In North America, we are losing the war against invasive species. Inexplicably, we believed we could engage in a global economy, reaping all the best the world has to offer, and not succumb to the hitchhikers. But countless organisms, including unwelcome plants and animals, embraced the opportunity to expand their territory. Hardly a day goes by when we don’t read about some new pest eating our forests, munching our crops, or suffocating our fisheries.
During the past hundred years, beekeepers have fallen victim to many international pests including varroa mites. But the mites that have caused so much damage are just one species on an impressive list. Wax moths, small hive beetles, tracheal mites, and foreign pathogens have all played a part. And now, here in my home state, we have Asian giant hornets.
A true bug from Asia
Recently, another immigrant pest settled in the northeastern states: Lycorma delicatula, the spotted lanternfly. Not a fly nor a lantern, the spotted lanternfly belongs to the Hemiptera, the family of true bugs. It is a planthopper, a creature that does more jumping than flying and acquires its nourishment from sucking the juices from plants.
The spotted lanternfly hales from southern China, Taiwan, India, and Vietnam where it has natural enemies that hold the populations in check. But like most invasives, it has few natural enemies outside of its endemic region.
A real showstopper
Unlike some unwelcome organisms, the spotted lanternfly is drop-dead gorgeous. In fact, most of its life stages are striking, sporting colors usually reserved for race cars and wrapping paper.
The adults, which begin to appear in mid-summer, are the most noticeable. Their wings — pale pinkish cream with black splotches — fold over their bodies at rest. But when they fly, they reveal vibrant red underwings that look too pretty to squish. At least at first. The showy adults are frequently mistaken for fluttering moths and are easily dismissed as harmless.
The nymphs, though less arresting, are also handsome. The early-instar nymphs have no red, but are jet black with white spots everywhere, even on their legs. By the fourth instar, the nymphs develop their own crimson jacket, artfully trimmed in black and splattered with bright white polka dots.
Welcome to Pennsylvania
You never know where an invasive species will breach your borders, but this one chose Pennsylvania. The first recorded sighting was in Berks County, back in 2014. Even then, biologists feared the worst, and rightfully so.
By March 2021, just seven years later, the offspring of that first introduction had expanded into 34 Pennsylvania counties. With zero loyalty to Pennsylvania and despite massive quarantine programs, the lanternfly soon radiated into Connecticut, Delaware, Maryland, New Jersey, New York, Ohio, Virginia, and West Virginia. Sightings have also been reported in Indiana, Massachusetts, North Carolina, and Rhode Island. And since I began writing this article, Kansas was added to the list.
A tree that grows everywhere
Invasive species seem to love North America, no less now that it’s home to so many other invasives. The spotted lanternfly probably thought it had died and gone to heaven when it landed on our shores. Why? Because the first thing it found was none other than its favorite host plant, Ailanthus altissima, the invasive tree-of-heaven. Scads of them.
I first learned about tree-of-heaven in grade school when I read A Tree Grows in Brooklyn, a novel by Betty Smith. I loved that book and read it several times, always wondering about the penny bank nailed to the floor and the invincible tree that grew through cracks in the sidewalk.
It was many years before I connected the tree in the story to the ones that grew in my childhood backyard. The smooth-barked trees with sumac-like leaves shed pastel clumps of winged seeds. The seeds spun madly as they fell, looking like miniature whirlybirds. I spent brisk fall afternoons chasing them across the lawn, giggling, trying to catch them in mid-air. My mom called them weeds, but I loved those trees.
The lanternfly’s lucky day
It just so happens that tree-of-heaven is native to China and Taiwan, just like the lanternfly. Imagine the lanternflies’ delight when, so far from home, they discovered their favorite host plant growing in cascading waves across the landscape. How could they be so lucky? So much food, so little time.
Tree-of-heaven was introduced to North America back in the 1700s in — get this — Philadelphia. (Way to go, Pennsylvania.) It became popular as a shade tree, especially in urban environments, because it was easy to establish and grew rapidly. The original importers were prescient because the tree has been establishing itself easily and growing rapidly ever since. According to the Texas Invasive Species Institute, tree-of-heaven has spread into no less than 44 states. Can the lanternfly be far behind?
If the spotted lanternfly were a picky eater, we wouldn’t have a problem. The planthoppers could scarf down the tree-of-heaven until there were no more trees and finally no more planthoppers. Only it doesn’t work that way.
Unfortunately, lanternflies are not fussy eaters. They especially like fruit trees, nut trees, hop vines, grapevines, maples, birch, and willows. They even like Christmas trees, ornamental flowers, and mixed vegetables. But if those things are not on the menu, they will find alternatives. One glance of anything green spurs them to tuck in their napkins.
Eating in stages
The lanternfly’s diet relates to its life stage. Spotted lanternflies undergo hemimetabolism (incomplete metamorphosis), meaning they go from egg to nymph to adult.
In late summer, when the adults are flying, they mate. The fertile female then lays a clutch of eggs on a convenient vertical surface. The smooth trunk of a tree works wonders for this, but so does a rock wall, the side of a truck, or a rural mailbox. After the female covers the eggs with a waxy secretion, she finds a second location and repeats the process. Each egg mass, gray and flat, contains 30 to 50 eggs that overwinter in place.
In spring, the eggs release nymphs that undergo four instars. The first instar nymph, dressed in black with white spots like a reverse dalmatian, appears in April or May. These wingless creatures immediately crawl skyward, searching for the succulent upper growth of their host plant, usually a nearby tree-of-heaven but a tender willow or maple will do. The second and third instars soon follow, looking like slightly larger versions of the first. All three are black and white.
By the fourth instar, people are seeing red. Brightly colored nymphs — now black and white and red all over — are eating everything and leaving trails of sticky sap. The sap, a type of honeydew, is an insect excretion. The nymphs eat more than they can digest, forcing the sap straight through the digestive tract and out the back end without ever being processed.
After the fourth instar, the lanternfly transitions into an adult planthopper. The adults and all the nymph stages have powerful legs that allow them to leap to a new food source whenever the mood strikes. The brightly painted adult wings look impressive, but they’re not much good for flying. Instead, the adult lanternfly leaps from plant to plant just as the nymphs do, eating whatever it pleases, including upwards of 70 crop plants.
Problems with honeydew
The piercing and sucking mouthparts of the lanternflies drain the plants of nutrients and water, often causing the leaves to wilt and turn yellow. In addition, the rich deposits of honeydew excreted by the bugs drip from the leaves and stems, glazing the lower foliage and understory plants with a layer of rich sap.
The accumulated sap becomes a Petri plate of nutrition for a variety of sooty molds, including species of Fumago, Scoias, Capnodium, and Cladosporium. Once the molds become established, they block sunlight from reaching the leaves, interfering with photosynthesis and further damaging the plants.
In addition, the honeydew attracts many types of insects, including bees, ants, and wasps. The food-gathering insects annoy people and become food for even more predators, which further annoy people. Everyone, in fact, seems vexed by these creatures, with the notable exception of a few intrepid beekeepers.
A deep dark mystery
Several years ago, some Pennsylvania beekeepers began finding dark honey where they didn’t expect it. It was simply in the wrong place at the wrong time of year. Perplexed, they argued about what it might be. Chestnut? No. Buckwheat? No. Avocado? Not a bleeping chance. When nothing seemed to fit, they collected samples for DNA analysis and sent them to the state university.
What they found was a shocker. The DNA was a match for Ailanthus, the ubiquitous tree-of-heaven. But those trees produce very little nectar from the small green blossoms that appear in spring. Furthermore, tree-of-heaven has been established in Pennsylvania for nearly 300 years, nearly as long as the honey bees themselves. If the honey came from tree-of-heaven, someone would have noticed by now.
Once researchers began looking at individual trees, the answer became clear. Drips and drops of honeydew slid down the smooth trunks and coated the plants beneath. At first, the honeydew was easy to miss because it was hidden beneath writhing layers of honey bees frantically collecting the sweet deposits, carting it off to their hives as fast as apisly possible. The DNA mystery was solved.
Honeydew honey is nothing new. Bees the world over have found honeydew to their liking and, in some regions of the world, honeydew honey is popular with humans too. It is often darker than nectar-based honey, slightly less sweet, and rife with assertive flavors. It is sold under a variety of names, including tree honey, bug honey, and forest honey.
Because honeydew honey can be high in ash — a characteristic that goes hand-in-hand with dark colors — beekeepers like to remove it from their hives before winter. Too much ash in the digestive system is associated with water retention and, ultimately, honey bee dysentery.
From what I’ve heard, lanternfly honey is especially viscous with an alarming reddish-brown color. It has a flavor reminiscent of dried fruit — sweet in the way molasses is sweet — and tends to be especially sticky.
Last year, a few enterprising beekeepers hopped on the opportunity to sell a unique product: lanternfly honey. I tried to buy a sample, but it was simply unavailable. The few people I talked to said sales were brisk and demand high. Some sold out in just hours, others took orders for the following year. One beekeeper told me she had multiple supers of mysterious dark honey that she’d never seen before. She ended up selling it as buckwheat because she didn’t know what else it could be.
The beekeeper’s dilemma
Not all beekeepers are happy about the lanternfly invasion. Some fear that their signature varietal honeys will become contaminated with honeydew, lowering both the quality and the price. One beekeeper told me he was harvesting more frequently, trying to protect his crop from the ubiquitous honeydew by removing any that looked too dark.
Other beekeepers fear the pesticides used to control lanternflies — including dinotefuran, imidacloprid, carbaryl, and bifenthrin — will spill over into crops that support honey bees, or that the lanternflies themselves will devour the plants that provide winter stores. Biodiversity specialists, especially those concerned with pollinator conservation, have similar worries. They, too, fear the reckless application of pesticides and loss of plants that support wild populations of bees, butterflies, and flower flies.
Swatting, stamping, and swearing
A quick Google search will reveal dozens of different methods of controlling spotted lanternflies without poisoning all the local pollinators, including your bees. Entomologists suggest learning to recognize the three main life stages of the insect and then choosing control methods that work best with each.
You can scrape egg clusters from vertical surfaces with a hive tool or paint scraper. Once you learn to recognize them, they are easy to spot and remove. The scrapings can be sealed into a double-layered plastic bag and simply put in the trash. Or, if you prefer, you can douse them in alcohol, hand sanitizer, or household bleach.
The nymphs love to climb tree trunks, so some folks wrap sticky paper or inverted duct tape around the trunks of trees. Next, using a garden hose, they shoot the lanternflies out of the trees. When the nymphs crawl back up, they get caught in the tape. The downside is other things also get caught in the tape, so this method is best when someone is there to monitor the traps and keep other animals away.
Adults are best smashed, squished, or flattened with a shoe, flyswatter, bat, or your trusty hive tool. They can also be sprayed with insecticidal soap or vinegar, or collected with a shop vac or butterfly net.
Milkweed — yes, the type that is essential to monarch butterflies — is deadly to lanternflies and both the adults and nymphs will die soon after ingesting it. So an easy win-win for the environment is to plant more milkweed around your lawn and garden.1
Into the unknown
Like most invasives, the spotted lanternfly is likely here to stay. Although some people suggest that eliminating the tree-of-heaven would help, others argue we still don’t know if the tree-of-heaven is essential to the spotted lanternfly or merely a preferred plant. It could be that a scarcity of tree-of-heaven could speed up the lanternfly’s preference for something else.
Until we know more, just keep smishing, smashing, and smearing. Oh yes, and enjoy that dark honey — just don’t raise lanternflies on purpose to produce it.2
Honey Bee Suite
Notes and references
For an extensive list of spotted lanternfly controls, see French and Pickering (2018) The spotted lanternfly: 10 tips to fight the infestation. https://frenchandpickering.org/lanternflies/
A short version of this story first appeared in Countryside and Small Stock Journal, Volume 105, Number 4, pp. 33-35, July/August 2021.