Hand picking, by snapping each fruit from its stem, has been the traditional method of harvesting Florida oranges (Citrus sinensis) and grapefruit (C. paradisi) for processing. A harvest mechanization program was active from about 1960 to 1985, but mechanical methods were not adopted. In July 1994, a new harvesting research and development program was initiated by the Florida Department of Citrus. The growers are taxed about $0.01/field box of production to fund the program. An industry Advisory Council oversees the program, and recommends projects and funding. The new program has provided training videos to improve hand harvest management/productivity, developed several methods for mechanical harvesting, and discovered/evaluated several fruit abscission agents. Mechanical harvesting use is increasing, and about 6880 of the 237,498 ha (17,000 of the 586,859 acres) of oranges were mechanically harvested during the 2002-03 season. Two mechanical systems can increase labor productivity by 5 to 15 times and reduce unit harvesting cost by 50% or more. Such savings are essential for effective competition in free-trade markets and for operation with resident labor. Many old-style plantings will need to be replaced over the next 10 years. The harvesting program accomplishments are discussed.
Randolph Beaudry, Paul Armstrong and Galen Brown
Elasticity, internal C2H4, CO2, and O2, diameter, firmness, and starch index were determined for ripening `McIntosh', `Red Delicious' and `Golden Delicious' apple fruit. Elasticity, measured by the acoustic impulse response of the apple, has previously been found to correlate with fruit firmness after harvest (Armstrong and Brown, 1992) and was studied as a possible index of apple harvest maturity because it is a rapid, non-destructive measurement that could be adapted for field use. However, elasticity did not correlate with firmness or other maturity parameters for fruit attached to the tree. Fruit temperature influenced internal gas levels, probably due to its effect on metabolic activity. An increase in the temperature-compensated internal CO2 level occurred for fruit having an elevated internal C2H4 concentration (> 0.02 μl/L), which suggested that the climacteric respiratory increase associated with ripening occurred while fruit were attached to the tree.
Nancy L. Schulte, Edward J. Timm and Galen K. Brown
`Redhaven' peaches [Prunus persica (L.) Batsch] were dropped onto several impact surfaces to determine impact conditions that initiate bruising. After impact, the peaches were tested for flesh firmness and sorted into firm, soft, and very soft groups for bruise analysis. The drop height that did not bruise decreased as fruit softened. The peach shoulder area bruised most easily. A drop of only 8 mm onto a hard surface initiated bruising on a soft peach, whereas a Poron 15250 cushion could protect the peach for a ≤85-mm drop. Impact damage threshold estimates were developed for the three flesh firmness conditions. The threshold estimates and impact history information collected by an instrumented sphere can be used to develop handling equipment design and operation guidelines that essentially avoid impact bruises on peaches.