The Termites That Sank New Orleans

| Tue Oct. 14, 2008 5:37 PM EDT

399px-Coptotermes_formosanus_shiraki_USGov_k8204-7.jpg A new study in American Entomologist suggests termites damaged New Orleans dikes enough for Hurricane Katrina to knock them over. The researchers first noticed termite trouble five years before Katrina struck. They found Formosan subterranean termites in floodwall seams made of bagasse—the residue from processed sugarcane. Formosan termites love the stuff.

After the 2005 breaches, the researchers inspected 100 seams, including three areas with major breaks. Seventy percent of the seams in the London Avenue Canal had been attacked by insects, and two major dike breaks occurred there during Katrina. Twenty-seven percent of seams in the ravaged 17th Street Canal also showed termite damage.

The Formosan subterranean termite is an invasive species native to China, where it damages levees. Besides eating at bagasse seams, the termites may have contributed to the destruction of the levees of New Orleans by digging networks of tunnels that funneled water and undermined the levee system. Ooops. . . The authors suggest that New Orleans' 350 miles of levees and floodwalls be surveyed for termite damage.

Julia Whitty is Mother Jones' environmental correspondent, lecturer, and 2008 winner of the Kiriyama Prize and the John Burroughs Medal Award.