AgJobs is the bill that was written in 2003 to reform the H2A ag worker visa and one of the provisions of that bill was to give the union broad access to the workplace to organize.
More importantly, AgJobs also has the path to citizenship/green card language that makes the worker easier to organize. Temp workers are hard to organize.
Make the employers of illegal aliens pay the full cost of bringing in non-American workers, i.e. K-12 education for the illegal aliens' kids, health care, etc.
You will be amazed at how quick those employers find American workers to do the work.
Illegal immigration is the mother of all corporate welfare programs.