Modified Over-the-Row Machine Harvesters to Improve Northern Highbush Blueberry Fresh Fruit Quality

Lisa Wasko Devetter,Changying Li,Wei Qiang Yang,Scott Korthuis,Fumiomi Takeda

doi:10.3390/agriculture9010013

Abstract

Improved blueberry mechanical harvesting (MH) equipment that maintains fresh market quality are needed due to rising costs and decreasing availability of laborers for harvesting by hand. In 2017, a modified over-the-row (OTR) blueberry harvester with experimental catch surfaces and plates designed to reduce fruit bruising was evaluated. The catch surfaces were made of neoprene (soft catch surface; SCS) or canvas (hard catch surface; HCS) and compared to hand-picked fruit (control). Early- and early/mid-season ‘Duke’ and ‘Draper’, respectively, were evaluated in Oregon, while late-season ‘Elliott’ and ‘Aurora’ were evaluated in Washington. Harvested berries were run through commercial packing lines with fresh pack out recorded and bruise incidence or fresh fruit quality evaluated during various lengths of cold storage. The fresh pack out for ‘Duke’ and ‘Draper’ were 83.5% and 73.2%, respectively, and no difference was noted between SCS and HCS. ‘Duke’ fruit firmness was highest among MH berries with SCS, but firmness decreased in storage after one week. Firmness was highest among hand harvested ‘Draper’ followed by MH with SCS. For ‘Elliott’ and ‘Aurora’, fruit firmness was the same across harvesting methods. ‘Draper’ exhibited more bruising than ‘Duke’, but bruise ratings and the incidence of bruising at ≤10% and ≤20% were similar between hand and MH ‘Draper’ with SCS after 24 h of harvest. ‘Aurora’ berries had similar bruise ratings after 24 h between hand harvesting and MH with SCS, while ‘Elliott’ showed more bruise damage by MH with both SCS and HCS than hand harvested fruit. Although our studies showed slightly lower fresh market blueberry pack outs, loss of firmness, and increased bruise damage in fruit harvested by the experimental MH system compared to hand harvested fruit, higher quality was achieved using SCS compared to HCS. We demonstrated that improved fresh market quality in northern highbush blueberry is achievable by using modified OTR harvesters with SCS and fruit removal by either hand-held pneumatic shakers or rotary drum shakers.

Highlights

Northern highbush blueberry (Vaccinium corymbosum L.) produces fragile and perishable berries that have been traditionally harvested by hand to maximize quality and postharvest longevity when sold on the fresh market
Machine harvesting research for northern highbush blueberry began in the 1950s, but to date has met limited success for fresh market operations
The percent of packed blue fruit that were marketable differed by cultivar, but were similar between mechanical harvesting (MH) with HCS and SCS (Table 1)

Summary

Introduction

Northern highbush blueberry (Vaccinium corymbosum L.) produces fragile and perishable berries that have been traditionally harvested by hand to maximize quality and postharvest longevity when sold on the fresh market. Obtaining sufficient labor for harvest operations is increasingly difficult due to the rising costs of labor coupled with the decreasing availability of workers. Mechanizing and automating harvest operations is an important and growing area of research among blueberry and other specialty crop growers. The goal in developing viable machine harvest technologies for fresh market blueberry is to engineer equipment that can efficiently harvest berries while maintaining the quality and postharvest longevity necessary for this sector of the market. Machine harvesting research for northern highbush blueberry began in the 1950s, but to date has met limited success for fresh market operations.

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Discussion

Conclusion