This all happened before in California. The fruit harvest all fell to the ground and rotted because no Americans wanted to work for shit wages and Trump was patrolling the border. Then the prices of fruit skyrocketed and people started complaining. I emember my cousins in Oroville telling me all about it.
Discussion
Markets /can/ fix this however with proper planning.
A free market would fix it automatically, no planning needed, but to keep national borders (denying free trade between parties that strattle the border) then you need planning to compensate.
I accept there is a practical need for national borders, but I still see them as primarily a violation of freedom.
To isolate for security reasons, there will be a disruption period but yes eventually it will settle.
Forget the wages, many dont want to work in the heat. Office and white collar jobs have spoiled them. Heat stroke for everyone and as you mentioned wasted harvest.
Which puts the farmer in more debt