These 5 tiny pests are creating big trouble for Indiana's environment

Indianapolis Star

15 hours ago

A few of Indiana's tiniest transplants — invasive worms, moths and beetles from overseas — have made massive changes to Indiana's ecosystems over the past several decades.
Some of the creepy-crawlies currently wreaking havoc on North American ecosystems have been in the United States for over a century, lurking out of sight. But others, like spotted lanternflies, are newer threats, and they're sweeping through Midwestern forests, fields and gardens with a fury.
In Indiana, some tree species have almost disappeared, vineyards are under threat and even urban gardeners are starting to see the health of their soil decline. Without natural predators, the pests are difficult to stop.
But it is possible to slow them down.
Scientists are quarantining infected forests, disrupting mating seasons and encouraging Hoosiers to learn how the creatures spread. Here's what you need to know about how five tiny pests are causing chaos in Indiana.
At first glance, an Asian jumping worm looks like any other slimy earthworm — they're slender, squishy, and probably squirming around in your garden beds.
But while most worms burrow deep into soil and poop out nutrients across the layers, Asian jumping worms stay close to the surface. Their castings, which look like used coffee grounds, is easily washed away by rainfall, and it's almost impossible to grow native plants, fruits or veggies in the low-nutrient dirt left behind.
The worms were brought to North America from eastern Asia over 100 years ago, but they've only recently become a major threat. Over the last decade, their populations exploded and began to spread rapidly across the Midwest. Now, Asian jumping worms have been reported across multiple cities and counties in Indiana, including Indianapolis and Bloomington.
'We're finding them kind of everywhere,' said Robert Bruner, an entomologist at Purdue University. 'People are sitting up and paying attention a lot now because their damage to the soil structure is really hard to fix.'
Stopping their spread is tricky, too. Bruner theorizes the worms and their eggs are being moved through contaminated soil, mulch and compost. His advice to gardeners: Stop sharing soil with your neighbors, leave new bags of fresh dirt to dry in the sun for a few days, which can kill worm eggs, and report any sightings of Asian jumping worms you find.
Ash trees used to line the streets of Indiana cities by the tens of thousands. Their huge canopies and leafy cover provided ample shade for Hoosiers far and wide. But now, most of these native trees are dead.
The tiny emerald ash borer is to blame, according to entomologists. The bright green wood beetles hail from Eastern Asia, and were first found in Indiana in 2004. They've since spread to every county in the state.
Emerald ash borers can kill a healthy ash within six years of first contact. After burrowing just underneath the bark, the beetles feast on tree tissue, which eventually disrupts an ash's ability to internally transport water and nutrients.
Despite killing most of their primary food source, emerald ash borers persist. The beetles survive in pockets across Indiana and neighboring states, feeding on the remaining ash living in backyards and forest groves.
'Emerald ash borer is a constant concern because there are still ash trees and people are still trying to preserve them,' said Bruner. He thinks the beetles have become a permanent part of the Indiana landscape.
Because dying ash trees can crash to the ground and endanger their surroundings, city officials and residents have removed dead and dying trees by the thousands. But some ash trees in parks and backyards have been preserved through recurring pesticide applications, a process that can sometimes save Hoosier homeowners money in the long run compared to the hefty cost of tree removal and replacement.
Spongy moths are the one of the most dangerous defoliators in the United States, meaning they can and will chew through as much foliage as they find. In 2021, the moths defoliated over nine million acres of forest across the country according to Purdue University.
An amateur entomologist brought spongy moth specimens to Boston from Europe in the late 1860s — the moths escaped, obviously — and the creatures have been chewing their way through New England and further west ever since.
But it isn't exactly the fuzzy, winged insect that is destroying forests. Rather, it's the larval stage of the moth's life cycle posing the threat: Caterpillars need to eat.
As they prepare to metamorphose, spongy moth caterpillars devour the leaf tissue from over 300 species of trees and shrubs: preferably oaks, but tamarack, white birch, pine and spruce, too.
Usually, trees can survive their first defoliation. But when their leaves are shredded up and eaten away year after year, trees quickly lose their ability to fend off disease and store energy over the winter, leading to death.
In Indiana, the spongy moth outlook is 'pretty bad,' according to Bruner. Roughly three quarters of Indiana's 4.4 million acres of forested land is at risk, according to the Indiana Department of Natural Resources (DNR).
The moths pose such a serious threat to Indiana's ecosystems that the DNR puts counties with large infestations into quarantine to prevent further spread. In some areas, the DNR is even spraying pheromones to confuse and disrupt mating between male and female moths, said Bruner.
Right now, the moths are largely sequestered to northern Indiana, but past sightings further south, like in the Hoosier National Forest, have entomologists on high alert.
Armed with piercing-sucking mouthparts and a penchant for hitchhiking, invasive spotted lanternflies found their way from the East Coast to Indiana by 2021. Every year, the bugs travel a little further into the state, jeopardizing forests, vineyards and orchards.
The creatures aren't technically flies. Rather they're planthoppers, which are more closely related to cicadas and aphids. And they're destructive.
By piercing into a plant's vascular tissue, spotted lanternflies suck up sap to get nutrients. Then, they excrete oodles of honeydew — a sugary, watery mess — over everything nearby, which attracts other pests and allows sooty mold to grow.
Spotted lanternflies can also destroy agricultural crops. In Indiana, scientists are worried about the vineyards strewn across the state. When thousands of spotted lanternflies swarm feed on grapevines, they can weaken the plants, reduce yield and kill them off entirely. They also attack black walnut and maple trees, which could impact the local maple syrup and timber industries, said Bruner.
The planthopper's path of spread across the United States has closely followed railways, and Bruner expects to see them spread even further south this year. Hoosiers can report spotted lanternfly sightings to the DNR by submitting information through the agency's online portal.
Asian longhorn beetles aren't a current threat to Indiana's ecosystems, but they're still keeping some entomologists up at night.
In the late 1990s, the beetles were found in Indianapolis and Porter County, according to previous reporting from IndyStar, and the threat was immediately eradicated, said Bruner.
But Asian longhorn beetles still exist in Ohio forests, albeit quarantined, and Bruner is encouraging Hoosiers to stay on high alert in case the beetle finds its way back to Indiana.
'They're one of the nastiest ones,' he said. 'If you see one, it means it's already too late.'
Asian longhorn beetles bore deep into tree trunks and gouge out large holes, creating chambers inside trees where young beetles feast and grow. They have a slight preference for maple trees but are happy to munch through most hardwoods, like elms, willows, birches and sycamores. As they emerge from trees, they leave behind small, perfectly circular holes — about the size of a No. 2 pencil.
Dying trees are left carved up and hollowed out, lacking access to internal water or nutrients.
"Trees can't survive that level of damage," said Bruner. 'Typically, you have to eradicate all the trees within that area just to guarantee they don't spread.'
The DNR encourages residents not to move firewood, which can easily spread pests like the Asian longhorn beetle, and report potential sightings to [phone].
IndyStar's environmental reporting project is made possible through the generous support of the nonprofit Nina Mason Pulliam Charitable Trust.