Increasingly, the availability and cost of labor is straining the specialty crop sector of agriculture. Specialty crops destined for fresh markets are often harvested by hand because of the fragile and perishable nature of the fruit. Interest in developing mechanical harvesting equipment that can substitute for the increasing shortage of hand labor is growing, especially for specialty crops such as blueberries. Research into mechanical harvesting of blueberries has been ongoing since the 1950s with over-the-row (OTR) machines and portable, heldheld vibrators. Only the V-45 blueberry harvester (BEI Intl., South Haven, MI) has clearly demonstrated that fresh market fruit quality as good as hand-harvested fruit can be achieved through mechanical harvesting (Peterson and Brown, 1996). Because of several design limitations of the V-45 (e.g., slow ground speed for optimum harvest efficiency and need for certain canopy architecture to prevent plant damage), it was not widely adopted by the blueberry industry (Takeda et al., 2008, 2013). Mechanical harvesting blueberry fruit can substantially improve labor productivity and harvest efficiency while also reducing labor costs (Brown et al., 1996; Casamali et al., 2016; Monroe and Levin, 1966). However, problems with damage to fruit during the mechanical harvesting process with OTR machines makes delivery to fresh markets and postharvest longevity problematic (Brown et al., 1996; Casamali et al., 2016; Morris, 1983; Yu et al., 2012), especially in northern highbush blueberry (Vaccinium corymbosum) and southern highbush blueberry (complex hybrids of V. corymbosum and Vaccinium darrowii). Northern highbush blueberries for fresh markets need to maintain acceptable quality for 2 to 3 weeks or longer after harvest to reach distant and oversea consumers (Brown et al., 1996). Blueberry species and type [e.g., southern highbush, northern highbush, rabbiteye (Vaccinium virgatum)], as well as cultivars within those species and types, vary in response to mechanical harvest (Casamali et al., 2016; Malladi et al., 2013; Takeda et al., 2008). Therefore, understanding the interactions of highbush blueberry type and plant characteristics that are best suited for machine harvest could help lead to advancements in developing cultivars better suited for machine harvest.
Handheld shakers have been used on a small number of farms (Haven Harvesters, personal communication), but varying fruit detachment response among cultivars showed that this technology needs further development (Casamali et al., 2016; Malladi et al., 2013; Takeda et al., 2017). New advancements in shaker technology as well as ergonomics may benefit blueberry operations of many scales. Takeda et al. (2017) demonstrated that pneumatic shakers could remove 3.5–15 times more blueberries (grams per minute) compared with hand harvest. Differences in picking rate were observed across cultivars. For example, the shakers removed as much as six times more fruit (grams per minute) than by hand in ‘Draper’ and ‘Legacy’, and nearly 16 times in ‘Liberty’ blueberries. Moreover, soft fruit catching surfaces reduced the impact force and bruise damage to blueberries; the percent of bruise area in ‘Draper’ when using pneumatic shakers and modified catching surfaces was less than by hand harvest [1.5% and 3% with the shakers and hand, respectively (Takeda et al., 2017)].
To achieve advances in mechanical harvesting of fresh-market fruit and make equipment that is commercially viable, new technology is needed to improve harvesting efficiency and make it economically feasible for blueberry producers to adopt. To elicit producer attitudes toward mechanized harvest for fresh-market blueberry, a survey was conducted over 2 years. The objective was to create a baseline for establishing future directions in research and extension activities related to the use of mechanical harvesters in the blueberry industry. This effort is part of a larger project, “Scale Neutral Harvest Aid System and Sensor Technologies to Improve Harvest Efficiency and Handling of Fresh Market Highbush Blueberries,” funded in 2014 by the U.S. Department of Agriculture (USDA) National Institute of Food and Agriculture Specialty Crop Research Initiative program (project number 8080-21000-025-09-R). The goal of the larger project is to develop a semimechanical blueberry harvester that would exert less damage to fruit destined for fresh markets compared with standard OTR machines, but increase the picking efficiency relative to hand harvesting. This survey will provide information and perspectives for future research and development of harvester technology based on the blueberry industry’s needs.
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