Aquatic plants ›

Azolla

Alerts

There are no azolla alerts right now.

General Infomation

A small, floating aquatic fern. It can form a dense mat that completely covers the surface of a water body.

Biological Control

Biological Control of Aquatic Weeds with Triploid Grass Carp

Fair to Poor

Chemical Control

Herbicide, Formulation and Mode of Action Code
Amount of Formulation
Active Ingredient Rate or Concentration
Herbicide, Formulation and Mode of Action Code

2,4-D amine (various) MOA 4

Amount of Formulation

See label

Active Ingredient Rate or Concentration

2 to 4 lb/acre

Precaution and Remarks

Thorough wetting of foliage is essential. Apply in 100 to 400 gallons of water per acre. Use low pressure, large nozzle, and spray thickener. For use on nonirrigation ditchbanks only. Do not apply to water.

Herbicide, Formulation and Mode of Action Code

bispyribac (Tradewind) 80% MOA 2

Amount of Formulation

1 to 2 oz/A

Active Ingredient Rate or Concentration

0.8 to 1.6 oz ai/A

Precaution and Remarks

Controls duckweed, mosquito fern, salvinia, water hyacinth, water lettuce, and water pennywort. Apply with at least 30 gpa water volume. Include appropriate adjuvant.

Herbicide, Formulation and Mode of Action Code

carafentrazone (Stingray) 1.9 lb/gal, MOA 14

Amount of Formulation

3.4 to 13.5 fl oz/acre

Active Ingredient Rate or Concentration

0.05 to 0.2 lb/acre

Precaution and Remarks

Controls water lettuce, waterhyacinth, salvia, duckweed, mosquito fern, and water spinach. Rates vary according to target species. Methylated seed oil or nonionic surfactant recommended.

Herbicide, Formulation and Mode of Action Code

diquat (Reward) 2 lb/gal MOA 22

Amount of Formulation

0.5 to 0.75 gal/ surface acre

Active Ingredient Rate or Concentration

1 to 1.5 lb/acre

Precaution and Remarks

Weeds controlled: pennywort, salvinia, waterhyacinth, waterlettuce. Apply in a spray volume of 150 to 200 gallons of water per acre plus 1 pint nonionic surfactant.

Herbicide, Formulation and Mode of Action Code

diquat (Reward) 2 lb/gal MOA 22

Amount of Formulation

1 gal/surface acre

Active Ingredient Rate or Concentration

2 lb/acre

Precaution and Remarks

For duckweed control, apply in a spray volume of 50 to 150 gallons of water per acre. Take care to cover all plants on water and damp marginal areas. Will require retreatment. A nonionic surfactant at 0.5% by volume will be needed.

Herbicide, Formulation and Mode of Action Code

glyphosate (various) MOA 9

Amount of Formulation

See label

Active Ingredient Rate or Concentration

See label

Precaution and Remarks

For control of waterlillies, spadderdock, and lotus, apply as foliar spray on a calm day when there is little to no wave action. Vegetation must be on or above the surface for treatment to be effective. A nonionic surfactant (e.g. Cide-Kick or Induce) is required with Rodeo. If applying from a boat, take care not to create waves that may wash the herbicide off floating leaves. Will not control small floating plants, such as azolla, duckweed, or watermeal.

Herbicide, Formulation and Mode of Action Code

imazamox (Clearcast) 1 lb/gal, MOA 2

Amount of Formulation

32 to 64 fl oz/acre

Active Ingredient Rate or Concentration

0.25 to 0.5 lb ai/acre 50 to 150 ppb

Precaution and Remarks

See label for specific weeds controlled. A nonionic surfactant or methylated seed oil is recommended for foliar applications. Spot treatments may be made with up to 5% solution by volume.

Herbicide, Formulation and Mode of Action Code

imazapyr (Habitat) MOA 2

Amount of Formulation

1 to 4 pt/acre

Active Ingredient Rate or Concentration

0.25 to 1.5 lb/acre

Precaution and Remarks

Rates vary according to target species. Retreatment of some plants may be required. A nonionic surfactant is recommended. Will not control small floating plants, such as azolla, duckweed, or watermeal.

Herbicide, Formulation and Mode of Action Code

penoxsulam (Galleon) 2 lb/gal, MOA 2

Amount of Formulation

2 to 5.6 fl oz/acre

Active Ingredient Rate or Concentration

0.03 to 0.09 lb/acre 5 to 150 ppb

Precaution and Remarks

A nonionic surfactant is recommended for foliar applications.

Herbicide, Formulation and Mode of Action Code

triclopyr (Renovate 3) MOA 4

Amount of Formulation

0.5 to 2 gal/acre

Active Ingredient Rate or Concentration

1.5 to 6 lb/acre

Precaution and Remarks

Rates vary according to target species. Addition of approved nonionic surfactant is recommended.

Presentations

There are no presentations for this topic right now.

Publications

There are no publications for this topic right now.

Species Data

Habitat

Prefers slow-moving and shallow water. It is strictly a freshwater plant and is intolerant of saline water. The fern is common in swamps and other slow-moving bodies of water. Azolla is often found growing with other duckweeds.

Leaves

Leaves are velvety, small, and frilly. They overlap to create a uniform cluster of plants. Leaf color ranges from green to crimson red and may change during the season. Each leaf has two lobes, and leaves are arranged alternately along the spine of the plant. Spores are produced on the base of the lobes.

Similar Species

Azolla caroliniana is very similar in appearance to Azolla pinnata, a federal noxious weed. A. pinnata is a slightly larger plant, with a Christmas tree shape. If you see A. pinnata, please contact a state official.

Aquatic Plants App

Whether you're a professional botanist or a casual nature enthusiast, the NC State University (NCSU) Aquatic Weeds app has detailed information on a wide variety of aquatic weeds to assist in identification.