Aussie Insect May Help Fight Melaleuca Menace

A tiny, golden-brown fly from Australia may help fight melaleuca--an aggressive invader that's crowding out native vegetation in Florida's Everglades. ARS and Australian scientists based at Indooroopilly, about 500 miles north of Sydney, worked with a University of Florida colleague to extensively study the helpful insect. Now the Indooroopilly team is shipping the fly to ARS co-researchers in Florida for final tests.

Scientists at the ARS Australian Biological Control Laboratory in Indooroopilly were the first to pinpoint the Fergusonina fly, which they are calling the melaleuca bud gall fly, as a candidate biological control agent to attack melaleuca.

The plant is native to Australia but isn't a problem there. In Florida, melaleuca takes over about 15 acres a day.

To find this and other promising organisms to curb melaleuca, the scientists scrutinized thousands of melaleuca trees at sites along the eastern Australia coastline--melaleuca's primary native range.

The female Fergusonina fly deposits her eggs in melaleuca's growing tips, or buds. Melaleuca responds by forming galls in the buds. The galls are pink swellings, typically marble-sized.

Inside the gall, the little fly develops into an adult, then emerges to find a mate and start a new generation. Galled tips won't form new flowers that would otherwise produce vital seed, said John A. Goolsby, the Indooroopilly lab's director. Studies by Goolsby and co-researchers with Australia's Commonwealth Scientific and Industrial Research Organization indicate the fly is unlikely to attack other vegetation.

Goolsby's team has shipped more than 8,000 freshly harvested melaleuca galls, with the Fergusonina fly inside, to ARS entomologist Gary R. Buckingham and University of Florida colleagues at Gainesville for further study with other plant species. If the fly passes those tests, scientists will likely seek federal and state approvals to free it at melaleuca-infested sites. The insect would complement the work of the melaleuca leaf weevil, Oxyops vitiosa, released in Florida in 1997 after similar research in Australia and the United States.

ARS is USDA’s chief research branch.

Scientific contact: John A. Goolsby, ARS Australian Biological Control Laboratory, Indooroopilly, Australia; phone: 61-7-3214-2821, fax 61-7-3214-2815, john.goolsby@brs.ento.csiro.au.