I believe the same is true for the california wine industry. What i find interesting is that the article http://www.parapundit.com/archives/002778.html talks about how automated the Australian wine industry is by comparison (dont know if thats true). The author asks why isnt Napa/Sonoma automated like the Aussies.

Hispanics are the backbone of the wine industry, pure and simple, says Pete Seghesio, CEO of Seghesio Family Vineyards in Sonoma County. Year-round, most of the vineyard work is done by Hispanics—everything from pruning vines in the winter months, to thinning grapes and leaves during the growing season, to the actual harvest.

"We can't do what we do without them," Seghesio says. "California cannot make 90-point wines without the hand care of these individuals. We're not Australia, where many of the [farming operations] are done by machines. It's impossible to make the kind of quality wine we're making in California today without this labor force of hands." ... The bottom line, though, is this, says Seghesio: "If people really knew the percentage [of Hispanics working in California] that's driving our economy, there wouldn't be any of this talk from our government."


>SNIP
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>>There is not a single industry, including agriculture, in which a large majority of workers are not legal citizens.
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>I know that the majority of workers in the poultry and meat industry in the U.S. certainly are. Soon that will be case in the home construction industry as well (if it is not already). I guess you don't have a Purdue chicken plant near you?
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>http://www.hrw.org/backgrounder/usa/un-sub1005/
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>Immigrant workers make up the majority of the labor force in the U.S. meat and poultry industry. Along with immigrant counterparts in the agricultural sector, they literally feed the people of the United States. Despite this central role in U.S. economic life, immigrant workers are not accorded the rights, recognition and respect they deserve for their contributions. Instead of integration into the host society with full application of labor rights and labor standards, they are marginalized in a huge underclass laboring in substandard employment conditions.
>...