Spotted Lanternfly: Research Update
This presentation summarizes the current research projects.
- [Julie] Hi, my name is Doctor Julie Urban, I am a senior research associate in the Department of Entomology here at Penn State in University Park.
And I conduct research on spotted lanternfly and am engaged in helping organize some of the research projects that are going on, because there's so much that we don't know about this insect.
And so what I am presenting to you today is a bit of an overview in terms of where we are right now in spring of 2018 in terms of studies that have been done and studies that are going to be conducted on spotted lanternfly.
And so since this is a veracious phloem-feeding insect that feeds on a wide variety of things, but feeds on grape, this is where we'll start our show.
We know that spotted lanternfly was an invasive insect that was introduced to, that was basically found, it invaded Korea in 2004.
And there the biggest economic impact was damage to grape.
And so what you're seeing here is a study that my student, Erica Smyers, who's working on her PhD and she had been working with our retired faculty member, Mike Saunders, who is our grape expert.
And what you see there is her experimental lab where those are grape cuttings.
And so what she did this last summer is that she tested the efficacy of 20 insecticides that are labeled for use on grape and she sprayed those on grape cuttings and then introduced spotted lanternfly adults.
And she performed, it was a highly replicated study, she lived out in a quarantine zone, and basically here we have our preliminary recommendations and findings for treating spotted lanternfly on fruit and grape.
And so what's interesting here, and so these have been turned into recommendations for growers, and this is the most information we have at this point on insecticides.
And generally, the take home here is that the neonics and the carbamates, those classes were much more effective than the pyrethroids.
And I'm an evolutionary biologist by training, so I'm learning, I'm stretched into this world of applied work, but what's really interesting about these results is that the class of insecticides that are pyrethroids are those that are most effective against our more recent, an invader that's problematic that's gets dealt with in grape and tree fruit, that's brown marmorated stink bug.
And so pyrethroids are the go-to for treating brown marmorated stink bug and what we've seen from Erica's results is that that class of chemicals isn't going to be the most effective for spotted lanternfly.
So it seems that there very well could be that there's an additional spray that needs to happen.
And then what we know is while our extension agents, Emily Swackhamer and Amy Corman, have done some preliminary work looking at products available to homeowners and for organic use, that's still rather preliminary data and we don't really have recommendations for forestry ornamental as yet, although we have that in the planning.
And so what we have planned for this year is essentially to try to extend these studies on insecticides.
So what I wanna point out is that when I present to you this research that's being planned you'll notice that we're starting from a very applied end, what are these products that various stakeholder groups can use to treat spotted lanternfly?
Because these are gonna provide a more immediate, short-term solutions to this pest.
And then we have other research projects that are focused on more basic biology, which will provide insights into longer term, more sustainable means of control for spotted lanternfly.
So with respect to insecticides, we know that spotted lanternfly showed up on grape and peaches and nectarines last year in orchards, and so this is a concern.
If you noticed how many lanternfly are on that tree, that was really unnerving to see.
And so we have Dave Biddinger and Greg Krawczyk, who are Penn State faculty and extension folks out at the Fruit Research Center in Biglerville.
And they're going to be conducting experiments looking at insecticide efficacy on fruit trees in quarantined greenhouses that were actually in the quarantine zone.
We're going to build tented greenhouses that'll allow them to test these products in the quarantine zone where spotted lanternfly occurs.
Also, Tracy Leskey is a collaborator in West Virginia and she's in the process of getting us permitted to develop a spotted lanternfly colony at Fort Detrick in Maryland.
And there she'll be able to look at, in a more controlled laboratory setting, insecticide efficacy and the efficacy of residues in terms of figuring out how long various pesticides remain active and potent against spotted lanternfly.
So that's one of the really important sets of studies we have lined up for this summer.
Also we know that spotted lanternfly is not just a problem on orchard and grape commodities, it's also a problem in homeowners yards.
And so we notice, if you can see in this picture, that that is a silver maple, that was a photo taken by a landscaper who's a consultant for us, Brian Walsh, and he's been sharing his observations with us.
And you can see that this is a treated silver maple tree that was treated with a (mumbling) insecticide, which was effective in killing lanternfly.
You see all the lanternfly on the bottom, on the ground.
But more lanternfly continued to feed on that tree.
And so you could get a sense of how heavy the feeding load is from these insects.
And so we're interested in here looking at what insecticides are going to be useful, but also this opens up a whole series of questions that need to be addressed.
What are other aspects of damage that we see with that kind of sustained feeding for large insects?
And so what we're going to do is we're also going to look at the impacts on the physiology of trees that are fed upon by spotted lanternfly.
What we don't know, what the components are to spotted lanternfly saliva and we don't know if maybe there's some metabolites there that might impact tree physiology, and so that's one aspect that we're doing.
And also we're interested in how that feeding might impact the health of trees, because we've seen that there's weeping and slime flux and alcoholic flux, so trees are starting to show some potential injury from spotted lanternfly.
And so we want to determine what those effects are.
Also we're interested with respect to impacts on physiology of the plant, we're interested in exactly what lanternfly is doing to grape.
So you can see this is a picture that my student Erica took in the vineyard.
And we're interested in feeding thresholds, how many lanternflies feeding on a grape plant is important enough for the grower to treat it?
Basically what is that economic threshold for damage?
And so we're going to be doing a series of studies on grape in vineyards where we introduce various levels of feeding load or various numbers of insects to the plants and we have Michela Centinari, who is viticulturist, and Jodi Timer, who works at extension at the Erie Station.
We'll be looking at the various aspects of grape physiology, sugar, berry quality, et cetera, to assess the impact of spotted lanternfly feeding on grape.
Also we know that from the impact that spotted lanternfly had on grape in Korea, the largest impact on grape had to do with sooty mold.
And so basically lanternfly is a phloem-feeding insect.
Phloem is rich in carbohydrates or sugars, so if you're drinking a lot of sugar you're excreting a lot of sugar.
And so a sooty mold grows on that honeydew and you can see the liquid on the plant is actually that honeydew excrement from spotted lanternfly and this was a problem, this is actually a picture taken in a vineyard in southeastern Pennsylvanian, and that is sooty mold growth that is growing on spotted lanternfly honeydew.
And so that damage, basically that blocks photosynthesis in the leaves, and so again, we're interested in looking at the impact on plants.
But we're also, in my lab I have a student, Miriam Tellub and I, and we're looking to characterize those microbial communities that make up sooty mold in order to determine exactly what particular fungi, as well as perhaps bacteria, are growing out of control when we see the sooty mold.
And that might give us some insights into the presence of other microbes that are outgrown that might be there when the leaf is healthy that could be used as combatants potentially against the sooty mold.
So we really wanna characterize these microbial changes.
Also there's other things going on by other folks not at Penn State.
And so it's really important that we develop lures and attractants for spotted lanternfly to develop traps for it.
And so we have colleagues at in the USDA at the OTIS lab, Miriam Cooperband has been looking at products that serve as lures and attractants, so she's looked at various plant compounds and she's in the process of testing lures and traps.
And so we'll be employing those this spring.
And at Penn State Tom Baker, who's a chemical ecologist, he's been looking to see if spotted lanternfly has a sex pheromone, because that could serve as an attracted entrant in traps.
That's certainly what's been useful for brown marmorated stink bug.
But Tom to date has found there seems to be no evidence of spotted lanternfly using any or having any sex pheromone.
And what's interesting that no plant hoppers are known to produce sex pheromones.
Other plant hoppers have been shown to use substrate-borne vibrations, so they call to each other by shaking the plant.
And they listen to each other, they call through the plant.
So we're, Tom and my lab, is looking at these non-pheromonal aspects of spotted lanternfly communication to see if we can see what might make them aggregate, 'cause could be useful for traps.
Along the same lines, Tom is looking at other aspects of behavior in lanternfly, specifically dispersal.
And so this is very interesting, because in the top picture you can see a bunch of lanternfly flying around and we're interested in characterizing how far adults can disperse, and we're concerned as to when we see this dispersal have they mated yet or not?
And so from Tom's initial research this year it suggests that when we see these massive flights of spotted lanternfly adults later in the season that is before they have mated, but again, we need to verify that this year.
Also along those lines, if you look, I'm looking at endosymbiont transmission.
And so in the bottom right of your screen you'll notice that you see our classic picture of spotted lanternfly and it has the beautiful yellow bands on the abdomen.
And what's interesting is that when you're out and you see your first spotted lanternfly adult and when you see the spotted lanternflies that are flying the abdomen does not appear that bright yellow, it actually is black.
The yellow bands are more along the sides of the insect and what Tom has observed is that after these flights, these females are very skinny when they're flying, and then they settle down and feed voraciously, and at that time you see that the females plump up remarkably and that's when they become gravid, their eggs develop, and that's when you see the yellow bands.
It's only later in the season after they've flown and after they've fattened up.
And so plant hoppers, that's my area of research, because they're phloem feeders, similar to aphids, they actually have bacteria that are housed in special organs in their abdomen, and those bacteria provision essential amino acids, which are nutrients that are missing in the plant phloem, but that they need for survival.
And so these bacterial endosymbionts feed them from the inside out.
And so what my work has done is we have done a series of dissections looking at these organs housing these symbionts and what we've noticed is that their development, they change over time.
And so what we know about lanternfly and other insects is that these bacterial symbionts need to be transmitted to offspring via the eggs.
And so that's how they pass them down generation to generation.
And so it's interesting, these symbionts have co-evolved with their plant hopper hosts.
And what we've observed in looking at dissections from the skinny females as they develop through to the adult females that at the early stages in development of skinny females and in males the organs housing the endosymbionts are highly intertwined with the digestive tract.
And because this is a phloem-feeding insect the digestive tract is all kind of wrapped around itself and so it's a really complex system and it's very difficult to tease the bacterial organs out of the digestive tract, but later in development as we perform these dissections we see that the organs housing the symbiont become less associated with the digestive tract and more associated with the developing ovaries in the female.
And this makes sense, because the insects need to transmit, pass these bacteria into the ovaries, but this is a whole, really interesting process.
And that's potentially, if we could figure out how to interrupt that, that's one place where it might give us some insight into possible control for lanternfly.
So anyway, these seasonal changes with respect to development and in my case, how they're dealing with endosymbiont development, that's one of the aspects that I'm looking at.
And again, you can see we're moving more toward more basic research, but also the potential for longer term solutions to spotted lanternfly management and control.
There's also an interesting thing.
Spotted lanternfly feeds on over 70 different species of plants, but it shows a definite preference for tree of heaven.
And so we're interested in does it require a tree of heaven?
And so Miriam Cooperband from the OTIS lab and Doctor Greg Setliff from Kutztown University have been looking at various host preferences in spotted lanternfly.
And what Miriam Cooperband's work has shown is that first instar nymphs can develop into adults if they're only fed tree of heaven, if they're only feed black walnut, or if they're only feed grape.
So they seem to be able to develop, but what we don't know and what that work has not been able to show is whether or not tree of heaven is required for them to successfully lay eggs that again hatch the next year.
And so in order to look at that aspect of the lifecycle we really need to do that in a controlled facility and that's what we're going to do in the quarantine facility that Tracy Leskey is setting up.
So we really, really need to answer the Ailanthus Question.
Work we're going to conduct this spring, building big enclosures around trees and we're just planning that now.
In the quarantine zone we're going to determine whether or not forth instars and adults can successfully lay eggs that will over winter on other trees other than tree of heaven.
And so we'll try to get at that with a field study this spring, this season, but also the work in the colony will let us answer that more thoroughly.
And that's really a key question, because Pennsylvania Department of Agriculture's management techniques and now USDA's management of spotted lanternfly has focused on removing or treating tree of heaven.
And so we need to know, do they really require a tree of heaven or not?
Because that's the basis of the central tool in the current control management plan.
So we need to answer that question.
Also, again, for longer term work, we need to determine if there are biological control agents, specifically parasitoid wasps that could be used against spotted lanternfly.
And so here we have at the USDA ARS facility in Delaware, Kim Hoelmer and Juli Gould at APHIS.
They've been traveling to China to look for predators and parasitiods of spotted lanternfly in the native range.
And the idea here is potentially these could be introduced to control spotted lanternfly.
If we do have a parasitiod that might be released, it's only safe to release it when you know what impact it has on non-target plant hoppers and other closely related insects, so my colleague Charles Barlett at University of Delaware is rearing plant hoppers that are non-targets to test this out for this bio-control and we're hoping to rear some of those plant hoppers in my lab as well.
But also it's interesting to ask the question are there any parasitoids already here that might be using spotted lanternfly eggs?
And so here our colleague, Houping Liu, at the Pennsylvania Department of Conservation and Natural Resources and Jason Mottern at USDA, they found that actually a parasitoid that already is here, it's not native, but it was introduced to control gypsy moth, that it actually is already parasitizing spotted lanternfly eggs.
And so that's one of the publications that's come out so far.
And they continue to look at that and they're continuing to look for other parasitoids already here, because this might be some longer term solutions for our control of spotted lanternfly.
Also, just to wrap up, another aspect of research that I'm working on is looking at the genetics of spotted lanternfly.
Looking at, we call them microsatellites, those are genetic markers that are used in humans in paternity testing, but basically I've been using microsatellites that were developed by the Korean scientists when spotted lanternfly was invasive in Korea to determine if we know the origin of spotted lanternfly.
Because if we know where it came from we can hone in our search for native parasitoids and predators a little bit better.
And what we know so far is that it did not come from Korea, we need to develop markers that are a little bit better to provide better insight.
We believe it came from China, but we need to have better sampling and more microsats to test that more aggressively.
And so my lab is currently developing those microsatellites, but we're also, we'll be using those, so when spotted lanternfly shows up in other areas we'll be able to use those genetic markers to determine if it's a new invasion or if it's spread of spotted lanternfly that's already here.
So again, these will be longer term tools to allow us to monitor and track the spread and population structuring of spotted lanternfly.
And so with that I think that gives you the quick tour of research that ranges from applied to basic that will hopefully provide us with more immediate and then longer term answers to spotted lanternfly management in terms of research that's being conducted this year.
Thank you very much.