Florida Citrus Greening Scenarios are Explored

Florida Citrus Greening Scenarios are Explored

006During the next decade, Florida orange production could sink by another two-thirds unless better solutions to the fatal bacterial disease citrus greening aren’t found.

That’s the worst-case scenario presented recently to the Florida Citrus Commission in a new, long-term citrus production forecast by Marisa Zansler, chief economist at the Florida Department of Citrus, and Tom Spreen, emeritus professor of agricultural economics at the University of Florida and a department consultant. The commission is the Citrus Department’s governing board.

Spreen presented three forecasts based on different computer models of the future, including one based on no research breakthroughs on greening and no change in current production trends, such as declines in yield, or the boxes of fruit harvested per tree, and in the shrinking number of trees and commercial grove acres.

The pessimistic model projects Florida growers harvesting 27.3 million boxes of oranges in the 2026-27 season. That compares to 81.6 million orange boxes harvested in the recently completed 2015-16 season and 242 million boxes in 2003-04, the last season unaffected by greening or hurricanes.

“I hope that scenario is not more likely,” Spreen said. “It’s a very scary picture. There’s no other way to put it.”

One factor affecting yields on greening-infected trees has been a significant increase in the levels of pre-harvest fruit drop, which began appearing in the 2011-12 season. Other factors include smaller fruit size, which means more fruit to fill a standard box, thus a lower total harvest.

But the most optimistic scenario makes some big assumptions, including investing at least $500 million in planting new trees at a 255 percent replanting rate over the number of trees lost each season, he said. Growers would need to sustain that rate every year over the next decade.

The current replanting rate is 50 percent, largely because many growers are unwilling to make the investment until researchers find better methods against greening.

Even at that aggressive replanting rate, Florida growers would produce just 100 million orange boxes in 2026-27, or less than half the production 12 years ago.

Florida growers can achieve the optimistic scenario, said Spreen, citing high levels of replanting in the late 1980s and early 1990s following three major destructive freezes in 1983 to 1989.

But it would take a scientific breakthrough in breeding a new citrus tree that is tolerant or resistant to greening, he added. Tolerance means the tree would get infected but suffer less damage, notably yield loss, and resistance means the tree would be less susceptible to infection.

“We just need that light at the end of the tunnel to show up, and then we’ll see a burst of new planting similar to what we saw in the 1980s,” Spreen said.