On another note, it IS the government's responsibility for taking millions of Americans out of the work force that would qualify for just this type of work.
Return welfare to the private (religious) realm where it belongs, and the bums will be shamed into doing some work (or starve: he who will not work, nor shall he eat).
The numbers are pretty clear and inarguable regarding unskilled and semi-skilled construction labor: illegal aliens have reduced the average gross wage rate by 20 to 50 percent compared to 1976-1979.
I personally spent come time doing research on this based on comments I heard from Steve Camarata of the Center For Immigration Studies during a radio interview. It turns out that Camarata and I both did construction labor during our college summers at just about the same time (late-70's), and for just about the same hourly rates ($6 to $8 per hour).
Camarata stated - and I have verified - that any of the major statistical measures would have construction laborers making a 1970's-normalized $18 to $29 per hour on today's job site. But we all know anecdotally that illegals are being paid about 80 percent to as little as 50 percent of those normalized rates (e.g., $12 to $16 an hour for illegals).
I would imagine that agricultural and all other unskilled and semi-skilled jobs are likewise paying substandard wages compared to the rates of 30 years ago.
When American businesses stop paying for this marginally cheaper but illegal commodity (peasant Mexican labor), Americans will most certainly take the jobs that employers now just don't feel like paying at livable wages.
Sorry, but American employers need to be reminded with "the big stick" that what they are doing is not merely unethical, not merely subversive to the U.S. economy, but a federal felony that can land them in very hot water.