Oxadiazon is the active ingredient in the herbicide Ronstar, intended for preemergence or early post emergence application. When applied to soil during these phases, oxadiazon controls the growth of certain undesirable weeds such as broadleaves, grasses, sedge, brush vines, and bramble.
Oxadiazon is labeled as practically non-toxic to mammals, non- to slightly toxic to birds, and moderately to highly toxic to fish. It should never be applied directly to water or where surface water is present as it can contaminate water sources.
Oxadiazon is an inhibitor of protoporphyrinogen oxidase, an essential enzyme in plant growth.
Oxadiazon (Ronstar) may be used for weed control on established perennial turf (bluegrass, bermudagrass, St. Augustine grass, fall fescue, etc.) and is registered for commercial use in nurseries, turf, non-food crops and commercial landscapes.
The EPA classifies oxadiazon and Ronstar as category II chemicals (moderate toxicity) requiring the word WARNING to be visible on the label. Excessive exposure of oxadiazon may cause skin, eye, and nose irritation. It has also been classified as "likely to be carcinogenic to humans" based on lab tests performed on mice and rats where liver tumors increased after long-term, repeated exposure.