Diuron is a systemic herbicide that blocks photosynthesis by binding the D1 protein of photosystem II, used for selective control of germinating grasses and broad-leaved weeds in fruit crops, cereals and legumes. Absorbed through roots and translocated upward, it starves susceptible seedlings of the energy needed for growth. Registrations specify application rates, timing and buffer zones, and monitoring programs check treated crops against maximum residue limits. Users must follow label rates and avoid applications near water, where the compound can affect aquatic plants.