Larry Bledsoe is spending his summer on the lookout for foreign invaders with wings and a penchant for destruction.
It isn’t easy. Among his tasks: venturing into the humid heat to lay traps laced with a sex pheromone engineered to attract a pesky species of moth known as the Old World bollworm.
Last summer, the Purdue University entomologist and his research team dissected more than 1,400 snared moths, using tiny tweezers to pull out the pests’ internal reproductive organs to examine under microscope. It was the only way to confirm the true identity of a species with near-identical cousins.
Not finding a single Old World bollworm among the many moths was good news: It meant Indiana had gone another year without infestation of an invasive species that could bring the state’s $3 billion agriculture industry to its knees.
The bad news? Indiana, like the rest of the nation, is being invaded an increasingly rapid rate by exotic species that create havoc. State and federal officials point to the increase in global trade and the ease in which invasive species can hitch a ride on everything from luggage to shipping palettes.
“Screenwriters in Hollywood couldn’t come up with any scenario that we’re not already dealing with all the time,” Bledsoe said.
The U.S. Department of Agriculture estimates 50,000 non-native insect, plant and animal species have arrived in the county in the last 300 years. Only fraction are categorized as invasive – labeled so because of the environment and economic damage they do.
How and why they arrived varies. Kudzu was imported from Japan to control soil erosion in the Southeast U.S. But the aggressive vine, which can up grow up to a foot a day, has spread north into Indiana, threatening to smother the state’s forests with its dense canopy. State wildlife officials have spent years beating back the Asian purple loosestrife to keep it from suffocating wetlands. It was introduced to the U.S. 200 years ago as an ornamental plant.
Last week, officials with the Indiana Department of Natural Resources announced they would install a mesh fence across a 700-acre marsh in northeast Indiana to keep the voracious Asian carp from moving into the Great Lakes, where it threatens a $7 billion fishing industry. The carp were imported in the 1970s to control algae in commercial catfish farms in the South. They escaped when floods washed them into the Mississippi River.
“We’re spending an ever-increasing amount of time and resources fighting invasive species,” said Phil Marshall, a DNR entomologist and forest health specialist.
Like Bledsoe, he fears the arrival of insects and other species into areas where they have no natural predators.
“We don’t want another Emerald ash borer,” said Bledsoe of the tree-killing insect that arrived in Michigan from Asia on packing material and rapidly infested neighboring states. “That was like the cows getting out of the pasture without us knowing it. They were far from home before we found them, and by then, it was too late.”
Efforts to eradicate the intruders vary. Wildlife officials are reluctant to use pesticides and herbicides, concerned about potential damage.
“You don’t want the cure to be worse than the cause,” said Lenore Tedisco, director of the Center for the Earth and Environmental Science at IUPUI in Indianapolis.
The USDA cites studies that estimate the annual cost of environmental and economic damage done by invasive species in the U.S. at $120 billion. That includes detection and eradication efforts, port inspections and damage done to crops.
The Indiana Invasive Species Task Force, formed last year to coordinate federal, state and private efforts to combat invasive species, is working to ward off the coming danger. Of particular concern are invasive pests such as the Old World bullworm that could damage the state’s major field crops, including 12 million acres of corn and soybeans.
“There’s not an invasive species that’s cheap or easy to get rid of,” Tedisco said. “And it’s only going to get more expensive and difficult.”