An In-Depth Look at Aquatic Herbicides

Overview

When aquatic weeds overtake a pond or lake, they can quickly disrupt ecosystems, hinder recreational activities, and reduce water quality. Managing plant overgrowth often requires aquatic herbicides, which are specialized chemical treatments designed to control unwanted vegetation in water environments.

With a variety of herbicides available, each having special properties and working in a different way, selecting the right one can be a challenge. Understanding how aquatic weed herbicides work, the types available, and the factors to consider when choosing one is essential for effective weed control.

Product labels often list many of the plants controlled by that product, as well as suggested rates. Reading product labels is an important part of responsible pond and lake management.

Dibrox

Dibrox is a highly effective broad spectrum aquatic herbicide designed to kill almost all problem weeds in lakes and ponds. This herbicide is a liquid that is diluted with water before being sprayed over the treatment area, making it easy to apply. The product sinks down right where it is sprayed because it is heavier than water. Even in slow moving waters, Dibrox will typically only move about five feet in any direction where it is sinking.

How Does Diquat Work?

The active ingredient in Dibrox is diquat. Diquat herbicide absorbs into the plant parts it touches and disrupts photosynthesis. Because photosynthesis doesn’t occur and the plant needs the chemical energy produced from the process, this halts further growth.

In the end, lack of plant growth leads to death of these plant parts. The whole process takes 17-21 days from the time of application. For optimal results, Dibrox should be reapplied as new weeds emerge, which is typically four to six weeks after the first weeds died off.

Which Types of Weeds Does Dibrox Control?

Floating and submerged weeds are targeted by Dibrox. It can be used to treat duckweed, water lettuce, water hyacinth, coontail, curly leaf pondweed, and different types of milfoils.

Dibrox diquat aquatic herbicide works in both lakes and ponds. When applying to a pond, it is recommended to either spot treat areas or only one-third to half of the pond at a time. This is because if the whole pond were to be treated at once, oxygen depletion and possible fish kills can be a result of all the weeds dying off at once and using more oxygen than they produce.

This herbicide is an excellent option for controlling weeds in lakes and ponds. With its fast acting and easy to use formula, Dibrox remains a popular choice for those looking for an efficient solution to managing aquatic vegetation. Whether addressing large infestations or maintaining clear water, this herbicide provides an effective and reliable way to keep water bodies weed free.

Spritflo

Spritflo is a broad spectrum herbicide for ponds that provides long lasting results by requiring an extended contact period in the body of water. To apply, simply pour Spritflo in multiple areas of the pond, allowing it to naturally spread and target problem vegetation.

The active ingredient in Spritflo, fluridone, disperses throughout the pond, ensuring even coverage and widespread effectiveness. This makes it an efficient option for those looking for an herbicide that continues working overtime without frequent reapplication.

How Does Fluridone Work?

Unlike some fast acting herbicides, Spritflo fluridone aquatic herbicide prevents plants from forming a protective pigment that keeps chlorophyll from breaking down in the sun, which prevents the plant from making food for itself, ultimately starving the plant. The process takes 30-45 days with the parts per billion (ppb) consistently high enough to kill target weeds.

There are multiple brands of fluridone on the market, and the percentages of the active ingredient vary, so it is important to check the label for the percentage of fluridone as well as the amount of product needed since it is based on average depth.

Which Types of Weeds Does Spritflo Control?

Spritflo is a broad spectrum herbicide and targets many invasive submerged plants such as coontail, milfoil, pondweeds, Elodea, and others. Spritflo also targets floating plants such as duckweed, spatterdock, and even water lilies.

This herbicide is a low maintenance yet highly effective choice for those seeking a reliable solution for controlling weeds in ponds with no outflow. Many people apply Spritflo fluridone twice per year: in the spring/early summer, and in mid-summer.

Since it does not require a labor intensive application process, Spritflo is ideal for pond owners who want an easy to use method for keeping their water free from bothersome aquatic plants. By constantly preventing weed overgrowth, this herbicide for ponds helps improve water quality.

Semera/ Flumigard

Semera and Flumigard are highly effective aquatic herbicides for ponds and lakes that work to control a variety weeds. These herbicides come in both liquid and granular forms that both need to be diluted with water, then applied. Semera and Flumigard are just different brand names for the same flumioxazin aquatic herbicide.

When dealing with stubborn aquatic vegetation, especially watermeal, it is recommended to mix Semera or Flumigard with a surfactant to maximize absorption and improve effectiveness. It is important to spray every plant directly for full control.

If an entire pond is covered with watermeal or other floating vegetation, it may take multiple treatments since only one-third to one half the surface should be treated at a time in order to avoid oxygen depletion as the plants die off.

How Does Flumioxazin Work?

By interfering with chlorophyll production, Semera and Flumigard starve plants to death. These herbicides are particularly effectively at addressing aggressive infestations of watermeal and other floating plants, ensuring clearer water and a healthier aquatic environment.

For those looking to maintain clean, healthy water, Semera or Flumigard provide a powerful solution to keep unwanted vegetation under control. Regular applications may be necessary depending on the severity of the weed problem, but with proper use, Semera and Flumigard offer a dependable and efficient approach to aquatic plant management.

Which Types of Weeds Do Semera and Flumigard Control?

Semera and Flumigard control a multitude of weeds such as milfoil, coontail, Hydrilla, and some pondweeds. They also provide control of filamentous algae. Flumioxazin, the active ingredient in Flumigard and Semera, is the only herbicide that will provide full control of watermeal plants, which are tiny floating plants that look like small green pieces of cornmeal.

Hydrothol

Hydrothol granular aquatic algaecide and herbicide is designed to control a wide range of submerged aquatic weeds and algae. Hydrothol should not be used in a pond because it can be toxic to fish if they are trapped in a small area with the product. In a lake, fish will sense the active ingredient, a salt of endothall, and they will avoid the area until the product is neutralized. For best results, Hydrothol should be directly broadcast over problem areas where weeds and algae are actively growing.

How Does Endothall Work?

Hydrothol gets evenly distributed over the problem area, sinks down, and attaches to the plants to kill them. This endothall aquatic herbicide disrupts essential plant processes by interfering with protein and lipid production. This interferes with the plant’s respiration and cell death occurs.

Hydrothol acts as both an herbicide and a mild algaecide, making it a versatile choice for those looking for lake weed control products that target multiple types of vegetation.

Which Types of Weeds Does Hydrothol Control?

Hydrothol controls nearly all submerged weeds and algae. It will provide great weed control in lakes for many plants such as coontail, pondweeds, or milfoil, and good control of Hydrilla. This product also controls filamentous and planktonic algae, making it a good broad spectrum granular option.

While highly effective, Hydrothol is best applied to large bodies of water where only a small section of the lake is being treated. This way, fish have plenty of places to go while the Hydrothol gets to work on the plants and neutralizes.

Compared to other herbicide options, Hydrothol offers a fast acting, dual purpose solution that provides control of unwanted aquatic vegetation. With proper application, it remains a powerful tool for maintaining clear and healthy water bodies.

Imox

Imox is a sprayable herbicide for aquatic weed control in lakes and ponds. This product is broad spectrum and controls most emergent and floating plants. It is most effective when mixed with a surfactant, which enhances absorption and ensures thorough penetration into the plant. When applying Imox, mix it with the surfactant and water before spraying directly onto emergent or floating vegetation.

How Does Imazamox Work?

Imox is designed to target emergent weeds down to the roots. Its active ingredient, imazamox, works by inhibiting an enzyme only present in plants that is essential for protein synthesis. By disrupting this process, Imox effectively halts plant growth, eventually resulting in death.

Most aquatic herbicides are contact herbicides, meaning they will kill the parts of plants they come into contact with at the time of application. Imox is systemic, meaning it travels through the plants down to the root system. This is ideal for tough to control plants with vast root systems that grow back every year.

Once absorbed, this herbicide works its way down to the roots, providing long lasting control. The first year Imox is applied, 60-90% control can be expected. If any weeds come back the following year, one more application is recommended in late summer to early fall, and then 90-100% control can be expected.

Imox is safe to use in and around the water and is a highly effective and sustained method for aquatic weed management.

Which Types of Weeds Does Imox Control?

Imox kills emergent and floating weeds such as, cattails, water lilies, primrose, Phragmites (common reed), grasses, and more. Nearly any plants that come up out of the water or grow at the water’s edge can be controlled with Imox.

For best results, Imox should be applied when the plants are mature, toward the end of the season. This way, there is plenty of space to get the product onto, and the plants are getting ready to pull their energies down to the root system, pulling the herbicide down to the roots as well.

Water lilies should not be pulled out after treatment because their root systems are so vast and the Imox will continue to move through them. Cattails can be cut down once they are brown and crispy. Phragmites and other woody reeds may need higher rates of application; check the Imox label for rates of the target species.

Liquid 2, 4-D Amine and Navigate

Liquid 2, 4-D and Navigate are selective herbicides designed to target specific aquatic weeds. Liquid 2, 4-D and Navigate both work best when applied to a quarter acre or more to ensure proper distribution and absorption.

The active ingredient in both products is 2, 4-D aquatic herbicide. There is a slight difference in the formulation, but they work the same way. One gallon of liquid 2, 4-D or 50 lbs. of Navigate each treat the same area, about a half acre.

How Does 2 4-D Work?

Both herbicides derive from 2, 4-Dichlorophenoxyacetic Acid, a systemic herbicide that disrupts plant growth by mimicking the plant growth hormone auxin. This leads to uncontrolled growth, which cannot be sustained, and eventually plant death, making these products particularly effective for controlling invasive species such as milfoil and coontail.

Which Types of Weeds Does 2, 4-D Control?

These products offer great control of certain invasive plants such as milfoil, coontail, watershield, water hyacinth and more. 2, 4-D can also kill water lilies but will take several treatments to kill the roots.

Typically, people apply 2, 4-D to water lilies early in the season. The plants are pushing their energies up and out to keep growing at this time, and not enough of the 2, 4-D can be absorbed to move to the roots and kill them as well.

Liquid 2, 4-D is a liquid that is sprayed over the treatment area while Navigate granular aquatic herbicide gets broadcast over the treatment area. Navigate and 2, 4-D work best when applied when the plants are actively growing.

Both products need about 24 hours of contact time in calm, non-turbulent water for optimal effectiveness. Because of this, they are considered second-line options for aggressive control of problem plants and should be applied according to label instructions.

Conclusion

Selecting the right aquatic herbicide is essential for effectively managing unwanted vegetation in ponds and lakes. Each herbicide has unique properties, application methods, and target plant types.

Whether using Dibrox or Spritflo for floating and submerged weed control or Imox for emergent plants, understanding the product effects and proper usage ensures optimal results. Additionally, factors such as water conditions and reapplication frequency should be carefully considered.

By utilizing the appropriate herbicide and following best application practices, pond and lake owners can maintain healthy water environments free from excessive weed growth. Responsible herbicide selection not only enhances water quality and usability but also promotes a balanced ecosystem. With informed decision making, aquatic herbicides can be powerful tools in weed management, ensuring long term benefits for both recreational and ecological purposes.