Mosquito Fern

Mosquito fern (Azolla caroliniana) have small fern-like leaves that turn from green to red as the plant ages.  Small roots dangle into the water from each leaf.  The tiny clusters of leaves are usually 1/2 to 1 inch across.  Mosquito fern will form a layer on the surface of the pond that will move around with the wind and can sometimes cover the entire pond if conditions are calm.  Heavy infestations can shade sunlight and reduce productivity.  It is often associated with duckweed and from a distance can look like a Euglena bloom during its red phase.

Management Options

Mechanical Options

Mosquito fern can be removed from the pond through physical measures (booming, raking, etc.).

Biological Options

Grass Carp will consume mosquito fern but they have low effectiveness at controlling it.

Chemical Options

The active ingredients that have been successful in treating mosquito fern include: Diquat (G), Fluridone (G) and Penoxsulam (E). E = excellent, G = good

Return to the non-rooted floating vegetation page