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Growing Grounds

May/June 2012 Volume 103 No. 3

© 2002-2013 SAN DIEGO FLORAL ASSOCIATION and John Blocker.
This story may not be published in any form or copied onto another website without written permission from
San Diego Floral Association.

After a Devastating Outbreak,
Fear of Pierce’s Disease Haunts California Grape Growers

By John Blocker

In 1999, when more than 300 acres of grapes in Temecula became infested with Pierce’s Disease, a shudder ran through grape growers worldwide. The disease, caused by bacterium Xylella fastidiosa clogs the water-carrying tissue of the grape plant, leaving the leaves scorched and the vines to die. The glassy-winged sharpshooter, an insect native to the southeastern United States and northeastern Mexico, proved to be the culprit. It arrived in California around 1990 and began transmitting the disease from plant to plant as effectively as mosquitoes carry the malaria parasite from person to person. The glassy-winged sharpshooter was better at spreading Pierce’s Disease than the sharpshooters already in the area. Three million dollars worth of vines were soon lost.

The $525 million raisin, wine and table grape industry of California immediately took action. The California Department of Food and Agriculture restricted the movement of plants that might carry the glassy-winged sharpshooter into other grape-growing areas of the state. To investigate the pest, groups such as the American Vineyard Foundation, the California Department of Food and Agriculture and the United States Department of Agriculture gave millions of dollars to researchers at the University of California as well as other universities throughout the country. Beginning in 2001 the California Department of Food and Agriculture sponsored a yearly conference to study Pierce’s Disease. France and other countries prohibited entry of plant material from California that might carry the glassy-winged sharpshooter.

Why such a fierce reaction to the appearance of a disease in one small portion of California’s grape-growing industry? The answer can be traced back to 1886 when the first outbreak of Pierce’s Disease began in the city of Anaheim and completely destroyed the grape industry in Orange County, as well as in most of Los Angeles and San Bernardino Counties.

Newton B. Pierce Lends a Name

Newton B. Pierce studied this earlier outbreak for the United States Department of Agriculture and published his results in 1892. Although he never determined the cause of the disease, his analysis was so extensive the disease was named after him.

His analysis begins with Cortez, who in 1524, acting as governor of Mexico, issued an edict for all small farmers to grow grapes and other crops. He ordered growers to plant yearly for every hundred Indians “one thousand vine shoots or other useful plants of the best kind, in the best location and at the fittest time, until for every hundred such Indians there should be five thousand plants well placed.”

Grapes flourished in the New World, and that caused a problem. The wine producers in Spain feared they would lose a new and burgeoning market. The Spanish government passed laws obstructing wine production in the new lands. For hundreds of years no new grape varieties could be imported in most of the New World. Local wines were heavily taxed, and only Spanish wine could be legally sold.

But imported grapes in the New World continued to be planted. The Catholic Church did not comply with the new laws. The church’s stated reason for cultivating the imported vines was to provide wine for the sacrament of Holy Communion. Farmers out of reach of the mother country’s authority also continued to grow these grapes. Two hundred years after Cortez’s edict, vines could be found in most areas of Mexico.

The Mission Grape in California

It was this grape, first brought to the New World to comply with Cortez’s decree and isolated for hundreds of years from cross-breeding with other European varieties, that was brought by the missionaries into California. This variety is still known throughout California as the Mission Grape.

The Spanish ship San Antonio arrived in San Diego harbor on April 11, 1769. The expedition established San Diego as the first European settlement on the West Coast of North America and led to the establishment of a string on missions along the California coast.

Hurbert Howe Bancroft wrote in his History of California, “Vallejo has heard from his father and others of the fundadores (founders) that vines were brought up in 1769 and planted in San Diego.” Surviving records do not explicitly list grapes as one of the commodities brought to San Diego in 1769. But if they were not brought with the first expedition, they certainly were brought soon after by succeeding supply ships.

In 1803 Alexander von Humbolt, one of the great explorers and geographers of the period, studied the California region for more than a year. While in Mexico City he wrote that good wine was being made at all the missions from San Diego to San Luis Obispo and as far north as Santa Clara and San Jose.

Captain John Hall wrote in his log book of his voyage along the California coast in 1822, “Santa Barbara had all kinds of fruits for sale at a reasonable price including grapes and pears; good wine could be procured from the friars at Mission San Juan, and San Diego had an abundance of grape vines from which good wine was made.” Bancroft wrote that the San Gabriel Mission had 165,579 vines in four vineyards in 1834. He wrote that in 1839 there were 8,600 vines in San Diego. By 1848 when California became part of the United States, there were 200,000 grape vines in California and a considerable amount of wine and brandy was exported.

Almost all the grapevines planted in California prior to 1853 were Mission grapes. The Mission grape was easy to propagate and could be produced more cheaply than the European varieties. After 1853 European varieties began to be imported to California.

By 1858 there were over 4 million vines in the state, with Los Angeles County having more than 1.65 million, Santa Barbara 900,000 and San Diego County 50,000 vines. Grapes had become a major crop in Southern California, particularly in the Los Angeles area. The Mission grape was still widely grown.

H. A. Haraszthy is known as the father of the wine industry in California. He was sheriff of San Diego County during the early 1850s and founder of Buena Vista Winery in Sonoma County in 1857, a winery still operating today. He wrote, “The California climate, with the exception of the seacoast … is eminently adapted for the culture of grapevines, and it is proved conclusively that no European locality can equal within 200 percent, it productiveness.” He also wrote, “The oldest inhabitants have no recollection of a failure in the crop of grapes.”

But in 1886 disaster struck the vineyards in Anaheim. Mission grapevines grown in the New World for hundreds of years without disease problems were now dying en mass. An article in the Anaheim Gazette from that year reported: “Vines that appeared vigorous and healthy three weeks ago are beginning to shrivel and dry, and the berries are dropping off. This is true principally of the Mission vines.”

The next year other varieties imported from Europe, including Muscat and Zinfandel, began dying also. Soon most of the vines from the San Gabriel Valley to Pomona were dead. Diseased grape vines were found as far away as the Otay River Valley and El Cajon in San Diego County. Pierce’s Disease destroyed about 25,000 acres of grapes and the loss was estimated at $10 million.

Despite efforts by the wine industry during the past 100-plus years to breed varieties resistant to Pierce’s Disease or to cure infected vines, no antidote has yet been found. Controlling the glassy-winged sharpshooter with pesticides or through biological control, removing the bacteria’s other hosts, and culling diseased plants from the vineyard are still the only remedies. Today, fear of another major outbreak remains strong.

–John Blocker worked with the agricultural industry in San Diego and has attended garden conferences and viewed gardens around the world during the past 20 years. From 1998 to 2008, he was on the board of the California Garden and Landscape History Society.


Newton B. Pierce, California Vine Disease
(Published by the Authority of the Secretary of Agriculture, Washington D. C., 1892).

“News and Research About Pierce’s Disease,”

Lynn Alley, “Researchers Uncover Identity of Historic California Grape,” Wine Spectator (February 2007).


DNA of the Mission Grape

In December 2006, a team of Spanish researchers, headed by graduate student Alejandra Milla Tapia at the Centro Nacional de Biotecnología in Madrid, announced they had discovered the origin of the Mission grape widely grown in California. Using DNA evidence they discovered the Mission grape was an exact match for a variety called Listan Prieto or “dark or black Palomino.” This grape was widely grown in Castile during the 1500s, but is rarely grown in Spain today. It is still grown for winemaking in the Canary Islands under the Spanish language name Palomino Negro.

This story may not be published in any form or copied onto another website without written permission from
San Diego Floral Association.

Mission: To promote the knowledge and appreciation of horticulture and floriculture in the San Diego region.



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