Invasive insect threatens iconic Florida citrus

By Tamara Lush

Associated Press

Published: Sunday, Aug. 24 2014 12:00 a.m. MDT

Experiments study everything from how fast the psyllid flies to how it's attracted to the odor of an infected tree. One French researcher has tied the bug to a string and a post to measure its flight patterns. Another study, underway at an organic grower's groves, assesses whether tiny wasps can be released en masse to gobble the bad bugs.

For three decades, horticulture professors Jude Grosser and Fred Gmitter have worked at the center, mostly studying citrus breeding and genetics. The two men are rock stars in the citrus world because of their vast knowledge. Now, much of their focus is on greening.

Grosser and Gmitter have discovered that a certain variety of orange trees grafted onto one particular kind of rootstock appears to be more tolerant to greening. Those trees could play a big role in managing the disease down the road.

"A lot of people are looking for miracle cures, but the answer for greening will be a number of different pieces," Grosser said.

The pair want a solution and fast. They've spent their careers developing different fruit varieties, such as easy-to-peel and extra-juicy oranges. Some varieties are nearly ready for release and sales, they said, but most growers don't want to take a chance on anything new until greening is gone.

"We need to give the tree a chance to beat the disease," said Grosser. "How can we do that?"

Since 2008, $90 million has been spent in Florida on greening research, much of that money raised by growers from a tax they pay on every box of citrus that's picked. And the 2014 federal farm bill included $125 million for greening research.

Growers are also taking matters into their own hands. Some have tried putting giant tents over their trees and using the sun's heat in an attempt to kill the greening.

Rick Kress, president of Southern Gardens Citrus, one of the state's largest juice suppliers, has hired a private team of researchers to work on genetically engineering a greening resistant tree with the DNA from spinach.

Kress knows that introducing juice from a genetically modified orange would create another hurdle because of the public's perception of such foods. But the alternative — no juice at all — is unthinkable.

"Irrespective of the challenges, Florida orange juice is not going to go away," he said. "Because Florida had the disease first, we're on the forefront of dealing with it and finding a solution that will ultimately benefit the entire United States citrus industry."

California growers, who raise the majority of the U.S.'s fresh citrus crop, are also petrified of greening. The psyllid has been found in various places around that state, and greening was detected in one residential tree in Los Angeles in 2012. California researchers are doing their own experiments and piggybacking on the Florida research. In Texas, greening has struck fewer than 200 commercial trees, and the disease has not been spotted in Arizona.

In Polk County, Hunt has been planting new trees to replace the diseased ones. He realizes that this is a gamble; psyllids prefer to munch on young, tender leaves. But if he can keep the bugs away long enough for the new trees to grow and bear fruit, maybe by then researchers will have found a solution to greening.

"We can't let this thing go down on our watch," he said.

Hunt had always hoped his family's younger generation would one day take over the business. But now he worries that Florida juice could become a niche product, similar to pomegranate juice. It's something he's reluctant to contemplate.

"You don't want to put your head in the sand and say everything's OK. It's not OK," he said. "But you have to get up in the morning and go to work believing that we will win the battle."

Follow Tamara Lush on Twitter at http://twitter.com/tamaralush

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