by MEREDIT BAUER-MITCHELL, UF/IFAS
A much-anticipated research project on citrus greening is coming to fruition, marked by the start of another harvest of a key citrus grove in Fort Pierce.
Harvest on the Millennium Block project, a seven-year University of Florida research project is underway, and researchers will use the data collected from fruit harvested from 2022 to 2026 to analyze how much these potential solutions offer farmers hope against citrus greening, with results expected later this year.
The damaging crop disease has decimated Florida orange and grapefruit groves, reducing production across all citrus-growing regions, reaching over 80% of the state’s citrus, and the Millennium Block was envisioned as a place where bold risks could be taken in the fight against citrus greening. The Millennium Block, which was planted at the UF Institute of Food and Agricultural Science’s (UF/IFAS) Indian River Research and Education Center (IRREC), in 2019, is now a 5,000-tree research project with trees that were bred to be tolerant to citrus greening, said Flavia Zambon, assistant professor of citrus production at UF/IFAS IRREC.
Citrus greening, or Huanglongbing, remains one of the most destructive challenges facing Florida’s citrus industry. Spread by a tiny bug called a psyllid, the bacterium that causes the disease attacks trees from the inside out, reducing fruit quality, yield and ultimately killing entire groves. Infected trees produce smaller, misshapen and bitter, green fruit – if they produce any at all. The disease spreads quickly through the flying insects, making containment difficult once a grove is infected.
“Citrus greening is a fundamental threat to the Florida citrus industry, and we’re eager to see the results of this long-awaited research trial to see what options we can suggest for farmers for greening-tolerant citrus varieties,” Zambon said.
The Millennium Block includes various citrus varieties in four research trials, one including 18 grapefruits and three commercial rootstocks, and the other three with 32 rootstocks grafted with Ray Ruby grapefruit, Glenn Navel sweet orange and UF-950 mandarin.
Harvest will continue through early February, and citrus will be pulled and juiced to be tested for physical marketable qualities, such as size, and juice quality attributes, such as sugar concentration and acidity, which affect the price that growers can expect to receive for their fruit.
“There are all these attributes that need to be in balance for both growers and consumers,” Zambon said.
In addition, they will evaluate the amount of market-quality citrus grown, both by the amount of fruit and by the total weight.
Researchers also used drones to evaluate the health of the Millennium Block’s trees and to see if there is a correlation between canopy size and the amount of fruit it produced – another potential predictive tool for farmers.
Maintenance for the Millennium Block is funded in part by the John T. Moose IRREC Enhancement Endowment.
Provided by UF/IFAS