Florida released Australian insects to control an invasive tree, then range fell 75%

For decades, a tree from Australia spread across South Florida’s wetlands with little to hold it back. Melaleuca quinquenervia, often called paperbark, had been introduced to Florida for practical reasons, including landscaping and efforts to alter wet ground. It eventually escaped those uses and established dense stands across parts of the Everglades and surrounding wetlands. By the early 1990s, estimates put its spread at close to half a million acres.The response was not limited to cutting trees down or treating them with herbicide. Florida and federal agencies also turned to an unusual source of help: insects from melaleuca’s native range in Australia. The idea was straightforward. Find organisms that naturally feed on the tree, test them carefully, and introduce those capable of attacking melaleuca without becoming a threat to other plants.The first of these insects was released in Florida in 1997.How an introduced tree became a Florida problemMelaleuca had several advantages once it became established in South Florida. It grows rapidly, tolerates wet conditions and produces enormous numbers of seeds. A single tree can produce millions of seeds a year. Its dense growth can rep...