This fact sheet is an attempt to clear up many of the misconceptions people have about spotted lanternflies. All facts below are a guide based on actual observed behaviors, combined with reputable science.
For the record, it's lanternfly or lanternflies, one word, not lantern fly or lantern flies.
What are spotted lanternflies?
Spotted lanternflies (Lycorma delicatula) are planthoppers from the order Hemiptera like our native aphids, cicadas, or leafhoppers. We have many native species of planthoppers in the US. Spotted lanternflies, however, are native to countries in South East Asia.
Can they bite?
No, they cannot. Their mouthparts, which are fused into a straw-like beak that they insert into plant tissue to suck up sap (phloem), are not capable of penetrating human skin. We have heard several stories of and from people who think they have been bitten by a spotted lanternfly, but couldn’t swear that they either saw the physical bite take place, or that it wasn’t a horsefly, mosquito or other such native insect. We have personally been in highly infested areas and literally covered with dozens of spotted lanternflies at a time, and have never been bitten. The only thing close to a bite we have experienced is a pinch or poke from the legs of the lanternflies hanging on to us. (Check out the picture of the tarsal claw in our photo section)
Can they damage my house?
No, not directly in the manner that termites or carpenter ants can do structural damage. There can be secondary damage in the form of sooty mold, egg mass residue and similar issues.
Why are they in my neighborhood?
Several years ago, (September 22, 2014) they were discovered in southern Berks County, Pennsylvania. They probably arrived as an egg mass, stuck to a pallet or similar packing material and were received by an unsuspecting recipient who did not notice them. We suspect that they were introduced several years before they were first detected in September 2014. Since then they have been breeding and spreading.
What do they do?
They hatch in the spring as wingless nymphs. The nymphs hop around and feed, molting several times before their final molt into adults that can fly. In the first three stages, nymphs are black with white spots and can be easy to overlook, as they are small and look somewhat like ants. In the fourth stage, the nymphs are more conspicuous as they are larger and red in coloration. The final molt into adults begins somewhere around the third week of July, but individuals can remain in the late nymph stage as late as October. The adults then begin to migrate out to new areas (especially on warm, breezy days) from the end of July through October. Around the third week in September, they begin mating, and then they lay eggs. The eggs are laid in groups and the groups are contained in a plaster-like covering in masses. The adults will continue to feed intermittently after egg laying, and hang around until a heavy frost kills them. Undisturbed egg masses will overwinter and then hatch out in the spring, continuing the cycle. Each egg mass usually contains 30-50 eggs and we believe a female can lay 2-3 egg masses before they die.
What do spotted lanternflies eat?
Spotted lanternflies eat sap from plants. They prefer Ailanthus trees (tree of heaven), walnuts and grape vines as a first choice, most any other hardwood tree as a second choice and with much less frequency, pine trees. They have a very wide range of host plants.
How do they eat?
Spotted lanternflies feed by sucking sap from plants with a straw-like mouth part called a proboscis. The proboscis is located between the two front legs. Spotted lanternflies do not have chewing or biting mouth parts. They do not have stingers. They do not chew on leaves. They likely utilize small existing holes in tree stems and trunks that are so small, they are nearly microscopic.
Why are they on my house?
Spotted lanternflies take advantage of any structure to rest or climb on. They have no interest in your house, it’s just in their way. They also like to gather on warm house surfaces when the weather is cool. We have even observed them climbing telephone poles in areas without tall trees. Once at the top of the poles, they spread their wings and take advantage of the height to fly further distances.
Can they fly?
Spotted lanternflies can fly very well. They are not agile like a dragonfly or housefly, but more like a moth. Early on, people first encountering them reported them as “not able to fly far, but short distances similar to a grass hopper”. While they are powerful hoppers (hence the term planthopper), additional observations have changed this notion. They can fly relatively high and far, but not with any great level of agility. They also tend to crash land. On a hot, breezy day they can be seen crashing into houses, cars, trees, or anything else that they encounter.
Are they eating my trees?
Probably. This is a difficult question to answer. Spotted lanternflies are known to “host” (feed) on many different hard wood trees that we have in our landscape. That said, they tend to have preferred choices that they feed on, such as Ailanthus, walnuts or grape vines. This means that they will choose certain species first if possible, but settle for what is available. Often on a given property, amongst trees of the same species, there will be preferred specimens, meaning that of three silver maples one is absolutely covered with spotted lanternflies, and the remaining two are not. This is what we call a “hot tree” and we can use this fact to our advantage killing spotted lanternflies.
Are they killing my trees?
We believe that they probably are. This is literally the multi-billion-dollar question when it comes to Pennsylvania’s hardwood forests (Pennsylvania is the number one exporting state for hardwoods), grape industry (number 5 nationally), apples (number 3 nationally) and landscapes regarding spotted lanternflies. There are some indications that continued intensive feeding after several years can kill a tree, especially younger or stressed trees. The best way to consider this question is in light of the fact that they are drinking sap, which is the life blood of the tree. A healthy tree in a wet year can give up lots of sap before it is a concern (think maple syrup), however persistent heavy feeding (especially on a “hot tree” loaded with thousands of adults) may greatly weaken a tree, making it susceptible to other insects or diseases, or maybe killing it outright. Unfortunately, we are going to find this out the hard way. There is always a risk that they may become a vector for transmitting a disease from tree to tree.
Why is my tree “raining”?
Spotted lanternflies suck sap and digest it, concentrating the sap into a sugar rich excretion (urine) that is politely termed “honeydew” in the entomological vernacular. The “rain” you are seeing is actually a high volume of spotted lanternfly honeydew falling from the branches above. In some cases we have seen infestations so bad that we prefer to wear a rain coat when working under the trees. If you have a large tree that is raining spotted lanternfly honeydew and you care about the tree, you should seek professional help to clear the tree.
What is honeydew?
Honeydew is the polite term for the liquid waste excretions of sap sucking insects such as spotted lanternflies. With spotted lanternflies it is clear, sticky and sugar rich. Honeybees, yellow jackets, butterflies and other sugar gathering insects have been observed gathering honeydew directly from the anuses of spotted lanternflies. On a heavily infested tree, the trunk can be seen almost swarming with honeybees and yellow jackets trying to collect the honeydew.
Why is my tree/ porch/ deck/ etc. turning black?
When you see a black coating beneath a tree infested with spotted lanternflies, you are actually looking at a fungus called “sooty mold” that is growing on the sugar rich honeydew dripping from the spotted lanternflies in the tree above. Sooty mold is mainly a nuisance, but in some extreme situations has actually smothered out understory plants beneath the trees. It is unpleasant and requires lots of elbow grease to remove from patios, decks and lawn furniture.
Why are there so many spotted lanternflies?
The simple answer is because they breed in large numbers and very few native predators will eat them. We have witnessed spiders eat them when they can catch them in webs, praying mantis eat them, when they can catch them, and yellow jackets actually seeming to eat dead spotted lanternflies. They don’t seem to attack live ones however. In their native countries, there are probably multiple predators that keep their populations in check.
What else eats spotted lanternflies?
The short answer is not much. We have heard reports of different types of birds being seen eating them, but not in any great numbers. We also find spotted lanternflies with missing wings and legs that could indicate a bird “tasting” them and spitting them out. We gave them the “chicken test”. As anyone who has owned chickens knows, chickens will eat pretty much any insect they encounter with great enthusiasm. When we tried feeding spotted lanternflies to our chickens, they came running to see what the prize was and then turned their backs on them. This seems to indicate that they are unpalatable to birds, but more research is needed beyond the chicken test. Some general predators have been observed eating spotted lanternflies, such as praying mantis, wheel bugs and spiders. Unfortunately the numbers of lanternflies are too overwhelming for those predators to have a significant impact at this point.
Should I try to kill them?
Yes, you should kill spotted lanternflies when you encounter them, HOWEVER!!!!!!! Please do so in a safe manner. We have heard all kinds of stories about people using incredibly toxic substances to kill spotted lanternflies, including spraying them with kerosene. THIS IS NOT NECESSARY!!!! If you are going to use an insecticide, please do so safely. If it doesn’t seem to work, this is not the green light to “use the rest of the bottle”. In Pennsylvania, the label is the law. If you do not use the insecticide as directed on the label, you are violating the law and legally responsible for the results. A simple solution of 1/4 cup of liquid dish detergent and one gallon of water sprayed on heavy enough to coat them is very effective at killing the lanternflies that you can safely reach.
What is the state doing about this?
The Pennsylvania Department of Agriculture (PDA) has been studying and trying to stop the spotted lanternfly since it was first reported. When it was first detected on Sept. 22, 2014, PDA immediately reached out to the United States Department of Agriculture (USDA) who assembled a Technical Working Group of experts with members from Penn State Extension, faculty in Penn State’s Department of Entomology, and researchers at other institutions in the US and Asia. One member of that committee told me that she had spotted lanternflies sent to her by the first week of October 2014 for her to begin her line of research. These experts have been heavily involved in studying this and continue to expand collaborations with scientists throughout Asia to slow and stop the spotted lanternfly. There are many hard-working people on the ground who are consumed with finding a solution to this situation.
Should I report spotted lanternflies if I find them?
You should only report spotted lanternflies if you find them outside of the current quarantine zone. If you are within the current quarantine zone, you probably shouldn't tie up more time of the people charged with inspecting new locations for spotted lanternfly presence. This situation is unprecedented and the PDA did not have infrastructure in place to handle the onslaught of public contacts. They are working hard to catch up.
I don’t have tree of heaven (Ailanthus altissima), why are spotted lanternflies on my property?
Early in the rush to figure out what spotted lanternflies are and what they do, Ailanthus, or “tree of heaven” was identified as a preferred host for the spotted lanternfly. This seemed to make sense because Ailanthus itself is an introduced invasive species also from Asia. Some researchers seem to feel that spotted lanternflies REQUIRE a meal from an Ailanthus tree before being able to reproduce and without that meal couldn’t lay eggs. Our opinion is that this concept is not true. We are eagerly awaiting a thorough, scientific study that proves this out one way or the other. There is no dispute that Ailanthus is a preferred host tree for the spotted lanternfly and that fact is a great opportunity when developing a strategy for killing spotted lanternflies on your property.
I am in the spotted lanternfly quarantine, what does that mean?
The spotted lanternfly quarantine has specific implications for different individuals and businesses that are within it. The most important thing is that you should try to slow the spread of this invader by not giving it a free ride to a new location outside of the quarantine. Be sure to not move firewood or yard debris without thoroughly inspecting it for egg masses. Try to do an inspection of your vehicle to make sure you don’t have hitchhikers in the nymph or adult form. We have witnessed a nymph clinging to the hood of a truck up to a speed of 35 mph without blowing off (traveling within the quarantine zone of course). If you are getting ready to travel, don’t leave your vehicle open unattended while packing bags, and don’t leave your windows rolled down, especially on warm days when adults are actively migrating. When you arrive at your destination, be watchful for hitchhikers as you unpack.
What can I do to help?
First and foremost, don’t make the situation worse. Don’t spread spotted lanternflies to new locations. Don’t indiscriminately poison your home or yard by using toxic home remedies or misusing pesticides. If you have spotted lanternflies, develop a strategy to control and kill them. The most important thing you can do beyond your own property, is reach out to your local state and federal elected officials. Request more funding to help the beleaguered “boots on the ground” employees of the PA Department of Agriculture, Penn State Extension Agency, and United States Department of Agriculture. None of these agencies were prepared for an invasion of this scale and have been overwhelmed. Ask what they are doing to support the front lines fighting this invasion.
Can the spotted lanternfly be eradicated from Pennsylvania?
Unfortunately, with each season that passes, with each expansion of the quarantine zone into more densely populated, highly mobile populations, it looks increasingly unlikely that we can eradicate this invader in the foreseeable future. There are some indications that native predators are “learning” to eat spotted lanternflies, but not fast enough. A natural predator from the spotted lanternfly’s home range may be identified and imported to help control the invasion, but this is a distant thought, at least a decade away according to a USDA representative on 9/24/17, and the quarantine will continue expanding. Pheromone traps similar to Japanese beetle traps may be developed, but are not available yet. It seems that we are going to have to suppress and control these invaders on our own as we try to minimize their impacts.
ONE LAST THOUGHT:
The spotted lanternfly is not the first invasive species to reach our state. It has been happening for centuries, since sailing ships first arrived in the new world and started moving plants and materials around the world. What has changed is the volume of materials moved, and the speed with which they are moved. As such, the frequency with which we are being overrun by new invasive species seems to be increasing with devastating results. The effects of spotted lanternflies are yet to be determined. Most indications are that it has a very real potential to be catastrophic to Penn's Woods, our agriculture and our landscapes.
A quick list of the more memorable and impactful recent invaders and their impacts are;
- Hemlock wooly adelgid. The decimation of our hemlock forests (and Pennsylvania’s state tree).
- Emerald Ash Borer. 100% mortality of untreated ash trees, sweeping from the Midwest to Pennsylvania in two short decades, this invasive is responsible for the death of millions of ash trees. We are presently watching the initial phases of this in southeast PA.
- Thousand Canker Disease. This disease slowly kills black walnut trees, is spread by twig beetles and is present in south eastern Pennsylvania.
- Brown Marmorated Stink Bugs. Having had huge impacts by damaging tree fruits early on, native predatory wasps are seemingly putting a huge dent in their numbers… stay tuned.
And for one more outside of our state, thankfully, so far;
- Asian Long Horned Beetle. Found in several states to date, and attacking most hardwoods, it’s presence has led to the complete removal, chipping and burning of every tree in some neighborhoods where it has been found. (picture your neighborhood with zero trees)
Earlier, in the 20th Century:
- Chestnut Blight. Arriving in the United States in the early 1900's, this disease virtually eradicated one of out most plentiful and widely used forest trees in mere decades. It is estimated to have killed in excess of 4 billion trees.
- Dutch Elm Disease. First reported in the United states in 1928, It has killed approximately 75% of our nearly 80 million previously existing native elm trees.
Ask your elected officials if they support more stringent import rules to prevent even more destruction of our natural resources.