Aquatic Weed Killer: Aquatic Herbicide List

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Aquatic weed killer, or lake weed killers are aquatic herbicides. Aquatic herbicides are chemical products that kill lake weeds. This page includes a description of the various types available to the pond and lake owner for lake weed control.

Most aquatic herbicide products have counterparts with the same or similar chemical make up in agriculture or horticulture. Glyphosate products like Rodeo, Aquamaster, Eraser AQ, Touchdown Pro, and AquaNeat are related to other commercial terrestrial products like Roundup, but Roundup should not be used for lake weeds because it is not labeled for aquatic use, because it contains a surfactant that is dangerous to aquatic wildlife. This is just one of the many reasons why label directions are important. Remember, the label  is the law!

There are 2 types of aquatic herbicides: Contact and systemic.

Systemic aquatic herbicides work by getting inside the plant and killing it to the root. Contact aquatic herbicides kill only the plant material they touch. Both have their place as aquatic weed killers, both must be applied correctly for optimum results, and neither will solve an aquatic weed problem unless there is proper follow up.

Systemic aquatic herbicides

Systemic herbicides move from one part of a plant to another untill the plant is dead, that is, if  they are applied properly. Keep in mind that too much of a systemic herbicide will cause it to behave like a contact herbicide, killing the top of the plant before the chemical has a chance to trans-locate to the root of the plant. This makes the systemic herbicide no more effective than a contact herbicide for long term control.

Complete control is sometimes difficult even with systemic herbicides, so, if the conditions which allowed for the plants growth initially are not changed, it, or something like it, will return.

Systemic aquatic herbicide list:

  • Butoxyethyl ester of 2,4-D. 2,4-D (granular form): Navigate and Aqua-Kleen
  • Triclopyr: Renovate
  • Glyphosate: Rodeo, Aquamaster, Eraser AQ, Touchdown Pro, and AquaNeat
  • Imazapyr: Habitat
  • Fluridone: Sonar and Avast

Contact aquatic herbicides

Contact herbicides tend to work rapidly killing only the plant material that they contact. Keep in mind that this is the sole extent of the herbicidal activity. If you apply this to one part of a single plant, it will kill only that part. You can expect the plant to return at some point if it is peranial, or if good growing conditions exist.

Contact aquatic herbicide list:

  • Alkylamine Salt of Endothall: Hydrothol 191
  • Compound copper: Cutrine Plus, K-Tea, Captain, Clearigate, Nautique, Komeen
  • Copper Sulfate: Sold under many names. Sold mostly as a crystal
  • Dipotassium Salts of Endothal: Aquathol, Aquathol K, and Aquathol Super K
  • Diquat: Reward
  • Sodium Carbonate Peroxyhydrate: GreenClean, PAK27, and Phycomycin

All products are not equal! Lake weeds should be properly identified before choosing an aquatic weed killer, and then, and only then can a proper course of treatment be undertaken. There may be restrictions on the use of a particular product in your area.

3 Replies to “Aquatic Weed Killer: Aquatic Herbicide List”

  1. I am looking for a systemic herbicide that will kill only the plants contacted and not those in surrounding areas. Primary plant we need to kill is water shield but only in selected areas. Location, northeast Pennsylvania.
    Is there any such herbicide?

    1. Any aquatic contact weed killer like “diquat” will work, but if you are applying it to any submersed plants, some will probably drift with the water onto other plants. Some of the granules like “Aquathol Super K” may offer less drift. With watershield the diquat should work pretty well. Diquat products normally don’t require much surfactant, but in the case of watershield, using the maximum may be in order. “Reward” diquat does not list watershild specifically, but it lists floating plants in general, and does not exclude it. Follow the label directions, and use a surfactant labeled for aquatic use.

      As for systemic aquatic herbicides, one of the 2-4d products will probably be best on watershield. Us surfactant, and check the specific regulations in your area, making sure that the label of your product lists the product for use on watershield in your area.

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