During the interwar period, California's labor-intensive agriculture transitioned from reliance on diverse immigrants to preference for Mexicans. Political movements to restrict immigration, the Great Depression, and labor unrest compelled farm employers to search for labor that could be used flexibly and deported easily. To achieve this objective, the growers needed a central organization that could foster unity and articulate their collective interest. The formation of the California Farm Bureau Federation and the American Farm Bureau Federation in 1919 and 1920 provided such a political platform. When lawmakers sought to apply the quota provision of the Immigration Act of 1924 to Mexico, the growers' strong presence at congressional hearings demonstrated their rising influence in policy making. Moreover, the clear difference between Filipinos and Mexicans with respect to deportability during the Depression affirmed the flexibility of Mexican labor. Finally, at the height of labor unrest in the 1930s, the American Farm Bureau leadership called for agricultural class consciousness to strengthen unity and maintain dominance over the striking workers. The development of grower organizations in this era set the stage for California agriculture's almost exclusive dependence on flexible Mexican labor in the ensuing decades. (Contains 10 notes.)