Davey's Diagnostic Laboratory - How it's Used & Common Diagnoses

Kodi Riedel, diagnostic laboratory supervisor at the Davey Institute, talks about her work in the lab, how a diagnosis happens and the common diagnoses she's seen in the lab.

In this episode we cover:  

• What is a diagnostic laboratory supervisor (00:39)
• New things seen in the lab (2:09)
• How Davey keeps up with tree trends (2:41)
• How arborists use the lab (3:40)
• The lab's busiest times (5:30)
• Abiotic issues (5:58)
• Kodi's Davey journey (9:27)
• What Davey's lab looks like (10:47)
• Diagnosing common conditions (13:14)
• The most common diagnoses (14:26)
• Handling fatal diagnosis (16:29)
• The best part of Kodi's job (17:40)

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

To learn more about the diagnosis lab, visit our Diagnostic Laboratory webpage here.

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

Connect with Doug Oster at www.dougoster.com. 

Have topics you'd like us to cover on the podcast? Email us at podcasts@davey.com. We want to hear from you!    

Transcript

Doug Oster: Welcome to the Davey Tree Expert Company's podcast, Talking Trees. I'm your host, Doug Oster. Each week, our expert arborists share advice on seasonal tree care, how to make your trees thrive, arborists' favorite trees, and much, much more. Tune in every Thursday to learn more, because here at the Talking Trees podcast, we know trees are the answer. I'm joined this week by Kodi Riedel. She is Diagnostic Laboratory Supervisor for the Davey Tree Expert Company in Kent, Ohio. Kodi, how are you?

Kodi Riedel: I'm doing great, Doug. How are you?

Doug: I'm doing great. Tell me about a Diagnostic Laboratory Supervisor. What is that job, and what does that laboratory do?

Kodi: Yes. The Davey Institute has a diagnostic lab. This lab is open for all of the Davey Tree service lines and their clients to use. We are a private lab, so Davey clients have to go through the Davey arborist to utilize our services. Like you go to the doctor to figure out what's wrong with you, we are a diagnostic lab, so we get plant samples from all over the United States and we tell people what's wrong with those. A lot of the times it can be insects, it can be mites, it can be fungal issues, bacterial issues. We can diagnose and tell people what's going on in their landscape and how to fix their problems.

Doug: Then I'm sure as things come into the country, we see new things all the time, and I'm sure that's-- An arborist can look at a hemlock tree and say, "Oh my gosh, it's filled with hemlock woolly adelgid." If it's something new and they're looking at it, they're sending it to you, right?

Kodi: Right. If it's something new to the United States or something they've never seen before, maybe it's a newer arborist who just wants to get familiar with the landscape. A lot of times it's just people wanting to confirm what they have, whether it's an insect or a scale, before they do treatments, to make sure that they're doing the right treatments.

Doug: What kind of stuff have you seen in the last maybe couple of years that have been new?

Kodi: New stuff? We have a lot of new stuff here in Northeast Ohio. We're close to all the ports, so we have the spotted lanternfly, the box tree moth. A lot of that stuff's at limited locations right now, and they're trying to quarantine different things to keep them from spreading to different areas. We don't see a whole lot of new things. Most of what we see is a lot of repeats and things that are already in the US.

Doug: Tell me a little bit about how you keep up with what's going on, where it might be diseases or pests. How does that evolve for you?

Kodi: There's a lot of different networks that we're a part of, like the American Pathological Society for Plants. Just staying up with-- the Ohio State has a great extension and programs that they keep education. The most challenging part is keeping up with nationwide items. Luckily, Davey is a nationwide US and Canada company, so we communicate with a lot of different departments in Davey to be on the same page, see what's going on throughout the country, what's going on in California, "Oh, a storm hit Texas. They're going to have some frost injury," this or that. We try to keep a communication line going on to keep us aware of what's going on in other places.

Doug: If an arborist suspects, let's just say something like oak wilt, what would they send you? What would you need from them to be able to determine if this is or is not oak wilt?

Kodi: There are a lot of specific diseases that we need really specific samples for. Oak wilt is one of those. Oak wilt, we would need fairly large branches. We say about a foot long by the diameter of no smaller than your thumb. We need those live branches. If they're completely dead, it's less likely to get the pathogen from the branch. If they're alive, we want something that's actively wilting. We call this the transition zone. Between that live and dead tissue is key, because that is where that pathogen is actively spreading. That's most likely where we're going to detect it.

Doug: In that case specifically, how does the arborist know what to take? Do they contact you specifically for that thing or do they have a sheet that says, "Okay, for sending a sample of oak wilt, they need this, this, and this"?

Kodi: It's a combination. If it's an experienced arborist who's used this diagnostic lab before or another diagnostic lab, not necessarily Davey's, they might know what to take. For new arborists, even if they are experienced, I encourage them to contact us and we can help direct them on what kind of samples to take. We have an internal field guide for them to take into the field that has one sheet information, documents with pictures of like, "Hey, if you're suspecting a root rot, this is what you send. If you suspect oak wilt, this is what you send. Canker diseases, leaf spots." We have all of that simplified into one document for arborists within Davey to use.

Doug: When is your busiest time?

Kodi: Anywhere from May, June to September sometimes. The heat of the summer somethings slow down. Spring is mostly when a lot of the new diseases and insects are coming out and emerging. People are out in the landscape, they see these issues, they call their arborist, the arborist then collects samples and then sends them to us.

Doug: You sent me some ideas on what to talk about. How do you pronounce this? Abiotic issues? Is that right?

Kodi: Yes. Abiotic. Yes.

Doug: What does that mean?

Kodi: There's two very broad categories that we group disorders into. Abiotic disorders is one of those. Abiotic means non-living agents. These are issues in the landscape that are caused by non-living organisms or non-living-- They're not organisms. They're just non-living agents. This can be anything that can be compacted soil, drainage issues, irrigation issues, lawn mower damage, weed whacker damage, restricted root space. You talk so much on this podcast about planting the right tree in the right place, all of those factors play into the health of that tree.

Doug: In the case of those issues, I'm sure it's probably dependent on which issue they suspect, in that case, what are they sending you?

Kodi: A lot of times we can't always detect or confirm abiotic issues. There's a challenge there. They try to get them to collect as much site history as they can from that client. Was this site recently-- Did they have construction? Is this sidewalk new? Did you maybe damage these roots when you were installing this sidewalk? Site history is so important. We have a submittal form that the arborist fills out with some of this information that they can supply to us.

That can help us, number one. Number two, obviously the information that that arborist supplies on that form is key. Number two is pictures. If that arborist can submit pictures of the site, maybe we can pick something up that they might be missing. I like to think of diagnostics as like a puzzle. We're just putting all those pieces together to hopefully find out what's going on with that plant.

Unfortunately, a lot of times, we're ruling things out in the diagnostic lab. We are limited on what the arborist sends us. Most of the time they send us a gallon bag, Ziploc bag of branches, leaves, and different pieces of that plant. We are limited to only telling them what we find on that sample. That's why it's so important for that arborist to collect a good quality sample that will help us diagnose what's actually going on. That's why we have that manual that says, how to collect samples. That is the key.

Like we mentioned, a lot of times it's ruling things out. We look for the insects. We look for the diseases. We look for spider mites. If we can't find anything and the symptoms that that plant is expressing that we see are consistent with abiotic issues and we don't find anything else, we can come up with the arborist and work together and say, "Hey, maybe you should do some site investigation, look into maybe sending some roots, maybe look into getting the soil tested." We try to work with the arborist to figure out what's going on.

Doug: That was my next question, was that, as this process is going on, obviously then you guys are communicating back and forth like, "I didn't find scale. I didn't find spider mites. Let's look deeper and see what's going on." Tell me how you got into this. What is your background for this job?

Kodi: I got into this-- I started as an intern working at the Davey Institute. I just stuck around. I went through my college in Kent State, biology, and I went for my master's in plant health management. That master's program was a great program for people working in the industry already, so I didn't have to stop my career to continue my school. That's how I got-- I was just a trained diagnostician as I worked with Davey. I worked my way up into the company and now I'm lab supervisor.

Doug: Tell me a little bit about what you get out of a job like this, like you said, solving the puzzle.

Kodi: Yes. It's always learning. We're always learning in the lab. A lot of the things we see are repeat issues, rhizosphaera needle cast, anthracnose, the scale, the spider mite. It's fun to find something that you've never seen before. It's fun. It's also challenging. It's fun to come to those conclusions. From my take, we're helping our industry by supplying them with answers and supplying them with correct management techniques.

Doug: Paint me a picture of this lab. How big is it? Are there microscopes everywhere? What would I see if I walked through the door of your lab?

Kodi: We've got some nice windows in the lab, which is nice for natural lighting. You walk into the lab, you'll see a bunch of-- The microscopes are key. That's how we diagnose most of our issues is by microscopes. We have compound microscopes. We have dissecting microscopes. By using those two together, we can figure out, majority of the time, what's going on in those plants.

We have also a culture wall, which in the summer is flooding full. A lot of the problems in the landscape are fungal issues. We sometimes have to culture them. That means try to give the fungus the environment to sporulate and reproduce. That's how we can identify them. This culture wall in the spring is just full of stuff, looking for cankers or fungal leaf spots or anthracnose. We're waiting for that fungus to sporulate, or we're just checking to make sure is it fungus or ruling fungus out.

We also have a small corner in the lab for some of our molecular work. We've been doing it for the past few years, is ELISA testing. This test detects certain proteins of a pathogen. Some of the harder things to culture or some-- Bacterial leaf scorch is a good one for that. We have a test for that. Verticillium wilt, it's a vascular wilt disease. We have an ELISA molecular test for that. We're working on expanding a lot of our molecular tests as well. Most of the work is done by microscopes and the molecular testing.

We have a lot of equipment in the lab too. We have a biosafety cabinet. We are a USDA permitted facility. We have to have certain equipment to contain any issues, diseases, or insects that come into our lab. We have a lot of larger equipment, an autoclave, a biosafety cabinet, that take up a lot of space, but they're necessary to contain everything that comes into the lab. We don't want anything spreading out and infecting Ohio. If it's from Texas and it's never been to Ohio before, we don't want to cause any issues.

Doug: As someone who's based in science, when you do get a sample in, do you sometimes look at it and just say, "Oh, I bet you that's this, this, or this," but then you've got to go through the test?

Kodi: Absolutely. Yes. We get a lot of boxwoods in. "Oh, it's leaf miner." "It's boxwood mite." "It's volutella blight." We can name the common ones. A lot of the symptoms do match up with the diseases or insects.

Doug: Let's say something like that, a boxwood with leaf miner. When you just look at the leaf, I'm assuming you're just going to know that it's leaf miners. Do you have to, though, take it another step? Do you have to cut it open, look at it, and confirm it?

Kodi: I'd like to, yes. We are a diagnostic lab, so on my perspective, we should go that extra mile. You can do that in the field, and that's great for arborists. Even arborists can open up that leaf and look for the larva inside. Sometimes that larva is not present. It's still good to open up that leaf to make sure it's not a fungal leaf spot. Symptoms can be tricky sometimes. We always try to confirm and find that test or look at those scores before we make a conclusion.

Doug: What are the number one things that you see that are repeats?

Kodi: The three most common ones we get, besides the abiotic issues, are spider mites, which are tiny little mites that crawl all over the foliage. They have piercing and sucking mouth parts. They'll pierce leaf tissue, suck out some of the nutrients, and then this can cause a silvery, stippling, speckling appearance on the foliage. They can be a serious issue. Most of the time, natural predators and natural processes will sustain those populations.

Another common issue is anthracnose. This is a fungal disease. This is a very broad category. It's not one pathogen that causes it. There's many species that cause anthracnose. Deciduous trees are a very common host of this disease. Your maples, your oaks, your elms, your dogwood, your sycamore, your birch. This disease infects when the leaves are very, very small and just emerging. As the leaves emerge, you'll start to see the symptoms. Typically, you'll see some irregular necrosis or browning on the leaf tissue. Sometimes the leaves will be distorted or curled. We see a lot of that. There's more than just those hosts that I listed. We find it on a lot of things. Very common fungal disease.

Then the other third one would be little insects called scales. These are also very hard to see. Similar to the spider mites, they have a piercing, sucking mouth part. They'll pierce the tissue, suck out nutrients. That's how they damage the plant. These ones are very hard to see. Sometimes they're very camouflaged into the bark or the leaves. Those are the three most common.

Doug: Since you have a distance between the arborist as the middleman, when you do diagnose something that is fatal and you have to tell the arborist and now he's going to have to tell the customer, are you able to keep that distance and look at it from a science perspective?

Kodi: Yes. We just communicate between the arborist and the arborist then communicates to the client. We can obviously help that arborist if they have questions or help prepare them and prep them with material before they have to talk to their client so they know they can educate their client of what's going on. Maybe if they want to replant, what can they replant with? Here are some alternatives. That way, this problem won't happen again. Between different parts of the Davey Institute, our diagnostic lab, or some of their technical advisors, we are there to support them and provide them with some answers.

Doug: When my arborist came to me and told me I had oak wilt, it was heartbreaking. It is what it is. Nothing we can do about it. It's nature. We can treat it as we can treat it and we'll see what we can do. Before I let you go, tell me the best thing about your job, the most fun you have doing your job.

Kodi: Oh, the most fun is the plants. I've always been outdoorsy. I've always loved the outdoors. You think in a diagnostic lab, we don't get out for work very much, which is a good and bad thing for Ohio, right? The weather is not always something you want to be in all the time. When I'm not at work, I'm usually outside spending time with plants. Even at work, it's nice because it's, like I said, the challenge piece of it. Then putting those pieces together, figuring out, looking at the different signs and symptoms that's on that plant, making conclusions, helping people in my industry with Davey, those are my biggest takeaways that I have.

Doug: That was great, Kodi. I appreciate your time. Boy, that was really interesting. One of these days I'm going to come and see that lab. I've got to see it.

Kodi: Yes. You're welcome. Come anytime.

Doug: Thanks so much.

Kodi: Thank you.

Doug: I found that to be fascinating. I hope you enjoyed it as much as I did. Tune in every Thursday to the Talking Trees podcast from the Davey Tree Expert Company. I'm your host, Doug Oster. Do me a big favor, subscribe to the podcast so you'll never miss a show. If you've got an idea for an episode, maybe a comment, send us an email to podcasts@davey.com. That's P-O-D-C-A-S-T-S@D-A-V-E-Y.com. As always, we'd like to remind you on the Talking Trees podcast, trees are the answer.

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