Washington State Noxious Weed Control Board.

Washington State Noxious Weed Control Board.

Washington State Noxious Weed Control Board.

Washington State Noxious Weed Control Board.

Wisconsin Department of Natural Resources.

Lake George Association (New York).

PBS. NOVA.

Virginia Department of Wildlife Resources.

University of California - Riverside. Center for Invasive Species Research.

Michigan.gov. Michigan Invasive Species Program.

The Michigan departments of Environment, Great Lakes, and Energy and Natural Resources confirmed a report of didymo, a nuisance freshwater alga, in a stretch of the Upper Manistee River in Kalkaska County. Also known as rock snot despite its coarse, woolly texture, didymo can grow into thick mats that cover the river bottom. The Manistee River finding marks the first detection of didymo blooms in the Lower Peninsula. In 2015, extensive mats of didymo were found on the Michigan side of the St. Marys River near Sault Ste. Marie in the Upper Peninsula.

If you observe didymo in the water, either as small, cotton ball-sized patches or thick blankets with rope-like strings that flow in currents, take photos, note the location and report it by using the Midwest Invasive Species Information Network, available online at MISIN.MSU.edu or as a downloadable smartphone app. The MISIN smartphone app will take a GPS location point if a report is made at the site; it also will allow you to upload photos with a report. Find more information on didymo and how to identify it at Michigan.gov/Invasives.

University of Georgia. Center for Invasive Species and Ecosystem Health.

Provides state, county, point and GIS data. Maps can be downloaded and shared.

University of Georgia. Center for Invasive Species and Ecosystem Health.

Provides state, county, point and GIS data. Maps can be downloaded and shared.

University of Georgia. Center for Invasive Species and Ecosystem Health.

Provides state, county, point and GIS data. Maps can be downloaded and shared.

University of Georgia. Center for Invasive Species and Ecosystem Health.

Provides state, county, point and GIS data. Maps can be downloaded and shared.

University of Georgia. Center for Invasive Species and Ecosystem Health.

University of Georgia. Center for Invasive Species and Ecosystem Health.

Provides state, county, point and GIS data. Maps can be downloaded and shared.

University of Georgia. Center for Invasive Species and Ecosystem Health.

Provides state, county, point and GIS data. Maps can be downloaded and shared.

University of Georgia. Center for Invasive Species and Ecosystem Health.

Provides state, county, point and GIS data. Maps can be downloaded and shared.

University of Georgia. Center for Invasive Species and Ecosystem Health.

Provides state, county, point and GIS data. Maps can be downloaded and shared.

University of Georgia. Center for Invasive Species and Ecosystem Health.

Provides state, county, point and GIS data. Maps can be downloaded and shared.