Editor's note: A special thanks to Dr. Monica Ozores-Hampton for coordinating The Immokalee Report.

Mechanical citrus harvest is still needed but with less shakingTen 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.

Unless one is completely fatalistic about the Florida juice orange industry, establishing commercially viable mechanical harvesting systems remains an important goal. Citrus greening, while a key factor in the recent demise of mechanized harvest, is also the number one reason why the Florida juice industry needs mechanical harvesting.

Citrus Research and Education Center citrus economist Ron Muraro documented a 125 percent, or $1,000 per acre, increase in production costs since greening took hold in 2006. Yes, in recent years, growers of juice oranges have been enjoying historically high fruit prices, but the uncertainty of whether these prices will hold into the distant future should drive growers and juice processors to develop new technologies that reduce production costs.

Mechanical harvesting remains the one area where the largest reduction in costs could occur.

Resolving the issues surrounding the abscission compound, CMNP, and carrying it through the Environmental Protection Agency registration process may allow existing equipment to operate with negligible tree damage.

UF agricultural engineers Reza Ehsani and Tom Burks are making progress to develop fruit pick-up machines, over-the-row harvesters and beater rods that lessen structural damage to the trees.

New equipment designs with or without CMNP could still revive mechanical harvesting and bring significant financial benefits to Florida citrus growers.


Dr. Fritz Roka is an associate professor and economist in the Food and Resource Economics Department based at the Southwest Florida Research and Education Center. He can be reached at fmroka@ufl.edu.