Permit writers may require that an Ecology-approved integrated aquatic plant management plan be developed for each waterbody or site before a permit will be issued for herbicide use. Several other herbicides are undergoing review and it is possible that other chemicals may be approved for use in Washington in the future. It is generally applied as a liquid to the leaves. Rodeo does not work on underwater plants such as Eurasian watermilfoil. Although glyphosate is a non-selective herbicide, a good applicator can somewhat selectively remove targeted plants by focusing the spray only on the plants to be removed.
Plants take several weeks to die.
A repeat application is often necessary to remove plants that were missed during the first application. Sonar Active ingredient fluridone . Sonar is a slow-acting systemic herbicide used to control Eurasian watermilfoil and other underwater plants. It may be applied in pelleted form or as a liquid. Fluridone can show good control of submersed plants where there is little water movement and an extended time for the treatment.