It's probably not your intention, but I greatly dislike this argument, as it's similar ones were made to justify previous inhumane practices that were legal before the conclusion of the US Civil war.
If manual labor is required for agriculture, let the market absorb the real cost and pay the workers the correct wage instead of exploiting them.
The process can be orderly. I live in a town with a couple of commercial orchardist, and they get their apples picked by workers on temporary work visas every year for decades now. These commercial orchards are apparently economically viable, even though they are smaller than a typical commercial orchard in Washington state, for example.
As with tariffs, I can imagine this situation being less orderly or predictable now. But I've seen both theory and practice work as intended.
A countries agricultural base being dependent on undocumented migrant workers is bad and should be corrected. However simply deporting all the migrants overnight with no further action doesn't fix the underlying problem, doesn't help the industry, and doesn't help the consumers.
All things being equal, people will generally choose to follow the law. So figure out why the migrants and their employers are choosing not to follow the law and fix that.
You could do like Australia, offer a working-holiday visa with the possibility to renew it for up to 3 years on the condition that you spend a certain amount of time working on a farm/ in rural area.
Loads of people do it in Australia and it helps tremendously. It's not perfect for sure, but it's something.
Consider this vague hypothetical, because I'm not American and don't care about the specifics:
Country A, average wage X; country B, minimum wage for legal residents 2X. People from A can on average get a pay rise by working in B while undercutting legal residents of B. Citizens of B then get the stuff cheaper than they otherwise would have, but also might not be as easy to employ.
Are current employment stats accurate? As in do they tell the right picture or is this a case of "lies, damn lies, and statistics"? Lots of people say it's the later, and unfortunately I'm not qualified to explore anyone's arguments.
I suppose that's fine if that is your solution. It's easy for me to say "things should probably cost more" because I can afford it.
If I'm allowed to fret a bit for my fellow countrymen, I confess I am saddened that they will have to decide between food or rent in the coming months/years. When my single mom raised my sister and I she had to make that same choice at times.
Ah, but you see the thing is here in the land of the free, we consider this type of thinking to be "Communism" and must be purged without any further thought.
If manual labor is required for agriculture, let the market absorb the real cost and pay the workers the correct wage instead of exploiting them.