LDWF Fights Giant Salvinia From all Angles on Lake Bistineau

Release Date: 10/05/2017

The Louisiana Department of Wildlife and Fisheries is taking an aggressive integrated pest management strategy to control giant salvinia on Lake Bistineau. The strategy involves a three-pronged approach including chemical, mechanical and biological methods to manage continued growth of the invasive plant.
Biological efforts include the stocking of salvinia weevils in areas of the lake heavily infested with the plant. In June, the department hosted a “weevil day” and provided salvinia weevils to Bistineau property owners who distributed the weevils near their property. Through this effort, volunteers released 115,200 weevils. In 2017 alone, the department stocked at total of 180,855 salvinia weevils in Lake Bistineau.
As of September 27, through the application of EPA-approved aquatic herbicides and surfactants, the department has successfully treated approximately 10,264 acres of giant salvinia through 403 operations totaling 3,252 crew hours. An operation is defined as one two-man crew over an 8-hour day. Through this chemical control method, LDWF spray crews and contract applicators utilize skiffs, airboats and helicopters to apply the herbicides. Currently the department has a contract to conduct aerial spraying on roughly 500 acres. This will be completed as soon as weather and lake conditions allow.
LDWF has utilized mechanical drawdowns for salvinia control on the lake since 2008. This method involves removing water from the lake to dry out large expanses of the plant. The 2017 drawdown began on May 1. This control method has the potential of removing large quantities of giant salvinia at low cost, reducing large areas of growth simultaneously, and works particularly well in drying giant salvinia stranded along the shoreline.
LDWF aquatic plant control biologists recently met with boom specialists in an effort to evaluate the use of boom to entrap large areas of giant salvinia on Bistineau. This may provide LDWF with a more effective and efficient method to conduct herbicide spraying.
The Louisiana Department of Transportation and Development is currently working to repair a slide on the lake side of the Bistineau dam. Additional repairs are needed in the outflow area of the spillway including clearing debris, adding rip-rap to prevent further erosion and making repairs to the damaged outflow apron. The work is tentatively scheduled to begin once the gates are closed on Nov. 30