Hi Kelly, What would be your preferred chemistry on watershield. Have had success with Habitat but perhaps there is a better approach.
In the wise words of Bill Cody, "it depends" - on the lake's design, degree of infestation, water-use restrictions, presence of any desirable plant species, ability to perform repetative treatments, etc.
HABITAT (imazapyr) will certainly control watershield whose pads have reached the surface (IE. subjected to direct spray-contact). However, any pads that are submerged at the time of application will be unaffected; thus requiring repetative treatments at regular intervals until the population is under control.
