There are a variety of milfoil species that occur commonly in South Carolina. While the Variable leaf watermilfoil ia a common native species, the Eurasian watermilfoil is a non-native, highly invasive plant and can be problematic. Read the information below to in an effort to determine which species you have.

Variable-Leaf Watermilfoil(Native)
Myriophyllum heterophyllum
Common Names:  Water milfoil, Coontail, Coontail Moss


Myriophyllum spicatum

myriophyllum spicatum - eurasian watermilfoilThis introduced species is readily distinguishable from its native counterparts. The growing plant will have a red coloration or tint with leaves in whorls of 4. There are up to 12 pairs of capillary segments (stalks) which help make these segments stiff and rigid unlike the native species. This species has the potential to become a major problem in the state because it is spread by fragmentation.


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milfoil is a problem in a lake

Control Methods:

South Carolina Law requires individuals to possess a Commercial Pesticide Applicators License in Category 5, Aquatic Pest Control, before they apply aquatic herbicides if the work is done for compensation on the property of another.  A license is also required, regardless of ownership, if the application is made to an area where public access to the treated site is expected.  Private swimming lakes, where the public would exposed to the treated waters, are the most obvious example of the latter requirement.   On all public facilities, such as golf courses, driving ranges, subdivisions, condominium/apartment complexes and mobile home parks, applicators are required to possess a Category 5 License to apply aquatic pesticides

1. Active Ingredient:  Triclopyr (Garlon 3)*
Product Name: Renovate 3, Tahoe, Trycera
Approximate Cost: $100.00-$125.00/gallon

Application Rates:
3-8 quarts/acre as a broadcast spray or as a 1.5 percent solution with hand-held sprayer.
This product should be used with an approved surfactant at a rate of 1.0 - 1.5 quarts surfactant per 50 gallons of spray mix.
*Manufacturers list this product as a partial control agent

Use Considerations:
Triclopyr is not toxic to fish or wildlife at normal use concentrations. It can cause severe irritation to eyes and skin upon contact. It is suggested that it is used in a manner to reduce the possibility of drift. The proper personal protective equipment should be used as prescribed by the Federal label.

Water Use Restrictions:
For floating and emergent applications do not apply within 200 feet of operating potable water intakes when using 4 - 8 qts per acre. There are no setback restrictions for potable water intakes when 2 qts. per acre or less is applied to emergent vegetation. To make applications within these restricted areas, follow the label directions. There are no restrictions on the use of treated water for recreational purposes or for livestock consumption.

Application Methods and Tips:
Successful use of Renovate is dependent on contact of the herbicide with the plant foliage; therefore do not apply this herbicide to submerged vegetation. Do not apply the product when rain is likely within 12 hours post-treatment. Best results are achieved when treatments are made when most of the plants are in bloom. Coverage should be uniform and conducted on a spray-to-wet basis. Repeat applications will be required to maintain control of milfoil. READ AND FOLLOW THE HERBICIDE LABEL

2. Active Ingredient:
Ester of 2, 4-Dichlorophenoxyacetic acid
Product Name:  Aqua-Kleen, Weedtrine II, Navigate
Approximate Cost:  $2.50/lb - $125/50lbs

Application Rates:
100-200 lbs/acre

Application Methods and Tips:
  Best results will be achieved when the herbicide is applied during the spring or early summer.  Affects of the herbicide may not be noticeable for four to six weeks after treatment.  Granular 2, 4-D should be applied in a broadcast fashion by the use of a fertilizer or seed spreader to ensure uniform coverage of the treatment area.  Generally, control will be confined only to those areas in which the herbicide is applied, thus allowing spot treatment of selected areas where weed control is desired.  Higher application rates will be required in situations of dense weed growth, water greater than five feet deep or ponds with a short retention time (high volume turnover).  Follow-up applications may be required to gain desired control. Care should be exercised when treating ponds with dense growths of vegetation to prevent oxygen depletions due to decomposing plants.  No more than one-third of the pond should be treated at once, allowing 14-21 day intervals between applications.  Additional product directions and precautionary statements are listed on the herbicide container.  READ AND FOLLOW THE HERBICIDE LABEL.

Use Considerations:
  Do not use water from treated areas for irrigating plants or mixing sprays for agricultural or ornamental plants. Unless an approved assay indicates the 2,4-D concentration is 70 ppb (0.07 ppm) or less, do not use water from treated areas for potable water (drinking water).

2.  Active Ingredients:
Diquat dibromide salt
Product Name: Reward, Weedtrine D, Aqua-Clear
Approximate Cost:  $70 - $90/gallon

Application Rates:
1-2 gal/surface acre

Application Methods and Tips:
To control infestations of water milfoil with diquat a rate of 2 gallons per acre at a depth of 4 feet is needed.  For areas with depths less than 4 feet follow the chart detailing the gallons per acre for each depth less than four feet on the herbicide label.  For heavy infestations and depths over 2 feet deep surface spraying is not recommended.  In areas of early growth or light infestations, evenly distribute herbicide by pouring over the treatment area in strips 40 feet apart.  Dilution with water may be required in order to adequately cover the treatment area.  Treatment of water milfoil with this herbicide is more effective in low flow situations.  Do not apply diquat dibromide in muddy water as the herbicide will be inactivated.  Additional product directions and precautionary statements are listed on the herbicide container.  READ AND FOLLOW THE HERBICIDE LABEL.

Use Considerations: 
Do not use treated water as a drinking water source for 3 days after in water treatment.  Do not use treated water for livestock or domestic animal consumption for 1 day after in water treatment.  Do not use treated water for irrigation to turf and landscape ornamentals for 3 days after in water treatment.  Do not use treated water for irrigation to food crops and production ornamentals for 5 days after in water treatment.  There is no fishing or swimming restrictions for this aquatic herbicide.