Herbicides for Ditches & Ponds
- When dealing with aquatic herbicides, it is vital that you understand the environmental toxicity of the chemical. Each herbicide must be registered with the Environmental Protection Agency (EPA) and have use guidelines on its label. The guidelines indicate whether or not the herbicide is safe in and around water sources and fish and other wildlife.
- Herbicides are available in numerous types for weed control in aquatic environments. For example, copper-based herbicides can be used with other chemicals or by themselves. They are contact chemicals used for contained water sources like ponds or ditches because the effects can stay active for a week. A 2, 4-D herbicide is a chemical used for weeds found along the banks of ditches or weeds that float on the water that have already emerged. Diquat is a chemical that will become inactive when it touches soil, so it must only be used in clear water ditches or ponds. The herbicide Diuron should be applied to ditches or ponds after they have been drained, since it works on the roots of the weeds. Refilling of the pond or ditch should not be done for three or more days.
- Before using an aquatic herbicide, it is important to identify the species of weeds you wish to control so you can target only those plants. Once you have determined which weeds need to be controlled or eradicated, you can research the herbicides and choose the most applicable one.
- There are six main categories of herbicides to consider. Contact herbicides work on the surface of the plant, so the weed must be fully exposed for this type to work. A systemic herbicide can be applied to any part of the plant and works slower than a contact chemical, but it will work for an entire season and will not cause a depletion of oxygen because the weeds will not decompose too quickly. Selective herbicides are designed to react with certain species of weeds, while non-selective chemicals kill most species of weeds. There are also pre- and post-emergent herbicides. Pre-emergent herbicides will kill the weeds before they sprout, while post-emergent chemicals will kill the weeds only after they have emerged from the soil.
- There are important precautions to consider when using aquatic herbicides. Using too much of a pre-emergent chemical can kill important and beneficial species of plants that provide oxygen for fish or other aquatic creatures. Using the wrong chemical without reading the label thoroughly can contaminate the soil or other water supplies, or cause injury to animals or birds that drink the water.