best herbicide for duckweed Fluridone Liquid / Sonar AS Liquid from AquacideAvast! SC Liquid and Sonar AS Liquid are systemic herbicides for controlling weeds in freshwater ponds, lakes, reservoirs, irrigation canals, and drainage ditches. Avast! and Sonar AS Liquid provide excellent control of many difficult to control weeds, including Duckweed, while allowing desirable vegetation to remain. Avast! SC Liquid and Sonar AS Liquid are functionally equivalent. Same ingredient, same concentration, same uses. Different name. Treat

Avast! SC Liquid and Sonar AS Liquid are systemic herbicides for controlling weeds in freshwater ponds, lakes, reservoirs, irrigation canals, and drainage ditches.

Avast! and Sonar AS Liquid provide excellent control of many difficult to control weeds, including Duckweed, while allowing desirable vegetation to remain.

Avast! SC Liquid and Sonar AS Liquid are functionally equivalent. Same ingredient, same concentration, same uses. Different name.

Treat your entire pond. 

For ponds (waters less than 10 acres), treat entire pond or a minimum of 5 acres. For lakes (waters 10 acres or more), treat a minimum of 5 acres. Treating less than 5 acres or treating narrow strips may not produce satisfactory results due to dilution.

Avast! and Sonar AS Liquid are absorbed by leaves and stems directly from water and by roots from hydrosoil. In susceptible weeds, Avast! and Sonar AS Liquid inhibit carotene production. Without carotene, chlorophyll is rapidly destroyed by sunlight. Without chlorophyll weeds die. Initial results show a bleaching at growing tips of the weed. Within 7 to 10 days weeds begin to turn pink then white. Growth is halted and weeds begin to die. Results occur slowly. Under optimum conditions, full kill occurs in 30 to 90 days. Avast! and Sonar AS Liquid will not cause oxygen depletion resulting from rapid weed collapse.

For best results, apply Avast! or Sonar AS Liquid in spring and summer during the early stages of growth. Weeds are more easily controlled when treated at this time. Less material is required and results occur more quickly. Avast! and Sonar AS Liquid work on susceptible mature plants but will require higher application rates and more time to show the full effect of an application.

A little goes a long way.

Consistent concentrations of Avast! and Sonar AS Liquid need to be maintained in water for up to 45 days following application. Rapid dilution due to water flow will reduce results. Best results occur in ponds with little or no outflow.

To apply, determine the volume of water to be treated in acre-feet. Use 1 pint of Avast! or Sonar AS Liquid per 1.25 acre-feet. of treated water. Dilute with 5 to 100 gallons of water and apply uniformly over the surface with a Constructo Tank Sprayer.

Visible results in 7 to 10 days.

Use Sonar Q Granular when treating a portion of a large body of water. This will help maintain a consistent concentration at the treatment site by reducing dilution.

For Duckweed, split the calculated amount of Avast! or Sonar AS Liquid into 3 equal portions. Apply each portion separately at 10 to 15-day intervals. 

Water treated with Avast! SC or Sonar AS Liquid should not be used for irrigation for 30 days following treatment.

See Water Use Restrictions (Days).