I've got purple and green grape vines that are about 30-50 years old. About
8 vines on a trellis about 12 feet wide 5 foot tall. They are an eyesore.
The trellis is shot. It is located about 10 feet from my garden. Mowing
under them sucks. But it gives me a little privacy from my neighbors when I
bbq, or just want to sit out there. . Saying that, the Japanese beetles
devour them, and last year, I sprayed them on my corn a bit, and the
beetles left my corn mostly alone.

Should I keep them for that reason, Or if I take them down, will the
Japanese beetles go elsewhere. or give me a worse problem.

Diesel.