Scott Olson / Getty Images A migrant worker harvests watermelon from an irrigated farm field in the drought-stricken town of Vincennes, Ind., on July 18, 2012

Ralph and Cheryl Broetje rely on roughly 1,000 seasonal workers every year to grow and pack more than 6 million boxes of apples on their farm along the Snake River in eastern Washington. It’s a custom they’ve maintained for over two decades. Recently, though, their efforts to recruit skilled labor, mostly undocumented immigrants, have come up woefully short despite intensive recruitment efforts in an area with high rates of unemployment.

The Broetjes and an increasing number of farmers across the country say that a complex web of local and state anti-immigration laws account for acute labor shortages. With the harvest season in full bloom, stringent immigration laws have forced waves of undocumented immigrants to flee certain states for more-hospitable areas. In their wake, thousands of acres of crops have been left to rot in the fields, as farmers have struggled to compensate for labor shortages with domestic help.

“The enforcement of immigration policy has devastated the skilled-labor source that we’ve depended on for 20 or 30 years,” said Ralph Broetje during a recent teleconference organized by the National Immigration Forum, adding that last year Washington farmers — part of an $8 billion agriculture industry — were forced to leave 10% of their crops rotting on vines and trees. “It’s getting worse each year,” says Broetje, “and it’s going to end up putting some growers out of business if Congress doesn’t step up and do immigration reform.”

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Roughly 70% of the 1.2 million people employed by the agriculture industry are undocumented. No U.S. industry is more dependent on undocumented immigrants. But acute labor shortages brought on by anti-immigration measures threaten to heap record losses on an industry emerging from years of stiff foreign competition. Nationwide, labor shortages will result in losses of up to $9 billion, according to the American Farm Bureau Federation.

In Arizona, Nan Walden’s complaints mirror those of the Broetjes. Walden is vice president of the family-owned Farmers Investment Co., the largest grower and processor of pecans in the world, with 6,000 acres (2,500 hectares) of farmland in the Santa Cruz Valley, 35 miles (56 km) from the U.S.-Mexico border. Walden says the state system in place for luring seasonal workers is wholly inefficient and adds that Arizona’s infamous SB1070 immigration law has only compounded the problem, creating a climate of fear for Arizona employers and employees. “This has led to people leaving our state, going to other states without these ambiguous clouds and legal sanctions hanging over employers’ and employees’ heads,” says Walden.

Farming operations nationwide, from New York to Georgia to California, are reeling from similar labor shortages despite offering domestic workers competitive packages that include 401(k) plans and health insurance. Almost in unison, farmers complain that even when they are able to lure domestic workers to what often amounts to high-skilled, grueling work, it’s not long before they abandon the job.

North Carolina, whose four main crops are valued at $2 billion, has seen its labor supply vanish since nearby Alabama and South Carolina enacted restrictive immigration laws. “Clearly, immigration reform is as much a federal issue as maintaining our military or managing our money supply,” says Larry Wooten, president of the North Carolina Farm Bureau. “And this state-by-state regulation, with hyperenforcement, is putting pressure on farming operations here in North Carolina and across the country.”

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With the federal government sitting on the sidelines, some state legislatures in response to that pressure have started to consider enacting guest-worker programs, often after heavy lobbying from agricultural and business groups. Utah, for example, recently approved a program that, starting this year, will allow undocumented immigrants to work in the state legally as long as they pass background checks. The measure, though, is subject to federal approval.

Several other states, including California, Oklahoma and Vermont, have considered similar legislation. In Texas last year, Republicans signed off on a party platform that calls for a national guest-worker program. And just before the GOP convention in August, the Republican National Committee approved a platform on immigration that calls for a guest-worker program.

“We feel strongly that there has never been a greater need for federal leadership for immigration reform,” says Walden. “The United States farmer is still the most efficient in the world, and if we want to be in charge of our food security and our economy and add favorably to our balance of payments, we need to support a labor force for agriculture.”