Elias Torres will pick grapes this season for the first time in 25 years. The vineyard manager usually sends his laborers to do the work. But in the last two months, more than half of his 60-person staff has disappeared, he said, as a result of federal immigration crackdowns. So Torres, a 57-year-old quadruple bypass survivor, will pluck and sweat alongside field workers -- and even the vineyard owners who hire him to bring them in. "This is the worst labor shortage I've seen since I came here in 1961," said Torres, a native of Guanajuato, Mexico, who manages work...