spread to all 32 of Florida's citrus-producing counties.

2013-08-29-greeninggif.gifAn animated gif illustrating the spread of disease throughout Florida's citrus-growing region. (Joe Satran/The Huffington Post)

The disease hit Florida at a particularly vulnerable time. The state's growers had been grappling with citrus canker for several years, compromising trees' immune systems and growers' ability to resist economic pressure. Hurricanes Charley and Ivan in 2004 and Wilma in 2005 destroyed farms throughout the state, just as real estate developers were scrounging for land. Adding HLB to the mix was like aiming a flamethrower at a pile of crumpled newspapers.

"It is perhaps the most devastating disease that the industry has faced," said Matthew Salois, the director of economic research at the Florida Department of Citrus.

These calamities pushed untold numbers of farmers out of the industry. Between 2004 and 2012, the amount of Florida land planted with citrus shrunk by nearly a third, a loss of area bigger than the city of Dallas. Citrus production dropped from 292 million boxes of fruit in 2004 to 171 million in 2012. Average orange yields have sunk from 428 boxes an acre in 2004 to 338 boxes an acre today, despite ever-denser plantings of orange trees. The wholesale price of Florida oranges, meanwhile, has almost tripled, from a low of $2.89 a box in 2004 to $7.96 a box in 2012.

Infographic by Jan Diehm for The Huffington Post.

A widely cited study by researchers at the University of Florida put the overall economic impact of citrus greening on Florida's industry above $4.5 billion between 2006 and 2011 alone.

Moreover, because HLB can lie latent in trees for years, the full brunt of the disease is only now starting to materialize. In spring 2013, between 10 and 15 percent of the fruit on Florida's citrus trees fell to the ground before it could reach maturity, forcing the U.S. Department of Agriculture to revise its forecasts for Florida citrus production downward eight times. The USDA now predicts Florida farmers will produce just 156 million boxes of the fruit in 2013, 47 percent of what they sold in 2004.

By 2020, production could dip below 100 million boxes for the first time since 1964. That means that the price of orange juice -- already 50 percent higher than it was in 2004 -- is likely to climb even further in coming years, potentially making it a luxury on par with caviar and fois gras.

Scientists in Florida and elsewhere are hard at work on a cure for HLB. The citrus industry has poured over $70 million into research on the disease since it first landed in the United States. But until and unless they find an answer, the disease will remain a ticking time bomb strapped to the chest of Florida's citrus industry.


Maury Boyd, though, wasn’t willing see his industry’s future explode. A cancer survivor, he'd taken on a confusing and deadly disease before. Once Boyd figured out that eradicating symptomatic trees would destroy his business, he realized he had nothing to lose by trying to fight the trees' disease.

“If you're diagnosed terminal, do you go home and die?” he asked. “Or do you go to another doctor, and see if there's another option?”

maury boyd

Maury Boyd, president of the Winter Garden, Fla.-based McKinnon Corporation. (Photo by Ashley Boyd)

Boyd had studied horticultural science as an undergrad at the University of Florida, so he felt up to the task of finding some sort of solution. With the help of his farm manager, Tim Willis, he pored over the scientific literature on plant diseases in search of an answer.

In the two years following the spring of 2006, when his plants were diagnosed with the disease, Boyd devised a three-pronged strategy to combat HLB. The first task was to prevent greening from spreading further. To do that, he needed to eliminate the Asian citrus psyllid by spraying his trees aggressively with chemical insecticides. (Pre-HLB, Boyd, like many of his colleagues, had only sprayed his trees with petroleum distillates that smothered mites and other relatively innocuous insects.) He also needed to support the trees' natural immune systems to help them ward off the bacteria present in trees already infected with the disease. He accomplished this by applying potassium salicylate, a close chemical relative of aspirin, to his trees.

Boyd's key innovation, though, was to find a way keep infected plants’ leaves and fruit well supplied with vital micronutrients while bypassing their impaired vascular systems. He remembered learning, in college, about a horticultural principle known as Liebig's Law of the Minimum, which states that any deficiency in any nutrient, no matter how minor, will be a limiting factor in the development of a plant. He decided to try spraying micronutrients, such as manganese and boron, directly onto the leaves.

Others in the citrus industry, including researchers at the University of Florida, were not just dubious about Boyd's chances of success -- they were angry at him for trying. They worried that by refusing to rip out infected trees, Boyd would allow the disease to spread further throughout the state. Boyd even remembers them calling him "Typhoid Maury." At least one researcher, Tim Gottwald at the USDA, who has been studying HLB since 1985, still invokes the comparison.

"You're essentially leaving Typhoid Marys in the grove that are sitting there spewing the inoculum and are sitting there ready for the psyllids to pick up the disease," he said. "You actually exacerbate the epidemic by using a nutritional treatment in lieu of removing trees."

Boyd, though, suspected that the majority of the citrus trees in Florida were already infected with HLB, even if they weren't symptomatic and hadn't yet tested positive. If that were true, it would mean that it was already too late for quarantine. It was a risky hypothesis.

Luckily, Boyd's method seems to have worked. His aggressive combination of insecticides, immunological support and nutrition sprays reversed the decline of his trees. In 2009, his per-acre yield, after sinking for years, actually bumped up above its pre-greening high. And his trees no longer displayed the telltale mottled leaves and green fruit.

University of Florida professor Robert Rouse has conducted a long-running study of Boyd's groves to measure the efficacy of his program, and says that he's been blown away by its impact. "He's doing better with greening than he was before greening," he said.

before and after

Two photos of the same tree in one of Boyd's groves, taken by Robert Rouse as part of his study. The top one was taken in 2008, before Boyd implemented his method, while the bottom one was taken in 2012, after the method had a chance to resuscitate the tree.

With the validation of Rouse's study, Boyd preached the gospel of his method to everyone who would listen. He sent iPhone pictures of his flourishing trees to colleagues and researchers throughout the state, and gave presentations on his technique at citrus conferences whenever he could. And gradually, people started to listen.

Some variation of the "Boyd method" is now being used on all but two of the major commercial citrus plots in Florida. Even the owners of the two last two holdouts, U.S. Sugar and Florida's Natural, have applied similar techniques on some of their acreage.

"Everybody has rethought their approach to nutrition, and Maury Boyd is the reason for that," said citrus researcher Thomas Spreen. "In his own way, he has been a revolutionary."

Like Che Guevara and Robespierre, however, Boyd has his detractors. Gottwald may be the most vociferous, but he counts Mike Irey, the director of research at U.S. Sugar, and Jim Graham, a University of Florida researcher, as allies. They argue that rigorous controlled studies have failed to demonstrate that enhanced foliar nutrition does anything to counteract greening. The most they'll admit (and this only grudgingly) is that supplemental fertilization could correct nutrient deficiencies that predated HLB and improve yields without addressing the impact of the disease.

"Farmers by default are optimists. Otherwise they wouldn't be farming. Anything that they do with their own hands, they're going to believe, whether it's the right thing or not," Irey said.

"It's a devastating disease," he continued. "They're grasping at straws -- because the other alternative sucks, which is to pull out the trees."

huanglongbingA telltale mottled leaf. (Photo by Joe Raedle/Getty Images)

Yet the fact remains that, as Thomas Spreen put it, the overwhelming majority of Florida citrus growers have "hitched their wagon to the Maury Boyd horse, for better or worse." And many of them believe that it's saved their business.

One of the growers who ascribes his current prosperity to the Boyd method is Bobby Newsome, who manages the 11,000-acre Silver Strand Citrus grove as the head of the agricultural division at Barron Collier Companies. The company has been in the Florida citrus industry since the 19th century. (It's headquartered in Collier County, Florida, to give you an idea of how deep its roots go.) Newsome said that greening was spotted in the grove in 2009 and first dealt a crippling blow in 2010.

"It looked like the trees were going to die," Newsome recalls. "No one really knew what to do at that time; there was no real answer other than to eradicate the trees."

Then he heard about the success of Boyd's program. With no other alternatives, he tried it out. It worked. Yields, after plummeting for several years, stopped declining. With prices high, Newsome says he now "feels very bullish about the future of the industry."

But the Boyd method is tremendously expensive for growers to employ. It requires them to spend between $600 and $1000 an acre every year on insecticides and so-called “enhanced foliar nutrition sprays.” In concert with rising global demand for fertilizers, the method has pushed the cost of farming an acre of oranges to about $1,900 a year -- twice what it was before the emergence of HLB.

That’s proved a major windfall for the agribusinesses, such as Bayer CropScience and Syngenta, that manufacture the chemical insecticides effective against psyllids. Using data on citrus production provided by researcher Ron Muraro at the University of Florida, The Huffington Post calculated Florida citrus growers are now spending about $240 million a year on insecticides -- about 30 percent more than they were in 2004, even though they're farming about 30 percent less land and yielding half as much fruit.

Citing the need to protect proprietary data from competitors, representatives from Bayer refused to divulge specific sales data from Florida, but Alan Ayers, the company's director of state affairs and stewardship, did admit that business has been brisk. "We've had a pretty steady, good market down there in Florida with this class of chemicals," he said, referring to the insecticides that target psyllids.

Yet increased use of insecticides may be endangering human health. In its most recent report on pesticide residue, the EPA revealed that it had found traces of three insecticides in samples of orange juice it tested in 2011: carbaryl, imidacloprid and aldicarb.

Because all three are effective weapons in the fight against psyllids, their use skyrocketed in the wake of the discovery of HLB in Florida. USDA data show that, in 2009, Florida citrus farmers applied 3.8 times as much aldicarb, 4.9 times as much carbaryl and 7.6 times as much imidacloprid as they did in 2005.

Concentrations of carbaryl and imidacloprid found so far in orange juice are far below the levels that the EPA considers dangerous for humans (though both have been implicated in the mysterious bee die-off known as "colony collapse disorder").

Aldicarb, however, has been called the most toxic pesticide widely used in agriculture; 2000 people in the western U.S. became seriously ill after eating watermelons contaminated with it in the summer of 1985. In July 2010, the EPA issued a report arguing that even the low levels that had been detected in orange juice put frequent drinkers at risk of adverse health effects. Bayer, aldicarb's principle manufacturer, agreed to stop selling it to citrus growers immediately, and to taper off sales completely by 2015.

Maury Boyd said that he's never used aldicarb to kill psyllids, and that he's tried to keep his aerial spraying of pesticides at levels that are as low as possible, while still being effective.

Consumers who want to eliminate their risk of ingesting pesticide residue altogether should look to organic orange juice, as organic standards preclude the use of almost all synthetic chemical pesticides.

Ben McLean, the head of research and development at Uncle Matt's, the country's oldest and biggest producer of organic orange juice, said that his growers have been using parasitic wasps and organically-certified sprays to control psyllids, while applying many of the micronutrients Boyd advocates to their trees' leaves. So far, yields have stayed high enough to allow Uncle Matt's to expand their organic acreage by a third over the past four years. Still, organic orange juice remains a tiny fraction of the market, despite the buzz around the category.


The biggest problem with the Boyd method, though, isn’t the cost, or the love lost with the organic industry. It’s the fact that it doesn't actually cure HLB. It only masks the symptoms of the disease. As soon as you stop using it, these symptoms return. For that reason, growers, including Boyd himself, regularly compare it to the beta-blockers, HIV drug cocktails and dialysis that keep debilitating chronic diseases at bay in humans for many years.

Moreover, because it has never been tested on any other citrus industry, no one knows whether Boyd's method is a long-term solution, or a temporary Band-Aid that delays inevitable death. Some took the massive fruit drop of this past spring as evidence that the efficacy of the method was waning -- or even that it was never as great as growers hoped.

"The great question," citrus researcher Spreen said, "is, 'How long does it work?' Is this a solution that will continue to work year after year after year? Or is what we saw this year a sign that you've got a time limit on it?"

These questions have implications far beyond Florida. The disease is just now starting to hit the citrus industries of California, Texas, Arizona and Mexico. So far, growers in these regions have largely been able to contain greening by removing infected trees and killing psyllids -- but the experience in Florida and elsewhere shows that these methods rarely work forever.

Most scientists working on HLB are confident that they will be able to develop a viable, long-term solution to the disease at some point in the next 15 to 20 years. Promising work is being done to develop effective antibiotics for the trees, to breed hybrid trees that are resistant to the disease and even to splice genes from other organisms, like spinach, into citrus trees to make them immune to HLB.

But 15 to 20 years is a lifetime in this line of work. Experts worry that, before then, economic forces could nonetheless cause the citrus industry to implode even if some growers are still able to produce fruit.

"What might be fatal for the industry is if we have a total collapse of tree inventory while we’re coming up with the solution, which could have a ripple effect through pickers, the packers, the processors and so forth," said Browning. "Their economic viability relies on continued supply strength from the growers."

florida citrusFort Pierce grower David Hill harvests tangerines from an apparently healthy tree. (Photo by Joe Raedle/Getty Images)

Some major citrus growers have started to experiment with other crops as a way to hedge against collapse. There's been ample interest throughout the state in growing peaches or blueberries on former citrus groves. Some have toyed with the idea of growing olives or pineapples. Esteemed citrus researcher Bill Castle has dedicated his retirement to researching the possibility of growing pomegranates in Florida; he's identified several promising varieties. This year, the Barron Collier Company started an organic fruit and vegetable farm on a 45-acre parcel of its land and sold the produce through a CSA; there are plans to expand if all goes well.

Each one of these alternative crops could help individual farmers weather the storm ahead. But it doesn't appear that any of them could plausibly replace a significant fraction of the 530,000 acres currently planted with citrus. To paraphrase Jared Diamond paraphrasing Leo Tolstoy, it's an Anna Karenina problem. Each is unsuitable in its own special way.

Peaches and blueberries grow well in Florida, but American demand is so small that if just 10,000 acres were planted with each, prices would plummet, making the farms unprofitable. Pineapples are even more vulnerable to freezes than citrus. Vegetables and soft fruits are vulnerable to disease and pests in Florida's humid climate, and don't grow well in the sandy soil in which citrus trees thrive; Collier is growing its produce hydroponically. No one has yet built facilities for turning olives into oil or pomegranates into juice in Florida -- and you can't make a screwdriver with E.V.O.O. or POM Wonderful.

If the industry really does collapse at some point, the most promising use for the land may be the production of crops used for biofuels. Sugar cane destined for ethanol has been the principle lifeline for Brazilian growers forced out of citrus by the disease. But building a large biofuel industry in Florida could take decades and cost billions of dollars.

The essential problem with switching to any alternative crop, though, is that it would require the citrus industry to abandon millions of dollars of capital investment in the production of citrus -- not to mention millennia of collective experience in the industry.

And some of the excitement that welled up around these alternatives has died down since growers adopted the Boyd method with apparent success -- much like the way enthusiasm for alternative energy sources waned when fracking vastly expanded the pool of natural gas available. Though the Boyd method has driven up the cost of production, higher prices for fruit have largely kept citrus production profitable, at least for large-scale farmers.

"People who are good managers and doing everything right can still make good money on citrus," said University of Florida economist Rodney Clouser.

Boyd, for his part, now feels sanguine enough to think about expanding the McKinnon Corporation's orange business.

“I worry less about the future than I used to. I'm beginning to think now that this is sustainable,” he said.

"I'm 69 years old. I've got a daughter that just started working for me. I've got some good employees. I've got a good manager, Tim Willis, who's getting older too -- though he's not as old as I am," he added. "So I've been wondering, kinda, 'What am I gonna do?' I think what I'd like to try to do is buy an orange grove or two."

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