Le Sueur County has set aside AIS Prevention Aid funds for new infestations/introductions of Aquatic Invasive Species that are found within the County. Early detection and management is crucial to minimize the spread and impacts of the new infestation/introduction within a body of water and to surrounding bodies of water.
New infestations of Aquatic Invasive Species have been limited to Eurasian Watermilfoil and Flowering Rush in Le Sueur County. Zebra Mussels have been detected within the Minnesota River; however, they are not present within Le Sueur County lakes.
Eurasian Watermilfoil (EWM) was spotted in Lake Tetonka in October 2016. Hand removal efforts occurred in late October of 2016. In 2017, there was a follow up survey for EWM, and no EWM was observed. Lake Tetonka is hydrologically connected to Upper Sakatah Lake due to the Cannon River. Eurasian Watermilfoil is still being actively management by the Waterville Lake Association.
Eurasian Watermilfoil (EWM) was removed from Lake Francis in the fall of 2018. This was a continued effort to control an EWM infestation that began in 2017. Hand removal was selected due to the healthy population of native aquatic vegetation that resides in Lake Francis. Eurasian Watermilfoil is still being actively managed in Lake Francis by the Lake Association.
Upper Sakatah Lake
Eurasian Watermilfoil was detected in Upper Sakatah Lake in the summer of 2020. The presence of Eurasian Watermilfoil was located on the south side of the lake, in sparse patches, and found in shallow water. Le Sueur County informed neighboring counties and soil and water conservations districts, lake associations, and watercraft inspectors of the new infestation. Additionally, an article was posted in the local paper.
Le Sueur County partnered with the Waterville Lakes Association and the Minnesota DNR to treat the Eurasian Watermilfoil that was present. The treatment was completed on September 22, 2020. A chemical treatment was used, specifically 2,4-D Anime. Upper Sakatah Lake will be surveyed in 2021 to see how the chemical treatment worked, and if additional treatment methods are needed.
DNR staff surveyed Upper Sakatah Lake and found that the Eurasian Watermilfoil was still present in small, sparse patches. Chemical treatment was effective in keeping the population of Eurasian Watermilfoil low. However, the Eurasian Watermilfoil established on the northside of the lake. Since the population of Eurasian Watermilfoil was sparse on Upper Sakatah Lake, chemical treatment was not recommended. Hand removal was approved and completed in the fall of 2022. The lake will be surveyed in 2023 to see how effective the hand removal treatment is.
Maps were developed by Carli Wagner, MN DNR Aquatic Invasive Species Specialist
Eurasian Watermilfoil was detected and confirmed in August 2022 on Sunfish Lake. The population of Eurasian Watermilfoil is congregated to the eastern half of the lake. Sunfish is not a busy recreational lake and is pretty small. Furthermore there is no hydrologic connectivity to other lakes. More than likely EWM was introduced at access or on water related equipment. Le Sueur County posted a press release to inform county residents about the new infestation and informed neighboring counties as well. A chemical treatment, specifically 2,4 D Anime was used in September of 2022 to treat 0.57 acres of the EWM. A follow up survey in 2023 will occur to determine the effectiveness of the chemical treatment.
Map was developed by Carli Wagner-MN DNR Aquatic Invasive Species Specialist-Sunfish Lake
Eurasian Watermilfoil (EWM) was detected and confirmed on Tustin Lake in September 2022. During the time of the survey, an abundance of EWM plants and native plants were observed. Furthermore, Lake Tustin had a strong presence of blue green algae. Due to amount of plants and the blue green algae that was present, treatment efforts were not an option. Le Sueur County posted a press release to inform county residents about the new infestation and informed neighboring counties as well. Lake Tustin is hydrologically connect to Rays Lake and Lake Francis, which are both already infested with Eurasian Watermilfoil. The Minnesota DNR will survey Tustin Lake next year to see if treatment efforts would be possible.
Map was developed by Carli Wagner-MN DNR Aquatic Invasive Species Specialist