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Florida's Greening Disease Forces Farmers To Grow New Crops

Oranges in crisis: As an iconic Florida crop fades, another tree rises!

Greening disease, which causes trees to produce green and bitter fruits, has infected nearly all of Florida's groves. Even ripe oranges from infected trees have become smaller and less succulent. Citrus growers in Florida are facing some of the toughest challenges yet with their crops. Last year, the citrus industry’s crop was one of the smallest since World War II, due to a bacterial disease called citrus greening and an extremely rough hurricane season.

Citrus greening, also known as Huanglongbing (HLB), is a bacterial disease that affects orange trees and can ravage groves and nurseries. The disease can turn fruit green and misshapen and cause a bitter taste. No cure exists. But officials are hopeful that a newly discovered Donaldson tree could offer a reprieve to citrus growers struggling with greening, according to Ben Rosson, the bureau chief of Florida’s Department of Agriculture and Consumer Services.

“(Citrus greening) has truly been the most devastating disease that we have had in our industry," Rosson said. "And couple that with the hurricanes that we've had come through the last couple of years…that's the reason why the crop is so low this year." Growers found the tree by chance while giving a tour of a farm in Groveland, located in central Florida. A citrus farmer noticed that the Donaldson tree was still producing fruit and acting differently than other trees in the grove. "They did some fruit test to determine the Brix/acid ratio and determined, 'Hey, it's good fruit, is there something here?'" Rosson said. "This tree has been here over 30 years. It's surviving. It's holding on. It's doing well."

Officials also found that the Donaldson tree is continuing to produce fruit despite being infected by citrus greening. “It's still growing, it still has a good canopy on it. And the fruit is still good. It doesn't have the fruit drop that a lot of our early varieties have now,” he said. The hope is that the new tree will help rectify some of the problems seen in Florida's most precious crop since 2006, when citrus greening was first found. Rosson said around 200 million 90 pound boxes of oranges — the industry's standard measurement — were harvested that year.

That's compared to just over 41 million boxes in the 2021-2022 season, and a forecasted crop of 16.1 million boxes for the 2022-2023 season. Hurricanes Ian and Nicole pummeled citrus groves during last year's growing season, adding to an already weak crop. Rosson says registered citrus nurseries have each received two Donaldson trees from the state, and are now working towards getting them out to other growers. In 2004, Florida had an estimated 7,000 growers. Today, there are about 2,000. If the latest estimates hold, the state’s current growing season will yield 61% less fruit than last season.

In India, Australia, and parts of southeast Asia, pongamia grows wild as it bears little beanlike pods that, in India, are crushed and used for lamp oil. Terviva hopes to corner the tree’s American market; their plan, use it for biofuel production, fertilizer feedstock, and a more sustainable alternative to soybeans for protein.

Like citrus, pongamia grows in Florida’s unforgiving sandy soil. Unlike citrus, though, pongamia is mostly pest-resistant, has a lower cost of production, is drought-resistant, and can withstand wet conditions, and it requires minimal inputs. In fact, it requires a fraction of the irrigation necessary to keep citrus trees healthy. And unlike labor-intensive citrus, the pongamia can be harvested using a mechanized shaker. Pongamia trees produce a seed that looks a lot like a lima bean and acts like a soybean. The seeds are pressed to produce an oil that has a bactericide that can be sprayed on organic commodities for crop protection. The bactericide can be removed from the oil, which allows the oil to be used in food applications.

One of the challenges of the crop, grown in India, is that it blooms at different times, making efficient harvest difficult. The challenge for Terviva and other proponents of pongamia trees is trying to get them to bloom at the same time, and researchers have been working on finding varieties that do bloom at the same time



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