I read the article you posted.

The argument that "Americans don't want these jobs even when you up the wage and add benefits" is only supported by a couple of anecdotes from growers who have an interest in maintaining the supply of foreign laborers, and I don't think that is sufficient to make the point.

I would maintain that there is a wage at which a sufficient number of Americans would be willing to do farm labor. Whether that would raise the price of crops beyond what consumers are willing to pay for them is another question entirely.

As an aside, I'm not opposed to foreign workers in the US, but I do find the argument that they are needed because "there aren't any Americans who want to do this" to be a bit disingenuous.