In 2001, 880 tiny weevils were released to fight Texas’s worst weed

In 2001, the US Department of Agriculture decided to tackle giant salvinia, a floating weed causing problems in Texas and Louisiana waters, by introducing a tiny weevil. The weevil, native to South America, was already known to feed on the aggressive plant. Researchers released 880 of these weevils at four sites, carefully selected for their compatibility with the salvinia weevil.

The weevils targeted the growing tips of the plant, consuming it and hindering the plant's growth. By September 2003, the weevils had significantly reduced the coverage of giant salvinia, with only about 1% of the water surface affected at the release sites, while untreated areas remained fully covered. The experiment demonstrated the potential of biological control, using a small organism to manage a large-scale problem.

The weevils' success was not guaranteed, as previous attempts had failed due to environmental factors. However, the 2001 releases proved more resilient, surviving freezing temperatures and continuing to thrive. While the weevil proved effective in controlling giant salvinia, its success depended on the local climate, as extreme cold could prove fatal.