Mexican Migrant Farmworkers This photograph by Dorothea Lange shows a Mexican migrant and his child harvesting carrots in the Imperial Valley of California in 1935. Demand for Mexican labor declined during the Great Depression as displaced farmers from the Dust Bowl moved west to take jobs formerly held by Mexicans. Government deportations further decreased the number of undocumented Mexican laborers in the United States. Copyright the Dorothea Lange Collection, the Oakland Museum of California, City of Oakland. Gift of Paul S. Taylor.