Dimesulfazet Controls Schoenoplectiella juncoides and Eleocharis kuroguwai Emerging From Different Soil Depths While Maintaining Rice Safety

Dimesulfazet is a novel inhibitor of very long‐chain fatty acid (VLCFA) biosynthesis that exhibits strong activity against Cyperaceae weeds in paddy fields. To characterize the biological performance of dimesulfazet, its herbicidal activity and crop selectivity were investigated in comparison with other VLCFA biosynthesis inhibitors, namely butachlor and esprocarb, and acetolactate synthase inhibitors, namely pyrazosulfuron‐ethyl and metazosulfuron. Rice ( Oryza sativa ) plants, Schoenoplectiella juncoides , and Eleocharis kuroguwai were grown at different emergence or planting depths, and shoot fresh weight responses to herbicide treatments were evaluated. Dimesulfazet showed excellent selectivity between rice and S. juncoides . Unlike butachlor and esprocarb, dimesulfazet caused little injury to transplanted or surface‐placed rice even at application rates exceeding the recommended field rate, while effectively controlling S. juncoides emerging from a depth of 2 cm at only 18.8 g a.i. ha −1 . Dimesulfazet also controlled E. kuroguwai grown from tubers buried at depths of 1, 3, and 5 cm at the same application rate. Similar depth‐independent efficacy was observed for metazosulfuron and, to a lesser extent, pyrazosulfuron‐ethyl. These results demonstrate that dimesulfazet combines excellent crop safety with high efficacy against S. juncoides and E. kuroguwai emerging from different soil depths, distinguishing it from the conventional VLCFA biosynthesis inhibitors tested and making it a promising option for controlling problematic Cyperaceae weeds in rice paddies.