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STEP #3
CHEMICAL SELECTION
The choice of products available for aquatic plant control is somewhat limited as compared to lawn care chemicals,
however, the variety is sufficient to solve most problems. In fact, the applicator is often faced with making a
choice between alternative products. As stated within the Identification section of this book, "Many factors have been
considered in our recommendations such as effectiveness, toxicity, environmental impact, ease of application and
economics." For this reason, the Recommended Control Method should be chosen whenever possible. However, Alternative
Control Methods may be necessary to use in certain situations. Where a variety of nuisance species are growing within
the same area, it is usually not necessary to treat each species separately. Check all recommendations listed under
each plant identified and find a common chemical or chemical mixture. Select the higher recommended rate listed.
The product label will specify the information necessary to safely and effectively apply the chemical. It is a violation
of Federal Law to use a product in a manner inconsistent with its labeling. Therefore, READ THE LABEL CAREFULLY and make
note of the following considerations:
- Is the product registered for the intended use? Product labels will display an EPA Registration Number, indication
that they have met the government testing requirements. The sites in which the product may be used (lakes, ponds, fish hatcheries, etc.)
will usually be prominently displayed under the product name or listed under 'general information'.
- What are the water use restrictions, if any? Waiting periods for water use (swimming, fishing, irrigation, etc.) may be required for some products following chemical application. This information is found under 'directions for use' or 'precautions' on the product label.
- What formulations are available? The formulation refers to the form which the product is in when it is purchased. Recommended products on this web site include liquids and granulars. Choosing between a liquid and a granular product with the same active ingredient will usually depend upon the location of plants to be treated, the size and nature of the treatment area and the types of application equipment available. Generally, liquids are more concentrated and less expensive to use on a per acre basis than granular products. Therefore, they are designed for large or continuous area treatments. Granular products are more efficient and economical to use on growth in deeper water (greater than 4 feet), in small treatment areas (less than 1 acre) or where some minimal flow is apparent.
- How does the product work? Simply stated, chemicals kill plants in one of two ways. Systemic herbicides are taken up by the plant and internally disrupt their growth or metabolic functions. Generally, systemics will travel throughout the system, killing the entire plant. Contact herbicides basically affect the exposed portions of the plant such as leaf and stem surfaces. They may create chemical imbalances, disrupt energy flow or cause physical damage to the plant surfaces.
- When are these products best applied? Product labels will often recommend when a product will work at its optimum. Usually the stage of plant growth, season and/or water temperature will be specified on the product label.
- How is the product applied? Directions for use will recommend the appropriate dilutions, equipment, application techniques, product handling and other instructions necessary for applying the product.
- What plants are controlled? Some considerations might be given to determining whether the product chosen will kill plants other than the main nuisance species. Stands of certain types of vegetation may be desirable. Listings of plants controlled are found on the label. Selective herbicides will kill a limited number of species, whereas broad range herbicides kill a wide spectrum of plant types. By using selective dosage rates or products, it is possible to selectively maintain desirable vegetation while killing off nuisance weeds.
- What precautions must be taken in using this product? Not unlike many household cleaners, medicines and personal care products, aquatic herbicide and algaecide labels provide specific instructions on handling, storage and container disposal. Mainly, these are reminders to use common sense. Read these instructions carefully as they are intended to reduce risks and prevent accidents associated with product misuse. A general listing of 'Precautions' is found on page 88.
Some of the recommendations are tank mixes made by mixing two compatible chemicals together prior to application.
Advantages of tank mixing might include increased effectiveness, reduced costs and/or simplified application.
Surfactants are also suggested for use with some products. These are soapy materials that help chemicals stick to foliage.
They are usually recommended for treating emergent vegetation and are added in small amounts to diluted chemicals.
Use of non-ionic, agricultural surfactants such as Cide-KickŪ II work best.
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Descriptions and pictures are from the book "How to Identify and Control Water Weeds and Algae", Edited by James C. Schmidt, 5th edition revised 1998, copyright 1976 Applied Biochemists |
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