oxadiazon

Oxadiazon is a synthetic, soil-applied herbicide used primarily as a pre-emergence treatment to control a range of annual grasses and some broadleaf weeds in turfgrass, ornamentals, and landscape plantings. It belongs to the oxadiazole family of herbicides and is marketed under various brand names, with Ronstar one of the most well known. Formulations include granular and liquid products that are applied to the soil surface or incorporated shallowly before weed seeds germinate.

Mode of action and selectivity are consistent with soil-applied pre-emergence herbicides: oxadiazon creates a soil barrier that inhibits the germination or early development of susceptible weed seedlings. It is generally selective for established turfgrasses when used according to label rates, but sensitive species or newly seeded lawns can be injured if rates are exceeded or application timing is inappropriate.

Application guidelines emphasize timing and irrigation. Oxadiazon is most effective when applied before weed germination in the appropriate season for the climate, followed by irrigation or rainfall to move the chemical into the root zone. It is commonly used on residential and commercial lawns, golf course roughs, and ornamental turf. New seedings or plugs should not be treated until the stand is established, and users should follow label directions regarding re-entry intervals, compatibility with other products, and crop rotation.

Environmental and safety considerations include limited water solubility and moderate persistence in some soils. It may pose risks to aquatic life if runoff or drainage carries it into water bodies. Humans and animals should handle and apply the product according to the label, using appropriate protective equipment and avoiding drift or exposure. Regulatory status varies by country, but oxadiazon is registered for use in turf and ornamental applications in many jurisdictions.