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Australian Bug Imported to Fight Pesky Plant in U.S. Everglades

Robert P. King
Cox News Service
September 24, 2001
 
A stubby Australian beetle is taking a bite out of one of Florida's most
noxious pest plants, just as federal scientists hoped when they released
the bug into the Everglades more than four years ago.

Now they're
preparing to unleash a second insect from Australia, with the same goal:
reining in the fast-breeding, water-guzzling melaleuca tree.



The first insect, the melaleuca snout beetle, is doing even better than researchers had expected in nibbling the tree's buds and new leaves, according to the U.S. Department of Agriculture.

The new arrival, called a psyllid, is an aphid-like insect with toxic saliva whose larvae cover the tree with tufts of cottony wax. Researchers hope to start releasing the psyllids in January.

By themselves, the insects will probably not eradicate the melaleuca, another Australian native that has swarmed over 400,000 acres since people brought it to Florida in the late 1800s. But researchers hope the pair will slow the melaleuca's growth after crews whack the trees with blades and poisons.

"That's what we're trying to do, to suppress the ability of the melaleuca to move back to areas where it's been cleared," said Ted Center, research leader at the USDA's Invasive Plant Research Laboratory in Fort Lauderdale.

Introducing a Predator

Already, some small melaleuca trees are dying after the beetles ate their leaves and stopped them from flowering.

Researchers released 8,000 beetles initially, then later harvested 200,000 from the wild and spread them to 150 sites around the state, Center said.

They plan to start a major redistribution effort next month in Palm Beach County, Florida, which is crawling with melaleuca trees but is still relatively beetle-poor, said USDA researcher Paul Pratt.

Both of the imported insects are intended to give the tree what it never had in Florida: a natural predator.

A handful of native Florida beetles, aphids, and worms nibble on the melaleuca, but few can withstand the oils secreted by its leaves. And other threats—such as fire, poison, or attempts to chop it down—prompt a melaleuca tree to drop its tens of millions of seeds.

Government agencies have spent millions of dollars trying to eradicate the papery-barked tree, using a "hack and squirt" method in which crews carve the trunks with machetes and spray them with herbicide. But the crews have to keep going back to kill new saplings, and most melaleucas are off-limits on private land.

Despite the insects' promise, any tinkering with ecology is fraught with possible unknown consequences, and federal regulators still have a hoop or two that must be jumped through before they authorize the psyllid's release.

After all, Florida is teeming with noxious plants and critters—from the Brazilian pepper to the slithering, sex-changing Asian swamp eel—that someone once considered a worthwhile addition to the state's ecological mix. The melaleuca itself was supposed to beautify the state while helping to drain the Everglades.

Concerns About Consequences

What if these new insects turn into pests themselves—for instance, if they adapt to their new surroundings by developing a taste for oranges?

"In the actual environment, we don't have control over what we brought in," said Laurie Macdonald, an activist with Defenders of Wildlife, who warns against "the Jurassic Park syndrome" in tinkering with nature. "Granted, the melaleuca is a huge problem, but we don't want to replicate the problem," she said.

Other environmental groups say they're satisfied that years of research on the insects have provided enough safeguards.

"The USDA has been very careful about how it releases these insects," said Mark Kraus, conservation director for Audubon of Florida. "This is a lot different from, 'Hey, let's bring melaleuca over because it will dry up the Everglades,' or, 'Let's bring marine toads into Florida because they'll kill insects.'"

The snout beetles have caused no problems for agriculture since being released over four years ago, said Pat Cockrell, director of agriculture policy for the Florida Farm Bureau Federation.

Before releasing the snout beetle, the USDA kept it for years in a quarantine lab in Gainesville, Florida, to prove it wouldn't devour other plants, even if no other food were available. The psyllid is still in the Gainesville lab, where federal researchers also had to assuage fears that the insects harbor plant diseases.

The USDA had hoped to begin releasing the psyllids in November, but bureaucratic delays could push that back to January, Center said.

Other insects may be on their way. The agriculture department is also studying a fly that carries nematodes that cause tumor-like growths to form on melaleuca trees. But another insect, called a sawfly, is on hold because toxins from a similar fly have been blamed for livestock poisonings in Europe, Australia, and South America.

Copyright 2001 Cox News Service

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