WUFT | News and public media for north central Florida
A Bitter Harvest
By Katie Shealy
April 29, 2026 at 11:50 PM EDT
Is a Florida citrus “herbicide of choice” behind a cluster of Parkinson’s disease among growers and researchers?
Steve Caruso woke as he did every morning—tired, but ready to get to work.
He stepped gingerly out of bed, stretched his stiff back and pulled on a plaid shirt and blue jeans. He smiled as he kissed his wife, Jill Caruso, on the forehead. She reminded him to take his medicines before heading off to work as the CEO of Florida’s Natural Growers, the popular fresh orange juice brand and one of the world’s largest citrus grower cooperatives.
He pulled on his Florida’s Natural cap and shoved a hand in his pocket to try and calm a tremor. His hand shook so much that it jingled the spare change in his jeans. Jill Caruso remembers those jingling coins as one of the earliest signs of her husband's Parkinson’s disease. He died of its complications in 2023 at age 75.
“He loved his job,” said Jill Caruso. “He loved it, and he would be here today if he could. He tried to fight this thing but couldn't any longer.”
Caruso is among a number of prominent Florida citrus growers and citrus researchers who died after battling Parkinson’s disease, which carries higher risks for people who work in agriculture. They include Ferdinand Duda, a poor immigrant farm boy who helped build A. Duda & Sons into an agricultural giant, and Walter Phillips, the last of Orlando’s pioneering Dr. Phillips citrus family. The late University of Florida citrus researchers Thomas Wheaton, Clayton McCoy and Charles Barmore, who all worked in the IFAS Citrus Research and Education Center in Lake Alfred, also died with Parkinson’s.
UF neurologist Dr. Michael Okun, director of UF’s Norman Fixel Institute for Neurological Diseases, treated Caruso before he died and has cared for others in citrus and related industries who tie their Parkinson’s to exposure to agricultural chemicals including the herbicide paraquat. While correlation doesn’t imply causation, Okun said these and other Parkinson’s clusters in specific industries and places should not go unheeded.
The stories track with increasing scientific evidence of the influence of agricultural chemicals on Parkinson’s disease, Okun said, especially the herbicide paraquat, which was widely used in Florida’s citrus groves.
“Parkinson’s is not just a disease of aging,” Okun said. “It is a disease influenced by the environment—and paraquat sits at the center of that conversation.”
Family tradition
Steve's grandfather, Philip Caruso, immigrated from Sicily to New York at age 12 and started out pushing a fruit cart through the city streets. By 1924, he led the largest produce wholesaler in the country. In 1925, he moved to Florida to begin purchasing citrus for the company. His sons, including Steve Caruso’s father, Austin, took over the business after World War II and built one of Florida’s biggest citrus empires. Austin wanted young Steve to work from the ground up to learn every aspect of the groves and business. Steve would go on to grow the family business from the original Bluebird brand through multiple negotiations and acquisitions into Florida’s Natural—one of the top-selling orange juices in the United States.
“He was just a hard worker and he loved people,” said Jill. “He was very organized to run a company—to delegate without a problem. He was very loving to his family.”
His years of farm work included a harrowing chemical exposure at 16 that he never forgot, according to his widow. One morning while rumbling along on the tractor, the clutch stuck and the tractor jolted into a large sinkhole full of water, dragging Steve down with it. He was stuck in the driver's seat, submerged up to his neck in chemical-tinged runoff from the surrounding groves, trying to wriggle his legs free. Finally, he managed to dislodge himself and swim to safety. Sopping wet, he worried more about how mad his father would be about the tractor than the chemicals. He considered himself lucky the big machine didn’t tip over and trap him underneath.
But later, he thought a lot about those chemicals, Jill said, particularly Paraquat dichloride, more commonly known as paraquat, the chemical used most heavily on the Caruso family’s groves. Chevron Chemical Co. sold the herbicide under the brand name Gramoxone beginning in the 1960s, with one plant pathologist telling Florida farmers it was “the most exciting weed killer to come out of this decade.”
Its toxicity had become clear by 1969, when Florida restricted its use to commercial agriculture. More than half a century later, thousands of farmers would sue Chevron and Syngenta, the multinational agribusiness that has produced Gramoxone since 2000, saying they did not understand just how dangerous the herbicide could be.
Syngenta rejects the claims of a causal link between paraquat and Parkinson’s disease, saying it is not supported by scientific evidence. Syngenta referred WUFT safety questions to its website devoted to paraquat and the media, where the company stresses that “paraquat is safe when used in line with registered label instructions.”
Okun said he believes the research linking paraquat to Parkinson’s is strong enough to trigger the “precautionary principle”: when an activity raises such serious threats to human health or the environment that precautionary measures should be taken even if cause-and-effect cannot be replicated in human research studies.
“We can't take people and do a study ethically where we randomize half the people to get a toxin. So we can't give half the people paraquat and half the people not,” said Okun. “So the companies that are in the space sort of have this advantage that you know you can't do those studies. So you can delay, delay, delay.”
Multiple studies link paraquat exposure to increased risk of developing Parkinson’s— the disease that Steve Caruso would develop in his late 30s and fight for decades of slow decline until he passed away on August 23, 2023.
“We found that people who mixed or applied paraquat were at about a two and a half times greater risk of later developing Parkinson’s compared to those who did not,” said neurology professor Caroline Tanner at the Weill Institute for Neurosciences at the University of California, San Francisco.
In the groves, Jill Caruso said, her husband and many citrus workers of the era would spray paraquat and other chemicals without wearing protective equipment. She said that when it was windy, the chemicals would blow onto their clothes and faces. Jill Caruso doesn’t trust chemicals after watching what her husband went through.
“There are a lot of orange juice farmers that have Parkinson's,” she said.
Florida citrus and Parkinson’s
When summertime rolled around, Roland Wiygul Jr., known as Rusty to his friends, had one thing on his mind—getting to the beach. During his teenage years, the only thing standing in his way were his chores in the citrus groves. He spritzed peroxide in his hair and hopped in the driver's seat of his Jeep CJ, hoping his locks would get lighter and his tan would get darker.
Wiygul cruised between the rows with four or five jugs of paraquat that he hand-mixed to spray on the base of young citrus trees to prevent weeds from choking them out. He worked shirtless, with a pair of shorts and either rubber boots or tennis shoes—depending on how he felt that day.
“We’d get some irritation on our skin sometimes, but we thought it just isn't gonna hurt us,” said Wiygul, who still works in the industry as grower affairs consultant for Florida Citrus Mutual. “Now, I'm 76 years old and diagnosed with Parkinson's disease.”
Wiygul was diagnosed with Parkinson’s and myasthenia gravis (MG), a chronic neuromuscular disease. He attributes his Parkinson’s to his youth spraying paraquat and other chemicals in the citrus groves with no protective equipment.
Looking back on those summers in the groves, Wiygul wishes he would have known the dangers so that he could have better protected himself from chemical exposure. Today, the Environmental Protection Agency requires paraquat to be used by only certified applicators with full protection.
“I really screwed myself up with this stuff,” said Wiygul. “I truly believe that, in my case, paraquat is attributed to some of my problems.”
His role with Florida Citrus Mutual had Wiygul in close contact with Caruso. The industry is a tight-knit community working together across the state to bring iconic Florida citrus and juice to the market. Wiygul saw what Caruso went through and has seen other long-time citrus workers follow not far behind.
“He was one of the nicest fellows I've ever met,” said Wiygul. “He was a smart businessman—he was a grower. He took good care of his people that worked for him.”
Lake Alfred Citrus Research and Education Center
A short drive south from Wiygul’s office at Florida Citrus Mutual is the Lake Alfred UF/IFAS Citrus Research and Education Center (CREC), UF’s oldest and largest off-campus experiment station. New Yorker writer John McPhee described it in his 1966 book “Oranges” as “an intelligence service for the citrus industry.”
There, the prominent citrus scientist Bill Castle, since named to the Florida Citrus Hall of Fame, spent decades in different groves conducting groundbreaking research. Castle worked with growers for 35 years, walking their groves and collecting fruit samples.
Castle conducted between 60 and 70 field trials over his career, collecting fruits from groves across the state with his bare hands, not knowing what chemicals he was being exposed to on each farm. Castle was diagnosed with Parkinson’s in 2018 but said he felt symptoms as early as 2015.
Chemical exposure has been an occupational hazard for researchers since the dawn of science; Sir Isaac Newton’s death has been attributed to mercury poisoning. In a famous modern case, Dr. Tim Greenamyre, a neuroscientist and physician who did groundbreaking work that linked the insecticide rotenone to Parkinson’s, developed the disease himself. Greenamyre worries his decades of exposure to rotenone and similar compounds in the lab may have caused it.
During his career at the CREC, Castle said he saw at least five of his colleagues diagnosed with Parkinson’s disease. “It was a big puzzle,” said Castle.
In the 1960s, Ortho weed killers, then owned by Chevron, were advertised for containing paraquat and sold for household use calling the herbicide a “crackshot” and a “revolutionary new chemical.” The state of Florida restricted paraquat’s use to commercial agriculture in 1970, but headlines as far back as the 60s highlight the controversy surrounding paraquat. The photos show researchers at the Lake Alfred CREC, including McCoy and Wheaton who have died with Parkinson’s, and Castle, who is living with the disease. (Photos courtesy of Lake Alfred CREC Library, graphic by Katie Shealy/WUFT News) (2000x1600, AR: 1.25)
The U.S. Centers for Disease Control and Prevention defines a cluster as “an aggregation of cases grouped in place and time that are suspected to be greater than the number expected, even though the expected number may not be known.”
Castle asked a supervisor if an investigation might be warranted, but the supervisor described the cases as coincidental. Castle wasn’t so sure but didn’t push the issue any further.
Okun remembers feeling the same way 25 years ago when he was an early-career neurologist and people came into his office concerned that something in their environment was causing Parkinson’s.
“When we think of orange groves in Florida, you know, at the beginning of my career… I saw all these people coming in from the citrus industry, and they would say, well, I have this, and this person has this, what do you think?” said Okun. “I would say, oh it’s just a coincidence."
Okun said he feels guilt and regret for approaching those conversations that way, especially considering what he knows now about environmental factors and their links to Parkinson’s.
Okun's patients brought up the same concerns that Castle did—that there seemed to be a higher incidence of Parkinson’s surrounding them at work, or in a neighborhood.
“People that are working on these orange groves, where they're spraying this herbicide over and over and over,” said Okun. “They're getting these huge exposures, and we're seeing clusters of disease.”
With stronger scientific research linking environmental factors and Parkinson’s, Okun said he believes it is more important than ever to report and study clusters to protect people going forward.
IFAS officials said in a statement to WUFT that “The health and safety of IFAS researchers is always a top priority.” Associate vice president of communications Chris Vivian and CREC lab director Michael Rogers both stressed that IFAS closely follows EPA and label guidance for use of all agricultural chemicals, though Rogers declined to discuss whether he had been approached about Parkinson’s among researchers and how the lab has handled any concerns.
“I have to speak for them when I say that I always wondered if it was more than a coincidence,” said Castle.
Growing Concern Over Paraquat
Paraquat was commonly “the herbicide of choice” for weed control in Florida’s citrus groves. Back when Caruso and Wiygul were teenagers working in the groves, it could be used by anyone. But amid greater understanding of its dangers in 2016, the EPA restricted its use to certified applicators.
Brett Bultemeier, director of the UF/IFAS Pesticide Information Office, explains how important it is to take gloves off properly after paraquat application to avoid spreading the chemical to exposed skin. (Katie Shealy/WUFT News) (5184x3456, AR: 1.5)
The stricter regulations include requiring applicators to wear a long-sleeved shirt, long pants, shoes and socks, protective eyewear, specific chemical resistant gloves and an approved particulate respirator. Mixers and loaders must wear the same personal protective equipment plus a chemical-resistant apron and face shield—a far cry from Wiygul’s days of spraying in just a pair of shorts and rubber boots.
To ensure paraquat doesn’t touch exposed skin, it’s essential for applicators to follow protocol to a T when pulling protective equipment on and off, said UF agronomist Brett Bultemeier, Extension assistant professor and director of the Pesticide Information Office at UF/IFAS.
Paraquat applicators are required to be licensed to purchase or use the herbicide and must complete additional paraquat-specific training. Syngenta, the company that sells paraquat under its name brand Gramoxone, provides the only EPA approved paraquat training course in the nation. A second approved course offered by the National Pesticide Safety Education Center (NPSEC), was discontinued last year due to financial and logistical reasons according to Wayne Buhler, interim executive director of NPSEC.
This March, Syngenta announced that it will stop producing paraquat due to “significant competition from generic producers around the world, which has eroded Syngenta’s competitiveness in the production of this herbicide.”
The decision also followed the lawsuits and increased pressure to ban paraquat in the United States. In a written statement to WUFT, the company said it “maintains a commercial presence for paraquat in select strategic markets.”
Syngenta manufacturing site in St. Gabriel, Louisiana, where the company makes Gramoxone, its paraquat herbicide. (Katie Shealy/WUFT News) (2657x1771, AR: 1.5002823263692828)
UF’s Bultemeier is concerned about who will provide the paraquat training once Syngenta doesn’t have a stake in producing the herbicide.
“There are other manufacturers of paraquat, but they must still abide by all of the rules,” said Bultemeier. “I did become concerned about the training because knowing that there is one training and Syngenta is the one that has the training—what is their interest in continuing?”
In its statement to WUFT, Syngenta wrote that the company recognizes its paraquat training program is essential to certified applicators across the country. It will continue to provide the training while Gramoxone inventories still exist. In the meantime it is evaluating options to transition the program to another host to ensure continuity.
Calls for a ban
Okun is among a number of neurologists, along with the Parkinson’s Foundation, the Michael J. Fox Foundation, and other advocates, calling on the United States to join 74 other countries in banning paraquat.
“How much do I think Parkinson’s disease is preventable—I think a ton of it is,” said Okun. “Diseases have causes. When we find the root causes, that’s how we can prevent diseases and also develop treatments.”
The EPA has declined to ban paraquat when weighing the agricultural benefits of the herbicide against the risks to human health when used according to safety protocols with the proper protective equipment.
Agroecologist Alex Stuart, an international project manager at Pesticide Action Network UK, said while many in the agriculture business still see paraquat as “the herbicide of choice,” the health concerns mean that’s no longer the case.
“There’s this perception that there’s more labor required or that it’s just not feasible, but there are loads of other options available,” said Stuart. "Paraquat has been banned in the U.K. since 2007, and that has led to no yield decline, as we’ve seen the same in other countries.”
Parkinson’s changed the lives of Steve Caruso and others who spent years in Florida’s groves. While no one can be sure whether environmental exposure is to blame, a common thread ties them together.
“I just feel like that's the chemical that gave Steve Parkinson's,” said Jill Caruso. “I really feel like that. I’m really afraid of all these chemicals.”
This story is part of Poisoned Pathways, an investigation into chemical exposure and Parkinson’s disease supported by the Pulitzer Center and reported by the WUFT Environment & Ag Desk at the UF College of Journalism and Communications.
(3125x313, AR: 9.984025559105431)
He stepped gingerly out of bed, stretched his stiff back and pulled on a plaid shirt and blue jeans. He smiled as he kissed his wife, Jill Caruso, on the forehead. She reminded him to take his medicines before heading off to work as the CEO of Florida’s Natural Growers, the popular fresh orange juice brand and one of the world’s largest citrus grower cooperatives.
He pulled on his Florida’s Natural cap and shoved a hand in his pocket to try and calm a tremor. His hand shook so much that it jingled the spare change in his jeans. Jill Caruso remembers those jingling coins as one of the earliest signs of her husband's Parkinson’s disease. He died of its complications in 2023 at age 75.
“He loved his job,” said Jill Caruso. “He loved it, and he would be here today if he could. He tried to fight this thing but couldn't any longer.”
Caruso is among a number of prominent Florida citrus growers and citrus researchers who died after battling Parkinson’s disease, which carries higher risks for people who work in agriculture. They include Ferdinand Duda, a poor immigrant farm boy who helped build A. Duda & Sons into an agricultural giant, and Walter Phillips, the last of Orlando’s pioneering Dr. Phillips citrus family. The late University of Florida citrus researchers Thomas Wheaton, Clayton McCoy and Charles Barmore, who all worked in the IFAS Citrus Research and Education Center in Lake Alfred, also died with Parkinson’s.
UF neurologist Dr. Michael Okun, director of UF’s Norman Fixel Institute for Neurological Diseases, treated Caruso before he died and has cared for others in citrus and related industries who tie their Parkinson’s to exposure to agricultural chemicals including the herbicide paraquat. While correlation doesn’t imply causation, Okun said these and other Parkinson’s clusters in specific industries and places should not go unheeded.
The stories track with increasing scientific evidence of the influence of agricultural chemicals on Parkinson’s disease, Okun said, especially the herbicide paraquat, which was widely used in Florida’s citrus groves.
“Parkinson’s is not just a disease of aging,” Okun said. “It is a disease influenced by the environment—and paraquat sits at the center of that conversation.”
Family tradition
Steve's grandfather, Philip Caruso, immigrated from Sicily to New York at age 12 and started out pushing a fruit cart through the city streets. By 1924, he led the largest produce wholesaler in the country. In 1925, he moved to Florida to begin purchasing citrus for the company. His sons, including Steve Caruso’s father, Austin, took over the business after World War II and built one of Florida’s biggest citrus empires. Austin wanted young Steve to work from the ground up to learn every aspect of the groves and business. Steve would go on to grow the family business from the original Bluebird brand through multiple negotiations and acquisitions into Florida’s Natural—one of the top-selling orange juices in the United States.
“He was just a hard worker and he loved people,” said Jill. “He was very organized to run a company—to delegate without a problem. He was very loving to his family.”
His years of farm work included a harrowing chemical exposure at 16 that he never forgot, according to his widow. One morning while rumbling along on the tractor, the clutch stuck and the tractor jolted into a large sinkhole full of water, dragging Steve down with it. He was stuck in the driver's seat, submerged up to his neck in chemical-tinged runoff from the surrounding groves, trying to wriggle his legs free. Finally, he managed to dislodge himself and swim to safety. Sopping wet, he worried more about how mad his father would be about the tractor than the chemicals. He considered himself lucky the big machine didn’t tip over and trap him underneath.
But later, he thought a lot about those chemicals, Jill said, particularly Paraquat dichloride, more commonly known as paraquat, the chemical used most heavily on the Caruso family’s groves. Chevron Chemical Co. sold the herbicide under the brand name Gramoxone beginning in the 1960s, with one plant pathologist telling Florida farmers it was “the most exciting weed killer to come out of this decade.”
Its toxicity had become clear by 1969, when Florida restricted its use to commercial agriculture. More than half a century later, thousands of farmers would sue Chevron and Syngenta, the multinational agribusiness that has produced Gramoxone since 2000, saying they did not understand just how dangerous the herbicide could be.
Syngenta rejects the claims of a causal link between paraquat and Parkinson’s disease, saying it is not supported by scientific evidence. Syngenta referred WUFT safety questions to its website devoted to paraquat and the media, where the company stresses that “paraquat is safe when used in line with registered label instructions.”
Okun said he believes the research linking paraquat to Parkinson’s is strong enough to trigger the “precautionary principle”: when an activity raises such serious threats to human health or the environment that precautionary measures should be taken even if cause-and-effect cannot be replicated in human research studies.
“We can't take people and do a study ethically where we randomize half the people to get a toxin. So we can't give half the people paraquat and half the people not,” said Okun. “So the companies that are in the space sort of have this advantage that you know you can't do those studies. So you can delay, delay, delay.”
Multiple studies link paraquat exposure to increased risk of developing Parkinson’s— the disease that Steve Caruso would develop in his late 30s and fight for decades of slow decline until he passed away on August 23, 2023.
“We found that people who mixed or applied paraquat were at about a two and a half times greater risk of later developing Parkinson’s compared to those who did not,” said neurology professor Caroline Tanner at the Weill Institute for Neurosciences at the University of California, San Francisco.
In the groves, Jill Caruso said, her husband and many citrus workers of the era would spray paraquat and other chemicals without wearing protective equipment. She said that when it was windy, the chemicals would blow onto their clothes and faces. Jill Caruso doesn’t trust chemicals after watching what her husband went through.
“There are a lot of orange juice farmers that have Parkinson's,” she said.
Florida citrus and Parkinson’s
When summertime rolled around, Roland Wiygul Jr., known as Rusty to his friends, had one thing on his mind—getting to the beach. During his teenage years, the only thing standing in his way were his chores in the citrus groves. He spritzed peroxide in his hair and hopped in the driver's seat of his Jeep CJ, hoping his locks would get lighter and his tan would get darker.
Wiygul cruised between the rows with four or five jugs of paraquat that he hand-mixed to spray on the base of young citrus trees to prevent weeds from choking them out. He worked shirtless, with a pair of shorts and either rubber boots or tennis shoes—depending on how he felt that day.
“We’d get some irritation on our skin sometimes, but we thought it just isn't gonna hurt us,” said Wiygul, who still works in the industry as grower affairs consultant for Florida Citrus Mutual. “Now, I'm 76 years old and diagnosed with Parkinson's disease.”
Wiygul was diagnosed with Parkinson’s and myasthenia gravis (MG), a chronic neuromuscular disease. He attributes his Parkinson’s to his youth spraying paraquat and other chemicals in the citrus groves with no protective equipment.
Looking back on those summers in the groves, Wiygul wishes he would have known the dangers so that he could have better protected himself from chemical exposure. Today, the Environmental Protection Agency requires paraquat to be used by only certified applicators with full protection.
“I really screwed myself up with this stuff,” said Wiygul. “I truly believe that, in my case, paraquat is attributed to some of my problems.”
His role with Florida Citrus Mutual had Wiygul in close contact with Caruso. The industry is a tight-knit community working together across the state to bring iconic Florida citrus and juice to the market. Wiygul saw what Caruso went through and has seen other long-time citrus workers follow not far behind.
“He was one of the nicest fellows I've ever met,” said Wiygul. “He was a smart businessman—he was a grower. He took good care of his people that worked for him.”
Lake Alfred Citrus Research and Education Center
A short drive south from Wiygul’s office at Florida Citrus Mutual is the Lake Alfred UF/IFAS Citrus Research and Education Center (CREC), UF’s oldest and largest off-campus experiment station. New Yorker writer John McPhee described it in his 1966 book “Oranges” as “an intelligence service for the citrus industry.”
There, the prominent citrus scientist Bill Castle, since named to the Florida Citrus Hall of Fame, spent decades in different groves conducting groundbreaking research. Castle worked with growers for 35 years, walking their groves and collecting fruit samples.
Castle conducted between 60 and 70 field trials over his career, collecting fruits from groves across the state with his bare hands, not knowing what chemicals he was being exposed to on each farm. Castle was diagnosed with Parkinson’s in 2018 but said he felt symptoms as early as 2015.
Chemical exposure has been an occupational hazard for researchers since the dawn of science; Sir Isaac Newton’s death has been attributed to mercury poisoning. In a famous modern case, Dr. Tim Greenamyre, a neuroscientist and physician who did groundbreaking work that linked the insecticide rotenone to Parkinson’s, developed the disease himself. Greenamyre worries his decades of exposure to rotenone and similar compounds in the lab may have caused it.
During his career at the CREC, Castle said he saw at least five of his colleagues diagnosed with Parkinson’s disease. “It was a big puzzle,” said Castle.
In the 1960s, Ortho weed killers, then owned by Chevron, were advertised for containing paraquat and sold for household use calling the herbicide a “crackshot” and a “revolutionary new chemical.” The state of Florida restricted paraquat’s use to commercial agriculture in 1970, but headlines as far back as the 60s highlight the controversy surrounding paraquat. The photos show researchers at the Lake Alfred CREC, including McCoy and Wheaton who have died with Parkinson’s, and Castle, who is living with the disease. (Photos courtesy of Lake Alfred CREC Library, graphic by Katie Shealy/WUFT News) (2000x1600, AR: 1.25)
The U.S. Centers for Disease Control and Prevention defines a cluster as “an aggregation of cases grouped in place and time that are suspected to be greater than the number expected, even though the expected number may not be known.”
Castle asked a supervisor if an investigation might be warranted, but the supervisor described the cases as coincidental. Castle wasn’t so sure but didn’t push the issue any further.
Okun remembers feeling the same way 25 years ago when he was an early-career neurologist and people came into his office concerned that something in their environment was causing Parkinson’s.
“When we think of orange groves in Florida, you know, at the beginning of my career… I saw all these people coming in from the citrus industry, and they would say, well, I have this, and this person has this, what do you think?” said Okun. “I would say, oh it’s just a coincidence."
Okun said he feels guilt and regret for approaching those conversations that way, especially considering what he knows now about environmental factors and their links to Parkinson’s.
Okun's patients brought up the same concerns that Castle did—that there seemed to be a higher incidence of Parkinson’s surrounding them at work, or in a neighborhood.
“People that are working on these orange groves, where they're spraying this herbicide over and over and over,” said Okun. “They're getting these huge exposures, and we're seeing clusters of disease.”
With stronger scientific research linking environmental factors and Parkinson’s, Okun said he believes it is more important than ever to report and study clusters to protect people going forward.
IFAS officials said in a statement to WUFT that “The health and safety of IFAS researchers is always a top priority.” Associate vice president of communications Chris Vivian and CREC lab director Michael Rogers both stressed that IFAS closely follows EPA and label guidance for use of all agricultural chemicals, though Rogers declined to discuss whether he had been approached about Parkinson’s among researchers and how the lab has handled any concerns.
“I have to speak for them when I say that I always wondered if it was more than a coincidence,” said Castle.
Growing Concern Over Paraquat
Paraquat was commonly “the herbicide of choice” for weed control in Florida’s citrus groves. Back when Caruso and Wiygul were teenagers working in the groves, it could be used by anyone. But amid greater understanding of its dangers in 2016, the EPA restricted its use to certified applicators.
Brett Bultemeier, director of the UF/IFAS Pesticide Information Office, explains how important it is to take gloves off properly after paraquat application to avoid spreading the chemical to exposed skin. (Katie Shealy/WUFT News) (5184x3456, AR: 1.5)
The stricter regulations include requiring applicators to wear a long-sleeved shirt, long pants, shoes and socks, protective eyewear, specific chemical resistant gloves and an approved particulate respirator. Mixers and loaders must wear the same personal protective equipment plus a chemical-resistant apron and face shield—a far cry from Wiygul’s days of spraying in just a pair of shorts and rubber boots.
To ensure paraquat doesn’t touch exposed skin, it’s essential for applicators to follow protocol to a T when pulling protective equipment on and off, said UF agronomist Brett Bultemeier, Extension assistant professor and director of the Pesticide Information Office at UF/IFAS.
Paraquat applicators are required to be licensed to purchase or use the herbicide and must complete additional paraquat-specific training. Syngenta, the company that sells paraquat under its name brand Gramoxone, provides the only EPA approved paraquat training course in the nation. A second approved course offered by the National Pesticide Safety Education Center (NPSEC), was discontinued last year due to financial and logistical reasons according to Wayne Buhler, interim executive director of NPSEC.
This March, Syngenta announced that it will stop producing paraquat due to “significant competition from generic producers around the world, which has eroded Syngenta’s competitiveness in the production of this herbicide.”
The decision also followed the lawsuits and increased pressure to ban paraquat in the United States. In a written statement to WUFT, the company said it “maintains a commercial presence for paraquat in select strategic markets.”
Syngenta manufacturing site in St. Gabriel, Louisiana, where the company makes Gramoxone, its paraquat herbicide. (Katie Shealy/WUFT News) (2657x1771, AR: 1.5002823263692828)
UF’s Bultemeier is concerned about who will provide the paraquat training once Syngenta doesn’t have a stake in producing the herbicide.
“There are other manufacturers of paraquat, but they must still abide by all of the rules,” said Bultemeier. “I did become concerned about the training because knowing that there is one training and Syngenta is the one that has the training—what is their interest in continuing?”
In its statement to WUFT, Syngenta wrote that the company recognizes its paraquat training program is essential to certified applicators across the country. It will continue to provide the training while Gramoxone inventories still exist. In the meantime it is evaluating options to transition the program to another host to ensure continuity.
Calls for a ban
Okun is among a number of neurologists, along with the Parkinson’s Foundation, the Michael J. Fox Foundation, and other advocates, calling on the United States to join 74 other countries in banning paraquat.
“How much do I think Parkinson’s disease is preventable—I think a ton of it is,” said Okun. “Diseases have causes. When we find the root causes, that’s how we can prevent diseases and also develop treatments.”
The EPA has declined to ban paraquat when weighing the agricultural benefits of the herbicide against the risks to human health when used according to safety protocols with the proper protective equipment.
Agroecologist Alex Stuart, an international project manager at Pesticide Action Network UK, said while many in the agriculture business still see paraquat as “the herbicide of choice,” the health concerns mean that’s no longer the case.
“There’s this perception that there’s more labor required or that it’s just not feasible, but there are loads of other options available,” said Stuart. "Paraquat has been banned in the U.K. since 2007, and that has led to no yield decline, as we’ve seen the same in other countries.”
Parkinson’s changed the lives of Steve Caruso and others who spent years in Florida’s groves. While no one can be sure whether environmental exposure is to blame, a common thread ties them together.
“I just feel like that's the chemical that gave Steve Parkinson's,” said Jill Caruso. “I really feel like that. I’m really afraid of all these chemicals.”
This story is part of Poisoned Pathways, an investigation into chemical exposure and Parkinson’s disease supported by the Pulitzer Center and reported by the WUFT Environment & Ag Desk at the UF College of Journalism and Communications.
(3125x313, AR: 9.984025559105431)