DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is an herbicide that inhibits photosynthesis. It was introduced by Bayer in 1954 under the trade name of Diuron. ==Mechanism of action== DCMU is a very specific and sensitive inhibitor of photosynthesis. It blocks the plastoquinone binding site of photosystem II, disallowing the electron flow from whe...