1.   Cut the vines back to two or three buds.

2.   I was the prince who had to march up the aisle, cutting great vines and killing dragons with a cardboard sword.

3.   If a watermelon is ripe, they cut the vine near where it meets the melon and flip the melon over so its yellow belly is facing upward.

4.   Or you can cut the vine where it emerges from the ground and paint the stump with either of those chemicals to minimize resprouting.