Simply put, they aren't willing to pick crops.
Maria Machuca, a spokeswoman for the United Farm Workers in Washington, D.C., says hard labor in the fields isn't going to attract legal residents or native-born Americans who have other options that, for some, include waiting out a bad economy at home by collecting unemployment checks.
Santiago Gonzalez has not been able to escape the labor shortage.
This year, he planted a mere 10 acres of onions, down from a 700-acre crop two years ago. Planting 700 acres of crops is expensive — and Gonzalez couldn't find an investor willing to take the risk.
"It's a huge investment," he says, "and my usual partner was afraid that we wouldn't be able to find the workers."
Agriculture is a $10.3 billion industry in Arizona, which has seen a slight drop in its number of farms over the past three years. Last year, the U.S. Department of Agriculture reported that there were 15,500 farms operating in Arizona, down from 15,637 farms in 2007.
In 2010, there were about 17,900 fewer acres of Arizona land used grow the nation's food supply, compared to 2007.
Industry experts estimate that the labor shortage will only aggravate that trend and that it will have a ripple effect outside the world of farmers.
Tom Nassif, president and CEO of Western Growers, a coalition of Southwest farmers, told congressional leaders that it wasn't just about America losing its farms, but that "for every farm worker job that goes, an additional two to three U.S. jobs in other industries will go with it. America could lose its domestic supply of fresh produce and accelerate the flight of farming to Mexico and beyond."
For now, Arizona farmers continue to produce.
Corn is grown on more farms than any other crop and sold during spring in Arizona, followed by squash and cantaloupe, according to the USDA National Agriculture and Statistics Service.
Arizona farmers are also busy each spring harvesting apricots, tomatoes, lemons, oranges, potatoes, cucumbers, lettuce, peaches, grapefruits, and onions.
In summer months, they deliver zucchini, radishes, tomatoes, watermelons, grapes, apples, radishes, sweet peppers, cucumbers, figs, pears, and black-eyed peas.
The fields in Arizona are worked just as hard in the fall and winter, when states in other regions are buried under snow. During the mild winter months, farmers are harvesting basil and broccoli, lemons and lettuce, spinach and squash, and key limes and kohlrabi (a German turnip that looks like a baby cabbage and tastes like crunchy broccoli).
Sustaining the industry has been a challenge for farmers in need of workers to harvest the land's produce. Not only are farmers at the mercy of Mother Nature, they also contend with state and federal lawmakers adopting ever-stricter anti-immigration measures.
Arizona and its stack of anti-immigrant laws have created new challenges for farmers as potential workers, fearful of deportation, relocate to other, more immigrant-friendly states.
The first of Arizona laws targeting illegal immigrants came in 2004, when lawmakers required voters to provide proof of citizenship to cast ballots, a way to ensure illegal immigrants weren't participating in the democratic process. Later, they crafted measures aimed at keeping undocumented immigrants off the payrolls in Arizona and from receiving public benefits, such as food stamps and unemployment pay, and making it harder for them to access education by demanding out-of-state tuition from undocumented college students.
The most controversial law, signed by Governor Jan Brewer a year ago, makes it a crime to be in Arizona without proper documents and mandates that local cops enforce federal immigration laws.
A federal judge has blocked the most stringent provisions of the Support Our Law Enforcement and Safe Neighborhoods Act, known more commonly as SB 1070, until the courts can determine its constitutionality.
The law may be hung up in court, but some immigrants aren't waiting around to see whether it will be thrown out.
A study by the Public Policy Institute of California estimates that about 92,000 illegal immigrants fled Arizona from 2008 to 2009 as a result of the state's Legal Arizona Workers Act, a law that made participation in E-Verify mandatory for Arizona employers. And as word of the harsh laws spread, it also disrupts the flow of immigrants who would normally arrive in time to harvest Arizona's crops.
Several other states, including Georgia, Colorado, Mississippi, Missouri, Pennsylvania, South Carolina, Tennessee, Virginia, and West Virginia, have adopted similar laws.
"Arizona agriculture is very labor-intensive," says Joe Sigg, a lobbyist for the Arizona Farm Bureau, adding that because fruits and vegetables grown here are sold as fresh produce, taking care not to damage their appearance carries greater importance. It also makes them that much harder to harvest.