The spotted lanternfly was first found in the United States in Berks County, Pennsylvania, in 2014. The destructive pest, which is native to Southeast Asia, likely hitched a ride on something imported from Asia to Pennsylvania. Since 2014, the insects have been spotted in eight states, having spread from Pennsylvania to Virginia, Massachusetts, Delaware, New Jersey, Maryland, Connecticut and New York.

Spotted lanternflies spread in many ways — they can attach to live plants, metal on vehicles, and wood that has been cut down and transported such as firewood or Christmas trees.

NJ.com tells the story of a woman who wound up with hatched spotted lanternflies inside her Warren County, New Jersey, home in early January 2018 when her Christmas tree was still in the house. An inspection of the tree uncovered two egg masses on the trunk with the potential to hold up to 100 eggs. It's not surprising the insects found their way into a home via holiday decor: A typical Christmas tree may hold up to 25,000 bugs, although most of them are microscopic.

The good news for the homeowner is the spotted lanternfly isn't harmful to humans or other animals, so while it may have been unsettling to find strange insects in her home, no one was in danger. The insects are not known to bite or sting.

The bigger concern is that the egg masses were on her Christmas tree. If the eggs hadn't begun to hatch inside her house, when she was done with the tree it would have been put outside where the eggs could have hatched and the insects could have spread. It's spreading populations of the spotted lanternfly that have agriculture experts on high alert — and urging residents to be on high alert, too.

Be on the lookout

Invasive species experts are urging people to learn more about the spotted lanternfly (Lycorma delicatula). The short video above shows all the stages of the spotted lanternfly to help you identify it from egg mass to adult.

The U.S. Department of Agriculture (USDA) sees the pest as such a threat that it has allocated $17.5 million in emergency funds to help the Pennsylvania Department of Agriculture fight the infestation with a focus on a three-mile perimeter that surrounds the core infested area.

Pennsylvania issued a quarantine to control lanternflies. Everyone in quarantined counties must inspect wood and vegetation that leaves the county, as well as vehicles, trailers and other mobile equipment before they leave the county, according to the Pennsylvania Department of Agriculture. Businesses must also get permits before moving products or vehicles around inside or outside the quarantined areas.

Delaware and New Jersey have similar quarantines, reports the Lansing State Journal. New York has a quarantine on goods entering the state from infested areas.

Michigan state park workers will use ZIP codes in those quarantine areas to contact campground visitors who are coming from infested areas and make sure they have checked their vehicles and equipment.

The concern is that the U.S. spotted lanternfly population will become large enough to do the same damage the species has done in Southeast Asia. The USDA says these trees and plants are at particular risk: almonds, apples, apricots, cherries, grapes, hops, maple trees, nectarines, oak trees, peaches, pine trees, plums, poplar trees, sycamore trees, walnut trees and willow trees.

Both nymphs and adults feed on the stems and leaves of these plants, sucking sap from them. That causes a reduction in photosynthesis that can weaken or kill a plant. The damage can also encourage mold that may attract other harmful insects.

Because they're an invasive species, spotted lanternflies have few natural predators in North America. That doesn't mean they're untouchable, though. According to a study published in April 2019, two native fungal pathogens have been "decimating" spotted lanternfly populations near Reading, Pennsylvania. It may not stop the overall invasion, but it is a big discovery, researchers say, since the naturally occurring fungi could be used to develop new ways of controlling spotted lanternflies.

What you can do

Lanternfly egg mass spotted on a tree in Pennsylvania. (Photo: U.S. Department of Agriculture [public domain]/Flickr)

It seems the spotted lanternfly population is most often spread when it's transported by humans. Citizen vigilance is going to be an important part of combating the potentially devastating effects of this insect. If you find egg masses, eggs or hatched spotted lanternflies at any stage of development, here's what you should do.

If you can, collect a specimen at any stage of life that can be taken to your state's agricultural extension lab for verification.

With the GPS function turned on, take a photo with your smartphone or camera of any stage from egg mass to adult. Submit it to your state agricultural extension lab.

Destroy any egg masses, eggs or insects by scraping eggs or putting insects into a plastic bag and filling it with rubbing alcohol, as shown in video above.

This interactive map can help you find an agricultural extension in your state.

A Pennsylvania state website is pretty clear in its advice to residents: "Kill it! Squash it, smash it...just get rid of it. In the fall, these bugs will lay egg masses with 30-50 eggs each. These are called bad bugs for a reason, don't let them take over your county next."

You can also call these spotted lanternfly hotlines with questions or to report sightings in Pennsylvania or New Jersey.

Pennsylvania: 1-888-422-3359

New Jersey: 1-833-223-2840

For now, the spotted lanternfly seems to be isolated to the East Coast, but if the insect spread from Southeast Asia to the East Coast of the United States, it can certainly spread to other parts of the country.