Experts gave testimony on giant salvinia at a Congressional natural resources subcommittee hearing led by Rep. John Fleming at LSUS June 27.
Dearl Sanders, an invasive species specialist for the LSU AgCenter who has reared weevils that have been used to control giant salvinia on local water bodies, and other witnesses were invited to offer their ideas for control or eradication strategies of the invasive species and costs involved.
Efforts that have been employed include herbicide sprays, mechanical control, booms, drawdowns, educating the general public and weevils.
Billy Montgomery, chairman of the Lake Bistineau Task Force which has members in Webster, Bossier and Bienville parishes, said he welcomes help from the LSU AgCenter. At its meeting in Minden March 31, the task force passed a resolution requesting the LSU AgCenter conduct further research on ways to control salvinia.
The LSU AgCenter has been involved in investigating and implementing control measures for giant salvinia since 1999, Sanders said.
The larvae of the weevils ease some of the problem by burrowing into the rhizomes of salvinia, Sanders explained. Adults consume leaves and buds, inhibiting plant growth. Larval feeding causes the leaves to first darken and then drop off. The combined feeding of larvae and adults kills the plant.
In partnership with the Louisiana Department of Wildlife and Fisheries, the LSU AgCenter facilitated collection and transport of more than 30 tons of weevil-infested salvinia with approximately one million weevils to Lake Bistineau and four other north Louisiana lakes in 2009.
Sanders said the weevils have reduced salvinia 90 percent in some areas in south Louisiana, but have not survived the cold winters in the Shreveport area. He said research needs to be directed on finding a strain that can accommodate low winter temperatures.
The LSU AgCenter has helped establish weevil nurseries in Lafourche, Terrebonne and St. Charles parishes. The initial weevil nursery in Gheens was used to develop the protocol for salvinia and weevil production, the timeline for weevil population growth and the optimum times for weevil harvest and distribution.
Various panel members explained that salvinia grows in thick mats and blocks sunlight, deoxygenates the water and leads to fish kills. It clings to boat motors and trailers and doubles surface area covered every day and a half..
One treatment chemical costs $1,851 a gallon, according to Robert Barham, secretary of the Louisiana Department of Wildlife and Fisheries.
He called salvinia a "science fiction challenge" and named Lake Bistineau the poster location.
Rep. Henry Burns said residents along Lake Bistineau have had broken dreams because their real estate values, retirement homes and waterfront amenities are being taken from them because of the salvinia problem. "The No. 1 question I'm asked is 'when are we going to get our lake back?'"
"We will continue to contain this invasive species by utilizing a number of different strategies including simple things like making absolutely sure that once a boat is removed from a lake, the boat owner does not allow giant salvinia to hitchhike home," Fleming said.
Damon Waitt, senior director and botanist at the Lady Bird Johnson Wildflower Center at the University of Texas at Austin, said he camped, caught his first fish, skied, met girls and snuck his first beer at Bistineau. "Nature deficit disorder did not exist at Bistineau. It is sad to think these kinds of experiences are no longer available to the 11 year olds of 2011," Waitt said.
"You have in this room all the ingredients to address the threat of giant salvinia (research, biocontrol, herbicide programs, volunteer support, a management plan). What seems to be lacking is the recipe that combines these ingredients into a coordinated effort that will solve the giant salvinia problem," Waitt said.
He recommended integrated management resources across jurisdictional boundaries.
Rep. Louie Gohmert of Tyler, Texas, joined Fleming in making statements and asking questions.
Mary Ann Van Osdell is assistant communications specialist for the LSU AgCenter. She writes news releases about AgCenter activities in the 22 parishes of North Louisiana, including Webster. She has a B.A. in Journalism from LSU in Baton Rouge.