Persistence and movement of ethofumesate in soil*

Summary: Persistence of ethofumesate [(±)2‐ethoxy‐2.3‐dihydro‐3,3‐dimethylbenzofuran‐5‐yl‐methansulphonate] in soil was associated with soil temperature. Ethofumesate applied at 4.5 kg/ha in November persisted about twice as long in soil as that applied the following March. In another field study, 88–91% of the herbicide had dissipated after 24 weeks in sandy loam soil, compared to 72–77% in loam soil when it was applied at rates of 2.2, 3.4, 4.5, and 9.0 kg/ha. The rate of degradation was independent of the initial rate of chemical applied. The time required for 50% of the herbicide to dissipate in sandy loam and loam soils was 7.7 and 12.6 weeks, respectively. The movement of ethofumesate in these two soils over a 24‐weeks sampling period was confined mainly to the upper 7.5 cm of the soil profile.