ON 15 ACRES at Howey-in-the-Hills in Lake County, a citrus grove once abandoned by its owner has new life, witnesses say. Hamlin orange trees with obvious symptoms of greening are growing healthy, new leaves.
“My goal was just to make a perfect, healthy living soil,” explains Ed James, owner of J & R Groves. “By fixing the soil, all of a sudden the trees started getting fixed. The byproduct of healthy soil was a healthy tree.”
After rebuilding his soil for more than five years, the 30-year citrus veteran says he sees a “viable future” for his grove— and is planning to replant his additional 15 acres with citrus. “It works for me,” he says. “I’ve seen it.”
Florida’s citrus industry has been under siege since citrus greening, also known as HLB or Huanglongbing, was first discovered in South Florida in 2005. Growers have been battling the disease with aerial sprays to kill the Asian psyllid, plus nutritional sprays, denser plantings, new varieties, and even a protective covering for trees designed to keep out psyllids.
Some tactics have helped, but nothing has provided the ultimate solution to greening.
Jim Syvertsen, University of Florida Emeritus Professor of Plant Physiology and Field Trial Program Manager for Citrus Research and Development Foundation / Commercial Product Development Committee says other growers also have been experiencing some measure of improvement with what he calls the “spoon feeding” of water and nutrients. “I can attest that I have seen partial recoveries in different blocks around the state,” he says.
“Nobody I know of has been achieving yields in the presence of HLB equal to the yields they were achieving 10 years ago before HLB,” Syvertsen says. His study of five microbial soil amendments during a three-year period shows no benefit to trees infected with greening, although there was a benefit to uninfected trees. Few of the microbes survived; it was difficult to recover them from the soil after three years of applications, he observes. “I don’t doubt at all what he’s seen is true,” he says of James. “Whether or not the trees will recover to the point where there will be a profitable yield— that’s another issue.”
Andrew Meadows, director of Communications for the Bartow-based growers’ cooperative, Florida Citrus Mutual, says, “I can say we hope all proposed solutions work and the industry is exploring everything, including soil treatments.” At this point, enthusiasm is the result of what people are seeing at James’ grove. One witness is Graeme Sait, the Australian owner of Nutri-Tech Solutions, who travels the world teaching about nutrition farming. He visited James’ farm December 1 after teaching a four-day class in the area at the request of Guardian Soil Solutions. “We drove past grove after grove that looked like a holocaust,” he says, describing the James farm as an “oasis” and a “completely resurrected grove.”
“You can barely tell they have the disease,” he adds. To him, the solution is in soil health. For example, one nutrient missing in Florida soil is sulfur. “If you haven’t got sulfur, you can’t fight off disease,” he explains.
Another witness is Dr. Ki Kim, an entomologist with the independent research firm Florida Ag Research of Thonotosassa, who visited the grove November 17. “I was stunned by the way it looked. All the citrus trees were already infected with greening. I could see the greening symptoms,” he says. “I think it’s kept in check, possibly by natural enemies, beneficial insects.”
While some of the leaves showed effects from greening, the new growth was “perfectly fine,” he reports. The fruit looked “very good,” he continues. “I did see some dropped fruit. There was a good number of fruits on the tree still.” “I think they are recreating the original community of beneficial insects that we used to have,” he says.
For growers with infected trees that are hesitant about continuing to spray insecticides, a rolled down cover crop program may be an alternative. Another visitor to James’ grove is Dr. Johan Desaeger, a nematologist for the University of Florida at the Gulf Coast Research and Education Center south of Balm. “What I saw was trees that looked healthy,” he says. “I saw a grower that was happy with what he was doing.” A healthier soil could have an impact on citrus roots. “You have to have a healthy root system,” Dr. Desaeger says. “One way to increase your system is to add more organic matter to the soil.”
Citrus greening has taken a toll on the state’s citrus industry, which has an economic impact of $8.6 billion annually. Researchers have been hard at work to find a cure while developing more greening tolerant varieties that will— at the very least— buy the industry time until that cure is found.
by CHERYL ROGERS
Reprinted in part from CentralFloridaAgNews.com