Shortages of farm labor hit Florida, California. Are they due to immigration enforcement?

In Florida, H-2A farm guest worker program is increasingly used to solve labor shortages on farms. In California, after a catastrophic pear season last year, farmers are ernest about getting a broad guest worker program into place. The increased demand may be due to stricter enforcement against illegal workers. In any event, H2A use is up 500% in Florida.
In Florida:
Florida growers and farmworker advocates say that the number of guest workers being employed picking Sunshine State crops is up 500 percent. Last year, there were about 1,000 guest workers legally in the United States under the federal program — referred to as H2A — with about 16 employers applying for workers.
In 2006, that ballooned to about 5,000 with more than 70 employers applying, says Greg Schell, a Lake Worth labor attorney and farm worker advocate. The unresolved immigration debate is likely to force even more employers to tap the H2A program, under which a guest worker visa is good for 364 days.
President Bush has been pushing for an extensive revamping of immigration law. He wants a guest worker program and the possibility of eventual citizenship for many illegal immigrants already in the country. In the past, H2A has not been broadly used by Florida growers because of its costly and complicated nature. Exactly who is going to be paying the additional costs of the program for farmers in unclear, but, all things being equal, growers are likely to pass the cost along to consumers.
Spencer said that labor was the primary obstacle to getting his crops to grocery store aisles during the past year. The shortage was unprecedented for an industry that relies so heavily on Latino immigrant workers. There has also been a drastic increase in the number of H2B workers. It is a sister program open to industries other than agriculture that tops out at a set number of issued work visas. The measure has been used in the past in landscaping, manufacturing and construction.
In California:
Growers say aggressive security patrols along the U.S.-Mexico border have created a labor shortage that’s left apples hanging on trees in Washington state, marred berry harvests in Oregon and delayed the onion harvest in Texas. The American Farm Bureau Federation has warned labor shortages could cause $5 billion in losses to the agriculture industry.
The economic threat is particularly acute in the nation’s top agricultural state where more than one-third of the nation’s farmworkers are employed, California farmers say. Last summer, a quarter of the pear crop in rural Lake County rotted on the field when pickers never showed up, said Toni Scully, a pear packer there.
“Throughout the summer, farmers were cobbling together workers to meet their immediate needs,” said Jack King, national public affairs manager for the California Farm Bureau Federation. “When we failed to push something through last year, we vowed we’d be back.”