Insects to Control Harmful Trees

By George Grow

This is the VOA Special English ENVIRONMENT REPORT.

Researchers are planning to use natural enemies to stop the spread of a harmful tree in the American state of Florida. The melaleuca tree threatens to spread throughout the Everglades. The Everglades is a system of wetlands that is home to many kinds of plants and animals.

Scientists with the Agricultural Research Service have been exploring natural methods to control the melaleuca. The tree is native to Australia. In that country, more than one-hundred kinds of insects feed on it and keep it under control. The melaleuca was first brought to the United States in the early Nineteen-Hundreds. But it had no natural insect enemies in its new environment. So melaleuca trees spread uncontrolled across the southern United States.

The tree kills and replaces other plant life in the Everglades. It is now blamed for environmental losses of up to one-hundred-seventy million dollars a year.

The Fergusonina fly is a natural enemy of the melaleuca. An extremely small worm, called a nematode, lives inside the fly. A team of American scientists is working with the Australian Biological Control Research Laboratory. They collected Fergusonina flies from Australia. The scientists put the flies on test plants to see if they attacked them. They found that the flies are likely to survive and reproduce only on the melaleuca trees in Florida. The flies would not harm other plants. This information was important for officials who approved a request to send thousands of flies to the University of Florida for additional tests.

Ted Center is the chief of the Agriculture Department's Invasive Plant Research Laboratory. He says tests show that the Fergusonina fly and the nematode are genetically different from other insects that attack other plants. He says this means that they eat, live and reproduce only in one kind of plant. The scientists now are planning more testing before proposing the release of the insects in the Everglades.

Four years ago, scientists from Florida and Australia released another natural enemy of the melaleuca, the snout beetle. Scientists have released more than fifty-thousand of those insects in south Florida. The scientists believe the Fergusonina fly and nematode would help the beetle and strengthen the effort against the melaleuca trees.

This VOA Special English ENVIRONMENT REPORT was written by George Grow.