Science
8:00 pm
Wed June 26, 2013

New Bugs In Florida Stymie Researchers, Threaten Crops

Originally published on Thu June 27, 2013 5:34 am

With its pleasant climate, Florida has become home to more exotic and invasive species of plants and animals than any other state in the continental U.S. Some invasive species have been brought in deliberately, such as the Burmese python or the Cuban brown snail. But the majority of species are imported inadvertently as cargo.

Amanda Hodges, who heads the biosecurity research lab at the University of Florida, says that until recently, scientists saw about a dozen new bugs arrive in Florida each year.

"But we've seen in the last few years, we've actually seen an increase in the number of new introductions," Hodges says. "We've seen more like 24 new arthropods."

These new bugs are being studied inside the biosecurity lab. After signing in and putting on a lab coat — measures designed to make sure the invasive pests being studied don't escape — you would find graduate student Ashley Poplin. She's studying one of the newest threats to American agriculture: the brown marmorated stink bug.

"These are the little guys. They kind of have an orange abdomen and black markings," she says. "It almost looks like a black spider, but of course this has six legs instead of eight."

The bug was first discovered in Allentown, Pa., but has now spread nationwide. In Florida, it threatens vegetable crops and the state's ornamental plant industry. With time, researchers are confident they'll identify natural predators and parasites that will help them control the stink bug. It's a strategy that takes time and work, but almost always pays off.

There's one pest in Florida, however, that so far has defied the best efforts of scientists and the agriculture industry. It's a tiny bug called a psyllid, and it poses a huge threat to Florida's $9 billion a year citrus industry. The bug was only discovered eight years ago in Florida's citrus groves, says Marjorie Hoy, an entomology professor at the University of Florida. Since the discovery of the psyllid, Hoy says, Florida lost a good portion of its crops.

"It's been a disaster since then," she says. "From 860,000 acres, I think we're down to roughly 600,000 acres or less."

For decades, Hoy and other researchers used parasites and predators to successfully combat a series of invasions by bugs that preyed on citrus trees. But with this latest invasion, entomologists may have met their match. The psyllid, combined with bacteria it carries, causes citrus greening, a disease that kills orange trees and makes the fruit unusable.

To combat it, citrus growers have turned away from biological controls and are using pesticides and nutrient sprays. For Hoy, it's been disheartening.

"It's a very sad situation because Florida citrus was one of those premier examples of how to grow citrus with the least number of pesticides," Hoy says. "It's just heartbreaking."

The citrus industry is reeling from greening, not just in Florida, but also in California and Brazil. Meanwhile, researchers are scrambling to develop better traps, stronger trees and possibly even transgenic solutions. Scientists are studying ways to alter the genome of citrus to make it more resistant to greening.

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Transcript

AUDIE CORNISH, HOST:

Ever since the explorer Ponce de Leon waded ashore in Florida, the state has proven hospitable to foreign visitors - in some cases, overly so. We're talking here about exotic plants and animals, including pests such as fire ants, giant African snails and even Burmese pythons. NPR's Greg Allen met some researchers who are working to hold the line against Florida's most numerous invaders: bugs.

GREG ALLEN, BYLINE: Few people spend more time with bugs than John Capinera. He's chairman of the University of Florida's Entomology Department. Capinera started his career in Colorado, but he says anyone interested in bugs is drawn to Florida.

JOHN CAPINERA: This is like the mecca for entomology. Florida has got all the big bugs.

ALLEN: Capinera and his colleagues stay busy looking for ways to control the bugs that plague farmers, gardeners and homeowners in Florida. It's a long list that includes whiteflies, termites, Africanized honeybees and the Asian tiger mosquito. And Capinera doesn't just study bugs, he also has a thing for snails and slugs.

CAPINERA: This is delightful. This is a slug.

(LAUGHTER)

ALLEN: In Capinera's lab in Gainesville, he has stacks of clear plastic boxes, each home to a crawly something he's studying. He opens one that contains an unknown species of slug.

CAPINERA: It's a huge thing.

ALLEN: It's an ugly gray, four inches long, flat on the bottom. And Capinera says slugs like this are suddenly turning up all over Florida.

CAPINERA: They love lettuce.

(LAUGHTER)

CAPINERA: I feed them romaine. This is great. No name. We don't yet - haven't identified the species. We don't know the country of origin. Welcome to the world of exotic pests.

(LAUGHTER)

CAPINERA: Florida has a lot of these things, and it often takes a while to figure out what we have.

ALLEN: Some invasive species have been brought in deliberately - Burmese pythons, for example, also the Cuban brown snail, imported by a scientist who dreamed of sparking Americans' appetite for escargot. The majority, however, are imported inadvertently as cargo: slugs hiding in pots of orchids from Thailand, bugs on cut flowers from Colombia. Amanda Hodges, who heads the biosecurity research lab at the University of Florida, says until recently, scientists saw about a dozen new bugs arrive in Florida each year.

AMANDA HODGES: But in the last few years, we've actually seen an increase in the number of new introductions. We've seen more like 24 new arthropods.

(SOUNDBITE OF DOOR OPENING)

ALLEN: To enter the biosecurity lab, you sign in, go through two doors and put on a lab coat - measures designed to make sure the invasive pests being studied don't escape. Inside, grad student Ashley Poplin is studying one of the newest threats to American agriculture: the brown marmorated stinkbug.

ASHLEY POPLIN: These are the little guys, kind of have an orange abdomen and black markings. It almost looks like a black spider. But, of course, this has six legs instead of eight.

ALLEN: It's a bug first discovered in this country in Allentown, Pennsylvania, which has now spread nationwide. In Florida, it threatens vegetable crops and the state's ornamental plant industry. With time, researchers are confident they'll identify natural predators and parasites that will help them control the stinkbug. It's a strategy that takes time and work but almost always pays off. But there's one pest in Florida that so far has defied the best efforts of scientists and the agriculture industry.

It's a tiny bug called a psyllid, and it poses a huge threat to Florida's $9 billion a year citrus industry. University of Florida entomology professor Marjorie Hoy says it was only discovered eight years ago in Florida's citrus groves.

MARJORIE HOY: It's been a disaster since then. From 860,000 acres, I think we're down to roughly 600,000 acres or less.

ALLEN: For decades, Hoy and other researchers used parasites and predators to successfully combat a series of invasions by bugs that preyed on citrus trees. But with this latest invasion, entomologists may have met their match. The psyllid, combined with bacteria it carries, causes citrus greening, a disease that kills orange trees and makes the fruit unusable. To combat it, citrus growers have turned away from biological controls and are using pesticides and nutrient sprays. For Hoy, it's been disheartening.

HOY: It's a very sad situation because Florida citrus was one of those premier examples of how to grow citrus with the least number of pesticides.

ALLEN: The citrus industry is reeling from greening not just in Florida but also in California and Brazil. Meanwhile, researchers are scrambling to develop better traps, stronger trees and possibly even transgenic solutions. Scientists are studying ways to alter the genome of citrus to make it more resistant to greening. Greg Allen, NPR News, Miami.

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