[Excerpt] The spring of 1933 ushered in a wave of labor unrest unparalleled in the history of California agriculture. Starting in April with the Santa Clara pea harvest, strikes erupted throughout the summer and fall as each crop ripened for harvest. The strike wave culminated with the San Joaquin Valley strike, the largest and most important strike in the history of American agriculture.
All told, more than 47,500 farmworkers participated in the 1933 strikes. Twenty-four of these strikes, involving approximately 37,500 workers, were under the leadership of the Communist-led Cannery and Agricultural Workers Industrial Union (CAWIU). In a dramatic reversal of its previous record of repeated debilitating losses, twenty of the CAWIU-led strikes resulted in partial wage increases while only four strikes ended in total defeat for the union. The remaining strikes, including three spontaneous walkouts, two American Federation of Labor (AFL) led strikes and two led by independent unions, resulted in partial gains in four out of the seven conflicts.