Chemical control requires the use of aquatic herbicides that have met strict EPA standards for use in an aquatic environment. As a result, the herbicides are of low toxicity to fish and wildlife (and subsequently man) when used according to guidelines, rates, and restrictions specified on the label for each herbicide. Some herbicides have limited livestock (cattle) restrictions before reentry into treated areas.

Chemical control has its limitations. Application of herbicides may require specialized equipment and expertise. Some herbicides can be very expensive, and some may not provide prolonged weed control. Rooted aquatics usually develop in water that is too shallow or too clear. Even after treatment of the vegetation, the conditions conducive to aquatic weed growth may still exist. Reoccurrence of the same or another weed problem is often likely, requiring additional applications of herbicides. It is important to eliminate the conditions that encourage the growth and spread of aquatic plants.

Before applying an herbicide, correctly identify your aquatic weed using our dichotomous plant key or thumbnail photographs. This page will provide links to information on the most effective and economical herbicides for control of specific weeds. Assistance in aquatic weed identification and control is also available from the Mississippi State University Extension Service (your local county agent), the Natural Resources Conservation Service, and the Mississippi Department of Wildlife, Fisheries and Parks. In most cases, you can ship or mail a sample of your weed in a ziploc bag with no water to any one of these offices, and a biologist can make an accurate identification.

You must know the surface area and/or volume of water in the pond, since the amount of herbicide to use is determined by either the surface area or water volume to be treated, depending on the type of vegetation problem. The herbicide label will tell how much should be used per surface area of vegetation or per volume of water to be treated. For assistance in calculating treatment levels go to our management calculations page.

For effective aquatic weed control, you must select the proper herbicide and apply it properly. Some herbicides may be used directly from the container; others must be mixed with water or water plus a surfactant before being used. Always follow label instructions and precautions when applying herbicides. Some may be applied by hand (low volume, spot spray), while others require the use of power sprayers (high volume, tank mix).