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Science / Space

The Battle Against Citrus Greening

Robin Sussingham

Agriculture Commissioner Adam Putnam calls citrus greening "as bad a situation as it could possible be for Florida signature crop." That's why the state's citrus farmers have spent more than $60 million of their own money over the last seven years to save their crops. Lake Alfred, in Polk County, is headquarters for intense research efforts to cure citrus greening.The $9 billion Florida citrus industry is counting on these scientists for a solution, and  the pressure is on.
All the 250 employees at the University of Florida's Citrus Research and Education Center are -- in one way or another -- focused on the same thing: the eradication of citrus greening.
Dr. Harold Browning heads the foundation charged with funding research at the center and at the other universities doing work on greening. For the 6 foot five former college basketball player, it's now crunch time in the battle to save the industry. "Growers really need help, right now," he says.

Citrus greening is a terminal disease. When it infects a tree, its leaves yellow and branches die back. The fruit becomes bitter and unmarketable. They fail to ripen -- staying green -- and drop to the ground.
The citrus research center was established in 1917, in the heart of Florida's citrus industry. There are more than 40  laboratories, plus greenhouses, groves, and the world's largest library devoted to citrus.
Browning shows me around a concrete block building that home to the citrus nutrition labs. In the absence of an actual cure, a big push for growers is to try to make sure the tree has optimal nutrition, so it might withstand infection.

The bacteria that causes greening is spread by a tiny insect, called a psyllid. Scientists in the center's entymology labs are trying to learn as much as possible about that insect, and how to control it.
"This lab is working on transmission of pathogen by the insect vector,"Browning says, "so they're looking at the timing of how long it takes for the insect to feed on the plant before they can pick up the bacterium."
Browning says the scientists who work at the center feel an unusual amount of pressure to be successful.
"There are a lot of expectations out in the industry, and they're unrealistic," he says,  "because they're forced by the need that they have. And the scientists who normally work in an environment where they're not being asked every day if they've solved the problem, are moving outside their comfort zone and making comments about progress before it's time."
Browning says that administrators need to protect the scientists, many of whom are quite early in their careers, from outside pressure.
"And if we didn't do that, there would be parades of people here very day wanting to know have we got a solution yet."
The urgency is understandable. Greening now affects every citrus-producing county in Florida. Growers are reported losses of up to 40 percent of their crop. And the most recent USDA estimate of next season's orange crop is down six percent.
The most immediate need is for some kind of therapy that can be given to an infected tree to make it healthy again. The long term goal is to wipe out the disease or find a way to make the trees resistant. Browning says the citrus research foundation is now funding 130 projects.
"Science isn't easy," he says, "and I tell people, this is a tremendously complicated system. We have every reason to fail. But we can't afford to."


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