Advertisement

Imported beetles consuming air potato plants in Hernando

 
More than a decade after it was found feeding on potato vines in Nepal, the leaf beetle is dining in Hernando.
More than a decade after it was found feeding on potato vines in Nepal, the leaf beetle is dining in Hernando.
Published Oct. 16, 2014

It may be the happiest beetle invasion since the Beatles.

And it's almost as hard to miss.

All you have to do is look around for towering, tree-strangling strands of potato vine. Their usually bright-green, heart-shaped leaves are, in much of the county, wilted and lacy — or, as scientists say, "skeletonized."

The fleshy parts of the leaves have been consumed by small, red beetles called Lileoceris cheni, which in 2002 were found munching on potato vines in Nepal, part of the plant's massive native range.

That range includes much of Africa and Asia. It does not include the American South, meaning the vine has no native enemies here. Which is why potato vines have become such a big problem — "one of the most aggressive weeds ever introduced to Florida," according to a 2010 study published by U.S. Department of Agriculture researchers — and why the beetles are big news.

Not just releasing them, a process that started in 2011 and has become more common since; scientists have now released about 1,000 batches of the beetles and more than 300,000 individual insects. No, the news is that in much of the state the beetles are taking hold, showing that they can control a weed that has grown mostly unchecked in the United States for decades, even centuries.

"The beetles are doing great," said Bill Overholt, an entomologist who works at the University of Florida research station in Fort Pierce.

He added, though, that they don't seen to be doing quite as well in the southern part of the state, where the plants go dormant but, because of the warm weather, the beetles don't. Many of them can't find enough food to make it through the winter.

Potato vines were first documented in the United States in 1771, Overholt said.

And though there has been a lot of speculation about how the plant made it here — including that an edible variety was stowed in slave ships coming from Africa — there is solid documentation that by 1905 the plants had arrived at the Orange County botanical garden of Henry Nehrling.

A few years later, according to the USDA study, Nehrling had concluded that "with the exception of the kudzu vine, I have never seen a more aggressive and dangerous vine in Florida."

That didn't stop the plant from being sold to homeowners as an ornamental well into the 1960s, Overholt said.

And that is why the worst infestations tend to be in older towns, a prime example of which is Brooksville. One of the thickest growths of the vine, on S Hale Avenue, is also one of the best places to see the beetles' headway.

There, wispy, brown leaves far outnumber healthy ones. The plants go dormant in the winter, said Bill Lester, the urban horticultural agent at the Hernando County Cooperative Extension Service.

The vines will grow back with less vigor in the spring, Lester said, and face a waiting population of beetles ready to eat their shoots and the potato-like "bulbils" that are the vines' main form of reproduction.

Keep up with Tampa Bay’s top headlines

Keep up with Tampa Bay’s top headlines

Subscribe to our free DayStarter newsletter

We’ll deliver the latest news and information you need to know every morning.

You’re all signed up!

Want more of our free, weekly newsletters in your inbox? Let’s get started.

Explore all your options

Inside and outside the city, there are similar signs that the beetles have been at work. That's true even though relatively few have been released, Lester said. The only releases that he is aware of in Hernando, he said, were in 2013 at Brooksville's Tom Varn Park, and this year at Chinsegut Hill and the Chinsegut Nature Center, both north of Brooksville, and on preserved land west of U.S. 19.

"We're getting calls from people all over saying, 'All of a sudden I've got this beetle eating my air potato,' " Lester said.

"They're pretty close to . . . spreading over Hernando County."