Melaleuca quinquenervia Native to Australia, this tree was first introduced into Florida during the late 19th century as an ornamental species because it has attractive flowers, white papery bark, and is easy to grow. By the early 20th century, nurserymen had discovered that seeds scattered along the edge of the Everglades would produce an abundance of seedlings that required no care and could be harvested for a handsome profit. Unfortunately, the trees survived and multiplied only too well - today Melaleuca infests nearly 400,000 acres of Florida's Everglades ecosystem. Melaleuca produces massive numbers of seeds which it holds in capsules that can remain on the branches for years. When a branch dries out due to fire, breakage, chemical treatment, etc., the capsules open and release the seeds. The multi-agency Melaleuca Management Plan identified this facet of Melaleuca's biology as the main impediment to bringing this Everglades invader under control and identified Biological Control as the technology needed to reduce the seed production of this tree.

Flowers Melaleuca forest Seed capsules

Scientists began searching Australia for Melaleuca-damaging insects during 1986. Over 400 been discovered, many of which reduce flower and seed production. Several are being studied to ensure they are safe to import into Florida. The first of these, the melaleuca snout beetle (Oxyops vitiosa), was released in Florida during 1997. It feeds on the growing plant tips, which kills seedlings/saplings and prevents flowering.

(Click on any of the images below to view a full-sized version.)
Oxyops vitiosa	Oxyops vitiosa damage to tips of melaleuca saplings	Defoliated melaleuca tree

Lophyrotoma zonalis Fergusonina sp gall

The melaleuca sawfly (Lophyrotoma zonalis) defoliates trees, robbing them of the resources needed to produce flowers. Tube-dwelling caterpillars of the moth Poliopaschia lithochlora feed on young leaves. A sap-sucking psyllid (Boreioglycaspis melaleucae) stunts growth which reduces seed set and weakens or kills saplings. The melaleuca flower weevil (Haplonyx sp.) destroys flower buds, mature flowers, and immature seed capsules. The melaleuca gall-fly (Fergusonina sp.) causes leaf and flower buds to gall, thereby terminating growth of these plant tissues. Other potential biological control insects are still under investigation.

(Click on any of the images to view a full-sized version.)
Poliopaschia lithochlora	Boreioglycaspis melaleucae	Haplonyx multicolor

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