In California, for example, about 325,000 workers are estimated to be at risk of deportation.
Already farmers and labour contractors are pondering how they might respond.
Some are buying equipment to do the job now done by Mexican immigrants.
Others have been talking to their workers to assure them they will be doing all they can to secure their continued employment.
Farmers are far from the only ones in the food chain who could be hit hard by mass deportations. Meat packers, for example, are major employers of illegal immigrants.
So are the contractors who build barns.