Showing Florida How to Oust an Invasive Pest

By Alfredo Flores
November 1, 2004

The spread of the invasive tree melaleuca is being thwarted in Florida, thanks to a cooperative program that includes enlisting the help of the tree's natural enemies in Australia.

The collaborative effort is being carried out by the Agricultural Research Service (ARS), the University of Florida's Institute of Food and Agricultural Sciences, and the South Florida Water Management District. ARS is the U.S. Department of Agriculture's chief scientific research agency.

The effort is called the TAME Melaleuca Project, which ARS established in 2001 to help control melaleuca. Melaleuca quinquenervia was introduced to South Florida in the late 19th century as an ornamental plant, but this fast-growing, fast-spreading tree has displaced native plants and animals, dried up wetlands and created major fire hazards.

TAME takes an areawide approach to managing this Australian pest on public and private lands. Paul D. Pratt, a research entomologist at the ARS Invasive Plant Research Laboratory in Fort Lauderdale, Fla., is the project's director, while entomologist Cressida Silvers serves as the coordinator.

The purpose of TAME is to demonstrate the effective integration of biological control into other management strategies, including use of herbicides and mechanical removal of melaleuca, to achieve long-term results. Especially sought are control treatments that reduce existing infestations and prevent new ones, while minimizing risks to non-target organisms.

The first natural enemy released against melaleuca was the melaleuca leaf weevil, Oxyops vitiosa. More than 8,000 of the weevils were released at 13 locations in 1997. Today, millions of the quarter-inch-long weevils are eating the young leaves of melaleuca trees. The second biological control agent, the aphid-like psyllid Boreioglycaspis melaleucae, has also been effective. This tiny insect feeds on the tree's clear sap. Young melaleuca seedlings are the most vulnerable. To date, approximately 350,000 psyllids have been released at a variety of South Florida locations.

The TAME Melaleuca team will publicize data on the project web site (http://tame.ifas.ufl.edu), in handbooks and brochures, and at outreach events.

Read more about the research in the November issue of Agricultural Research magazine.