Air Potato Beetles Bring Down Invasive Air Potato Vine Statewide
AIR POTATO BEETLES AT WORK
Bernadette Stange leaned backward like a palm tree yielding to wind, balancing herself on the forest floor under a dome of 2-story high pine trees tangled with ropes of vines dressed in polished spade-shaped leaves. She was at 10 Mile Creek Preserve in Fort Pierce, Florida. The scent of pine mixed with the warm afternoon earth. A slice of light highlighted a vine in front of her.
Stange said, “uh-huh…they’re here…they got here on their own.” Stange nods and moves towards a vine, lifting a single leaf.
As she pointed at a red dot, Stange tells a public relations specialist, “This is the air potato beetle. We didn’t do any releases at this park. This beetle and his group found their way here and are doing their job,” she said in her sharp New Zealand draw.
The candy apple red beetle was the size of a small button on a green Christmas sweater, and the leaf on which the bug sat had shot-out–holes all over it. All of the leaves on all of the vines within view were splattered with holes. And a few more red dots were on a few leaves on the vines inside the vine and pine dome.
REARING AIR POTATO BEETLES
Stange is a laboratory technician in the University of Florida Norman C. Hayslip Biological Control Research and Containment Laboratory. She rears insects for mass distribution for biological control programs in Florida, where invasive bugs, weeds and animals are out-competing natural vegetation and animals.
The costs to manage the invasive species are used for chemicals, plant removal with heavy earth-moving machines–and labor. Air potato needs to be controlled because it creeps and climbs Florida’s native trees, smothers them, and then leaves the trees in the dark. With no sunlight, a full-grown palm tree will collapse under the weight of the mass that an air potato vine will become.
The air potato beetle is a tiny, powerful hero in Florida. It can take down the air potato vine to the small size that it is in its native African and Asian habitats. The beetle munches the vine’s leaves to pieces.
According to scientific literature, air potato was introduced into Florida in 1905 as a medicinal plant, said Carey Minteer, assistant professor of entomology at the University of Florida’s Norman C. Hayslip Biological Control and Research Laboratory. Minteer leads research at the lab where Stange rears the insects. The lab is part of the university’s statewide Institute of Food and Agricultural Sciences.
“It grows all over Florida and smothers acres of land in state and national parks. But, with the air potato beetle program, the vine will look more like it does in its native environment. Soon the vine will be much smaller and will no longer be a problem in Florida’s environment,” said Stange.
MASS REARED IN SCREEN ROOMS
The air potato beetles had been mass reared in three stand-alone structures that looked like screened porches in a grassy area next to the lab where Stange works. Inside each structure, air potato vines grew like magic beanstalks, climbing the structures from the ground-up, onto their white ribs and grey-screen walls, and grasping and clasping the structure’s ceiling into a chokehold, a dense variegated emerald and jungle green mass. In the ground, where each vine had originated, ugly-brown, knobby, air potatoes had been deliberately planted to produce the vines. And all along the vines, the red dot beetles could be heard, if one listened carefully, to the wings, or the noise of the insects eating the nuisance leaves on the unwanted vines. Stange said she and a group of volunteers had given out about 500,000 beetles within the last five years.
“Soon we won’t have to rear and give out any more air potato beetles because they are now rearing themselves in the wild,” said Stange. “The work started more than 10 years ago for this successful biological control program.” The work started with scientists who searched the air potato’s native range in Africa, Nepal, and China. The air potato beetle was found in Nepal and China, feeding on air potato vines there. The beetle is the air potato’s “natural enemy.”
PROGRAMMATIC SUCCESS THROUGHOUT FLORIDA
Ken Gioeli, a local extension agent who gave out beetles and quantified the program’s progress and success, said Florida is the epicenter for successful biological control programs because the scientists in the state know what they are doing. He said successful insect releases have been made in Florida to control invasive trees, insects and aquatic plants. Gioeli worked with the Melaleuca tree program for which insects for biological control were released.
“Melaleuca trees used to grow like fire in the Florida Everglades and soaked up so much water, some of the native plants were dying,” said Gioeli. “Now the trees are disappearing with two biological control enemies at work.”
Florida is not the only place in the world where biological control has helped scientists chop down invasive plants and insects with biological control. In Hawaii, pānini cactus once crowded out livestock from prime pastureland. But now, three insects and a plant fungus keep it down to size, according to the University of Hawaii.
PROGRAMMATIC SUCCESS IN CHINA
Writing in the New Yorker magazine, Richard Rayner tells the story of how biological control saved a city from certain embarrassment over a naked trees issue. Just before the 2008 Summer Olympics in Beijing, an entomologist from Finland saved the city. Kari Heliovaara was hired to find a solution to the city’s leafless deciduous trees before the games would begin. Heliovaara used his own game to end the problem—or what Rayner called insect warfare. Heliovaara found that larvae of moths and sawflies were eating the leaves from the trees and convinced the Chinese game officials his plan to mass rear parasitized cocoons would end the problem and put leaves back on the city’s trees.
Heliovaara and a team of scientists got to work that spring. They arranged for the construction of 20 laboratories throughout Beijing and reared the insects inside the buildings to meet the deadline for the summer games.
“Inside each lab are many rearing rooms, and thousands of larvae are feeding in each room simultaneously. Parasites are released into the room to lay their eggs in the larvae,” said Heliovaara at the time he did the work.
In June 2008, more than 1,000 Chinese students attached millions of parasitized cocoons by hand to the city’s trees. Weeks later, an army of 20,000 parasites were born from the cocoons and put the moths and the sawflies out of business. The foliage returned to the city’s trees. Beijing was all dressed in green healthy trees when the city welcomed the world as its Summer Olympic host.
“The key to biological control is to match a species to its true enemy so there are no non-target effects, that’s what Florida’s scientists do well,” Gioeli said.
Gioeli said a mammal species, the mongoose, was released in 1872 on the island of Trinidad to control rats in cane fields, but no scientific study was performed to determine other species would not be impacted in a negative manner. But once there were few rats to eat, the mongoose turned to preying on domestic chickens, wild birds, even pet cats and dogs.
“Today, species released as biological control agents are studied for about 10 years so that those introduced will not harm other plants, animals, or people,” Minteer said. “The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service approves all biological control agents species released in the U.S. to protect crops, natural heritage plants, wildlife and people.”
The value of biological control is that it saves the state millions of dollars and protects our natural resources without chemicals and costly labor. And — it keeps working year after year.
“Now that the air potato beetle is doing nature’s work, air potato will be much less of a nuisance,” said Minteer.