uncertainty about trained laborers ( California Tomato Growers Association, 2015 ; Florida Tomato Committee, 2018 ; USDA, 2016 ) force the fresh-market tomato industry to seek a mechanical harvesting system to reduce dependence on farm labor. Most of the U
physiological maturity ( Ferguson et al., 2005 ). Harvest is done by hand labor over a period of ≈2 months. Increased labor costs and low labor availability have intensified industry interest in mechanical harvesting. Unusually low temperatures during flower bud
to mechanical harvest ( Studer and Olmo, 1971 , 1974 ). Berries on dried rachises tend to detach from clusters with their pedicels (cap-stems) attached ( Studer and Olmo, 1971 ), which helps to prevent rupturing and tearing of the berries ( Studer
Red raspberry (Rubus idaeus L, cv. Meeker) was grown with either 3-m or alternate 3-m and 1.5-m between-row spacing. Canes were trained as: a) pruned upright bundles, b) pruned and individually woven canes, or c) unpruned looped bundles, all secured to wires 1.5 m high. Training did not consistently affect yield as obtained with a Littau mechanical harvester. Fruit size was smallest in the unpruned bundles. The amount of fruit that dropped between or during harvests was substantial, but was similar for row spacings and training systems.
Mechanical harvesting of certain fruit vegetables has been commercially practiced for many years, but only fresh-market tomatoes have been added to that list since 1970 (6). This review includes those fruit vegetable crops for which machine harvesting is an established commercial practice, and considers aspects of the harvesting and handling systems which affect the quality of the fruits.
Field studies were conducted in 1991 with `Jalapeno-M' and `TAM' Jalapeno pepper. Plants were established by direct seeding at 10, 20, 30, and 40 cm in-row plant spacing. Lodged plants, fruit quality and yield were monitored. A commercial snap-bean harvester was evaluated for harvest. Closer plant spacings resulted in greater yields and reduced plant lodging. No interaction of variety with plant spacing was observed. There were, however, differences in several yield parameters due to variety. Fruit quality characteristics of mechanically and hand harvested pepper stored at 6 C were similar. The use of the mechanical snap-bean harvester appears to be a feasible technique to harvest Jalapeno pepper.
Several spacing, cultivar, ethephon and harvest sequence studies were made on summer squash in 1989 evaluating cultural practices which maximized marketable once-over yield of fruit for processing. Optimum spacing was 30 cm within rows and 45 cm between rows. The zucchini and yellow hybrids producing the highest marketable yield were `Classic' and 'Gold Slice', respectively. Ethephon applied at 0.77 kg/ha resulted in higher yield than no ethephon. Harvesting two times followed by a seven day delay before a once-over, destructive harvest produced a marketable yield equal to three harvests/week for three weeks. A prototype mechanical harvester has been used successfully on yellow hybrids; zucchini hybrids require more force for successful fruit separation.
An internal rate of return technique was used to analyze and compare 4 orchard densities producing ‘Golden Delicious’ apples (Malus domestica Borkh.) on a “typical” Pennsylvania fruit farm with a fresh market system and both hand and mechanical harvested processing systems. Medium and high density systems had similar rates of return both of which were higher than the low density systems. The high density system had higher net returns per unit area than the medium density systems.
Succinic acid-2,2-dimethylhydrazide (daminozide) applied to ‘Raven’ blackberries at 4000 ppm and to ‘Raven’ and ‘Brazos’ at 2000 ppm between full bloom and first color development and at 2000 ppm in a multiple application applied at full bloom, 2 weeks, and 3 weeks after full bloom resulted in reduced berry size and yield with no beneficial effects on fruit quality. (2-Chloroethyl) phosphonic acid (ethephon) applied to the same cultivare at 1000 ppm 4 days prior to the first harvest increased the amount of fruit mechanically harvested on the first harvest. Ethephon treatment improved color but resulted in mechanically harvested fruit having lower soluble solids and acidity.
Research was conducted to develop a cultural system that would permit a destructive mechanical okra [Abelmoschus esculentus (L.) Moench] harvest. Okra grown at a highly dense (HD) plant population of 25 × 23 cm and destructively harvested by machine was compared with control plants spaced at 90 × 23 cm and repeatedly and non-destructively harvested by hand. The control N fertilization regime was 45 kg·ha-1 of N preplant, followed by one or two topdressings, each with 22 kg·ha-1 of N. Treatments applied to HD plots were designed to be multiples of the control N fertilization levels. Preplant fertilizer was added such that the sum of residual soil N plus the added fertilizer would total to 45, 90, or 135 kg·ha-1 of N for the standard, intermediate, and highest rates, respectively. Topdressing rates were 22, 44, or 66 kg·ha-1 of N for standard, intermediate, and highest, respectively. Topdressing was timed to follow a mechanical harvest of the HD plots. Since there was only one mechanical harvest in the two 1995 studies, topdress N treatments did not affect yields from mechanical harvest in that year. Nitrogen treatments had few effects on fruit yield per hectare of HD okra, even when stem N concentrations equaled or exceeded those of control plants. The highest N rate tended to delay fruit production. Increasing N rates did not affect the marketable fruit yield obtained by mechanical harvest of HD plants expressed as a percentage of the total cumulative marketable fruit yield from control plants. Physiological factors appear to be limiting the potential for densely planted okra in a destructive mechanical harvest system rather than horticultural factors such as N nutrition.