New mechanical harvest options

A number of issues are driving the move toward mechanical harvesting of fruits and vegetables. Labor issues continue to be high on the list of driving forces and include cost, availability and quality of that labor. Little doubt exists among growers that they must continue adapting to a changing labor scene. Fewer workers and increasing labor costs are the reality that growers face in their operations. Growers are facing aggressive competition from countries where labor costs are much lower. Research programs that look for new mechanical harvesting technology, new variety development and new planting modes suited to mechanical harvesting are increasing.

Developing systems that will help growers remain profitable and encourage them to continue producing food products is gaining momentum. Interagency research is increasing, and private industry is stepping up its efforts to improve existing mechanical harvesting equipment. Greater efficiency and more versatility in mechanical harvesting equipment is attractive to growers, and equipment that can be used to harvest more than one crop is a much better investment than a single-use harvester.

Trash is sorted by a chile cleaning machine, reducing extensive sorting by hand.

A new model of a commercially available berry harvester, along with prototype sweet cherry harvester and a chile machine, both expected to be commercially available soon, as well as a new model for citrus planting that would allow existing equipment to be used in citrus harvesting, are helping guide the move to increased mechanical harvesting that will help growers become more competitive in an increasingly global market.

Florida citrus mechanical harvesting field tested

While disease outbreaks can be devastating to growers and to an entire industry, the greening disease that hit Florida orchards in recent years may have inadvertently led to a more concerted effort toward developing mechanical harvesting equipment for citrus.

Dr. Reza Ehsani, associate professor, agricultural and biological engineering, University of Florida (, cited one positive outcome of the greening disease outbreak. Ehsani said, “Growers began to think that maybe they can’t plant a tree and expect to harvest it for 40 years, that maybe they should plant high-density orchards, smaller trees in higher numbers.” The greening disease may have actually presented opportunities for mechanical harvesting to become a major focus with the development of an integrated system that is suited to mechanical harvesting. Mechanical harvesters have been designed to harvest traditional orchards. Ehsani noted that mechanical harvesting technology for citrus harvesting was developed in the 1960s with trunk and canopy shakers. Neither mode was widely adopted.

“Growers were reluctant to use the shaking technology because they feared damage to their trees. Currently only about 6 or 7 percent of Florida citrus is harvested mechanically. The machines are very expensive and very large,” Ehsani said.

“It’s much easier to design a smaller machine for the smaller trees. We just did some field tests using both an Oxbo olive harvester and a BEI blueberry harvester. Our preliminary tests indicated that using existing over-the-row harvesting equipment, such as those for olives or blueberries, it is possible to harvest dwarf citrus trees. Both systems need some modifications before adopting for citrus harvesting.”

An over-the-bush Oxbo olive harvester provided good harvesting results for dwarf citrus trees in UFL trials.

Sweet cherry mechanical harvester

With a multicomponent approach, Washington State University is addressing a complex issue of helping to sustain the sweet cherry industry. Dr. Matthew Whiting, WSU director of the sweet cherry research program ( noted that labor issues are spurring the sweet cherry research program’s work in developing a sustainable production, processing and marketing system. Whiting cited not only increasing labor cost and availability but also concern in the industry about the quality of labor. For example, aging labor crews may include less experienced or less dedicated workers. “These succeeding generations may not be as methodical or efficient, and may not pick a clean crop. This can greatly lower the value or actually cause the crop to be rejected,” Whiting said.

As part of the USDA Specialty Crop Research Initiative, development of a total system is under way with a mechanical harvester a primary component. Whiting said, “We collaborated with Don Peterson, now retired USDA engineer. Peterson and USDA technician Scott Wolford worked on the development of a mechanical harvester at USDA Appalachian Fruit Research Center, Kearneysville, W. Va.

“We’ve made some improvements to the catching frame, improving the efficiency of the system,” Whiting said. “We’re looking at remote operating, allowing better visibility for the driver. He is now in a fixed position, making it difficult to see the point of contact.”

The machine has been used in commercial orchard trials this year. Further refining of the machine is expected as it goes into commercial development in the coming year at Vinetech Equipment, Prosser, Wash.

Trash in harvested chiles must be removed before they reach market.

Chile cleaning machine aids mechanical harvesting

Labor costs and availability are major concerns to the New Mexico chile industry, and competition from imports of chile grown in countries with drastically lower labor costs and few regulations threatens the chile industry. Chile acreage is down from 34,500 in 1992 to 8,500 acres this year. The entry of a chile cleaning machine into the mix of mechanization of the chile industry is encouraging news to growers. Developed at New Mexico State University’s Manufacturing and Technology Center (M-Tec) (, the chile cleaning machine prototype has been through a number of revisions. It has been used in commercial chile harvests and is expected to go into commercial development in the private manufacturing sector soon.

Improvements to the earlier designed sweet cherry harvester allow improved efficiency.

Ryan Herbon, M-Tec engineer, is managing the project and has worked on the development of a number of technical aspects of mechanizing the chile industry including the recent chile destemming machine. A series of design elements incorporate shaker technology that allows the chile to be carried into troughs where it is routed for processing. Stems, twigs and leaves, known as trash, are major issues in mechanically harvested red chile, and hand sorting of trash from the harvested chile crop is a labor-intensive component of the harvest process. “There’s a lot more difficulty with trash in the harvest after frost occurs,” said Herbon. Chile plants become more brittle, breaking more easily and dropping into the harvested chile.

Jaye Hawkins, executive director for the Chile Association, noted that the while the currently downturned economy has resulted in more workers available for the chile harvest, mechanization remains a primary need for the industry. The New Mexico Chile Association is the major funding source for development of a system that includes new variety development that works well with mechanical chile harvesting.

Nancy Riggs is a freelance writer and frequent contributor. She resides in Mount Zion, Ill.