Cultivation of the grape (Vitis vinifera, Vitaceae) began at least 8,000 years ago during the Neolithic period in the region of southwestern Asia and southeastern Europe around the Black and Caspian Seas (e.g., in present-day northern Iran, Georgia, Armenia, and Bulgaria). Evidence includes purported wine residues in specialized ceramic jars as well as changes in seed shape in the archaeological record of this region.
Grape was grown for its medicinal seeds (pips), fresh fruit (table grapes), dried fruit (raisins), and fermented (wine) and unfermented (juice) beverages made from the berries. With so many uses, grape became an important domesticated crop throughout Europe and Asia during early times. It was introduced to the Americas in the 17th century by the Spanish as a source of wine for Catholic ceremony.
Grape production in California began when Spanish friars established vineyards at their missions in the late 1700s. In 1839, Kentucky-native William Wolfskill planted a grape vineyard near present-day Los Angeles. Grape production on a larger scale began in earnest in the mid-1800s when Colonel Agoston Haraszthy brought over 100,000 cuttings from Europe to California. These plants provided a source of fruit for miners during the California Gold Rush. Englishman William Thompson planted a Mediterranean grape called the “Oval Kishmish” near Yuba City north of Sacramento around 1860. Today, this green-fruited variety is known as Thompson Seedless.
Table grapes are grown in two sections of California: in the southern end of the state in the Coachella Valley (Riverside County) and in California's Central Valley, mostly in the southern San Joaquin Valley (primarily in Kern, Tulare, Fresno and Madera Counties). Most production has been and continues to be in the Central Valley. Throughout the state, over 50 varieties are grown for table grapes, the fruits varying in color from green (e.g., Perlette, Thompson Seedless, Calmeria) to red (e.g., Red Globe, Emporer, Crimson Seedless) to bluish-black (e.g., Autumn Royal).
Table grape production is a year-round operation in California. Vines are pruned in the winter and begin to blossom in the spring. When the fruits reach the correct size, sugar content, and color specific to a particular variety, they are harvested by hand with special clippers. Since grapes must be harvested when fully ripe (they do not become sweeter during storage), it takes trained professional workers with years of experience to decide which grapes are ready for picking. Both the U.S. Department of Agriculture (USDA) and the California Department of Food and Agriculture (CDFA) are involved in setting and monitoring grape production standards, including the recognition of when fruits are ripe and bunches should be collected.
Harvest begins in late spring to early summer in the desert area of the Coachella Valley. In the southern San Joaquin Valley, grape-picking starts in late summer and continues until late fall. Most grapes are packed in the field. Bunches are trimmed, inspected, and then carried to the end of the rows by wheelbarrels where they are weighed and packed for shipment at portable packing stands. From the field, packed bunches are placed on pallets and transported to a cold storage facility to quickly cool the fruits and treat them with sulfuric dioxide to enhance shelf life. Once cooling is completed (usually within 12 hours or less), the grapes are moved to a storage room to await transport. Those not immediately shipped to market can be kept in climate-controlled storage at 30–33°F with 90–95 humidity for several weeks.
The fresh fruits known as table grapes were first shipped from California to eastern states in 1869. Today, California continues to be the nation's top producer of this crop.
During the 2010 season, California's industry shipped nearly 100 million boxes of table grapes (California Table Grape Commission, News Release, March 3, 2011) equaling close to 1 million tons of fruit (National Agricultural Statistics Service, USDA, 2011). Roughly 60% of these grapes were sent to various locations within the country and the rest were exported to 62 countries around the world. Nearly half of the value of the crop (over $600 million) came from the international exports. Major importers of California table grapes include Canada, China/Hong Kong and other parts of Southeast Asia, Mexico, Central America, and Australia, with lesser markets in the United Kingdom, New Zealand, and many more countries.
In this age of biosecurity awareness, many of our trading partners are increasing scrutiny of imports in an effort to stem the spread of pests and diseases to their countries. Concerns with respect to table grape imports include the transfer of weed disseminules, diseases, spiders, and insects on or within the table grape bunches themselves.
Australia and New Zealand have been among the countries to impose specific rules regulating table grape imports from California, as well as from other countries. In addition to stating their concerns and requirements in the specific work plans agreed upon by the USDA and our trading partners, Australia and New Zealand, like most countries, have larger, more general lists of organisms that are regulated with respect to purposeful or accidental import. The appearance of a restricted organism in a table grape shipment from California can result in the delay or destruction of the shipment by the importing country.
The pre-clearance programs negotiated by the USDA during the last decade have proven to be highly conducive to the smooth export of various California crops, including table grapes. The program allows inspectors in California to test table grape bunches for contaminant organisms, to identify these organisms, and then to stop or continue the exportation of these lots as appropriate. However, as the volume of exports have grown, the process of pre-clearance has been hampered by the lack of quick and accurate identification tools, causing some lots to be rejected because of lack of identification of a suspect organism. Hence, this effort to provide better identification tools.
Site Last Modified: March 15, 2012