Total acreage harvested by mechanical means was 47,754, just over 28 percent of the State’s total raisin-type grape acreage, according to the Pacific Regional Office of USDA’s National Agricultural Statistics Service. The Overhead Trellis Management System was used on 13,695 bearing acres in 2015, accounting for 8 percent of the total raisin-type grape acreage. Fresno and Madera County growers have 48 and 40 percent of the Overhead Trellis acreage in the State, respectively. Kern County growers have 10 percent of the Overhead Trellis acreage. Other mechanical harvest systems include Continuous Tray at 19 percent of the acreage and South Side with about one half of 1 percent of the raisin-type grape acreage. Open Gable accounted for less than one half of 1 percent of the total raisin acreage.
Although Fresno County has the most acreage with mechanical harvesting, at 33,746, that acreage only represents 28 percent of the Fresno County raisin-type grape acreage. Kern and Madera County growers harvest 21 and 40 percent of their raisin-type grape acreage by mechanical means, respectively.
By variety, Thompson Seedless grape acreage with mechanical harvesting is 35,041 or 23 percent of the total raisin-type grape acreage. Seventy-two percent of the Fiesta grape acreage is harvested mechanically and 56 percent of the Selma Pete acreage is harvested mechanically.
Most California raisins are produced by sun drying after placing bunches on paper trays on terraces between vine rows. The Overhead Trellis System has led to increased production of dried-on-the-vine raisins, increased machine harvesting, and decreased hand labor use.
The Pacific Regional Office of USDA’s National Agricultural Statistics Service, in cooperation with the California Department of Food and Agriculture, conducts an annual grape acreage survey. The 2015 Grape Acreage Report, published in April, summarized the latest survey results. At the request of the raisin industry, an additional question was added to the grape acreage survey form the past nine years to gather information on raisin-type acreage that is harvested mechanically. In addition to the mechanical harvest data, producers were asked to update acreage by variety and year planted. Growers were initially contacted by mail and follow up was done by telephone. This report summarizes data for mechanical harvest methods of raisin-type grapes. The totals included are only for those that voluntarily reported to this survey.
Read the full USDA California Raisin Grape Mechanical Harvest Report (.pdf)