Living with EAB

Minnesota has been living with emerald ash borer (EAB) since it was first found here in 2009. Over the years, the invasive insect and its effect on trees have become more widespread, causing communities to create action plans to respond as they lose ash trees. The southern half of Minnesota is considered generally infested with EAB and it continues to push its way north. EAB experts Jonathan Osthus and Karen Zumach join host Jennifer Burington to give advice on keeping our forests as healthy as possible while living with EAB. 

Smarty Plants is a podcast of the Minnesota Department of Agriculture. Visit www.mda.state.mn.us/plants-insects/smarty-plants for more episodes. Look for a new episode of Smarty Plants every month.

Transcript

Jenifer Burington: 0:19

Welcome to Smarty Plants, a Minnesota Department of Agriculture podcast, informing citizens about invasive species that affect our environment and agricultural resources. My name is Jennifer Burrington, and I will be your host. Trees are a big part of what makes Minnesota a beautiful place to live and enjoy the outdoors. Invasive forest pests can threaten that beauty by putting our tree health in jeopardy. Today, we are joined by Jonathan Osthus and Karen Zumach to discuss the emerald ash borer or EAB. An invasive insect and best management practices now that it is widespread in Minnesota. Jonathan is the Emerald Ash Borer Technical Assistance Coordinator for the Minnesota Department of Agriculture's Plant Protection Division. He began working on the early detection and management of Emerald Ash Borer shortly after it was first found in St. Paul, Minnesota in 2009. Thanks for joining us, Jonathan.

Jonathan Osthus: 1:10

Thanks for having me.

Jenifer Burington: 1:12

And also we have Karen Zumach is the Director of Community Forestry for the Twin Cities based non profit. Tree Trust, and serves as the chair of the state's urban forest council, MnSTAC. Karen has worked with communities to assist in emerald ash borer management, and has elevated the importance of trees in our communities to anyone who will listen. Thanks for coming. Thanks for having me. All right, to start with, what is emerald ash borer, or EAB, and why should we be concerned about it?

Jonathan Osthus: 1:41

Well, emerald ash borer is a wood boring beetle that attacks and kills ash trees. So, in Minnesota, we have a very large ash forest resource. We have nearly a billion ash trees throughout the state. We have three types of ash trees that are native to Minnesota. Black ash, green ash, and white ash. And in communities, they often make up a large percentage of the community forest. So, uh, it often is, uh, one out of every five trees, or even more than that, that make up a community forest. So the impact of this insect is going to be very far and wide reaching. And the real issue with this, outpaces communities ability to deal with the trees, uh, uh, as they die.

Karen Zumach: 2:22

I think it's also important to note that Not only those trees that are planted on public property, but trees that are planted in people's yards, in people's parks, uh, all across the state are going to be impacted if they aren't already by Emerald Ash Borer, uh, and it is making a pretty significant impact on our urban forest population across the state

Jenifer Burington: 2:44

right now. So can you tell us a little bit more about each of your roles that you part you play in emerald ash borer management in Minnesota, um, both for the, for the state and then as with a private business. As

Karen Zumach: 3:01

the chair of the state's urban forest council, we've worked over the past seemingly ten years to help prepare communities for emerald ash borer. So really looking into providing those resources so that cities are prepared for managing emerald ash borer In addition to, uh, assisting with the education around the importance of funding to help communities manage Emerald Ash Borer. And then, uh, in my work with Tree Trust, we've worked really hard to help private property owners understand their, uh, risks in regards to Emerald Ash Borer. In addition to Uh, kind of replanting their tree canopy so that we can have a more resilient and diverse, uh, urban forest canopy on that private property where we know there's, uh, the best opportunity to increase, uh, that tree resource.

Jonathan Osthus: 3:55

In the Minnesota Department of Agriculture, they play the role in tracking the spread of the insect throughout the state. And so we really, uh, provide, uh, resources on where that pest is known to occur. We also come up with best management practices and recommendations for communities to help deal with the pest. And we implement things like biological control at that forest landscape level to help try to reduce emerald ash borer populations throughout the state. And we also enforce and, uh, implement regulations surrounding the insects. So those are things like quarantines that restrict the movement of any ash material or hardwood firewood.

Jenifer Burington: 4:30

Great. So To go into a little bit more in depth on how, what emerald ash borer is, how can we ID emerald ash borer? Like, give us a little bit of background on, like, if I see a green insect, is that emerald ash borer? Or if I see an ashtray, how do I tell if that has emerald ash borer in it or not?

Jonathan Osthus: 4:53

Great question. There's, there's really four ways to identify if it is actually emerald ash borer. Uh, we also have lots of resources on, uh, common lookalike insects that are available to, to help you identify it as well. But the, the main four ways to identify the insect are through finding the, uh, the larval feeding gallery. So they leave a, this tundling pattern on the surface of the tree underneath the bark that is very distinct. It's the only insect in ash that will create that pattern. And so they create an S shaped tunneling pattern that you can make out that tight S shape in that curve of where that larva is tunneling underneath the bark and disrupting the flow of water and nutrients between the root system and the crown of the tree. Additionally, there is the adult beetle itself, if you happen to come into contact with it. That's less common, as the beetle is usually up in the canopy of the tree. But as a community becomes more heavily infested, you may actually come into contact with the adult beetles. And they're about a half inch long by about an eighth inch wide. And they're that bright, iridescent green color. And when their wings are open, you can actually see on the abdomen that it's kind of this dark magenta colored. And then, additionally, there is the larva itself, if you happen to pull one out of an ash tree. Uh, the way you identify that is it has these two little spine like projections on the tail end of the larva that are called urogamphy. There are just these two little black pincers at the tail end, and if they have both of those at the tail end, you know it's emerald ash borer if you pulled it out of an ash tree. There are other native insects that have one of those, or none of them, but if they have those two little black pincers, you know it's emerald ash borer. And lastly, there is, the insect lives, leaves a D shaped exit hole when exiting the tree, and so it, there's this kind of nice flat side, and it creates a D shaped, um, that is indicative of emerald ash borer. However, that is only about An eighth inch wide and so it is really small and very hard to see and find on on the bark of a tree. Uh, so you're better off looking for those S shaped galleries that are, that tunneling pattern on the surface of the wood, uh, or the, the larva or the adult beetle itself. Other signs and symptoms that you might want to look for, uh, when trying to see if your tree is infested with emerald ash borer are things like woodpecker foraging damage. So when a tree is infested with emerald ash borer, woodpeckers really like to feed on the, the larvae underneath the bark. And oftentimes they will slough off some of that outer bark, creating what we call a We call it blonding, or that blonded appearance. And within those blonded areas, you can see these small, dime sized, uh, shallow woodpeck holes. And that is a clear indication of some insect activity in the tree. And if you see that in your ash tree, that's a sign you might be infested with emerald ash borer. Along with woodpecker damage, you may see things like vertical splits in the bark, where that tree has tried to heal around that larval feeding gallery, and it creates calc tissue around that, and as that tree continues to grow, that bark splits and creates a nice, um, Visual split where you can see that S shaped gallery on the surface of the wood in between that split bark. And other things to look out for are things like epicormic sprouting where that tree is putting off shoots lower down, uh, in the lower part of the canopy or at the base of the tree. That show that the tree is stressed and things like canopy thinning where that's an overall thinning of the canopy There's fewer leaves smaller leaves more light penetrating through the canopy

Karen Zumach: 8:16

I'll just offer it's always a good idea to make sure you know what an ash tree looks like So in addition to all those great signs and symptoms, we always like to make sure that people can actually identify a tree the ash tree in particular Uh, we found that if you kind of squint your eyes and you see that diamond shaped pattern, uh, that goes a long way to helping identify, uh, those ash trees, in addition to knowing that once you see it, you can't unsee it, uh, is one of those liabilities of understanding how to un to, uh, identify an ash tree. Uh, I'd also say that my best friend sent me a, a picture of her, uh, tree from New York and said, hey, can you tell me what's wrong with my tree? And sure enough, it was that blonding and the bark was all coming off the tree. Uh, and I said, well, yeah, I know what's wrong with your tree. It's got emerald ash borer. So, uh, I think that's really that tell tale sign that really helps people, uh, see that there's something going on, uh, especially during this leaf off season. Once we start to see those leaves come back, that thinning is really going to be the thing that is going to help people kind of be curious about it. Um, there was also the old adage when trees were still standing in Minneapolis, uh, if the tree has a green ring around it, you know it's an ash tree.

Jenifer Burington: 9:34

A lot of the trees in a lot of the cities, um, along the boulevards are going to be ash trees. That was planted a lot, um, and utilized as a, as a good tree at the time, until Emerald Ash Borer came along, um, and started to go after all of them. And so you talked a little bit about Minneapolis has had Emerald Ash Borer, we know. Where What else is Emerald Ash Borer found in Minnesota?

Jonathan Osthus: 10:02

Yeah, so Emerald Ash Borer is now currently found in 53 out of 87 counties in Minnesota. So, it was originally found in the South St. Anthony Park neighborhood of St. Paul in 2009. And since then it's been spreading throughout the state. And it's really found in much of the southern half of Minnesota, uh, in the central part of Minnesota. And it's now just starting to make headway in the north, northern part of the state. Uh, where a lot of our black ash forests are. And so, um, many, most people in the state are beginning to be impacted by this insect at this point. And I'd just like to mention that if you're ever wondering where emerald ash borer is known to be in the state, please check the Minnesota Department of Agriculture's Emerald Ash Borer Status Map as it provides all the locations that emerald ash borer has been confirmed.

Jenifer Burington: 10:52

Thanks. Yeah, that map works really great. You can type in your address in there and figure out exactly how close, um, a known infested tree is to your property, um, especially if you have, uh, like recreational property up north and stuff. You want to know, hey, has emerald ash borer been found near my cabin? Should I start worrying about the ash trees at my cabin? Um, so talking a little bit more about, uh, impacting the properties, how could Yeah. Emerald ash borer impact our properties both like our homes and any other forests that we have or any other cabins Anything that we have

Karen Zumach: 11:33

yeah, emerald ash borer I think is one of those things that we have to look at on multi Multiple levels because it's not just that impact to our own properties So that loss of shade that loss of cooling that those trees provide the property values that are lost when we lose those mature trees Uh, in addition to just that overall sense of just kind of, uh, nature in our communities, you know, there's nothing more devastating than seeing an entire block of mature trees be there one day and then the next day they're gone. Uh, so it does have a pretty significant impact, not only on our environment, but also on our health and well being. Uh, you know, it's, it's one of those things that I, I think we don't really appreciate until it's gone, uh, and just recognizing that, uh, those trees are providing a multitude of benefits, uh, in just lowering cortisol levels and helping us feel better generally, uh, improving our air quality and the store, improving the stormwater runoff. before it goes into our lakes and rivers, uh, so it's not just, uh, it's not just a my backyard problem. It's an entire community and our entire state problem, uh, because it's a billion ash trees and losing them is, uh, one of those things that isn't going to be easily replaced.

Jonathan Osthus: 12:55

Yeah, it can really be thought of as green infrastructure. And so it provides a lot of valuable tools to helping making our cities more beautiful places.

Jenifer Burington: 13:05

And we do have some very beautiful cities. I do like all of the green spaces. And I've, I've noticed that there are some, some areas that you can tell there were probably some ash trees there that it's not as much, not as much along that green space anymore. So what can we do to minimize the impact and the loss of these?

Karen Zumach: 13:28

Well, I'll just say that there is a, there is a potential to keep your trees on the landscape using, uh, a professionally injected pesticide that gets injected into the tree. Uh, this would be a, uh, systemic insecticide that stays within the tree for about two years. Uh, non neonicotinoid, so low risk to our bees and pollinators, but big impact to keeping those trees on the landscape. Do we believe that every tree should be treated? No, but there are certainly some good candidates for keeping those trees on the landscape so that we can preserve those environmental benefits. We can help those new trees that are growing as we're planting more and more trees. to diversify our urban tree canopy. Uh, and that can just really help that, make that easier transition, uh, from this over reliance on this population of ash trees, uh, to that next generation of tree canopy. Um, that's something that has been, uh, you know, it's one of those things, especially if you're on that leading edge of where Emerald Ash Borer is, uh, looking into and inquiring about getting your ash trees treated is one way to help keep that risk as low as you can. And keep ash, keep the emerald ash borer where it is. Uh, one of the things we've always been really proud of is trying to do what we can to slow the spread by keeping emerald ash borer where it is and keeping it out of where it isn't. And, uh, more and more we're seeing how important it is as we look to continue to protect that black ash resource. Uh, so the science can catch up. I know that there's going to be a time where we're going to be able to manage ash, ash borer in a way that can, can help keep those important black ash, uh, in our, in our natural spaces.

Jonathan Osthus: 15:12

Right. And it's, it's important to maintain that mature canopy. It takes 30, 40 years to get back what you've lost. And so that's maybe out of your timeframe, depending on how long you've been here. So, um, doing things like treatments, it is, it's very effective. and helping reduce emerald ash borer populations in localized areas. And other things that you might want to do, um, is just come up with a plan, uh, figure out what's in your yard. Um, if treatment's not a good idea, if it's a poorly sited tree, um, you want to come up with a removal plan, you want to deal with that tree before it's completely dead. As that can increase the costs and the hazards to nearby structures and people.

Karen Zumach: 15:53

I think it's someone from the DNR that said, uh, ash trees are predictably unpredictable once they're dead. So really making sure that you're managing that impact on the front end, especially if they're small ash trees. Just removing them, uh, and removing that ability for the, for the pest to really take, come in and take over. Uh, but getting rid of them before they're standing dead is, is absolutely, uh, important practice.

Jenifer Burington: 16:22

Yeah, and going along with that, like, we have to kind of make a decision, but can we just do nothing and let nature take its course? Like Kind of see what's going to happen if nature's going to take its course. We're going to end up with a bunch of dead ash trees, so What else, what should we, what should we do?

Jonathan Osthus: 16:39

Right, doing nothing sounds nice, but you're going to have to make choices eventually and so The ideas of doing proactive management and helping slow the spread and the rate at which ash trees die is really important Helps spread those costs out over a longer period of time If you let emerald ash borer just run through an area Uh, what you end up having is a lot of trees dying in a very short amount of time, and those trees are in locations that have to be dealt with, whether they're next to your garage, uh, in the boulevard, in your parks next to the play set, uh, they're hazards, and they could potentially harm people or property. So, um, you're gonna have to make choices, and if you can spread that cost out over, uh, many more years instead of a five to ten year window, you're, you're saving your residents money. And you're also giving other communities nearby that aren't yet impacted. more time to prepare for the eventual arrival of Emerald Ash Borer.

Jenifer Burington: 17:32

Thanks. And so, talking a little bit about, um, communities preparing for this and spreading out the, the management of Emerald Ash Borer over time, are there any resources available to help us manage Emerald Ash Borer?

Jonathan Osthus: 17:49

You know, there's, there's not much available currently for individual homeowners. Uh, mostly that's up. The, the inex expense of the property owner. Uh, I would say check with your city, uh, to see what resources are available. Uh, some examples would be, uh, if you, if you really can't afford the, the cost of, of that, uh, tree removal, if your, if your tree has died from emerald ash for, um, some, some cities will allow you to apply that cost to your property taxes over a number of years to help reduce that initial, uh, upfront sticker shock of, of removing a, a large mature ash tree. Uh, other things, uh, some communities do have financial assisted, assistance to homeowners that do qualify, and they have kind of locally set standards for that. Uh, there is a, uh, financial assistance map available, uh, online on the Minnesota, uh, Department of Natural Resources website, and, um, there are, uh, treatment discounts that some communities have set up with private tree care companies that, uh, provide a discounted rate to residents to treat their trees, to, uh, save their ash trees and maintain that mature canopy.

Karen Zumach: 18:56

Uh, at Tree Trust, we work with multiple municipalities to help, uh, again, incentivize that tree planting on private property through tree sales. Uh, and we do that with a variety of communities, uh, here in the metro, but also starting to branch out, as it were, uh, to other communities across. Minnesota. So, uh, providing that low cost incentive to plant a new tree on your property, uh, is one of the things that we're really trying to encourage as we're starting to make that transition away from ash trees.

Jenifer Burington: 19:30

Great, I know I've taken, um, purchased a couple trees from some, uh, tree sales through some soil and water conservation districts, um, around the state, and it's been fun to kind of see the variety of tree species that are available to plant instead of just like one or two options. You have like a lot of options to choose from. So with those trees that I have the option of. Uh, with the tree sails. Are there some other invasives like emerald ash borer that I should be concerned about and that we have maybe encountered in the state or that we haven't seen yet here in the state? And then what kind of impacts, um, could they have?

Karen Zumach: 20:14

Well, I'll just say that, uh, it hasn't quite yet arrived here, but there is a beetle, uh, that has, uh, been shown to, has, has been discovered, uh, east of here. And, um, Called the Asian Longhorned Beetle, which has a pretty distinctive, uh, appearance and impact, uh, and it's one of its, uh, most preferred hosts are maple trees, uh, so as we try to continue to diversify our urban tree canopy and, uh, just It's really important to take a look at that maple component in addition to the ash component because it is important for us to prepare for what could be down the road next.

Jonathan Osthus: 21:05

Right, and there are infestations of this Asian Longhorned Beetle or Starry Night Beetle in other parts of the U. S. There's active infestations in Ohio, New York, Massachusetts, and South Carolina. And you really don't want this pest to arrive because it does take a heavy handed response. The U. S. Department of Agriculture does implement eradication programs, but it really, um, what ends up happening is there's a lot of tree removal within an area. So keep that at bay, um, and be on the lookout. They leave large pencil tip size exit holes from, in maple trees, and a lot of times you'll see things like sawdust collecting, uh, at the base of the tree or in the crotches of branches.

Jenifer Burington: 21:48

And are there other Threats affecting trees that we should be looking for.

Jonathan Osthus: 21:54

Yeah, there's a few other things that, uh, are impacting Minnesota's trees that are kind of new and emerging. Um, we have recently, uh, found the elm zigzag sawfly. Uh, it was found at a few locations throughout the Twin Cities metro area. Uh, this is a pest that was first identified in North America in 2020 in Quebec, Canada, and has now been found in a number of East Coast and Midwest states. And so the elm zigzag sawfly, its larvae, defoliates elm trees. And so, well, trees can usually withstand a defoliation event pretty easily. If there is repeated defoliation, it can weaken the tree and open it up to other insects and diseases that could eventually kill the tree. And another thing to be on the lookout for is spongy moth. That's something that's been moving west for a long time. Uh, there is an active spongy moth trapping program that the Minnesota Department of Agriculture Uh, implements and it, it's very effective at identifying populations and then when those populations are identified, they are treated with either mating disruption or other, other types of treatments.

Jenifer Burington: 23:02

Thanks. So, that's kind of what we have to watch out for in the future. I guess going into our past, this isn't the first time we've had an invasive, uh, pest that has kind of infected a lot of our trees. Um, do you want to talk a little bit more, Karen, about something that we've had in the past that people might remember?

Karen Zumach: 23:26

Uh, yes. Uh, back in the 70s and 80s here in Minnesota, we were, uh, very much infested with, uh, Dutch elm disease, which was, I guess it would be infected when it, it would be infected. So Dutch elm disease, uh, was a disease and it's still, uh, moderately prevalent here amongst our elms that are still growing and regenerating. Uh, but at that time we had 90 percent planted elm trees across the metro. So when we think about, uh, Uh, the impacts of Emerald Ash Borer and how that relates to what we've dealt with, with Dutch Elm Disease. You know, there, you hear a lot about how, oh, didn't we learn from Dutch Elm Disease? Well, we did. Uh, we went from 90 percent planted elm trees to anywhere from 20 to 40 percent planted ash. So we're getting better, and this time around we'll be even more diverse and resilient. Um, Dutch Elm Disease was something that, uh, actually started Tree Trust. It was founded, uh, as a response to Dutch Elm Disease. In addition to the Minnesota Shade Tree Advisory Committee, both of those organizations started, uh, in response to Dutch Elm Disease. So, we've had some experience. What's old is new again. Uh, Is what we like to say with, uh, unfortunately with this emerald ash borer infestation and the similarities that we see between, uh, the past with dutch elm disease and what we're dealing with today. So, uh, I think we've learned the lesson, uh. Difficult, but we learned it and I think we are really on the right track to building our urban and community forests in a way that will make them more resilient and sustainable for future generations.

Jenifer Burington: 25:07

Thanks. And then I guess talk a little bit more about what steps can we take now to create a more resilient forest in the future. We've kind of talked a little bit about it, but if you want to give some specifics.

Karen Zumach: 25:20

Well, I think it's important to, you know, make sure you know what you have. So doing an assessment, working with the resources that are available for you, especially if you have a considerable acreage. The DNR has Uh, private property, uh, opportunities and, um, resources for landowners. Uh, in addition, uh, just on your, on your own property, taking a look at where you have ash trees or other trees, uh, that maybe need to be maintained and cared for. Uh, you know, keeping those existing trees on the landscape happy and healthy. Like Jonathan said, their infrastructure, they provide us benefits, uh, every day just standing there. So, uh, there's research that came out from the University of Minnesota showing that Just having a tree in your yard is providing energy savings to not only you, but people within that community within several blocks of where that tree is standing. So we know that those trees have considerable impact across communities. And then looking at what's going to be, uh, you know, what we'll call native here in 50 years. What is that climate of the future? Uh, going to look like here in Minnesota, and how can we start planting those trees now? So, encouraging those, the planting of trees that we see, uh, maybe further south in southern Minnesota or northern Iowa, recognizing that, you know, Zone 5, uh, here in the Metro is our new designation, and really, uh, kind of, Taking advantage of the opportunities to diversify, uh, the trees that we do plant and recognizing where those threats are with things like Asian longhorn beetle, spongy moth. What are those host trees and how can we make sure that we're minimizing, uh, the amounts of those trees that we're planting?

Jonathan Osthus: 27:10

Yeah, I'd just like to echo that sentiment, you know, maintaining, uh, a regular pruning schedule for the trees in your yard, uh, watering during drought, things like that, mulching around your tree, um, and just that, um, Diversity is really key here, uh, when you have all of one type of species, you have single point failures that can wipe out, uh, an entire species of tree, and kill the majority of the trees on your block. So you really want to take a look around you and try to plant something new.

Jenifer Burington: 27:40

Thanks, yeah, I definitely, uh, I'm gonna have to go and take a look at my yard and see. I don't think I have, I don't have any more ashtrays left, but I do know I might have some maples that are hanging around there, so I'll have to keep an eye on those. Thank you, Jonathan and Karen. It was great having you on the, to talk about Emerald Ash Borer today. I certainly learned a lot, and I'm sure our listeners did too. If you do have questions about Uh, your ash tree and you notice some blonding on it or you happen to see, uh, one of the insects this summer or any other invasive insect that you might, uh, have in your property, feel free to contact our Report a Pest hotline. You can email reportapest, all one word, at state. mn. us. You can also check out our website, www. mda. gov. state, mn, us, forward slash, report a pest, all one word again there. And you can use our really simple online form to fill it out, attach some pictures and send it in to us, and we will take a look at what you might have. This has been Smarty Plants, a podcast from the Minnesota Department of Agriculture. Our producer is Brittany Ravel, our editor is Larry Schumacher, and I have been your host. You can learn more about pests and other invasive species that affect our environment on our website at www. mda. state. mn. us. And while you head to our website, we'll be working on the next episode of Smarty Plants. See you there.