Evaluation of biodiesels from several oilseed sources as environmental friendly contact herbicides

Postemergence contact herbicidal activities of biodiesels from several oilseed sources were examined for potential use to control broadleaf weeds in turfgrasses. Cuphea, lesquerella, meadowfoam, milkweed and soybean oils were applied as 1 and 2% (v/v) aqueous emulsions plus a nonionic surfactant to 2-week-old seedlings of perennial ryegrass, velvetleaf and sicklepod in the greenhouse. All five biodiesels were more phytotoxic to sicklepod and velvetleaf than to perennial ryegrass. Several different surfactants were tested together as emulsions with 1% soybean biodiesel, with Triton X-100 being the most effective. These results indicate that biodiesels may be useful as environmental friendly contact herbicides in turfgrasses, as there are few contact herbicides options available for the homeowner market which will not cause turf injury.