Alarm spread through California agricultural centers Tuesday as panicked workers reported that federal immigration authorities were showing up at farm fields and packinghouses from the Central Coast to the San Joaquin Valley.

Large-scale immigration raids at packinghouses and fields in California are threatening businesses that supply much of the country’s food, farm bureaus say.

The nation’s most abundant harvest is ripening in California’s Central Valley fields, but the people at the heart of these agricultural communities are living in fear. Rumors of immigration raids — most unconfirmed — swirled from Colusa to Kern counties this week.