An attempted crackdown on minimum wage and child labor violations at berry farms in the Pacific Northwest has sparked a backlash that threatens one of the U.S. Labor Departments most potent tools for enforcing protections for farm workers. Blueberries grown on an Oregon farm. Like her sister, Librada Monjaraz Vasquez, 13, is a licensed worker harvesting blueberries at Forest Hills Farms in Hillsboro, Oregon.