Selectivity of Tefuryltrione between Rice and Eleocharis kuroguwai

Tefuryltrione is a new hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor, which has been recently registered for the use for paddy rice, Korea. Dose-response studies were conducted to compare rice safety and weed control efficacy of tefuryltrione against Eleocharis kuroguwai. When rice and E. kuroguwai were applied at a range of doses of tefuryltrione, <TEX>GR₉₀</TEX> values (the dose required to inhibit weed growth by 90%) of E. kuroguwai were <TEX>82.38-93.39g\;a.i.\;ha⁻¹</TEX> in two independent experiments. The <TEX>GR₁₀</TEX> values (the dose required to inhibit rice growth by 10%) of tefuryltrione for rice were <TEX>297.77-471.54g\;a.i.\;ha⁻¹</TEX>. As a result, the selectivity indices (<TEX>GR₁₀</TEX> for <TEX>rice/GR₉₀</TEX> for E. kuroguwai) of tefuryltrione were 3.19-5.72. Therefore, these results demonstrate that tefuryltrione has a relatively high selectivity between rice and E. kuroguwai with a high herbicidal activity against E. kuroguwai and a good rice safety.