CLEAR LAKE, Iowa — The Iowa Department of Natural Resources (DNR) has initiated treatment of Clear Lake with the aquatic herbicide Sonar A.S. to combat the invasive Eurasian watermilfoil. The DNR says this effort aims to prevent the plant from spreading further. Sonar A.S. works by starving the plant of a pigment necessary for photosynthesis. It has been effective in other Iowa lakes and poses no restrictions on activities like swimming and fishing at the planned dosage. Jason Euchner, an Aquatic Plant Management Biologist for the DNR, explained that the treatment involves using a low concentration of 5 parts per billion, requiring only 133 gallons of herbicide. The DNR will continue treatments through next spring, with bi-weekly water testing to adjust herbicide levels as need

See Full Page