Plant scientists seek to halt evil weevil

Florida's native bromeliad air plants are being devoured by a foreign insect invader and researchers are working hard to introduce a parasite to control the alien bug.

BY VIRGINIA SMITH

Daytona Beach News-Journal

GAINESVILLE - Behind door No. 2108 of the University of Florida's Department of Entomology is the world headquarters for control of an obscure Central American weevil with a black body and orange stripe.

The weevil eats bromeliads, a type of air plant, some varieties of which lives in trees throughout Florida. When the weevil passes through, whole treetop ecosystems crash to the ground.

In 1989, the weevil was first discovered by Broward County nursery owners in a batch of imported air plants.

''They sprayed the hell out of it, but it was too late. It had already spread,'' said University of Florida entomologist J. Howard Frank, who's been gunning for the weevil ever since.

Last year, the ''evil weevil,'' as Frank and others call it, was sighted in Merritt Island near Cape Canaveral on Central Florida's Atlantic coast, the most recent stop on its slow northward trek.

TIGHT FUNDING

In the entomology labs, in local plant nurseries, in the cloud forests of Honduras, and in state-of-the-art quarantine facilities, its human enemies are trying to stop it. But they haven't had an easy time.

Citrus-chewing moths and golf course-nibbling mole crickets get the high-profile funding, for instance, while evil weevil fighters must rely largely on fundraising drives by bromeliad societies around the state.

But the cost could be high if the weevil isn't stopped. Already it has sliced and diced its way through some of the state's biggest, most pristine and breathtaking forests.

Air plants don't actually live on air, but on light, humidity and decay. Bugs and small animals die in them, moisture collects in them, and their leaves absorb the brew. They're found only in the warmer regions of the Americas.

Most of the air plants native to Florida are members of the genus Tillandsia. Among the tillandsias are Spanish moss and what are sometimes nicknamed ''wild pines,'' green tufts that live high in trees and produce long, bright, blooming stalks of red and yellow.

In the wild, a vast canopy of air plants supports all kinds of life, frogs, bugs, birds, even snakes. They're part of what makes Florida look like Florida.

New Smyrna Beach native John Russell turned a high school science project on air plants into a 35-year career growing them. In their 45,000-square-foot nursery in Sanford, Russell and his wife, Jimye Kaye, care for hundreds of thousands of tillandsias, which offer their erratic leaves and geometric blooms in every direction.

In one corner of Russell's vast space are mats full of tiny seedlings painstakingly grown from the seeds of endangered air plants. Each group is labeled with the exact spot it was collected.

JUST IN CASE . . .

Russell is raising them as a safety measure, in case the plants go extinct. Of the 16 species that live in Florida, 10 are now listed by the state as threatened or endangered. Some are listed because they're just plain rare. Two were among Florida's most common plants until the weevil showed up.

The world contains a lot of weevils. Scientists guess there are 60,000 species. Weevils are known by their curved noses, which aren't really noses because weevils don't smell with them. Instead, they bite with them. Minus the nose, a weevil is essentially a beetle.

Before the evil weevil showed up in 1989, there existed a native Florida weevil whose larvae eat air plants -- but it's a picky eater and eats small plants. The evil weevil has a much broader appetite and goes for big plants.

The weevil lays eggs in the air plant's core. Its larvae chew it to a brown mushy pulp, until the plant simply disintegrates and its leaves fall off. (The evil weevil ignores Spanish moss because of the plant's shape.)

Something in the weevil's native Central America keeps it from destroying all the air plants. But in Florida, all bets are off.

The concept of ''biological control'' means stopping a harmful species with a helpful one, and it's known in nonscientific circles mainly for backfiring. Some creature is introduced to eat an animal or plant, then becomes an even bigger menace.

MAKING STRIDES

In recent decades, biological control has become more precise and successful.

''We have to provide extensive data to show that the natural enemy will be of no harm to the environment or domestic animals, humans or plants,'' said Ronald Cave, an entomologist working with Frank on the weevil project. ``It's expensive and it takes a while to do. But the results can be very nice and ecologically safe.''

To control an invader like the evil weevil using pesticides, Frank said, ``you'd have to call out the Air Force. It would cause untold environmental damage, and you'd need about $500 million.''

After the weevil was first spotted, Frank launched a search for it all over South Florida, where it was quickly making hash of bromeliads. Dying, fallen air plants littered the ground in Broward County, and the weevils were spreading. An army of bromeliad lovers was mobilized to help chart the weevil's course.

In 1992, Frank and a colleague got federal funds to collect the weevil in southern Mexico and to seek out a natural predator that might be used in Florida to kill it. They got the bug -- but no predator.

Two years later Frank called Cave, who was working in Honduras. He asked Cave if he knew of anything that ate the weevil. Cave did not, but he searched the cloud forests for rotten air plants, hoping to find some more weevil larvae -- and maybe, with a close enough look, some weevil-eating parasite hanging around.

He brought the plants back to his lab, letting the larvae eat away. But in a few weeks, just as the weevil larvae were supposed to start turning into weevils, something popped out of their skins.

It was maggots of another insect, and they'd conveniently eaten the weevil larvae's insides. The weevil larvae died.

Cave had his parasite, and it was nice and nasty. When the maggots grew up, they turned out to be a species of fly unknown to science.

If the scientists could just cultivate the fly, test it, and introduce it in Florida, they might stop the spread of the weevil. In a process that took five years, Frank and his colleagues secured permits and funds and set the flies up in a special quarantine building in Gainesville with triple doors. The flies had, Frank thought, everything a fly could want.

Then suddenly, he said, ''they died like flies.'' Frank blamed an air-duct problem for the die-off. And the weevil crusade was back to square one. That was seven years ago.

BEST WEAPON

The entomologists still thought the fly was the best weapon in their arsenal, even if it meant starting over. So they got more permits and more of the still-nameless Honduran flies. Cave is rearing the Honduran flies in a special facility in Fort Pierce, and so far, no system breakdowns have been reported.

The flies appear to be harmless to everything but weevils, and the scientists will apply this year for a permit to release them. But the flies are high-maintenance.

''They are difficult to rear,'' Cave said. ``They take a lot of manual labor and special conditions. Ideally, I'd like to release thousands, but we'll be lucky to release 50 or 100.''

Time and financial constraints prevent raising any more, he said. It will be a tall order for 100 flies to kill the hundreds of thousands of evil weevils chomping their way through Florida's treetops. But it's a start.