Dimethenamid

Dimethenamid is a selective herbicide used for pre-emergent control of annual grasses and certain broadleaf weeds. It is commonly used in corn and soybean crops. Dimethenamid is a member of the chloroacetamide family of herbicides, which also includes acetochlor, alachlor, and metolachlor.

Chemistry

Dimethenamid is a yellowish liquid with a slight odor. It is not very volatile, nor is it likely to evaporate into the air. It is moderately soluble in water and has low soil mobility. The chemical formula for dimethenamid is C12H18ClNO2S.

Mode of Action

Dimethenamid works by inhibiting the germination of weed seeds. It interferes with the plant's cell division process, specifically the formation of the cell plate, which is crucial for cell division in plants. This prevents the weed from growing and eventually leads to its death.

Health Effects

Exposure to dimethenamid can cause irritation to the eyes, skin, and respiratory tract. Long-term exposure can lead to more serious health effects such as liver and kidney damage. However, the Environmental Protection Agency (EPA) has classified dimethenamid as a Group E chemical, which means it is not likely to be a human carcinogen.

Environmental Impact

Dimethenamid is moderately toxic to birds, fish, and bees. It has a half-life of 14 days in soil, which means it does not persist in the environment for long periods. However, it can leach into groundwater if used in areas with high rainfall or permeable soils.

Regulation

In the United States, dimethenamid is regulated by the EPA under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). It is classified as a Restricted Use Pesticide (RUP), which means it can only be sold to and used by certified applicators.

Chemical structure of dimethenamid

See Also

• Pesticide
• Herbicide
• Chloroacetamide