Handheld cherry harvesters gain attention in study
Hooks, catch frames, bins to be tested in research project
By DAN WHEAT
WENATCHEE, Wash. -- Developing a good, handheld, shake-and-catch harvest system will be the primary focus of the final year of a USDA Specialty Crop Research Initiative to improve production and marketing of sweet cherries.
Various hooks to shake limbs, new catch frames and ways to get cherries into bins will be tested, according to Matthew Whiting, project lead and stone fruit physiologist at the Washington State University Irrigated Agriculture Research and Extension Center in Prosser.
Testing will include where shaker arms are attached to limbs, amounts of energy and variable rates of vibration.
Preliminary results show that two people operating a lightweight, handheld, shake-and-catch system can harvest 3 to 31/2 times faster than hand pickers, Whiting said.
Handheld units are the focus because they can be used in any cherry trees while a larger, shake-and-catch harvest machine can only be used in Y-trellis orchards, he said.
The handheld units are similar to those used in olive harvest, he said.
WSU, Oregon State University, Michigan State University and the University of California are involved in the four-year, $3.9 million project that addresses multiple aspects of producing and marketing cherries.
The project has tested new orchard designs of fruiting walls for more precise crop management, greater yields and to allow for mechanical pruning, thinning and harvesting to save labor costs.
Breeding for good abscission -- release of cherries from stems -- for stemless cherries to aid in mechanical harvest will take another 10 to 15 years to play out.
Biodegradable, breathable packaging has been developed to extend cherry shelf life and is ready for commercialization, Whiting said.
In talking to growers about the project at the North Central Washington Stone Fruit Day in Wenatchee, Whiting focused on upright fruiting offshoots -- UFOs -- to create fruiting walls. Six-foot trees are planted at a 45-degree angle to the ground, pointing south for less exposure to winter damage. The trees are bent over further and clipped to low horizontal trellis wire when limbs have grown 12 to 18 inches. Basal spurs and unwanted limbs are removed, leaving limbs spaced for vertical growth to establish the wall.
Fruiting can occur in the second year and fully in the fifth year, he said.
Most existing UFO orchards are vertical but there is more interest in a Y-trellis or angled design for potentially higher yields and better use of shake-and-catch mechanical harvest, he said.
The UFO system has 7 percent better packouts due to less bird and sunburn damage, Whiting said. It minimizes the environmental footprint by allowing zero-drift sprays instead of high-blast spray to reach through layers of tree canopy. Pesticides and water can be applied more efficiently and there's better use of sunlight, he said.
Three passes with mechanical pruners cuts pruning time to 8 percent of what it is by hand and younger pickers prefer upright fruiting walls for ease of picking over large, old trees, he said.