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Researchers Appear Close To A Remedy For Citrus Greening Disease


When you think about oranges and other citrus, Florida comes to mind. But a disease known as citrus greening has devastated the state's $10 billion industry, and the disease has spread to other states like California and Texas. But now, as Amy Green of member station WMFE reports, researchers think a cure is close.

AMY GREEN, BYLINE: The key to saving Florida's citrus industry might be this single tree, which is outside of Lakeland.

JUDE GROSSER: This tree has had citrus greening disease for about five years, and you can see that it's exceptionally tolerant.

GREEN: That's Jude Grosser describing what he calls the mother tree. It's large and lush, not at all like the sickly ones in this grove at the University of Florida Citrus Research and Education Center. This place is the world's largest devoted to a single crop and considered the front line in the fight against citrus greening. The disease renders fruit unusable by weakening and killing trees. Grosser helped develop this tree through conventional breeding. What excites him is that its offspring is similarly tolerant.

GROSSER: We've picked five or six 90-pound boxes of fruit off of this tree the past two years. And we've actually been sending it to Gainesville for Christmas gifts to the university administrators.

GREEN: The tree is among several that stand to be what everyone in the U.S. citrus industry dreams of, a silver bullet for citrus greening. In hardest-hit Florida, the disease has been unstoppable. Citrus growing acres have dwindled, reducing production by 70 percent from the industry peak nearly 20 years ago. It's decimated the leading crop in the state, which is second behind Brazil in oranges for juice.

Greening is spread by a tiny insect called a psyllid. It's been so unrelenting many believe the cure will be entirely new citrus trees developed through conventional breeding or genetic engineering that are resistant to greening.

MICHAEL ROGERS: There's a lot more hope now than we've had in the past.

GREEN: Michael Rogers directs the UF Citrus Research and Education Center.

ROGERS: When you think about five years ago where we were, not knowing if and when we were going to be able to identify a potential solution, now I think we're much closer to having that potential solution definitively identified and in the hands of growers.

GREEN: The problem is these trees face years of testing. That's why researchers like Ed Etxeberria are working on short-term remedies.

ED ETXEBERRIA: We have to find a way in which the antibiotics penetrate into the plant so they can act and cure the disease. So in this way, it's where I come in with a laser machine.

GREEN: Exteberria developed a machine that uses lasers to pierce the leaves, making way for an antibiotic injection similar to a person getting a shot. He demonstrates a smaller version in his lab. A tractor will tow the machine through a grove while its six arms fire the lasers, deliver the antibiotic and seal the wounds with a waxy substance.

I'm imagining this, like, Medusa-like...

ETXEBERRIA: ...Medusa-like, you're absolutely right. Yes, (laughter) that's right. It's like - you know, like a spider.

GREEN: A cure can't come soon enough for people like James Shinn, a fourth-generation Florida grower. He's sad as he walks through rows of citrus trees left bony and dying by greening.

JAMES SHINN: The problem we all have in this industry right now is we're running out of money. And if we're - if it's costing us more money to produce a crop than we're getting in sales, which it is at this time, we're running negative. And you can only run negative so many years and still be considered as a viable industry.

GREEN: Shinn has abandoned three groves and turned to peaches to help sustain his business. But he is a citrus grower and hopes one day to replace his peaches with new, greening-resistant trees. For NPR News, I'm Amy Green in Orlando. Transcript provided by NPR, Copyright NPR.

Amy Green
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