You're right, of course.
What will happen is that taxes will be raised to provide additional subsidies to fruit farmers so that their fruit can be picked and sold for the current price.
Raising prices will mean that more fruit will be imported from Mexico (as is already being done) and American fruit farmers will simply go out of business.
Thereby forcing us to constantly rely on imports for a supply of of anything that would have been produced through the employment of illegals. Thus lowering our GDP, which would in turn force us to run a larger trade deficit than the one we are currently running.