Saturday, Oct 25, 2014
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Citrus conference focuses on greening


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AVON PARK - It was ultimately a discussion of getting rid of useless minerals to stave off damaging citrus greening.

Tuesday at South Florida State College, almost 350 citrus growers from around the Florida attended a conference on crop root damage caused by high levels of acid-neutralizing bicarbonates in irrigation water, which encourages greening-like root damage in citrus trees. The result is it makes it harder for trees to take in soil nutrients, possibly causing another season of high instances of bad fruit falling to the ground before harvest, which happened during over the last two years.

Held in the school's theater, the conference was part of the 2014 Florida Citrus Growers' Institute and was led by Kelly Morgan, associate professor of soil and water science department with the Immokalee branch of the University of Florida Institute of Food and Agricultural Sciences (IFAS). Morgan, who has been with IFAS for 24 years, explained Thursday the conference was to explain short- and long-term solutions to the problem associated with the bicarbonates and greening, which shrinks a tree's root system. He said short-term fixes is the use of fertilizers and nutrients, while long-term solutions would include engineering genetic resistance to develop tolerance and continue to produce.

Morgan, who provides growers of Florida with science-based information on improved soil fertility and water management methods, said genetically-engineered resistance is "off in the future." He said the main goal is to curb and ultimately eliminate greening, which has cost Florida's economy an estimated $3.65 billion in lost revenues and 6,700 jobs since 2006 by reducing orange juice production, according to an IFAS study.

The U.S. Department of Agriculture recently projected the 2013-14 Florida orange crop to be 114 million boxes, and estimated the Valencia orange drop at 26 percent due to citrus falling off the tree before it's ripe enough for harvest and putting Florida's $9 billion a year citrus industry at risk. Florida growers picked 162.5 million boxes in 2009 but has gone down with greening -- a lice-caused bacterial disease that reduces fruit production and kills trees.

The conference mostly focused on root damage. He said bacteria is injected into root systems by the lice, called "psyllids," which sucks on root systems' juice or sap.

"It's like malaria with a mosquito and it spreads from one (tree) to another," said Morgan, who added almost all of Florida's 100,000,000 trees on 500,000 acres of citrus land is affected to some extent, up to 100 percent in the southern growing zones and 50 percent in northern counties such as Polk and Lake. "The goal was to look at ways to deal with the disease. Now, growers are producing less than half than they were four to five years ago."

Highlands County has approximately 63,000 acres of citrus groves, roughly 13 percent of the county's 1,000 square miles of land.

Ray Royce, Highlands County Citrus Growers Association executive director, said although he wasn't able to attend the conference, he saw the program and was sure attendees took valuable information to the groves. He said information that gives a good overview of greening contributors is important and that "stressors" such as acid-neutralizing bicarbonates foster greening.

"The tree is stressed so the effect of greening becomes more pronounced," he said. "It's critical that we manage any and all things that may put stress on the trees."

The problem with irrigation water containing bicarbonates - minerals of no to use the tree - is that they neutralize acids emitted by tree roots that help absorb nutrients from the soil. Morgan said before growers see the first signs of greening on leaves, the tree has probably already lost 30 percent to 50 percent of its root density, and up to 70 percent to 80 percent of the root system is gone in advanced cases.

Morgan, who is also involved with soil nitrogen and phosphorus availability, said another effect of bicarbonates is the pH - the measure of the acidity of a water solvent - has been increasing over the last three to four years. He said citrus produces best in soils between 5.5 and 6.5 pH but some irrigation water in groves statewide are over 7.5 pH. Morgan said oil bicarbonate levels rise with the use of high-alkaline water.

"We've now come up ways to treat irrigation water with highly-diluted (sulfuric) acid to reduce the pH of water and the soil. We can accomplish this; we have growers doing it already," he said. "We're seeing a positive effect. We're seeing them growing better and producing better. Yields are increasing because of the lowering of the pH of the soil."

Joe Davis Jr., president of Davis Citrus Management, Avon Park, attended the presentation. He said he got a lot of valuable insight into curbing greening, which whenever trees show yellowing above ground, usually a third of the root system is already infected and after two years, a tree begins to wane quickly.

Davis Citrus, started 50 years ago by his father, Joe Davis Sr., has about 350,000 trees on 2,500 acres in Highlands, Polk, Hardee and DeSoto counties. Davis Jr. said the conference was valuable in learning to prolong the life of roots.

"It was about keeping the roots healthy to keep the groves economical and profitable and to keep from losing an entire grove," he said. "I thought there was a lot of good ideas about focusing on root health,"

pcatala@highlandstoday.com

(863) 386-5855

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