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

Dozens of farmworkers have been arrested after uniformed federal agents fanned out on farms northwest of Los Angeles in Ventura County, which is known for growing strawberries, lemons, and avocados.

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. Whispers of immigration raids — most unconfirmed — swirled from Colusa to Kern counties this week.