What's that bug?
Invasives are a big problem; a new insect could be an even bigger one.
In subtropical regions of Southeast Asia, including eastern China, a strikingly unique, polka-dotted insect can be found hopping between its favorite food sources.
This peculiar bug, called the spotted lanternfly (Lycorma delicatula), is not really a fly at all but rather a species related to cicadas. Though it can feed on a wide variety of plant species, it prefers — and may possibly require — tree of heaven, a type of deciduous tree that is also native to its home region.
In 2014 in Berks County, just outside of Philadelphia, Pennsylvania, an awkward, unfamiliar arthropod was discovered. It was quickly identified as the spotted lanternfly and thought to have arrived as eggs on a shipment of stone from China in 2012.
The spotted lanternfly, usually kept in check by a type of parasitic wasp (Dryinus browni) back home, had found itself in an ideal situation in Pennsylvania. Its favorite food source, tree of heaven, was also there (brought over from China in the 1700s as a shade tree), the climate was relatively mild, and no effective predators existed — the perfect recipe for an invasive species to flourish.
Tree of Heaven
With a sense of urgency, the Pennsylvania Department of Agriculture enacted several quarantines and developed a management plan in cooperation with federal, state, and local agencies as well as non-governmental organizations. Concurrently, researchers went to work to learn as much as they could about the pest and perhaps identify a biological control — a natural enemy managed by humans.
Even with public education campaigns and management plans quickly put in place, the spotted lanternfly spread; as of late 2023, it can now be found in 14 states in the northeastern United States.
What's the big deal?
The lanternfly is particularly concerning because of its ability to thrive on a variety of species, from grapes and almonds to birch and willow. It not only feeds on a myriad of commercially valuable plants, but it also secretes “honeydew,” a substance that attracts wasps and leads to the growth of fungi.
Perhaps the biggest question right now is, “Will it reach the West Coast?” Though the Rocky Mountains provide a significant barrier to the lanternfly, the threat remains. A study from 2022 predicted the species will make its way to California, the country’s agricultural powerhouse, by 2033 without preventative management.
The map below is adapted from a study conducted by the USDA that modeled potential suitable habitat for the spotted lanternfly. The areas in dark red indicate high suitability. An uncontrolled infestation would have a detrimental impact on agriculture and the timber industry in the United States, and the economic impact could be astronomical; grape production alone is a $6.5 billion industry in the U.S.
Potential distribution of spotted lanternfly in the United States adapted from Fig. 3 of Wakie, et. al. 2020.
Though not particularly strong fliers, the spotted lanternfly is a fairly decent hopper and glider and can cover three to four miles using a combination of these movements. With that in mind, it seems unlikely they could get very far, let alone spread across the country. However, a recent study found that human-mediated dispersal methods — such as cars and trains — are driving the spread of this species.
Familiar foe
This is not the first time the U.S. has contended with a highly damaging species that spreads most easily and rapidly through human-mediated activities. In 1988 in Lake St. Clair, a small body of water bordering Detroit, Michigan that is sandwiched between Lakes Huron and Erie, an established population of invasive zebra mussels was discovered. Originally from the Caspian and Black Seas south of Russia and Ukraine, zebra mussels likely entered the country from the ballast water of ships in the Great Lakes.
Much like the spotted lanternfly, zebra mussels found themselves in ideal conditions upon arrival — ecosystems of ample, nutrient-rich freshwater and no effective predators. Now widely known in the United States, they reproduce quickly and outcompete other species for food and space, and once they are established in a water system, there is very little that can be done to get rid of them.
Not only do zebra mussels influence the productivity of the entire aquatic ecosystem, they also significantly damage infrastructure.
The spread of zebra mussels tells a spatial story of hard-fought battles; aggressive education campaigns, watercraft inspection programs, molluscicide treatments, and cooperative management efforts near the Mississippi River stalled their spread for several years. Unfortunately, that did not last.
For many years, the Columbia River Basin in the northwestern corner of the United States has been the last mussel-free watershed. Though the battle rages on to keep them out, quagga mussels — a species similar to the zebra mussel — were discovered in the Snake River in Idaho in September 2023, triggering an aggressive, rapid response plan. The health of the watershed is now at risk.
Know it, see it, squash it
If you're not from the Northeast, it's likely you haven't yet heard of the spotted lanternfly. However, significant efforts are underway to educate the public about this pest. As the site of the first detection, the state of Pennsylvania is perhaps the most advanced in their response and management efforts. Populations are being controlled through quarantine, physical destruction of the insect at any life stage, removal of tree of heaven, and pesticide applications.
Management and prevention plans are not just for states with established populations; many states without sightings already have action plans in place. California, Texas, and Missouri, just a few of the states within the suitable habitat range for spotted lanternfly, all have websites set up to report sightings and provide information to the public. Additionally, the USDA released their five-year plan in June 2023. This pest is spurring rapid action at all levels across the nation.
Various spotted lanternfly public outreach materials.
Public outreach continues to be a top method for early detection and management. Many states have come up with unforgettable slogans and eye-catching posters to turn everyone into a lanternfly hero. New Jersey wants you to "Join the battle. Stomp it out!" Pennsylvania uses, "Look before you leave!" to remind residents to check their vehicles for clingy pests. And Maryland has employed a more humorous approach — "Wanted" posters with photos of the bug in all life stages.
Managing invaders
Invasive species pose a serious threat across the globe. A recent report by the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) found they play a key role in 60 percent of plant and animal extinctions globally and cost economies more than $423 billion in damages and lost productivity. In the United States alone, invasive species cost more than $21 billion with the biggest impact on agriculture. Most surprisingly, a staggering 45 percent of all countries do not have a plan in place for managing these biological invasions.
Every invasive species is unique in its biology and behavior, and management often involves the best combination of tactics for a particular species; this is called integrated pest management (IPM), which is a science-based, sustainable, ecosystem-focused strategy for long-term management. In the United States, government agencies, from local to federal, are responsible for implementing management programs. They are informed by continued research to understand the invasive species and possibly identify new methods to contain it.
What can you do?
Early detection and response are critical, so the most effective strategy for stopping invasions is to stay alert. Here are some additional tips for fighting the good fight against any invasive species.
Double check the species
Before planting anything in your garden, make sure it is not invasive. Never order mysterious, "wildflower" mixes online. Always consult with your local nursery for safe suggestions.
Clean your boots and your clothing
Seeds, insects, and pathogens can easily hitch a ride on you. Thoroughly clean your gear before adventuring in a new area.
Clean your boat
Aquatic hitchhikers are sometimes tough to spot. Thoroughly inspect your boat or watercraft for specimens before entering a new body of water.
Don't pack a pest
Never travel with produce, plants, insects or animals that could become invasive in a new location. Additionally, don't move firewood that can harbor undetectable pests.
Don't release pets or plants
Do your research before taking in an exotic species; do not release them into the wild.
Volunteer
Look for events at your local parks and public spaces. Many need volunteers to help remove invasive plants or monitor existing plots.
Get educated
Learn about your local ecosystems; get acquainted with invasive species and how to best manage them. Most importantly, share your knowledge!
Explore More Invasives
No state is safe from invasives; here are some common species wreaking havoc in the United States. Note: many of these are located across the country; map pins are dropped where infestations originated or are most problematic.
Sea lamprey
Yellow starthistle
Water hyacinth
Purple loosestrife
Nutria (swamp rats)
Invasive carp
Emerald ash borer
Cheatgrass
Lionfish
Kudzu
Burmese python
Gypsy moth
Sea lamprey
Originally from: Atlantic Ocean Introduced: accidentally via St. Lawrence Seaway Harmful because: it kills roughly 40 lbs. of fish each year
Yellow starthistle
Originally from: Eurasia Introduced: accidentally via contaminated seed Harmful because: it crowds out native species, degrades forage quality for livestock, and consumes massive amounts of groundwater.
Water hyacinth
Originally from: South America Introduced via: humans as an ornamental. Harmful because: it forms dense mats on the water surface and restricts light reaching the underwater environment; this significantly reduces submerged plant life and oxygen levels
Purple loosestrife
Originally from: Europe and Asia Introduced via: humans for ornamental and medicinal uses Harmful because: it can become the dominant plant in a wetland
Nutria (swamp rats)
Originally from: South America Introduced via: the fur trade Harmful because: they gnaw through wetland plants and cause significant damage to crops; their burrow systems can destabilize infrastructure
Invasive carp
Originally from: Asia Introduced via: humans for help with fish farms and sewage treatment Harmful because: they outcompete neighbors and consume resources
Emerald ash borer
Originally from: Asia Introduced via: imported wood Harmful because: they destroy ash trees by tunneling under the bark and feeding on the part of the tree that moves water and sugars within the trunk.
Cheatgrass
Originally from: Eurasia and the Mediterranean Introduced via: accidental seed contamination Harmful because: it sets seeds earlier than native plants and uses up soil moisture to prevent germination of other species; it is also a wildfire hazard
Lionfish
Originally from: South Pacific and Indian Ocean Introduced via: aquariums and pet owners Harmful because: they prey on many native species
Kudzu
Originally from: China, Japan and the Pacific islands Introduced via: humans as an ornamental plant and forage crop; it was originally planted to reduce soil erosion Harmful because: it smothers plants and trees
Burmese python
Originally from: Southeast Asia Introduced via: the exotic pet trade Harmful because: it has no predators on the entire continent; pythons have consumed 90% of small and medium mammals in the Everglades, and they reproduce rapidly
Gypsy moth
Originally from: Europe Introduced via: importation for silk production Harmful because: it defoliates over 300 species of trees; it has damaged 78 million acres in the eastern US since 1970.
