Hybrid Watermilfoil Management Update - Fall ‘23

By Amy Kay, Black Lagoon Pond and Lake Management

The Sauk River Chain of Lakes Association (SRCLA), with support from their service providers and the Minnesota Department of Natural Resources, has implemented a plan for the management of Hybrid Watermilfoil (HWM) on the Sauk River Chain of Lakes. HWM was identified in both Horseshoe and Cedar Island Lakes in recent years and a management plan using the aquatic herbicide, ProcellaCOR (florpyrauxifen-benzyl) was chosen. ProcellaCOR is a selective, systemic aquatic herbicide meaning it has a tendency to control only the targeted species while having minimal to no impact on any other aquatic vegetation. Implementing the use of ProcellaCOR supports the objective of selectively managing the HWM to minimize the spread and establishment of invasive species while promoting an environment to support native plant growth. Research shows that ProcellaCOR is more effective than conventional technologies, particularly as they relate to the control of HWM, and may provide longer term (multiple seasons) of control. 

In 2022, ProcellaCOR applications were made to infestations identified by the SRCLA and their survey provider, Limnopro Aquatic Science, on Horseshoe Lake. This project resulted in successful control in the management sites. Additional infestations were found following the 2022 project on both Horseshoe and Cedar Island Lakes which the SRCLA chose to manage in 2023 following additional survey work to confirm and refine targeted sites of HWM.

On July 13, 2023, licensed aquatic pesticide applicators applied ProcellaCOR to 29 sites totaling 24.5 acres. Applications began just before 7:00 am and concluded at 12:30 pm. Additional survey work is planned to evaluate the effectiveness of the ProcellaCOR applications, monitor prior application sites and locate any new infestations on the Chain. .