2013 ASHS Annual Conference

In the early 1970s concern over the availability of harvest labor led to significant research on mechanical harvest on apples and peaches. This early research resulted in mass removal trunk shaking machines that detached apples by applying a centrifugal force to the trunk, which then fell onto catching frames and were collected and transported to a bin with conveyor belts.  This technology resulted in significant adoption of mechanical shake and catch harvesters in the largely processing growing regions of Western New York, Pennsylvania, Michigan, and California. However, fruit bruising was substantial. In an effort to design the tree for the machine, several tree designs were studied including the Geneva Y-trellis and the Lincoln apple canopy.  The Geneva Y-trellis growing system allowed most of the fruit to borne in a single plane so that there were few fruit-to-branch impacts as the fruit fell.  When the Y-trellis was combined with an impact trunk shaker, much less energy was imparted to the fruits than the centrifugal shakers. The best results with this system showed only 10% fruit bruising.  However, this technology was never adopted by the apple industry since by the late 1980s the interest in mechanical harvest of apples in the United States had waned, as it appeared there would be an endless supply of migrant workers who could harvest the crop relatively cheaply. In Europe a different approach was pursued to reduce harvest labor by developing harvest assist machines.  As early as 1980, researchers in the Netherlands had built machines that used humans to detach the fruit from the tree and then place it on conveyers to transport the fruit to a central mechanical bin filler.  These machines were best suited to simple trees narrow trees. Since the 1980s, numerous designs have been developed.  In general, research showed that these harvest assist machines could improve labor efficiency by only 15% to 20%. Their efficiency was greater with simple thin canopies and high tree planting densities. This relatively small improvement in labor efficiency did not result in rapid adoption of harvest assist machines.  However, slowly over the years more and more European growers have purchased these harvest but they have never been adopted in the United States. In the early 2000s, new concerns in the United States over  labor cost revived an interest in mechanical harvest and a new round of research began based on two concepts: harvest assist machines and robotics.