Written by James Burns
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.