Also known as stoneworts Is a branched multicellular algae that resembles Chara. Nitella has no true leaves but does have slender branches and branchlets. It does not have flowers and will not extend above the water surface as it grows mostly in shallow water. Finally, Nitella It is not rough to the touch and lacks the garlicky smell of Chara.

Prevention

Excessive growth of Nitella is caused by a surplus of nutrients in the pond water from nearby barnyards, crop fields, septic systems, lawns, and golf courses. To prevent its overabundance is necessary to reduce fertilizer application near the pond, maintain septic systems properly, redirect nutrient-rich runoff away for the pond and maintain a vegetative buffer strip around your pond.

Physical/Mechanical Control

Nitella may be removed with a rake using a Lake Rake, seine or wire screen. Repeated mechanical harvesting can help reduce stem densities, but escaped fragments can develop into new plants. Mechanical control is practical when used in conjunction with chemical control methods, or as a maintenance treatment around swimming or fishing areas. Algae removed from the pond should be raked and taken out of the water or deposited below the pond’s dam to ensure that nutrients contained in the vegetation do not re-enter the pond.

Dyes and colorants reduce aquatic plant growth by limiting sunlight penetration and reducing photosynthesis.

Macroalgae can sometimes be managed with a water pump that circulates the top layer of water in the pond.

Biological Control

Beneficial bacteria products and enzymes such as PZ900 feed on nutrients in the water making them unavailable for algae growth. Reducing nutrients can help prevent invasion.

Chemical Control

Various aquatic herbicides are effective in controlling Nitella. The products that have been most successful in treating Nitella include Cutrine Plus, Copper Sulfate, Propeller, Hydrothol 191, and Reward.

Copper Sulfate is a common algal treatment because of its availability and low cost. However, in very hard water, copper will bind with the calcium and precipitate out of solution rendering it ineffective as an algaecide. Before using copper is it best to test the pond water’s alkalinity and adjust copper treatments to alkalinity concentrations. All copper compounds can be toxic to fish.

CutrinePlus liquid and granular are chelated and inorganic copper base herbicides that are highly effective, fast acting, safe and easy to use. CutrinePlus liquid or granular do not have water use restrictions. CutrinePlus is toxic to trout, koi fish and goldfish.

Propeller is highly effective in spring and early summer, during the plants’ rapid growth phase. Propeller is rapidly degraded, and it has no environmental footprint.

Hydrothol 191 is a contact herbicide. Contact herbicides act quickly and kill all plant cells that are targeted. Hydrothol can be toxic to fish.

Reward is a fast-acting contact herbicide, highly effective in treating the larger biomasses that had formed by mid to late summer.