|Miller Stephen S,|
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 20, 1995
Publication Date: N/A
Interpretive Summary: Mechanical harvesting of fresh market peaches has the potential to greatly reduce the high labor cost of peach production. However, peaches ripen over an extended period of time and a single harvest time will remove some immature and some over-mature fruit along with peaches that are in the proper range of maturity for harvest and processing. We integrated a mechanical shake-catch-harvesting system with a mechanized peach production system and evaluated the potential of drip irrigation to narrow the range of ripening in peach. In addition, we studied the effect that mechanically shaking peach trees had on their long-term productivity. We found that irrigation tended to widen the peach maturity range and this reduced the percentage of marketable fruit removed with a single harvest. Six years after the first mechanical harvest, mechanically harvested trees had a higher death rate and lower fruit yield due in large part to accelerated disease development in these trees. We concluded that the potential for developing mechanical harvesting technology for peaches has no future unless cultivars are developed that can tolerate the mechanical shaking and produce fruit with a narrow range of maturity for a single harvest.
Technical Abstract: The purpose of this study was to evaluate the harvesting efficiency and productivity of a mechanical harvesting system on three peach cultivars (Prunus persica L. Batsch.) grown under three irrigation regimes. "Redhaven', 'Harvester' and 'Autumnglo' were grown with: 1) no irrigation; 2) full season irrigation; or 3) irrigation beginning four weeks before harvest and contunuing two weeks after harvest. Trees were trained to a free-standing "Y" with minimal hand pruning and mechanical hedging to maintain shape and remove excess growth. All cultivars were mechanically harvested with an over-the-row shake-catch harvester. 'Autumnglo' also had a hand-harvested treatment at all irrigated levels. The percentage of marketable firm ripe fruit mechanically harvested with a single pass ranged from 62% to 96%. In all years the non-irrigated treatment tended to have the highest harvest percentage suggesting that irrigation may widen the maturity range of peach and reduce the percentage of marketable fruit at a single harvest. Fruit damage ranged from 4% to 38% and was not significantly affected by cultivar or irrigation. A significant source of fruit damage was the pruning debris remaining in the canopy after hedging often became lodged in the fruit conveying system. Evidence was found that mechanical harvesting accelerated the decline and productivity of 'Autumnglo' through greater tree death and greater symptom expression of peach necrotic ring-spot virus. We concluded that the potential for a single mechanical harvesting of peaches is limited due to the unmanageability of the ripening window, high potential for fruit damage, and the possibility of accelerated tree decline.