WASHINGTON - Taking his blowhard act to Congress, comedian Stephen Colbert has told U.S. lawmakers he does not want Mexicans picking his tomatoes. And he expressed befuddlement that more Americans are not clamouring to "begin an exciting career" in farm work.

A straight-faced Colbert testified in character Friday at a House hearing on illegal farm workers. He offered what he called his "vast" knowledge of the subject after spending a day on a vegetable farm in New York.

Colbert described his ordeal of stooping to pick beans as "really, really hard." As he put it: "It turns out, and I did not know this, most soil is at ground level."

He pleaded with Congress to do something about illegal workers because "I am not going back out there."