How to treat Salvinia

Instructions for Agressive Salvinia molesta Treatment

  • Scientific Name: Salvinia molesta
  • Common Name: Salvinia
  • Family: Salviniaceae
  • Origin: Native to South America
  • Habitat: Mainly a weed of tropical, subtropical and warmer temperate regions. Salvinia is found in rivers, streams, lakes, dams, swamps, irrigation channels, drainage lines and other bodies of water.
  • Description: A free-floating green-brown freshwater fern with branching horizontal stems and submerged feathery roots. Fronds are oval shaped that become compressed in chains over time.
    Easily identified by the ‘hairs’ on the fronds.
  • Reproduction: In Australia Salvinia reproduces vegetatively. Spores are not viable. 

Environmental and other impacts:

Salvinia molesta is classified as a Weed of National Significance (WONs). It is a floating water weed with oval-shaped leaves that have many waxy hairs on the top of the leaf. It forms dense mats that take over waterways and reduces water quality. These thick vegetation mats can shade out any submerged plant life, impede oxygen exchange and light availability in the water column below, reducing water quality and causing the death of primary producers and disrupting the freshwater food chain. Dense mats encumber navigation, fishing and recreational activities and provide breeding places for vectors of disease.

Salvinia can produce by plant parts in two ways:

  • Plant fragments – If a part of the stem containing a node breaks away from the main plant it can grow a new plant. Damaged or dead plant material stimulates bud development. One pair of leaves can start an entire new infestation.
  • Daughter plants – Mature plants produce buds at the join between sections of the stem and these develop to form daughter plants.

Salvinia spreads to new areas by:

  • Attaching to boats, trailers and vehicles
  • Human activities such as keeping it in fishponds or aquaria and inappropriate disposal of the plant
  • Attaching to animals such as water birds, turtles or cattle.

Once in a waterway the plants can be spread by:

  • Water flows especially floods
  • Wind

Successful weed control requires follow up after the initial efforts. This means looking for and killing regrowth or new plants. Using a combination of control methods is usually more successful.

Salvinia is a hardy plant and is quite difficult to eradicate. Be prepared to apply multiple treatments.

AQ200 Treatment

Treatment Day 1:

1. Use AQ200 + Wetting Agent combo on Salvinia (please note it is best to treat on a day with no rain and minimal wind)

Mixing AQ200 + Wetting Agent

1a) Combine 400mL of AQ200 with the 150mL of Wetting Agent and dilute in 100L town/tank water (please note it is important to use clean water for this application). It is best to fill your spray unit with 80% of the water before adding the AQ200+Wetting Agent mix as the mixing causes the products to bubble.

1b) Spray diluted mixture directly onto Salvinia using a shower spray (not a mist spray). Ensure all Salvinia is well wetted.

Wait 7 days then move onto next treatment stage.

Treatment Day 7:

2. Seven days after applying the AQ200 mix, apply Surface Clear

Applying Surface Clear

2a) Surface Clear is applied at a rate of:
100ml per 100m2 of water surface area. Pour Surface Clear directly onto the water and it will spread itself. (Please note it is best to treat on a day with no rain and minimal wind and to allow the days following to be free of heavy rain)

Wait 7 days then move onto next treatment stage.

Treatment Day 14:

3. Repeat Treatment day 1

Wait 7 days then move onto next treatment stage.

Treatment Day 21:

4. Repeat Treatment day 7

Tips for eradicating

  • Do not fill up your dam until you have eradicated the current infestation of Salvinia.
  • Ensure Salvinia is well wetted when applying herbicide.
  • If Salvinia is layered, physically remove some before commencing herbicide treatment.
  • Ensure every little bit of Salvinia is gone. A little piece of the plant can begin to replicate and before you know it you have another infestation.
  • Be prepared for multiple treatments. Salvinia is a hard plant to get rid of but we will be there for you along the way.


Physical removal can be achieved by water skimmers or even using tools from around your house i.e. rakes, buckets etc. Ensure any Salvinia that is physically removed has no way of getting into the water body again.

Larger spray units are ideal for dealing with Salvinia, however any spray unit you have on hand will do the job. Ensure nozzle is on shower spray to get the best coverage.

It is advised to do follow up spray treatments to ensure Salvinia is eradicated.

by Aquatic Technologies
If you have any questions regarding looking after your dam or pond and what products are the most suitable for your situation, please read through the helpful articles on our site or feel free to contact our friendly team who can help you maintain proper health in your water body year round.
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