US scientists are planning to scale up deployment of laboratory-bred insects to battle invading plant species that threaten to throttle parts of Florida’s ecologically fragile Everglades wetlands.
The plant and seed-eating bugs, which include moths, mites and weevils, act as biological control agents — basically environmental gamekeepers — against the invaders.
They are to be produced in their hundreds of thousands at a new research laboratory planned jointly by the US Department of Agriculture (USDA), the US Army Corp of Engineers and the South Florida Water Management District.
The new “bug factory” facility is scheduled to open in September next year and aims to saturate areas infested with invasive plant species in a US$16 million program over 20 years.
This is considered a modest investment compared with the untold billions of dollars in environmental damage that can be inflicted by the non-native invaders.
While herbicides and physical eradication have been used for decades, scientists consider mass-produced biocontrol bugs a more effective weapon
“The goal [for each insect type] is to control 90 percent of the proliferation,” said USDA’s lead scientist for the project, Ted Center. “It won’t eradicate the invasive species, but it will do a lot of the work for us.”
The Everglades wetlands at the southern end of the Florida peninsula are one of the US’ most famous natural attractions.
Covering 810,000 hectares and designated an endangered World Heritage site by UNESCO, they are a mosaic of marshland and tree islands, famous for crocodiles, manatees, panthers and exotic birds, including plants and animals found nowhere else.
In recent decades, the Everglades ecosystem has been weakened by growing urbanization and polluted run-off from nearby farming and cattle operations.
While public attention has focused on the more visible invasive animal species, such as the Burmese python that has tangled with local alligators, experts say the plant invaders can cause just as much, if not more, havoc to the habitat.
One leafy invader is the fast-growing Old World Climbing Fern, which creeps up trees, blankets land with vegetation and accelerates the spread of wildfires.
“Some tree islands have -collapsed from the weight of the ferns,” said Center, adding that one biocontrol agent, an Australian moth, has achieved some limited success in pushing back the plant.
Another creeping interloper is the Brazilian pepper, which has infested over 283,000 hectares of public and private land.
About 1,400 of more than 25,000 non-native plants imported into Florida have established populations in the wild, with nearly 70 identified as ecosystem-damaging plants, according to research studies.
The USDA has targeted 11 invasive plants as serious threats to the Everglades.
Scientists believe the trespassing species come from the hundreds of exotic plants imported into nurseries in Florida every year.
The nurseries are virtually unregulated, catering to an extensive gardening market that must meet demand for new varieties of ornamental plants.
Searching for an insect predator for the Brazilian pepper, the USDA is three years into the hunt for a winning biocontrol bug, with scientists making several trips to Brazil, collecting 12 species to be used to build lab colonies for testing.
Because of a “glacially slow” regulatory process, it can take several more years for a biocontrol insect to be released into the Everglades. The period from identifying an invasive species through to its eventual reduction can run to about 20 years.