Although agriculture is gradually yielding to industry as the core of the state's economy, California leads the nation in the production of fruits and vegetables, including carrots, lettuce, onions, broccoli, tomatoes, and strawberries. The state also produces the major share of U.S. domestic wine. California's farms are highly productive as a result of good soil, a long growing season, and the use of modern agricultural methods. Irrigation is critical, especially in the San Joaquin Valley and Imperial Valley. The gathering and packing of crops is done largely by seasonal migrant labor, primarily Mexicans.
Fishing is another important industry.
Much of the state's industrial production depends on the processing of farm produce and upon such local resources as petroleum, natural gas, lumber, cement, and sand and gravel. Since World War II, however, manufacturing, notably of electronic equipment, computers, machinery, transportation equipment, and metal products, has increased enormously. Defense industries, a base of the economy especially in S California, have declined following the end of the cold war, a serious blow to the state. Farther north, Silicon Valley, between Palo Alto and San Jose, so called because it is the nation's leading producer of semiconductors, is also a focus of software development. California continues to be a major U. S. center for motion-picture, television film, and related entertainment industries, especially in Hollywood and Burbank .