University Place

Backyard Invasive Plant Pest Threats

– Hello, and thanks for coming to this talk today about backyard invasive plant pest threats at the Garden and Landscape Expo. It’s great to be back in person. We also have a booth for the Department of Agriculture, Trade, and Consumer Protection, where I work, and I’ve worked there as the Plant Protection Section Manager since 2015. And so before that, I worked as an entomologist with the Pennsylvania DCNR, the Sierra Club, and before that, graduated from the UW-Madison entomology department. So today again, thanks for coming. I’m gonna be going over some backyard invasive pest threats, and we’ll talk about what you can do to protect Wisconsin from the damage that these pests cause. And before we begin, I wanna first acknowledge Wisconsin’s tribal nations, our 12 tribal nations in the state and all the contributions of Indigenous people, both past, present, and future that have called Wisconsin home for generations. DATCP has a strong commitment to collaborate with and partner with these sovereign nations. Our Prairie Oak State Office building in Madison, which was featured on the title slide, occupies ancestral Ho-Chunk land, but every place you go in the state includes ancestral lands of tribal nations. And my hope is that by the end of today’s talk, you’ll be able to identify and report in the worst case scenario, some of the top invasive insects that are threatening Wisconsin’s backyard trees, shrubs and gardens.

And I specifically really want to talk to you as gardeners, because I know that you’re outside and you’re observing, and you’re part of the solution. With our small staff, we couldn’t possibly get all the way around the state to know when something first gets here. And that’s when it’s early to detect, means that we can respond rapidly and be effective, ideally at eradicating these pests before they damage our natural resources and our nurseries and our Christmas tree industry and other green industries in the state. So specifically, you see the images from left to right on the slide. I’ll be talking about the spotted lanternfly. And because I work for state government, I’ll be using a lot of acronyms today, SLF, Asian longhorned beetle, or ALB, hemlock wooly adelgid, HWA, and lastly, elongate hemlock scale or EHS. And we’ll talk about how to identify these pests, how to report them if you think that you’ve found them on the landscape, and what DATCP is doing to prepare for these threats, both in terms of regulations and surveys and outreach, like the outreach that we’re doing today during this talk and booths 403 and 404 at the Expo. And so a lot of the pests that DATCP and other regulatory agencies focus on are not native to Wisconsin or even North America. They’re introduced from other places. And that’s why they’re so dangerous, because our plants haven’t had time to co-evolve chemical defenses against them.

And they’re often escaping from natural enemies, whether that be predators or parasites, and that allows them to outcompete and often displace native, beneficial insects and other species and absolutely devastate habitats. I don’t know how many of you have lost your ash trees over the past few years to emerald ash borer, but that’s an example of just, an insect that has just devastated an entire genus of trees. And it remains to be seen how we’ll recover from that loss. And even though we’ve had over 450 introduced forest pests in the United States, only about 62 of those are known to be especially harmful. But those subset of introduced species are causing billions of damage to local, state, and federal governments and incurring hundreds of millions of dollars in lost property values per year. You think about the value that a tree or shrub gives to your backyard, both in energy savings and cooling and just habitat for birds and other wildlife, it’s a big loss. And if you’ve ever had to call an arborist to remove a tree in your backyard in a crowded residential neighborhood, it adds up pretty quickly. And so the first pest I’ll talk about today is known as the spotted lanternfly. And even though this pest kind of looks like a moth when it has its wings spread out and it’s very showy, spotted black, white, and red wings like that, it really likes to hold its wings tent-like when it rests, as shown in picture C there. All the lanternflies, and we have about 17 species in the United States do that.

But the only one that’s super colorful and showy is this introduced species here in the United States. They’re more common in tropical areas, and in some parts of the world like Thailand and other places, they’ll have these long head processes, like in picture E, that end in sort of a yellow or red tip that was once thought to glow. And that’s why they’re called lanternflies. But the spotted lanternfly was introduced here from Berks County, Pennsylvania in 2014. They think it came in probably as egg masses laid on flat stone in a stone yard. And it’s been spreading westward ever since. And you can see in the picture, it’s got some nymphal stages that are black and white spotted in the first three stages. And those are pretty hard to notice until you get to that fourth stage nymph or immature, which is red and white spotted that people start noticing as it feeds on ornamental plants. And then you get those big, showy adults that especially gardeners, but all members of the public have been easily able to notice and identify as that’s out there feeding in swarms in the fall. And so spotted lanternfly is native to China, India, and Vietnam, and they think it’s controlled by parasites there, but here, there really is no checks on its population.

And so since being introduced to Pennsylvania, you can see the blue areas on the map show that it’s spread to 11 states so far, and closest to Wisconsin, it was recently picked up in southern Indiana, near the Kentucky border on somebody’s property, a wooded property. DATCP has had some regulatory interceptions of this pest, but only a couple at this point. And they’ve been single dead adults. For example, picked up in a warehouse in Jefferson County, a dying report of a spotted lanternfly was sent into us for the Dane County Airport. Somebody saw, someone from Pennsylvania was coming in just at the right time of year and saw a dying adult on the jet bridge, but we’ve checked those out. And we don’t believe that we have spotted lanternfly in Wisconsin yet. And so this next map shows some climate modeling, which shows which parts of the country are most suitable for spotted lanternfly to establish. So it’s sort of a good news, bad news story. You can see that many of the states where it’s already present and introduced are very well-suited climatically for spotted lanternfly, but the northern part of Wisconsin probably is too cold and would kill this pest, at least at this point in our climate history. And so we are suitable in the southeastern parts of the state.

And of course, you can see states like Illinois have a lot of suitable habitat, knowing that spotted lanternflies’ favorite food is actually the invasive tree of heaven. And so other states to the east of us and the south have more of the tree of heaven than we do. And so right now, we’re at the time of the year when you would see spotted lanternfly egg masses. And as I mentioned before, it was first introduced on stones. So the females will lay those egg masses on anything, but especially tree of heaven, its preferred host food, and it will remain in the egg mass form until June or early summer, when those first instar nymphs come out and they molt and they get bigger and bigger until the fourth stage in July, when you’ll see the red and white spotted immatures. Those will molt one more time to become adults. And those adults are very late season feeders. They’ll come out to feed a little bit, but they’re mating also. And then after they mate, the females will lay those egg masses over winter. And I should say, feed a lot.

They’re sucking plant sap from their host plants. And this slide shows three different pictures of the spotted lanternfly egg mass over time. On the left you can see, it looks kind of waxy and putty-like at first, a gray egg mass that’s actually pretty hard to see against the side of a tree because it’s pretty well-camouflaged. Later on in the season, it ages and it cracks as it dries out. And then after the nymphs come out of those egg masses in the early summer, it actually looks like four or five rows of seeds where they’ve come outta there, but they’re actually hatched eggs of the spotted lanternfly. And I don’t know how many of you have seen egg masses on the sides of trees before. The one that’s most commonly found is the insect formerly known as gypsy moth or Lymantria dispar, and that’s shown on the right, it’s very beige and felty. How many of you have seen those on your oak trees or other trees in your backyard? Yes, and so those kind of stand out, especially when they’re first laid in mid-summer, and you can see that they’re, tend to be bigger. There could be up to a thousand gypsy moth caterpillars in that single egg mass. Whereas the spotted lanternfly, there could be up to 80, but with so many insects reproducing, that’s still gonna be a lot to feed.

And so you can tell the difference between those two species, just by the egg mass. Another thing that might be mistaken for spotted lanternfly in Wisconsin are brown marmorated stink bug immatures. You can see both of them have some black forms and red forms, but the brown marmorated stink bug on the left is not spotted. It doesn’t have those white spots on either the black ones or the red ones. And it’s coming out of a group of eggs rather than an egg mass, like the spotted lanternfly would on the right. And you can see that those nymphs are feeding on some tender stems. And that’s what the spotted lanternfly does. It’s sort of related to things like cicadas and other sucking insects; think boxelder bugs. And the beaks of the nymphs are able to penetrate into things like roses and other ornamentals, whereas the adults can actually feed on trees. And so this is about as bad as bad can get.

If you can see the trunk of this apple tree is just loaded with spotted lanternfly, sucking the juices out of that tree. And as these adults feed, they’re constantly excreting honeydew, or this sugary substance that causes black sooty mold to form. And that can inhibit photosynthesis, but even with all this feeding, and it could be on apple trees or peach trees, maples or walnut. In addition to tree of heaven, spotted lanternfly has been recorded as feeding on over 100 hosts. It’s really not causing as much noticeable damage to these orchards. Although, as you can imagine with numbers like this, it doesn’t make apple picking very fun or any sort of outdoor recreation in the fall. These insects are really out there from September, all the way ’til December potentially. And you know how our weather is different every year in Wisconsin, a hard frost is gonna take care of this insect, but we can never predict, is that gonna happen before Halloween, in November, or even December, worst case scenario. And the longer that season stretches out, the longer these adults are gonna keep swarming and feeding. And so, as I mentioned before, the spotted lanternfly really likes to feed on the tree of heaven, Ailanthus altissima, And that is probably because that tree is found in its native range, and it’s a restricted invasive species in Wisconsin.

So it’s not something that can be sold or anything that should be planted. And most of those populations of tree of heaven are in disturbed areas like roadsides, riversides, industrial areas in Dane, Milwaukee, Racine, and Kenosha counties. And so you can recognize that something is tree of heaven by its compound leaves with smooth, rather than toothed leaf edges and smooth, gray trunks and light brown twigs. Leaves and male flowers also smell like rancid peanuts. So that’s wonderful as a diagnostic tool, as gross as that sounds, and we tend to check tree of heaven. We use it as a survey tool at this point to see if we have spotted lanternfly in Wisconsin. It’s something that you can do too. I will say that the tree of heaven that I remember seeing in states like Pennsylvania was well-named, as in some states with a little warmer climate, those trees just get huge going up to the heavens, whereas in Wisconsin, as you can see on that picture way on the right, it’s more of a scrubby roadside tree or invasive restricted weed. And so while none of us would probably miss the loss of tree of heaven in Wisconsin, we might miss all of our grapes and vineyards in the state. And unfortunately, that’s why we’re concerned about the spotted lanternfly.

Its feeding severely damages grape vines, reducing yields by over 90%, increasing susceptibility to winter injury, causing vines to fail to set fruit the next year, and actually killing grape vines outright. And there have been reports from the east of vineyard owners having to spray up to 14 times a season for spotted lanternfly, as swarm after swarm just keeps arriving in the fall. In some other countries where this pest has been introduced like Korea, they’ve actually netted the perimeters of the vineyard, and that’s also been effective as a mechanical barrier to the pest. And so the reason spotted lanternfly has gotten to 11 states since 2014 isn’t because it’s a great flier. It’s not; it’s a plant hopper. And so it’s well-named. It likes to hop or just walk short distances on its own, even though it can fly, that’s not how it’s getting spread long distances. It is just an excellent hitchhiker. And you can see in the slide here, we’ve got nymphs, the red fourth instar nymphs on the wheel well of this vehicle, we’ve got an adult nicely, looks like it’s posing on the tail pipe of that car there in the middle image. And then all those egg masses on the camp chair.

If people are not inspecting that material, they could move the spotted lanternfly hundreds of miles, along with other cargo to start new infestations. And I’ve even seen videos of spotted lanternfly literally jumping onto rail cars in train yards. So it’s amazing, and that’s how it’s getting to other areas. And so we’ve been bracing for the spotted lanternfly at DATCP and working with partners at the DNR and other agencies for the last few years. And so we post about it on social media. We do outreach at trade shows and conferences like this one, we’ve put out billboards in the southeastern part of the state, and we’re also doing some surveys. But another thing that our agency does at the Department of Agriculture, is we try to stop that artificial hitchhiking or spread through something called quarantine regulations, and quarantine regulations are designed to try to keep spotted lanternfly contained in the areas where it is and put legal restrictions on any nursery or other business that might be moving plants, or in the case of spotted lanternfly, anything out of the infested area. So we’ve got nine states that have put up state quarantines for this pest because we don’t anticipate a federal regulation for spotted lanternfly at this point. Wisconsin is proposing an exterior quarantine to try to keep it out of the state, and we’ll be having public hearings on this regulation in April. So I encourage everybody to make comments and think about whether you would support something like that to protect Wisconsin’s vineyards, our grapes, our ornamental plants like roses, cucumbers, basil, all the plants that the nymphs could feed on.

You know, we really wanna keep Wisconsin spotted lanternfly free. And whenever we do a quarantine, we do allow for some commerce to continue, but a nursery would have to enter into something called a compliance agreement with DATCP in which they agree to mitigate risk. And so that might be by making sure that plants are inspected or treated before they’re shipped here. And then also making sure that everybody that works at that nursery knows how to identify and report spotted lanternfly right away, whether it’s egg masses, nymphs, or adults, so that we don’t get it here in Wisconsin. And so this just shows some of the places that DATCP staff have looked for spotted lanternfly over the past couple years, vineyards and areas with tree of heaven. And we found that because it’s such a preferred host on tree of heaven, that’s where we’re focusing surveys at this point. And we’re also recording where all those trees are. There might be a time that if it were to get to Wisconsin, we would remove those trees or have them treated to try to reduce host material. And we wanna know where tree of heaven is in Wisconsin. And so this next slide shows a baited circle trap that we use for spotted lanternfly.

And what’s different about these traps is that a lot of the trapping we do happens early in the growing season. So as soon as the snow melts or the certain flowers bloom, we’re out there looking, but for spotted lanternfly, we don’t start the survey ’til August, ’cause we’re targeting those fourth instar nymphs and adults. And as gardeners, that’s the best time for you to look too, because that’s emerging and those later in stages or instars are big, red, and noticeable. That’s the time to look for spotted lanternfly in your backyard. And so recently, we created a reporting form for spotted lanternfly. We had heard that other states like Pennsylvania had been getting upwards of 90,000 reports of this pest in a single year. And that would absolutely overwhelm us. So we’ve created a GIS-based form at slf. wi. gov, where if you think you’ve seen this pest, you can report it right away.

It’s also always good for any of the insects we’ll talk about today to try to collect a specimen, maybe in some rubbing alcohol in a pill bottle, so that if it’s the first detection in Wisconsin, we can verify that it is here and what to do next. Tree of heaven can also be reported by the public to UW-Extension. They’re also tracking that. And if you do happen to have it on your property, because it’s a restricted invasive, the DNR has information on their website about how to get rid of it. And that’s something that you wanna do because it can spread. And so the next pest I’ll talk about today is known as the Asian longhorned beetle. And it’s called that because of its long antenna. And you can see those antenna are as long as its entire body. It’s a large, wood-boring insect that’s in the order Coleoptera, which is just all the beetles. And native to China and Korea, it was first detected in New York in 1996 on likely solid wood packing material.

So if you recall that picture of the big container ship coming in, there are agency staff that try to inspect all of that. But as you can imagine, with the overwhelming volume of containers and pallets and packing material coming in, not all of that is getting inspected. And so that’s how pests like this can come in. And unfortunately, the difference between Asian longhorned beetle and our native longhorned beetles, which we have many species, this one attacks healthy trees, and it goes after maple, especially, but it will also attack birch, elm, horse chestnut, poplar, and willow. And those, once ALB gets into the trees, it’s considered incurable. You’ve gotta basically cut it down, chip it, burn it. There’s no way to treat trees because it’s just feeding so deeply into the wood and killing healthy trees, rather than the work that our native longhorned beetles do to kind of take out diseased trees or finish them off so to speak, much less damaging, and even could be considered beneficial. So if established across the United States, Asian longhorned beetle could cause the loss of 35% of the United States forest canopy, billions of trees valued over $600 billion, plus $41 billion in losses to the lumber, maple syrup, nursery, and tourism industries. So we definitely don’t want it here. This slide just shows that Asian longhorned beetle really loves any kind of maple.

So that’s the best kind of tree to look for this pest in your backyard. It could be red, silver, sugar, Norway, boxelder maple. It loves them all. And also considered moderately susceptible are elm trees, birch, horse chestnut, and ash. And then there’s a few trees like oak and basswood, cherry and apple that Asian longhorned beetle might not actually be able to complete its development on. And so they’re considered resistant. And so this slide is a little bit hard to see, but it shows in the green check marks that Asian longhorned beetle infestations have been completely eradicated from Illinois and a couple spots in New Jersey. And not shown on the slide is that it was also introduced into Ontario, into Toronto and Mississauga, and just finally declared eradicated as of 2020. So it was introduced in 2013 and they did all the management, which basically involves cutting a lot of trees down and eliminating those from urban areas, and then treating trees that are susceptible within a certain boundary. And so Asian longhorned beetle is not in Wisconsin.

We actually don’t survey for this pest because it’s so big and not very mobile that we are counting on the public, and we’re always looking for it on maple when we’re out and about. Now, one of the most recent infestations is a bigger cause for concern. ALB was just detected in South Carolina in 2020 across a pretty large area. And in that case, it wasn’t reported for several years, and it’s a large infestation in a snakey, swampy part of the state. I decided not to volunteer for that assignment, but good luck to them in that, and they’ve just started managing that pest and adding it to the federal quarantine area since 2020. And so this next slide just shows some Asian longhorned beetle life forms and its life cycle. So the adults are gonna come out of these perfectly round exit holes. It almost looks like a drill made this large exit hole in the side of your maple tree. And as the adults emerge, then they’re gonna feed a little bit and mate, and then the female will lay 35 to 90– They look huge on the slide, but they’re actually tiny eggs. And you can see in a little display at our booth, how tiny the Asian longhorned beetle eggs are, but they lay them in these ovipositioned pits in the side of the tree that the tree then has to heal over.

And from those eggs come the larva in the lower left image that just get bigger and bigger, and they start out feeding in the cambium and then they go into the sapwood and the heartwood, and that’s how they kill the tree. Once the larva are done developing, they turn into pupa in the lower middle image. And then those turn into adults. And Asian longhorned beetle just has the one generation a year, pretty typical insect life cycle. And so, as I mentioned, ALB is incurable. So all hosts within a quarantine zone are eradicated once this pest is detected. Generally, it’s been in urban areas, and susceptible trees outside that area are surveyed for symptoms and signs of Asian longhorned beetle to make sure, sometimes it’s hard to locate whether something is the epicenter of the infestation or whether it’s a satellite. And so they’ll keep looking within a certain quarter mile, half mile perimeter, and then even trees outside that boundary might be treated with insecticide if they’re in that preferred host list to make sure that nothing was missed. And so Asian longhorned beetle does look like other native longhorned beetles that we have in Wisconsin. And one of the most common ones is the whitespotted sawyer or pine sawyer.

I don’t know, have any of you seen this insect out and about on conifers? It’s basically a little smaller than ALB, and you can see that the back wings are not as shiny on the left, on our native insect as ALB on the right. ALB also has sort of bluish legs, if you can see that in the slide. And it also has, in the pine sawyer, it has a little triangular process between the two back wings called a scutellum that’s white in the pine sawyer and black in ALB. So you know that it’s just a native, no cause for concern, and another dead giveaway is if it is on a conifer near a pine forest up north, you tend to see those in the summer and it’s thank goodness, not ALB, not a problem. And so when I looked for Asian longhorned beetle, I was amazed in states like New Jersey, the shavings, the frass from the larva looked like somebody took a pencil sharpener and put that coarse frass in between two branches like shown in the upper left. And then you’d also see these egg pits. Like that’s after the female lays the egg in the upper middle image, that area that’s healed over. That’s a warning, if you see that on a maple, that you could have a problem with ALB. There’s perfectly round emergence holes. They’re so large.

I mean, if it’s over 5/8 inch long, that’s a bad sign, as well as crown dieback from the top down on a maple. Although of course, that’s not as diagnostic and could be caused by other things. So hemlock woolly adelgid is the next insect that we’ll go over today. Detected in the eastern United States in 1951, HWA is native to Japan. This is another sucking insect. So it’s actually in the same order as spotted lanternfly. And as the insects feed at the base of hemlock branches, you can see it kind of looks like cotton swabs at the bases of the branches when they’re actively feeding. That’s actually woolly wax secreted by the females. And that’s a dead giveaway that there’s a problem. And unfortunately, HWA weakens and kills eastern and Carolina hemlocks.

And it’s been spreading now currently in 20 states, including northern lower Michigan. So those lake counties have hemlock woolly adelgid. They think it came in on nursery stock from the east and they’re trying to eradicate it. And hopefully they will because that’s a little too close for comfort. Have any of you ever seen this pest if you’ve gone out east to states like Pennsylvania? All right. Well, it is super noticeable with those Q-tip looking things. It was really a shock. Hemlock is Pennsylvania’s state tree. So when I worked out there, I mean, I got some good experience, but it was a sad thing to see their state tree dying, millions of dead trees across the eastern seaboard where this pest has been introduced. And another interesting thing about this pest is that hemlock woolly adelgid is also found in the western United States, but it doesn’t kill or reach damaging levels on western or mountain hemlock there.

And they think it’s because that it might have been there for the last 20,000 years. And so that really points to that host resistance. The trees were able to develop defense chemicals against the adelgid, just like they have in Asia. And I don’t know how many of you enjoy the hemlocks in Wisconsin or have been up to northeastern Wisconsin, where most of them are located. I’ve also noticed every time you go to the fabulous Wisconsin Dells, I mean, you have to get a little bit away from the water rides, but we’ve got a lot of hemlock there too. And then it’s very popular in the southeastern part of the state. So it’s considered a keystone species. It supports unique wildlife, whether that be birds or insects or mammals or fungi. It’s also something that’s very important for moderating stream temperatures. And unlike, even Minnesota that has hemlock in its eastern part of the state, we are really close to being on the eastern or the western edge of hemlock’s range.

So we have a lot of hemlock in Wisconsin. We’ve got a lot to lose. And the nursery industry also cultivates hemlock as shrubs and trees, and there’s over 250 registered cultivars or varieties of Tsuga trees. And this next slide is gonna look a lot like the one that I’ll show you later for EHS. It shows where hemlock woolly adelgid has been introduced into the eastern United States. We already have a quarantine regulation on this pest here, and we have had close calls. And I will say, you’ll see in the slide on the life cycle for this pest, even though it’s super easy to recognize by those cotton swab females feeding on the undersides of branches, it is just microscopic and very hard to see in its immature form. And so it’s a real danger for someone to bring or import infested nursery stock of hemlock from anywhere in the east to Wisconsin for that reason. And so we do allow, we’ve got 20 nurseries in Wisconsin that have compliance agreements set up with us that make sure that they know how to identify the pests, that they make sure that they’re not bringing anything that hasn’t been inspected or treated for this pest. And so this is really, when I went to states like North Carolina, you could see entire mountainsides with dead hemlocks because of hemlock woolly adelgid.

In states that don’t have cold winters, this pest that actively feeds throughout winter is just not killed. So it’s laying eggs, it’s reproducing, it’s getting spread all over the place, and that’s leading to millions of dead trees because of HWA. And so this next slide is interesting. It shows that, this insect, which is mostly visible under the microscope has a really unique, interesting life cycle. There are absolutely no male hemlock woolly adelgid in North America. The populations are 100% female. They reproduce asexually and they have two generations a year. And so those females in the upper left, it shows a female with that white woolly wax removed. That’s what she looks like under there, under those Q-tip tops. She will feed all winter and lay up to 300 eggs per female, no need to find a mate or anything.

And so the second image on top shows the eggs with the wax removed around that bundle. From those, there are crawlers. And so that’s the image just below the eggs. Crawlers are the form of this pest that we’re most worried about because they have legs. They can blow around on the wind or on mammals or on people, other things to start new infestations. They’re only gonna infest hemlock, so no other hardwoods or conifers, but as soon as that finds a feeding site, the crawler will lose its legs and settle as these little nymphs that I mentioned in the lower left image. They’re super hard to see. So you may think you’ve got clean stock, but if they’re not actively feeding, they’re not producing that wax. And they’re just really hard to see. And so the main reason I included this image is just, it’s amazing how long the mouth parts are of this insect.

‘Cause you think of like, how does this little microscopic insect to get in there and penetrate the hemlock bark and kill hemlock trees? Well, the insect crawler is on the top with its legs, and its mouth part goes all the way down to the bottom of the slide. And that’s how it does it. It’s a very fine, microscopic image, but it’s gotta be six times as long as the insect itself. And so in states that have gotten hemlock woolly adelgid, they’ve treated high-value trees, thousands of them with pesticides like imidacloprid, and homeowners have done the same. And as much as you know, we never wanna use pesticides when we don’t have to, it has been found to protect trees for three to four years because hemlocks keep their needles of course, and highly effective against this pest. And so there were old-growth hemlocks in hemlock’s natural area in Pennsylvania. And the only way those trees were gonna survive is with this kind of treatment for this invasive pest that shouldn’t be there. And then the other thing that we tried to do and a lot of eastern states did was to release bio control predators against hemlock woolly adelgid. And the idea was not to just introduce one. And these were all grown painstakingly and expensively at a laboratory at the New Jersey Department of Agriculture.

And so we’d send them the infested hemlock and they’d send us the beetles. And so two of those were in the same family as ladybugs, on the left. And then the last one is Laricobius nigrinus. And so the two on the left were from Asia. And so they were collected from hemlock woolly adelgid’s native range, while the one on the right was actually collected from the western United States. And those Laricobius beetles need hemlock woolly adelgid to complete their development. And I think that bio control has its place. I mean, it’s been very hard for predatory beetles to keep up with the reproductive capacity of hemlock woolly adelgid, but you also have to admit that bio control is a more permanent solution than pesticides, and there are places where pesticides can’t safely go. And the cost of trying to treat all of the hemlock trees would be just absolutely prohibitive on a forest-wide scale. So the hope is to establish a complex of native natural enemies against the hemlock woolly adelgid.

And so for those of you that do have hemlocks or like to go camping where there’s hemlocks, it’s always a fun and good, important thing to flip over the branches and look for those white woolly masses, especially in the winter, but those masses will remain there even as new populations go to new growth to feed. So you can even see old, past infestations of adelgid by checking the undersides of your branches for this pest. You can also see thinning needles. If you see like your hemlock is just looking sick, yellowing foliage, you know, it’s worth checking for this pest. And then the last pest I’ll talk about today is called the elongate hemlock scale. Now, this pest is native to Japan and it’s spread to 20 eastern states. And you’ll notice the same states with HWA have EHS because these two pests often happen together on hemlock trees. But the difference between EHS and hemlock woolly adelgid is that this one can feed on all kinds of conifers. So it could be hemlock, its most preferred tree, but also it really seems to like firs, spruce, pine, yew, and other types of conifers, unfortunately. And EHS is harder to control with pesticides than HWA because it’s protected under these hard, waxy scales that I’ll show you.

And because the crawlers of this insect come out all through the season. And so there’s no good, perfect time to target them with something like horticultural oil. And similar to HWA, EHS can cause needle loss and conifer decline and death of the tree in combination with other stressors like drought. And so this slide just shows some of the weird life stages. I mean, I know that this is not what you probably think of when you think of an insect, and you’ll see that the elongate hemlock scale females have these brown, fish scale almost looking-like covers right on the needles of the undersides of hemlock and other conifers. And so the female is under that brown scale, and she can lay up to 20 little eggs that look like little jelly beans. And from those eggs, you can see a crawler escaping from that upper image, and that crawler has legs, and that’s what starts new infestations. There’s also males under the white scale coverings and they have wings, but they don’t feed at all. And they only leave the scale covering to mate, and then that’s it for them. And so similar to HWA, states in the East have released over 100,000 bio-controlled beetles to eat elongate hemlock scale and try to control them.

And although those beetles have likely established, they really haven’t been able to control this insect below damaging levels. And that’s something that might take years. And as I mentioned before, elongate hemlock scale can be controlled by applications of dinotefuran if systemic, but it is really difficult and it takes a long time, and it is often ineffective because those scales are just so protected under those coverings. And so even though we don’t have EHS in Wisconsin, I don’t know, have any of you gotten the news reports about Christmas trees being infested with live pests? If you did, that was elongate hemlock scale. So we’ve intercepted this pest over 40 times on fir Christmas trees and wreaths from the East, and also on hemlock nursery stock. It is not in Wisconsin and we do look for it every year. When we find it, we require that material to be pulled from the sales shelf. And you might have a yule bonfire of Christmas trees, or we might require that trees are chipped, and Minnesota has done similar regulatory actions against this pest that we just don’t want in the state, and our Christmas tree growers don’t want it. And our hemlocks and native balsam fir definitely don’t want it. So this is another pest that we’ve proposed an exterior quarantine for that we will be having a public hearing on in April.

And so the other thing that we are doing for elongate hemlock scale is outreach, like at this talk and on social media. And we’ve also advised people not to throw wreaths or trees that are from out of state just out in your backyard, like you would for the birds, for wildlife habitat. If you have any concern that they’re infested, you would not want these crawlers, which are just able to live for weeks and weeks on that cut material, to go and start a new infestation on one of our conifers in Wisconsin. And so this just shows how you can check for elongate hemlock scale signs and symptoms, that yellowing foliage in the left image, or obviously the scales themselves. If you flip over the branches and look at the needles of your fir, hemlock, spruce, pine, or yew trees. And so another thing that you wanna do as you’re looking for pests is make sure you know what tree you’re looking for. Both hemlock and fir trees have flat needles, but hemlock’s needles end in a point or taper. And they also have these round cones on the branches, where fir on the left does not. And then if you compare hemlock needles to spruce or pine, those are more round needles and they have white surfaces on the undersides of the hemlock needles only, not on the spruce or pine. And so there’s a bunch of things that you can do in general to protect Wisconsin from invasive species.

How many of you have heard the “don’t move firewood” message? So that’s great, most of you. DATCP has a firewood certification program that requires dealers to heat treat if they participated as a voluntary program or season wood to make sure there are no pests or diseases, if that firewood is gonna move long distance. And so another thing that people can do is just wash, inspect vehicles, or, you know, I’m sure if you’ve gone hiking, you’ve seen the boot brushes where you wipe off your feet before you go from one area to the next. That’s gonna prevent the spread of all kinds of invasives, whether it be plants, insects, or otherwise. And then just what you’re doing today. Thanks again for coming to the talk. And if you do think you found something, you can report new invasive species to the state. So not so much the Lymantria dispars or gypsy moths of the world, but definitely the elongate hemlock scales to our pest hotline at 866-440-7523. And then just doing what you’re doing today. Buying quality plants from licensed local nurseries can completely avoid the problem, of course, because if it’s grown in Wisconsin and we don’t have those pests, you won’t be risking bringing them into your backyard.

And then finally, with a lot of the aphid pests that are out there, you don’t wanna fertilize with nitrogen. That can cause a pest explosion for hemlock woolly adelgid, elongate hemlock scale, or basically any kind of aphid or scale, because they love that sugary sap, but they’re nitrogen limited. So you don’t wanna give them what they want. All right, well, thank you so much for being here again, and I’d be happy to take any questions. [audience applauding]