Editor's note: A special thanks to Dr. Monica Ozores-Hampton for coordinating The Immokalee Report.
click image to zoomCourtesy University of FloridaFritz Roka, with the University of Florida's Institute of Food and Agricultural Sciences, walks by a mechanical harvesting system being used in citrus groves near LaBelle, Fla. Ten years ago, the prospects for shifting the harvest of juice oranges from manual labor to mechanical systems loomed large. The Florida Department of Citrus was spending upwards of $2 million a year to develop new equipment and perfect abscission compounds.
University of Florida Institute of Food and Agricultural Sciences field days were attracting sizable crowds to listen and observe the latest developments in mechanical harvesting. Most importantly, mechanically harvested acreage increased from less than 6,000 acres in 1999 to more than 36,000 acres in 2004.
Trunk and continuous canopy shakers seemed to be making inroads toward becoming commercially viable harvesting systems. Many growers who used mechanical harvesting equipment reported that they were saving between 20 and 30 cents per box in their net harvesting costs.
These savings included the cost of gleaning crews, which worked behind the machines and ensured that upwards of 98 percent of the available crop was being harvested.
Mechanical harvesting helps cut production costs
Since 2004 mechanically harvested acreage has been dropping and rather precipitously in the past three years. Much of this reduction can be attributable to the one-two punch Florida citrus growers suffered that compromised the health of many of their trees.
First were the hurricanes of 2004 and 2005. Hurricane Wilma (2005), in particular, ravaged through southwest Florida where most of the mechanical harvesting was occurring. On the heels of these storms came citrus greening.
Even before 2004, many growers were leery about mechanical harvesting and the physiological stress that these machines imparted on their trees. Countering this fear was solid research by UF/IFAS scientists that consistently showed that well-nourished trees recover from nearly all injuries sustained during mechanical harvesting without loss of yield or productive life.
The analyses of grower records confirmed the research results that healthy trees overcame most, if not all, damage from mechanical harvesting equipment. The problem, unfortunately, is that the combination of hurricane damage and greening infection has rendered healthy citrus trees an endangered species in Florida.
The current management mantra among Florida growers is to relieve as much physiological stress on their trees as possible, and harvesting with existing mechanical equipment does not fit that objective.