The citrus teaching grove on the south end of campus is the last standing. All of the other citrus trees at the University of Florida are gone. These lone survivors on Hull Road are surrounded by a barbed wire fence.
The campus’ other 156 trees were uprooted because four showed signs of citrus greening. Greening is a terminal illness, and it spreads rapidly.
“There is no vaccine for citrus greening,” said Jason Smith, associate professor of forest pathology. “And if you don’t vaccinate a population, you’re putting others at risk.”
Citrus greening is a disaster for Florida citrus. It is spread when an Asian citrus psyllid, a tiny mottled brown insect, feeds on an infected tree, then nibbles into a healthy tree. Within a year, the fruit stops ripening near the stem. The shoots and veins turn a sickly yellow. The fruit shrinks in size. And the leaves take on a blotchy, mottled yellow-green pattern.
Since the disease was first detected in South Florida in August 2005, it has spread to nearly 30 Florida counties, including Alachua.
When Marty Werts was the grounds superintendent in the 2000s, he planted citrus trees on campus without official approval.
“My style…was to do what I wanted to do,” Werts, who is now retired, said. “And if I wanted to plant a tree there, I planted a tree there. I didn’t ask for permission. And that pissed a lot of people off. They say I’ve got one of those attitudes, you know?”
Back in 2012, UF students Jennie Fagen and Connor McCullough discovered greening in three campus trees while researching the disease. At the time, no action was taken.
When the conversation about citrus greening began again in Sept. 2013, Gloria Moore addressed the University Lakes, Vegetation and Landscape Committee about the problem on campus. She said that when she was on the committee six years ago, she warned Werts against planting the trees. She was concerned that the trees could infect the IFAS-maintained teaching orchard.
“You don’t just plant [citrus trees] in the ground and leave them,” Moore said. Commercial groves are being sprayed once a month with pesticides to keep the trees healthy, she said.
There were two options: spray the campus trees with chemicals monthly or remove them completely. The treatment is only preventative – it kills the psyllids but won’t heal the tree. It also leaves the fruit poisonous.
Smith feared that even if the sickly trees stayed on campus, students would continue to pick and try to eat the citrus. There is currently no organic treatment for greening.
“We’re very limited in terms of our ability to manage the campus,” Smith said.
That wasn’t always the case. Until 2007, Erick Smith (no relation to Jason) was UF’s urban forester. He “had his head in the trees every day, seeing what’s right and what’s wrong,” Werts said. “The university, in my opinion, lost something when they lost those guys.”
For the past five years, the Physical Plant Department grounds crew has taken over tree maintenance responsibility.
“It’s [citrus is] really high maintenance – more than what’s reasonable on a university campus,” Jason Smith said. “The grounds crew do what they can.”
The verdict was complete removal.
On Sept. 13, the grounds department began digging up the trees. By Oct. 8, all the citrus was removed. In the gouged earthy sockets, they planted apples, pears, magnolias and persimmons.
Just because the campus citrus is gone doesn’t mean that the teaching grove is safe. Since the disease is spread by an insect, any infected citrus in the area poses a risk for those remaining trees. All it takes is one psyllid sucking the sap from one infected orange tree to spread the greening.
“Taking the trees off of the campus doesn’t mean there will never be greening in Alachua County,” Moore said. “It just means we’re trying to make it happen a little slower.”
However, the citrus situation isn’t completely bleak. Kevin Folta, associate professor and interim chair of the horticulture department, sees greening as a teaching opportunity. This disease is training students how to prevent future outbreaks, he said, which could strike any fruit or vegetable.
IFAS is at the forefront of greening research. They are approaching the problem from all angles, searching for genetic managerial and nutritional solutions.
“I’m optimistic because I know the people working on the solution,” Folta said. “ I think we’re going to beat it.”