Close the border first. Then start complete inspections as a negotiated compromise. If the produce trucks back up and spoil, Mexico will want the wall and help pay for it.
Some history...how the French overcame Japanese VCR imports...the Poitiers border crossing:
The French designated the Poitiers customs post as the sole point for checking VCR imports from Japan.
This border post is in central France, manned by an only one clerk and is open at limited times
End result: hundreds of semi-trailers backed up for miles in rural France
And Japan promptly caves.