Lake Bistineau, near Heflin, Louisiana—drawn down seven feet from July 15, 2008-January 30, 2009. Yearly dewatering of the 200-year old lake at the maximum drawdown rate has been the only control measure which has provided significant results in reducing the giant salvinia, a free floating aquatic fern native to Brazil. Doubling in biomass every 3-5 days, the invader proliferates at a tremendous rate and causes havoc for recreational activities in northwestern Louisiana. Lake Bistineau—a long, narrow waterway encompassing 17,200 acres—was formed in 1800, when several thousand acres of land flooded because of a major log jam in the Red River.

I found it quite interesting to learn that during the Civil War, King’s Salt Works, located on Lake Bistineau, employed up to 1,500 men in salt-making. According to the historian, John D. Winters in The Civil War in Louisiana: “Water was taken from the brine wells and springs and boiled in huge pots and pans, and the wet salt further dried in the sun. As the war continued, the price of salt increased, and more and more people engaged in the salt industry.” (Internet)

Could salt be used to destroy giant salvinia in the 200-year old Lake Bistineau? Salt would indeed eradicate giant salvinia, but it would also kill the ancient bald cypress. Consequently, salt is not a reasonable solution for eliminating the salvinia infestation, and the Louisiana Department of Wildlife and Fisheries battles control over the thriving invader.