More evidence of milfoil and other invasive plants is emerging in New Hampshire. Plants like fanwort, water chestnut, and infectious algae like didymo (also known as “rock snot”) have been discovered in lakes, rivers and ponds throughout the state.

The N.H. Department of Environmental Services says traces of the intrusive organisms have been confirmed in 78 state water bodies. They can spread across entire lakes and ponds and can clog waterways with excessive growth.

The “aquatic hitchhikers” can be inadvertently transported on boats, fishing and diving gear, motors, trailers and other recreation equipment. State officials are asking boaters and anglers to help prevent them from spreading further.

Scott Decker, supervisor of the fisheries program at N.H. Fish and Game, said a two- to three-inch portion of an exotic plant can ignite water-wide infection. He said the plants can be identified upon visual inspection, and boaters and anglers should scan and clean their equipment frequently.

The DES and the N.H. Lakes Association have recruited more than 500 “Lake Host” volunteers to perform courtesy boat inspections and educate individuals about the infiltration of the plants at 92 state boat launches. The program has already helped protect water bodies from plant infection in 36 cases this year.