Arlington, Va. — The citrus industry and the U.S. Department of Agriculture are uniting to defeat citrus greening, but victory against the bacterial disease that first appeared in Florida in 2005 is still years away.
A workshop at the USDA Agricultural Outlook Forum on Feb. 21 looked at citrus greening and the future of the citrus industry, and panelists said Huanglongbing (citrus greening or HLB) has had a rapid and destructive effect in Florida. The disease has spread to other citrus growing regions of the country, but it has not had as devastating an effect on other areas.
While some believe the Florida citrus industry could be in serious peril of collapse within a few years because of HLB, researchers said finding genetically modified citrus trees immune to the disease could take a decade before commercialization.
Citrus greening was first identified Florida in August 2005, said Ed Stover, researcher with USDA Agricultural Research Service, and up to 70% of the state’s citrus trees are now infected. Within a few years of infection, many citrus trees become weak, have poor quality fruit, and heavy fruit drop, he said. Eventually infected trees may die or become useless, Stover said.
Florida’s citrus output has dropped from about 30 million field boxes in 2000 to about 15 million boxes in 2013-14, he said.
“It is getting worse all the time,” he said.
While there was optimism a few years ago that nutritional solutions could provide an answer, that optimism is slipping away, he said.
Some reports indicate up to 40% of the Florida citrus crop dropped from trees before harvest last season. Yield losses pinned on citrus greening in Florida have been pegged at $300 million annually. Growers are spending $500 per acre to fight citrus pests, said Prakash Hebbar, with the Citrus Health Response Program with the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service,
Panelists said the solution to citrus greening — spread by the Asian citrus psyllid — could involve either genetically modified insects or genetically modified citrus trees, researchers said, but other short- and medium-term solutions also are being pursued.
“I think there will be a series of solutions that will evolve over time,” Stover said. “In terms of transgenics there is a group of trees that have two different spinach genes produced by Erik Mirkov of Texas A&M University that are out in field trials that are reported to have significant levels of resistance,” Stover said.