MountainTrue and Save Lake Chatuge are excited to announce that a proposal from Aqua Services has been selected for control of the invasive parrot feather in the southern end of Lake Chatuge this year. The company will utilize two airboats, both capable of surface and deep-water application, to apply the herbicide ProcellaCOR at the appropriate rate(s) and depths. Customized rates will be applied to surface and subsurface plants depending on density, biomass, and water depth. The company conducted detailed mapping of the plants on Monday, February 26, in anticipation of drafting a contract with MountainTrue. While invoices will be based on the actual amount of herbicide applied, the total cost of this year’s treatment, including MountainTrue’s 10% project management fee, is anticipated to be around $220,000.

Pictured above: Map showing the 2024 season parrot feather management area at the southern end of Lake Chatuge in Towns County, GA.

The initial application will be performed when the water temperature is above 50 degrees Fahrenheit and the plants begin to put on new growth. While the timing will be based solely on when the Aqua Services professionals feel that the treatment will be most effective, we anticipate that it will occur no later than mid-April. Four follow-up visits will occur at two-week intervals after the initial visit. During each follow-up, applicators will survey the treatment area to assess the effectiveness of the prior treatment and provide spot treatments as needed based on survey results. The company has also quoted a per-acre rate so that if unanticipated regrowth occurs later in the season (after the four follow-up visits), we know the price of additional visits.

ProcellaCOR was developed in 2010 and was subject to dozens of peer-reviewed scientific studies for several years, leading up to its ultimate approval by the US Environmental Protection Agency (USEPA) in 2017. The active ingredient of ProcellaCOR, florpyrauxifen-benzyl, has been utilized worldwide for many years as an herbicide on food crops such as rice. It is applied directly into the water at the depth of the invasive plants. It is a systemic herbicide, meaning that the plant takes in the chemical and distributes it through its entire structure and roots rather than only killing the leaves. The plant dies off over a period of two to four weeks and breaks down naturally. Since ProcellaCOR works slowly and there will be cool water at the time of the initial application, slow plant decomposition is expected with little to no effect on dissolved oxygen levels. ProcellaCOR itself is short-lived and breaks down naturally and quickly, within three to four days.

According to the USEPA ProcellaCOR Pesticide Product Label, there are no restrictions for recreational purposes, including swimming and fishing, or for watering grass. The only restrictions for use of the treated water are for residential landscape plants and homeowner gardens. Almost all hazards described in the label are for the people who handle and apply the herbicide.

Before selecting Aqua Services, MountainTrue and a team of five people from Save Lake Chatuge reviewed proposals and credentials from five companies. We researched various potential methods of control, as well as several different herbicides, even going so far as to contact the manufacturers of the herbicides to speak with them about our specific project. Many of the research papers we found, as well as the species profile of parrot feather on the Great Lakes Aquatic Nonindigenous Species Information System website, were written in whole or in part by Ryan M. Wersal, Ph.D., who is an Associate Professor of Aquatic Weed Science at Minnesota State University, Mankato. Dr. Wersal did his doctoral thesis on parrot feather and is one of the world’s foremost experts on its treatment and control. We asked if he would help us decide on a treatment plan, and he agreed! After much exchange of information via email and phone, our group met with him virtually, and he recommended using the Auxin family of herbicides for treatment over all other potential methods and chemicals. ProcellaCOR was chosen because of its low use rate compared to the other auxin herbicides and because Aqua Services has used it with great success on other parrot feather infestations. 

While other companies also proposed using ProcellaCOR as a primary method of treatment, Aqua Services, based in Guntersville, AL, has been in operation in the south for more than 40 years, holds contracts with TVA for aquatic weed management, and quoted the lowest price for our project. Click here to read more about Aqua Services.

Complete control of the parrot feather infestation will take more than one year, but next year, we’ll have much less to treat, and there may be a period of years after that when no treatment is needed. MountainTrue will maintain the monies in the Parrot Feather Treatment Fund in perpetuity for the control of invasive aquatic weeds in Lake Chatuge.