It prevents protein production by shutting down shikimic acid pathways needed to produce glucose during photosynthesis. It's still going through photosynthesis, it's no longer producing anything in the end for the plant and it dies.That's why it's possible to make Round-up ready crops.We mow, drill in seed, and glypho bomb a day or two later. If it ain't green and growing, glypho won't have any effect on it at all. It doesn't kill vegetation by chemical means, it's a super sunscreen that blocks uv and prevents photosynthesis.