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Jacqueline K. Burns, Richard S. Buker III, and Fritz M. Roka

An abscission agent [5-chloro-3-methyl-4-nitro-1H-pyrazole (CMNP)] was applied to `Hamlin' and `Valencia' orange (Citrus sinensis) trees at concentrations ranging from 0 to 500 ppm in a volume of 300 gal/acre. Four days after application, fruit were mechanically harvested with either a trunk shake-and-catch or a continuous canopy shake-and-catch system commercially used in Florida. Harvesting conditions were varied by limiting the actual trunk shake time of the trunk shaker to 2, 4, or 7 seconds, or by altering the ground speed of the canopy shaker (1.0, 1.5, or 2.0 mph). In general, increasing duration of shake and the application of CMNP increased percent mature fruit removal and decreased the amount of fruit remaining in the tree. Increasing CMNP concentration decreased fruit detachment force but increased post-spray fruit drop. Comparison of short duration shake times in CMNP-applied trees with trees harvested at longer durations either sprayed or not sprayed with CMNP indicated no significant difference in percent mature fruit removal. The results demonstrate that CMNP application increases harvesting capacity of trunk and canopy shakers by reducing time necessary to harvest each tree while maintaining high percent mature fruit removal.

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Jacqueline K. Burns, Fritz M. Roka, Kuo-Tan Li, Luis Pozo, and Richard S. Buker

An abscission agent (5-chloro-3-methyl-4-nitro-1H-pyrazole [CMNP]) at 300 mg·L–1 in a volume of 2810 L·ha–1 was applied to Valencia orange trees [Citrus sinensis (L.) Osb.] on 22 May 2004. At this time, immature and mature fruit were present on the tree simultaneously. Three days after application, fruit were mechanically harvested using a trunk-shake-and-catch system. The power to the shaker head was operated at full- or half-throttle (FT or HT, respectively), and the duration of trunk shaking was 2 seconds at FT or 4 seconds at FT and HT. Mature fruit removal percentage and number of immature fruit removed, and fruitlet weight and diameter were determined. Mature fruit removal percentage with 2 seconds at FT or 4 seconds at FT harvesting ±CMNP, or 4 seconds at HT + CMNP was not significantly different and ranged between 89% to 97%. Harvesting at 4 seconds HT without CMNP removed significantly less mature fruit than any treatment. CMNP did not affect immature fruit removal by the trunk shaker. Harvesting at 4 seconds at HT removed significantly less immature fruit than 2 seconds at FT or 4 seconds at FT. No significant difference in fruitlet weight or diameter was measured between any trunk shaker harvest operation and CMNP treatment. Trunk shaking frequency was estimated to be 4.8 and 8.0 Hz at HT and FT, respectively. Yield in 2005 was determined on the same trees used for harvest treatments in 2004. CMNP did not impact yield. No significant difference in yield was seen between the hand-picked control and 4 seconds at HT, whereas yield in the remaining treatments was lower. The results demonstrate that CMNP application combined with low frequency trunk shaker harvesting can achieve high percentage of mature fruit removal with no significant impact on return yield of the following crop.

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Robert L. Rackham and W. Grierson

Abstract

‘Hamlin,’ ‘Pineapple,’ and ‘Valencia’ oranges and ‘Marsh’ grapefruit were harvested by hand and with either the limb clamp shaker, foliage (coil) shaker, or vacuum tube picker's aid. Harvesting trials were combined with tests of abscission sprays, pre- and postharvest fungicides, and simulated fresh fruit marketing. All mechanical shaker harvesting increased losses from cuts and punctures, but “plugging” was so reduced that percentage of sound fruit sometimes did not differ significantly from that in the hand picked controls. When mechanical harvesting was followed by the fungicide thiabendazole (TBZ) decay in ‘Hamlin’ oranges during simulated fresh fruit marketing was not significantly higher than in the hand harvested controls treated with diphenyl only. Mechanically harvested fruit from trees sprayed with benomyl (Benlate) always had less decay than hand harvested fruit without the benomyl spray, differences usually being significant. Abscission sprays were helpful only for crops intended for cannery use. Long stems on mechanically harvested fruit remain a problem.

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Arnon Dag, Smadar Boim, Yulya Sobotin, and Isaac Zipori

., 2009 ; Youssef et al., 2011 ), although we may speculate that those which are not indicated originated from rain-fed orchards. There are almost no such studies of fruit originating from modern, irrigated, and mechanically harvested orchards, although

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B. L. Tyson, G. G. Dull, and B. K. Webb

Abstract

High speed reflected light spectrophotometry was used to determine an optimum maturity distribution of mechanically harvested clingstone peaches (Prunus persica (L.) Batsch) for processing. Succinic acid-2,2-dimethylhydrazide (SADH) applied at pit-hardening, advanced the optimum harvest date from 3 to 5 days and increased the yield of processable fruit from 62% for the control trees to 80% for the treated trees.

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C. M. Mainland, L. J. Kushman, and W. E. Ballinger

Abstract

On 15 occasions, either Wolcott, Jersey, Morrow or Murphy cultivars of highbush blueberry (Vaccinium corymbosum L.) were harvested by commercial hand-pickers and over-the-row mechanical harvesters in eastern NC during 1970 and 1971. Compared with hand-harvesting, machine-harvesting reduced yield of marketable ripe fruit 19 to 44%. Compared with commercially hand-harvested fruit, machine-harvested fruit was 10 to 30% softer in compression tests; and when held for 7 days at 21°C, the fruit developed 11 to 41% more decay. Machine-harvested fruits sorted on a commercial cleaner were softened still more and developed 5 to 10% more decay than fruit mechanically harvested but not sorted.

Fifty times as many canes were damaged by mechanical harvesting as by hand-harvesting.

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Dale E. Marshall

For nearly 30 years, more than 75 different groups: producers, entrepreneurs, engineers, processors, consultants, state or federal researchers, or manufacturers have constructed over 195 harvesters attempting to mechanize the harvest of Capsicum peppers. Countries testing experimental harvesters include: Bulgaria, Hungary, Israel, Italy, Spain, the United States, and the former Soviet Union. Over 25 principles have been tested. In 1980, there were 10 different university, state, or federal research agencies experimenting with pepper harvest mechanization. However, in 1990, there were no active mechanization projects. At least 13 patents have been identified that have been issued on pepper harvesters and 65 patents on harvesting elements or principles for other crops that have been tested or might be used to harvest peppers. Interest in mechanization has resumed in the United States and a number of commercial harvesters are available. Harvester usage is expected to increase significantly by the year 2000.

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Justin R. Morris

Abstract

The mechanization revolution in the cane fruit industry has been a result of the increasing scarcity and expense of hand labor which has threatened to eliminate cane fruits as a processing crop in the United States.

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S.P. Vander Kloet and J. Pither

Periodic prescribed burns of lowbush blueberry barrens promote high yield, aid in weed control, and reduce fungal and insect damage. Whether such prescribed fires should be set in the autumn or the spring has been a matter of some dispute. Previous research on Vaccinium angustifolium Aiton suggested some advantages to autumnal burning, but few data have been collected on V. myrtilloides Michaux. To evaluate whether time of burning affected plant qualities most favorable for mechanical harvesting, such as stem length and lateral branching, a series of experiments was conducted on V. myrtilloides. Differences in stem length, numbers of lateral branches, and buds per stem were nonsignificant among plants burned in fall vs. those burned in spring. In three of four experiments, however, fall burns resulted in the growth of fewer lateral branches. Furthermore, among the four experiments, growth responses were more uniform following fall than following spring burns. We therefore suggest that, where possible, fall burns should be prescribed for blueberry plants that will be mechanically harvested.

Open access

J. R. Morris, D. L. Cawthon, and J. W. Fleming

Abstract

Temperature of fruit of Vitis labrusca L. cv. Concord at harvest was the primary factor governing the rate of postharvest quality changes. Fruit harvested at mid-day at 32°C remained at that temperature inside a bulk pallet box for 72 hours, regardless of diurnal temperature fluctuations. Without addition of SO2, alcohol concentration steadily increased after 12 hours holding the mechanically-harvested grapes in a bulk pallet box and reached 3% after 72 hours. Loss of soluble solids began immediately after harvest and after 72 hours, 44% of the soluble solids present at the time of harvest had been lost. Addition of S02 at harvest or no later than 6 hours after harvest aided in slowing postharvest deterioration. The addition of 80 or 160 ppm SO2 to a bulk pallet box of grapes mechanically harvested at a temperature of 35° was as effective in retarding postharvest deterioration of the quality attributes determined in this study as was harvesting at 24°. Harvesting at a cool temperature (24°) and SO2 addition will allow for extended holding of the raw product with minimal alcohol production and raw product quality loss.