Spotted Lanternfly Identification and Concern

Spotted lanternfly is an invasive insect in Pennsylvania that has the potential to threaten several important agricultural commodities.
Spotted Lanternfly Identification and Concern - Videos


Spotted lanternfly was first found in Berks County, Pennsylvania in 2014 and is a major threat to our agriculture industry. This video, updated in March 2018, discusses how to identify this invasive pest and describes its lifecycle and behavior. You will also learn about current conditions and quarantine areas, the research being conducted, and where you can learn more about spotted lanternfly.


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- [Narrator] Hello, my name is Emily Swackhamer, I'm a horticulture educator with Penn State extension in Montgomery County.

I'm going to talk about the invasive insect, the spotted lanternfly, how to identify it, and why we're so concerned about it.

The spotted lanternfly is a new invasive insect that was first found in Pennsylvania in 2014.

We now know that it is also in a small area in Virginia.

We needed a lot of education to enlist the help of everyone to fight against it.

When you see the spotted lanternfly in the media, you often see this image at the upper left with the wings displayed and you can see the red underwings.

But when the insect, in it's adult stage, is at rest you don't see those red underwings.

They are resting with their wings over their backs and they're kind of a (mumbles) moth color with very discrete black spots on their backs.

Spotted lanternfly was discovered in Berks County in September of 2014 and we estimate that it arrived in Pennsylvania during 2012 based on the condition of old weathered egg masses.

It is native to parts of Asia, including China, Vietnam, and Bangladesh and it was recently introduced into South Korea.

When it came to South Korea, it rapidly spread across the country in about three years time.

South Korea is approximately similar in size to Pennsylvania and we know that the spotted lanternfly has been here longer than three years.

And it hasn't crossed the whole state yet.

The experts attribute this to the efforts of many people that are working to contain it.

The spotted lanternfly does not bite people, which is something that people often ask about.

This map is from the Pennsylvania department of agriculture and so far the spotted lanternfly has been found in the southeastern part of Pennsylvania.

The map shows where, through their survey efforts, the Department of agriculture has found it, shown in the red dots, and then also the green dots show where they have looked for it, but they have not found it.

So there has been a lot of survey work going on in Pennsylvania.

This is a map from the Pennsylvania Department of agriculture showing 13 counties that are currently under quarantine.

And this is likely to change, so keep checking the Pennsylvania Department of agriculture website for updates.

It's important to know if your county is in the quarantine zone so you can be in the compliance with the quarantine order.

The spotted lanternfly feeds on a wide range of plants.

When they're in their young stages they seem to feed on almost anything.

So I have 70 plus plants, but we're adding to this knowledge all the time.

The picture shows a very young nymph that was on status in a home garden.

We've found spotted lanternfly on herbaceous plants including day lilies, basil, cucumbers, but primarily we think of them as a pest on woody plants.

They will feed on fruit crops; grape and apple.

They will feed on landscape trees and also timber trees.

So I have maple, birch, and sycamore listed, but there are others.

They'll feed on important native plants, including willow and staghorn sumac, and there are many others.

When they're in their young (mumbles) stages they seem to feed on a wider range of plants, but then as they mature their behavior indicates that they really prefer ailanthus altissima, which is the tree of heaven.

And this is an invasive species that was brought here from Asia years ago.

We also know that they really like black walnut and hops and that's based on host range experiments where researchers have put them in cloth cages exclusively on these plants.

And they were able to raise them through from the very first (mumbles) stage to adults on these three preferred hosts.

Ailanthus altissima, the tree of heaven, black walnut, and hops.

Here are some of the national rankings of some threatened Pennsylvania commodities.

Our hardwoods, we're the number one exporters in the US, and that is in the billions of dollars per year in value.

We're the fourth largest producer in the US of apples and peaches, and the fifth largest producer of grapes.

The spotted lanterfly has piercing-sucking mouthparts.

It's a big plant hopper and you can see that mouthpart on the underside of the insect in this picture.

It's almost like a straw that they'll insert into the sac conducting vessels, the phloem of the plant.

When the lanternfly are young, the mouthparts are small and tender and they tend to feed on the undersides of leaves and the petals of leaves, the soft parts of the plants.

But as they get more mature, that mouthpart is stronger and they can pierce right through older tough bark on trees and feed on the sap of the trees.

When the insect feeds on the sap, they're inefficient in the way they digest that substance.

And a lot of the sweet sap will flow through their bodies and come out the other end in a substance that we call honeydew.

The honeydew has a lot of sugars remaining in it.

And then there are fungi that will grow on that honeydew and we call that fungal accumulation that is often black in color, sooty mold.

So this is the sort of effect that we are seeing in Pennsylvania.

Here is an ailanthus altissima tree, the tree of heaven, one of it's preferred hosts and there's very high population of adults feeding on it.

The adults wound the tree bark with their mouthparts and you can see the sap flowing from the wounds.

But they're also ingesting the tree sap and excreting the honeydew and then there's sooty mold accumulating underneath this group of insects.

You can see the black accumulation at the base of this tree.

It's a sticky moldy mess and it develops an unpleasant sour sort of smell.

The stinging insects also like to collect this honeydew that's being excreted.

And in this picture you can see a yellow jacket that is collecting honeydew right out of the back end of the adult lanternfly.

So we have landscapes where there are many stinging insects buzzing around the trees, which is also problematic in residential landscapes.

This is a picture of a set of stairs made of trex decking and this family had a deck and stairs underneath a heavily infested river birch tree.

So the top steps in this picture show the accumulation of honeydew and sooty mold and also, you can imagine, that's probably a slippery safety hazard.

And the bottom step has been pressure washed and you can still see the pattern of the remnants of the sooty mold even after pressure washing.

So this is a problem in residential landscapes and can affect the value of some of the hardscape.

In September of 2017 the adults really took to flight and started to swarm around trees and tall structures.

We observed them flying better than we ever had really thought they did.

They were attracted to the warm sides of buildings, but they weren't really trying to get into the houses, like some of our other insects do.

The spotted lanternfly is not known to do any structural damage, it won't get into the wall space of your home and try to over-winter as adults.

The adults will all die when cold temperature come in early winter.

But we have had some problems where there's been companies coming through Pennsylvania and doing high pressure sales, trying to scare people into buying pest management services by telling them, falsely, that the lanternfly will hurt their houses.

So you can see that there's much more education needed so people are aware that these are not considered structural pests.

In this case, the family was using a shop vac to sweep up in the insects that were accumulating on their deck.

They swarmed to the warm side of the house and there was nothing there to eat and the desiccated and died.

So they could just sweep them up with the shop vac.

In September of 2017 we also observed the swarming behavior of the adults in relation to our fruit production areas.

There really weren't very many spotted lanternfly in this orchard until September and then when the adults took to flight they flew into the orchard in large numbers.

They are feeding on these trees, they're feeding on the woody parts of the trees, not on the fruit, but there's a lot of concern about the longterm health of the trees with this feeding pressure.

Also they're secreting honeydew and sooty mold can be forming, which is a quality concern for the fruit.

In the same orchard, they swarmed onto some of the grape vines.

The fruit producers can use insecticides to kill them.

In Pennsylvania the law is a site use requirement.

So this orchard, producer, could use an insecticide that was labeled for his fruit crops and the spotted lanternfly have not been particularly difficult to kill with traditional insecticides.

But the fruit producers are running into issues with intervals of use on pesticide labels and also how close to harvest they can use these products.

So this is causing major concern in our fruit production areas.

People are asking about the longterm health of trees that are fed upon my lanternfly.

This is a picture of a stand of younger ailanthus trees, tree of heaven, that sustained heavy populations of spotted lanternfly for two years.

And in the third year we started to observe death of these trees.

So the high populations may, certainly must also have health effects on other trees in residential landscapes and orchards.

This is a picture of high populations of nymphs on walnut.

And it's a seedling tree, you can see the nymphs in the center there feeding on the more tender parts of the tree and they're secreting lots of honeydew below.

This was a seedling walnut just next to the tree I just showed you, and this picture was taking on August sixth.

So the walnut seedling was completely defoliated by this feeding pressure and we'll be watching the seedling this spring to see how well it leafs out and if it's health has been compromised by this feeding action.

Here is a picture of a walnut that's a more mature tree and you can see the die back caused by these clusters of nymphs feeding on the tender young parts of the branches.

We observed similar die back in 2017 on willow and staghorn sumac.

I want to take you through the lifecycle of the spotted lanternfly.

We have observed one generation per year in Pennsylvania.

The eggs hatch, then there are young nymphs.

The nymphal stages are called instars.

So every time a young nymph sheds it's skin it's the next instar.

And then the adults appear.

In this picture we're looking at younger instars, this is a second instar stage and they are black with white spots.

So the first three instars are black with white spots.

Then the fourth instar develops a red coloration, as well.

And they really are quite pretty insects.

This is a high population of fourth instar nymphs on ailanthus altissima.

This tree was red from a distance of about 50 feet I could just see that the whole stem of this tree was red from the high numbers of spotted lanternfly.

This picture shows the transition from the fourth instar with the red coloration into the adult stage.

And this happened in early August.

The spotted lanternfly doesn't make any kind of a cocoon or pupi, goes directly from that fourth instar stage, the skin of that life stage will crack open and the adult crawls out.

When the adult first crawls out it's lighter in color, but it will darken as it dries.

We are seeing extremely high populations on some trees.

This is ailanthus altissima, but we have this sort of high levels on maples and willow, sycamore, birch, and some other trees.

The females start to lay eggs in September.

Each female can lay up to two egg masses.

Each egg mass has between 30 and 50 eggs.

She lays her eggs in rows and they're all right next to one another lines up and then she covers them with a secretion from her body to protect them.

When it first comes out it's white and wet, but it dries to a mud-like appearance.

This is a picture of an egg mass that I took in November and here the female covered most of the egg mass with the secretion, this waxy covering, but some of the eggs are remaining uncovered and that is not unusual to see that where she's somehow missed some of the eggs.

I went back and took a picture of the same egg mass in March and you can see the covering has really dried down, cracks had developed and it looks different than it did in November.

So I wanted to show you how the egg mass appearance changes over time.

This is a picture showing an egg mas that is completely covered and then above is an egg mass where the covering either was never deposited, or maybe it weathered away with rainfall.

And you can see the eggs lined up in rows.

This is the underside of a bench that was under a willow tree that had a high infestation, and you can see the egg mass here is a fresh one.

This picture was taken in November, and here are old egg masses from the previous year.

You can see the holes in the tops where the young nymphs had crawled out.

So of course this is a concern that people might move objects like this that have egg masses on them and if they move them to new areas and the eggs hatch we're very concerned that that's a way lanternfly can spread.

This is looking at the underside of a rock and there are five egg masses here.

So one, two, three, four, five.

This was a very protected area and we don't have any hope that in southeast Pennsylvania cold temperature will kill the insects over the winter.

Here is a birch tree that has a high number of egg masses, there were many, many eggs on this tree.

And you can see that by scraping and destroying these eggs you really can have an effect on the population.

There's another picture from late winter of 2018.

We found many, many egg masses under a piece of loose bark on a dead tree.

For some reason the females all liked that area to lay their eggs, probably because it was very protected.

We do know that there are some natural enemies of spotted lanternfly.

We have found spiders eating the, praying mantis, and this is a wheelbug, one of the assassin bugs.

And it's feeding, see it's (mumbles) right into the abdomen of this lanternfly it has killed and it's eating the content.

But researchers are looking for more specific parasitoids that might have even a greater effect in reducing their populations.

So we are working toward containment and control and hopefully in the long term, possible eradication.

The researchers are trying to develop more specialized targeted insecticides and these parasitoid that I spoke of and we all need to buy time for the researchers to be able to do their work.

For more information you can search spotted lanternfly PDA for the Pennsylvania Department of agriculture, or spotted lanternfly PSU for Penn State University.

And we are cross-posted a lot of our information on these two sites.

The PDA site has many maps that show the distribution of the insect at the moment and that is where the current quarantine information will be housed.

Thank you for your time.


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