Pendimethalin

Pendimethalin is a selective herbicide from the dinitroaniline class. It is used to control most annual grasses and certain broadleaf weeds in field corn, potatoes, rice, cotton, soybeans, tobacco, peanuts, and sunflowers.

Chemistry

Pendimethalin is a yellow-orange solid with a slight aromatic odor. It is practically insoluble in water but soluble in most organic solvents. The chemical formula of pendimethalin is C13H19N3O4. It is a member of the dinitroaniline class of herbicides, which also includes trifluralin, ethalfluralin, and prodiamine.

Mode of Action

Pendimethalin acts by inhibiting the germination and growth of weed seeds. It interferes with the plant's cell division process, specifically the formation of the spindle apparatus, which is essential for cell division. This inhibition prevents the weed from growing and eventually leads to its death.

Usage

Pendimethalin is applied pre-emergence, that is, before the weed seeds germinate. It can be used in a variety of crops including field corn, potatoes, rice, cotton, soybeans, tobacco, peanuts, and sunflowers. It is also used in non-crop areas such as lawns, ornamental plants, and forestry.

Environmental Impact

Pendimethalin is moderately toxic to birds and mammals but is highly toxic to fish and aquatic invertebrates. It has a low potential for bioaccumulation and is not likely to leach to groundwater due to its strong adsorption to soil particles.

Health Effects

Exposure to pendimethalin can cause irritation to the eyes, skin, and respiratory tract. Chronic exposure can lead to weight loss, liver damage, and changes in blood chemistry.

Regulation

In the United States, pendimethalin is classified as a Restricted Use Pesticide (RUP) by the Environmental Protection Agency (EPA) due to its toxicity to aquatic organisms.

See Also

• Herbicide
• Dinitroaniline
• Environmental Protection Agency

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