In East Texas, Residents Take On a Lake-Eating Monster

Caddo Lake under siege by a fast-spreading aquatic fern known as Giant Salvinia.

In what East Texans here liken to a horror movie, the furry green invader from South America, which is infiltrating lakes in the American South and abroad to growing alarm, is threatening to smother the labyrinthine waterway, the largest natural lake in the South, covering about 35,000 acres and straddling Texas and Louisiana.