Introduced Pests - Know the Signs and What to do

Lou Meyer, certified arborist at Davey's Chesapeake, Maryland, office, talks about  introduced pests like the emerald ash borer and spotted lanternfly, as well as diseases like beech leaf disease.

In this episode we cover:

• Emerald Ash Borer (1:17) (10:26)
  • What is it? (2:32)
  • Treatment (4:34)
  • Improving tree health (8:36)
  • Hybridizing (12:46)
  • Predators? (13:31)
  • Ash species - rethink approach to urban forestry (15:00)
• Spotted Lanternfly (15:57)
  • Trees it affects (19:45)
  • Treatment (20:54)
• Beech leaf disease (22:23)
• Good news! - treatment for trees (24:01)

To find your local Davey office, check out our find a local office page to search by zip code.

To learn more about the emerald ash borer, read our blogs, Emerald Ash Borer Facts: What Does the Emerald Ash Borer Eat?, Does Emerald Ash Borer Treatment Work? and The 101 on Emerald Ash Borer.

To learn more about the spotted lanternfly, read our blogs, How to Get Rid of the Spotted Lanternfly and Spotted Lanternfly (SLF) Alert: What You Need to Know.

Connect with Davey Tree on social media:
Twitter: @DaveyTree
Facebook: @DaveyTree
Instagram: @daveytree
YouTube: The Davey Tree Expert Company
LinkedIn: The Davey Tree Expert Company

Transcript

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[music]

Doug Oster: Welcome to the Davey Tree Expert Company's podcast, Talking Trees. I'm your host, Doug Oster. Each episode showcases one of Davey's certified arborists, sharing advice with everyone about caring for your trees and landscapes. We'll talk about everything from introduced pests, seasonal tree care, deer damage, how to make your trees thrive, and much much more. Tune in every Thursday to learn more because here at the Talking Trees podcast, we know trees are the answer.

Our guest today is Lou Meyer, he's an assistant district manager and certified arborist for the Davey Tree Expert Company. Lou, today we're talking about invasive pests. Oh, I'm telling you, this might be for you, you're a dentist, you've got to tell people these terrible things are coming or have been here and what we're going to do about them.

Lou Meyer: It can sometimes be a little depressing regarding these things, but the great news is that there are ways to counteract them. Although it's not great, this is part of a cycle that has been with nature ever since the beginning. As Disney taught us, there's the circle of life and we're just trying to get through it.

Doug: Let's start with the emerald ash borer, which out here in the east, I'm in Pennsylvania, you're in Maryland, but it has wiped out our ash trees. When was the first time you heard of the emerald ash borer? Because I remember when I started hearing about it, and it scared the heck out of me.

Lou: Let's see, the first time I heard about it was probably around 2012 or so. I was late to the game with it. I started in the tree care industry back in 2000, 2001 in Cincinnati, Ohio with a small independent operation. Then I bounced around with them for a minute, did some other things in life, and found my way back to horticulture as a landscape designer installer in Cincinnati also. We didn't mess around with ash trees too much. It was more ornamentals and whatnot. When I joined back or joined with Davey, I guess that was 2013, that's when I started immediately to hear a lot about it, obviously. 2013 is when it hit my radar when I was in the field as a plant health care technician and landscape technician.

Doug: Let's talk about the pest because it has been absolutely devastating wherever it's gone through. What does the emerald ash borer do?

Lou: The emerald ash borer is a pest species that's indigenous to Asia, and it came here on a pallet, that's how it was transferred. The globalization of business has a lot of benefits, but one of the detractions is that these pest species can travel around the world so fast. It attacks ash trees, which are members of the olive family. It can jump to other olive species, although extremely rare. It's not a threat. We don't worry about it. It works its way into our native ashes. The green, white, and blue ash are the three most populous ash species in the eastern United States, I imagine throughout the entire United States, but I've operated in Ohio and Maryland, to be honest with you, I don't know the exact range.

It's really devastating to the greens and the whites. The blue ashes are showing a little bit of resistance, not a tremendous amount, but a little bit, but it has a 99.7% mortality rate, is what we're seeing amongst the ash species. What it does, Doug, is it works its way through the cambium layer of the tree, which is the vascular system of the tree, and it cuts off the nutrient flow from the roots to the crown, then the sugars, the carbohydrates from the crown to the rest of the tree, obviously. It causes the trees to become very brittle. Depending on the severity of infestation, weather events, and other things, you're looking at a two to five-year window of when the pest initially strikes the tree to complete failure of the tree.

Doug: When do you know or how do you know when you can treat it? We'll talk about what you use to treat it in a minute, but how do you know when you get to an ash tree if you should treat it or not?

Lou: You start to see there's some distinctive features to infestation. One is the tree begins to die back from the tips. You see the tips of the tree start to not foliate in the springtime. Then there's very distinctive D-shaped exit holes from where the larvae are exiting from the tree in the springtime. Those are tough to identify unless you know you're looking for them.

The way that I see a lot in the field is you start to see the bark being pulled off by woodpeckers, and they're trying to get to the larvae. If you see a bunch of bark around the base of that tree, and shiny spots where the bark has been removed along the trunk, and you know, all right, the woodpeckers are going after the borers, and then you look for those D shaped holes. As far as treatment goes, there are some very successful products out there. As long as 50% of the crown is still alive, you've got a shot of saving the tree. If it's more than that, obviously, the more crown that's alive, the better your opportunity of saving the tree is.

Doug: Do you wait until it shows signs of the borer, or if I had a big giant ash tree that I love more than anything in the world and the ash borer was on its way to my area, would I start treating ahead of time, or do I have to wait until the ash borer actually gets to the tree?

Lou: No, that's a terrific question. You want to pretreat. You want to get that tree as ready as possible to face the borer. Again, with a 99.7% failure rate, there's no reason to wait. If you're in an area-- Pretty much the entire three-quarters of the United States is infested right now. If you are west of Colorado, you might not need to start treating right now, but it's knocking on your door. It'll be there soon. Talk to a certified arborist, if you have an ash tree that you want to save. Talk to a certified arborist in your area to discuss timing, but absolutely, if you're in Maryland-- I'm in Maryland. I've come upon ash trees here that show no signs of infestation right now. We immediately get them on a treatment plan to preventatively ward off any damage by the borers.

Doug: What can you guys do to treat a tree? What are you using to treat a tree so that we can keep it alive?

Lou: There's a couple of different approaches that we take. The most effective is a product called Emamectin benzoate. That is something that we inject into the trunk of the tree. It has two to three years worth of good solid coverage. That's one of the reasons why we like using that, is you don't have to apply it every year. It's very concentrated. You're injecting it into the tree so you're not affecting other plants with it, you're not pouring it on the ground. That has a very high success rate. Another product called Imidacloprid is something that we do a soil drench with around the root flare of the tree. That's an annual application. That's something that you put in every spring or every fall. It depends on your zone and weather and the rest but once a year for that one.

Doug: I'm just guessing that the bigger the tree, the more of that stuff you need to use, is that correct, or am I wrong there?

Lou: You're very correct. The application rate is based upon the size of the tree. In addition to those products that we use to fight the borer, we highly recommend improving the health of the tree as well. If you go to a doctor and say, "Hey, doc. I've got this or that. I feel these ailments." They say, "Well, here's your medicine." Your doctor is also going to take your blood pressure, ask you what your diet is, what's your sleep habits, because a healthy body fights off infections a lot better than non-healthy bodies.

Does that mean that a healthy ash will fight off the borer? No, not necessarily, but it'll be in a much better state to absorb those products and work with them and bounce back from the infection. In addition to the products that are fighting the borer, we do recommend feeding your trees as well. That's something that Davey does by deep root fertilization where we're shooting a product called Arbor Green PRO, which is a trademarked fertilizer that we've developed that mimics the forest floor of the United States as far as the nutrient makeup. It's the best thing you can give a tree to feed it. It's our peas and carrots. That's what we suggest as well.

Doug: Is there anything else? Would watering make a difference too? I know we'll treat it with the chemical for the pest, we'll fertilize, does watering come into this too?

Lou: Absolutely, yes. Again, water is how trees get their nutrients. There's a slurry underground of water, nitrogen, phosphorus, and potassium that the tree uptakes. You can put as much fertilizer into the ground as you want, if there's no water to mix with that to absorb into the tree, it's not getting into the tree. The trees need the water, much like you and I do. Yes, absolutely.

Doug: With the emerald ash borer, because it is a new pest, it'll come through an area, basically like you said, almost all the ash trees are gone. When it sprouts up from the bottom and we get another ash, does it get to a certain size and then the borer comes back and takes it, or do we know what's going to happen?

Lou: So far we have not had a successful reforestation of the ashes, no. I talked to Dan Herms, who's with the Davey Institute last week about it and he was one of the first ones to really do a lot of heavy research on the borer. He refers to as the orphaned cohort is the re-sprouting of the ashes in the forest of Southern Michigan and Northern Ohio especially, because the borer came into Detroit. I didn't mention that earlier. That's where it spread from. That's the epicenter.

When the ash tree starts to die from the borer, it almost knows. They react to it by sending out a tremendous amount of seedlings because they're genetic beings and their goal is to continue their DNA sequence. To do that, they have to put off seeds, especially when they know they're failing. We see in areas that are hit by the borer, we see a tremendous amount of new growth with the ash species volunteers popping up.

Unfortunately, we're not seeing success of those after a certain size. [unintelligible 00:12:03] 4 or 6 inches in diameter. I can't remember, 4 or 6 inches where they start to get hit again. The idea initially was, as the borer moves on from the areas, the food sources have been used up, it'll disappear but that doesn't appear to be the case right now.

Doug: Well, that's depressing, Lou.

Lou: Yes, it is, but there's always going to be a few that pop through. Like I said before, this is a cycle. This has happened with the chestnut blight, it's happened with the Dutch elm disease. Those weren't quite as devastating as the ash borer. Some good news for you, Doug, is that we are hybridizing. We being the industry, are hybridizing some of the American ashes with Asian ash species.

The emerald ash borer is indigenous to Asia and the ashes over there have learned to live with it and so with the hybrids that we're coming up with, one of the interesting cultivars is called northern treasure. That one is a mix of Manchurian and black ash and that is showing a pretty good resistance to the borer. It's a very pretty tree itself. It won't be the exact same but we can replicate it.

Doug: That is great news. Usually when we see these pests come and they don't have a predator, eventually mother nature helps us out. Is there any hope for that or do we know yet?

Lou: Yes, there is. That's a great question. There are some native wasp species that are starting to attack the borers and I believe we are releasing, us being the USDA, I think is releasing some predatory wasps and these are the wasps that sting us. These aren't the paper wasp or the ones that sting in the summer. These are wasps that will lay their eggs inside of the larvae and it'll kill them that way. We're seeing that. There was an interesting approach, I think it was the Penn State University, printed 3D female emerald ash borers and electrified them so when the males came in to mate with this fake female, it'll electrify them, which is an interesting way to approach it, but it wouldn't be produced at a mass level.

Doug: I love that idea though.

[laughter]

Lou: Yes, for the wasps. Back to your question, is it devastating? It's devastating to the ash species. In the forestry world, the opportunity that it has given us is to rethink how we approach urban forestry and plantings. It's devastating that we are going to lose so many ash trees, especially in the forested areas but so many cities were overplanted with ash trees as street trees and park trees. That's the real damage that we see usually on an everyday basis because we live in urban and suburban areas is trees along the streets dying.

What this has reminded us is to plant not monocultures, but polycultures, so different species of trees so that our cities can withstand species failure if that occurs, and they don't become just big buffets for a pest.

Doug: Well, let's move on from the dreaded emerald ash borer to another one that has started where I'm at in Pennsylvania called the spotted lanternfly. Have you guys seen that yet?

Lou: Yes. Actually, I saw my first spotted lanternfly in person about three months ago on a spray rig that came from a different territory. It was dead. It was a cadaver. It first came to Maryland in 2019 was a positive hit. The spotted lanternfly [unintelligible 00:16:36] Asian species. It's native to China, India, Vietnam, and Southern Asia, I suppose. It was first discovered in the United States in 2014 in Berks County outside of Philadelphia there and spread from there to Delaware, New York.

It hit Virginia in 2018, was the first positive ID and now West Virginia and Maryland as well.

Yes, it's around here. We're expecting it to be a problem in our area. Again, I cover Central Maryland in between Baltimore and DC. We're going to start seeing it this year. It's going to become a problem next year most likely.

Doug: What does it do? What is it attacking?

Lou: That's a great question. It attacks all sorts of stuff. It goes after, I want to say 40 different species of tree. There's a couple of upsides. Its favorite snack is the Ailanthus altissima, which is the Tree of Heaven which is an invasive tree that is a bit of a problem in the United States, so the good news is it loves that. As far as how it affects us, is it's a very abundant species. Once it hits a tree and its population is out of control, it looks like the tree is almost alive. The bark of the tree is just moving around.

What it does is it pierces the bark of the tree. It feeds on the sugars and then excretes a honeydew which in turn, it's a sticky, clear substance that attracts airborne mold so everything underneath the tree just gets this sooty, gray, shocky color, so cars, patios, benches, and the rest. Not only does it hurt the trees, but it's also just gross, a way to put it. The way it travels around a lot is by its egg masses. It lays its eggs in the Fall and you get these gray masses. What's a good way to put it?

It just looks like a patch of mud on the side of a car. It doesn't have to lay its eggs on trees, it could be on a car or an RV, something that's parked all summer and then you drive it once a year especially, because it's sitting for a long time, so boats, trailers, RVs, those things or trucks if you park a rig. If a semi is parked up in a truck stop in Berks County for three days while they're waiting for an order, that's plenty of time for a female to lay its egg mass on the side, then it travels down on the road. That's how it's spreading like crazy.

Doug: I have heard fruit trees, grape growers, stuff like that, these are some of the people that are really worried about this?

Lou: Yes, absolutely because their income is based upon their plants. The spotted lanternfly loves vines. If you're growing grapes for a winery or for edible grapes, also hops, they love hops. If you're in the beer industry, if you're growing hops, that can be a big issue.

Doug: Please tell me they're not going to shut down the beer industry.

Lou: They're going to do their best to, but I think once it gets to that [unintelligible 00:20:34] really kick into high gear. You'll see our revenge take on a whole new level. Fruit and nut trees, peaches, apple, the rest, maples. When you talk about trees that we have in our landscape, things in your yard, maples are hit especially hard by them.

Doug: What can you guys do about spotted lanternfly? Do we have a treatment yet?

Lou: Yes, there's stuff that we could do about it to kill them off when they're on your property. One thing we're seeing a lot of is the banding. You saw this with the gypsy moth, where you put the sticky tape around your trees. That works because they hop and they crawl up and down the tree so it catches them. The downside of that though, is that it also catches a lot of other things too. Everything from beneficial insects to bats, birds, squirrels, and important things to the environment.

That's one way to do it, but you're really catching everything. You can treat the trees, actually a lot like the emerald ash borer with the imidacloprid, you could use that. You could directly spray them with products that will kill them off, just zap them on sight. Some organic treatments do have immediate effectiveness, but not really good residual. Insecticidal soaps or neem oil. That'll smother the population that's currently there, but the next day other stuff can show right back up. Your best bet is those annual systemic products that stay in the tree.

Doug: All right, let's continue the bad news. What else is on the horizon?

Lou: For our region, the next big thing that we see coming our way is going to be the Beech leaf disease. This is one coming out of Northeast Ohio, is where it was first ID'd. It's in Pennsylvania. I want to say it's in Southwest New York also. I'm not positive. We don't know exactly what it is. It is affecting the saplings of the American beech mainly. It takes about three to four years from identification to the death of the tree is what we're seeing. Again, this is so new that I wouldn't put a whole lot of stock into what I'm saying, not because I don't know, but because we just don't know yet.

We think that it is a nematode which is like a microscopic worm that is doing the damage that we haven't completely certified that or confirmed that. It's in Pennsylvania. They've ID'd it on Long Island, and they've identified it in Connecticut also. I was looking at my notes. That's the next big thing on the horizon. I don't know, Doug, where you're at, how big a species the beech is, but here in Maryland, they're a pretty important species. That'd be tough to lose that one. We don't have any treatments yet. Again, because we haven't confirmed what's causing it yet. There's definitely trials going on, I do know that, to figure it out.

Doug: How about some good news? Tell me a little bit about how it feels when you do go out when you're looking at some of these trees, and I guess, especially now emerald ash borer, since we know what it is, since we know it's been around for a little bit. When you see a tree and you can save it for the people, that's got to be a good thing.

Lou: Absolutely. It feels good to be able to identify, prescribe, and treat a tree and see it pull through. There are trees that I treated six years ago, seven years ago that are showing signs of success against the odds, which is great. I think of the future generations, my kids, someday my grandkids maybe, being able to see mature ash trees. Sure, there'll be fewer of them, but it's like when I see a mature American elm tree that's in good shape. It's beautiful and it's rare, it's gorgeous. That's a pretty special thing.

A lot of times, trees are very emotional subjects to folks, especially when they're on their property. They planted this ash tree when their first child was born, or when they bought the house. Now 30 years later, here it is. There's this pest, can you save it? Sure, we can do that. That feels wonderful. Being an arborist is really cool. It's helping folks to really care for their properties, helping forests. Everyone loves a tree, right? Having those answers when people need them, it's a good feeling.

Doug: Lou, I'm going to finish right there because I wanted to finish on a positive note. That is wonderful stuff. Thank you so much for your time. The information is going to be invaluable for anyone dealing with those three problems. Thanks again for your time. It was good stuff.

Lou: Doug, thank you so much. It was a real pleasure.

Doug: Tune in every Thursday to the Talking Trees podcast from the Davey Tree Expert Company. I'm your host, Doug Oster. Next week, it's all about the bane of my existence, herds of deer, and how to keep your trees, shrubs, and landscapes safe from these four-legged marauders. Remember, for the Talking Trees podcast, we always say, trees are the answer.

[00:26:42] [END OF AUDIO]