Cunha says his group's workforce fell by 20 to 30 percent during last year's harvest season compared with the year before. By September, some farm crews were as much as 60 percent short of needed workers, Cunha said. He blamed stepped-up farm audits by U.S. Immigration and Customs Enforcement and the increased perils facing migrants along the border with Mexico.

"Workers were leaving agriculture because they were fearful of the audits and getting busted by ICE," Cunha said. "And then, when they went home, they realized it wasn't worth it to return because of the drug traffickers and human traffickers" preying on people crossing the border.

"They're not coming back," Cunha said. "The fear is too great."

Barbara Cecchini, who grows fruits and vegetables in Contra Costa County, said many of the seasonal workers who typically cut her asparagus crop didn't return last year. And numerous younger workers took off for other farms when harvest time arrived for blueberries and cherries – crops that generally pay higher hourly rates because of better profit margins at supermarkets.

"When our labor force shrinks, we have to shrink our fields," said Cecchini. As much as 20 percent of her asparagus went uncut last year, she said, because she couldn't find enough workers – young or old – to harvest the crop.

The work takes its toll

John Chandler worries about the physical toll on older workers. He said he doesn't want the oldest workers doing heavy lifting and seeks to ensure they have ample drinking water in the fields.

"A lot of ag work can be very physical," he said. "It just gets tougher to get down and pick up those boxes and lug those peaches. And we recognize that."

Macabeo Murillo, 58, worked on the Chandler farm 20 years ago, before moving on to work in a boat factory and as a lineman for Pacific Gas and Electric. Along the way, he raised two daughters who went into nursing and a son who became a city public works officer.

But Murillo recently returned to field work. His family house is near Chandler Farms. His wife has been in poor health, and Murillo wanted employment close to home. For him, returning to the work he performed as a young migrant didn't seem like a stretch.

"I found something I enjoyed," he said. "Our generation thinks differently about this work. We're responsible about putting food on our household table, about keeping the lights on and paying our bills."

Arcadio Castro, 59, is a foreman at the Chandler ranch. Castro was undocumented when he came to the United States in 1972 but was granted U.S. citizenship in 1995.

He said he often returns to visit his hometown in Zacatecas, Mexico, and still encounters young men there working on farms for as little as 100 pesos, or $8 a day, who dream of finding jobs in California.

But he said few can afford the $5,000 a coyote may charge to smuggle them across the border. And those willing to take the risk often prefer construction jobs in urban areas.

So Castro has come to rely upon – and appreciate – the veteran laborers willing to perform work many of their kids won't consider.

"You're not going to believe me, but the older workers are better," Castro said. "They go slower, but they work all day long. The younger ones start complaining. They say, 'Oh, it's so hot.' Then they climb up a ladder and start texting."

FARMERS, SENATORS, OBAMA OFFER PLANS

Amid intensifying debate over U.S. immigration policy, agricultural interests, a bipartisan congressional panel and President Barack Obama are calling for changes in farm labor policies that range from detailed proposals to more generalized statements.

Agricultural Workforce Coalition, includes the Agricultural Council of California, the California Grape and Tree Fruit League and the Western Growers Association

• Create two guest worker programs: one for seasonal laborers who could work up to 11 months before returning to home countries for 30 days; another for laborers working one-year renewable contracts with provisions to return home for 30 days over a three-year period.

• Grant legal work status for experienced undocumented farmworkers living in the United States in exchange for their agreeing to a multiyear obligation to work in agriculture.

U.S. Senate Bipartisan Framework for Comprehensive Reform

• Create a workable program to meet the needs of America's agricultural industry, including dairy, to find workers when American workers are not available to fill open positions.

The White House

• Create a pathway to citizenship by requiring undocumented immigrants to register, pass national security checks and pay fees and penalties before becoming eligible for provisional legal status. Call The Bee's Peter Hecht, (916) 326-5539.