The single greatest annual production cost for an established cider apple (Malus domestica Borkh.) orchard is the labor required to hand harvest. Reducing harvest labor time may increase the appeal and profitability of growing cider apples. Over-the-row mechanical harvest of cider apples using a modified Oxbo-Korvan 930 was evaluated in northwestern Washington, USA, in 2021, 2022, and 2023 in a fully mature cider apple orchard that was planted in 2014–2016. Sixteen cider apple cultivars grafted on ‘Geneva 935’ rootstock were summer hedged between 7 and 20 July each year of this study. Plant growth regulators were applied before harvest to equalize the timing of harvest among cultivars. There were no differences among cultivars for the percent of apples captured by the Oxbo-Korvan 930 harvester for the 3 years of this study. Across all years and cultivars studied, 82% of fruit were captured by the harvester. There also were no differences among cultivars for the percentage of fruit left on the tree by the harvester (9% of fruit on average), nor in the percentage of fruit dropped on the ground during harvest (9% of fruit on average). The overall mean number of branches broken during mechanical harvest across all cultivars was 1.4 per tree, and there were no differences among cultivars. ‘Sweet Alford’ had high spur removal (26 removed per tree), but excluding this outlier, only 6 spurs on average were removed per tree for all other cultivars. Laceration to fruit during mechanical harvest were positively correlated with mean fruit weight and mean fruit diameter. The overall average time required to mechanically harvest one tree in this orchard (1.8 m in-row spacing, 1495 trees·ha−1) was 5.3 s, averaging 2.9 s per row-meter traveled. The average time required to manually harvest one tree was 229 s (3.8 min). The juice quality of the mechanically harvested apples that were kept in cold storage and pressed within 42 d of harvest did not differ largely or consistently from juice quality of apples that were pressed within 3 d of harvest, except that sugars (measured through ºBrix and specific gravity) increased with storage time, as expected. Mechanical harvest using the modified Oxbo-Korvan 930 appears to be a labor-efficient and effective method of harvesting cider apples, and testing is needed in commercial orchards to evaluate its viability compared to other harvest technologies.
Brawner et al. (Tue,) studied this question.