Cyhalofop

Cyhalofop is a herbicide that is used to control grass and broadleaf weeds in rice crops. It is a member of the aryloxyphenoxy propionate (AOPP) group of herbicides, which work by inhibiting the enzyme acetyl coenzyme A carboxylase (ACCase).

Chemistry

Cyhalofop is a synthetic compound that is derived from phenoxypropionic acid. It has the chemical formula C_22H_20ClFNO_4 and a molecular weight of 411.85 g/mol. The compound is a white crystalline solid at room temperature and is slightly soluble in water.

Mode of Action

Cyhalofop works by inhibiting the enzyme ACCase, which is essential for the synthesis of fatty acids in plants. This inhibition disrupts the plant's lipid metabolism, leading to a cessation of growth and eventually death. The herbicide is absorbed by the plant's leaves and is then translocated to the meristematic tissues, where it exerts its effects.

Use in Agriculture

Cyhalofop is primarily used in rice cultivation to control grass and broadleaf weeds. It is applied post-emergence, meaning after the weeds have sprouted. The herbicide is effective against a wide range of weed species, including Echinochloa crus-galli, Leptochloa chinensis, and Digitaria sanguinalis.

Environmental Impact

Like all herbicides, cyhalofop can have an impact on the environment. It is moderately toxic to birds and mammals, but is highly toxic to fish and aquatic invertebrates. The compound is also persistent in the soil, with a half-life of up to 40 days.

Safety and Health Effects

Exposure to cyhalofop can cause irritation to the eyes and skin. Ingestion or inhalation can lead to symptoms such as nausea, vomiting, and difficulty breathing. Long-term exposure can potentially lead to liver and kidney damage.

Regulation

In the United States, cyhalofop is regulated by the Environmental Protection Agency (EPA). It is classified as a Restricted Use Pesticide (RUP), meaning it can only be used by certified applicators.