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Smarty Plants
Smarty Plants is a podcast exploring invasive insects and noxious weeds that threaten Minnesota’s natural and agricultural resources. Experts from the MDA’s Plant Protection Division cover important topics engaging the public in efforts to protect our environment.
Smarty Plants
Plants Get Sick Too
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Just like people, plants can get sick. Fungi, bacteria, and other pathogens are common causes of plant diseases. Learning to identify when plants are sick and taking proper steps to contain these diseases is an important part of keeping your plants healthy. Michelle Grabowski, research scientist with the Minnesota Department of Agriculture, covers the basics of plant disease and how you can help ensure the health of your plants.
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.
Welcome to Smarty Plants, a Minnesota Department of Agriculture podcast with the goal of informing citizens about invasive species that affect our environment and agricultural resources. My name is Eidan Silver, and I will be your host. You are about to listen to the second part of a two part episode. So if you haven't caught our first episode on noxious weeds in the fall, make sure to check that out, but that is not what we're here to talk about today. Today, we're talking about emerging and invasive plant diseases you might encounter when cleaning up your yard in the fall. With Michelle Grabowski, a research scientist at the Minnesota Department of Agriculture. Michelle is a plant pathologist with the MDA's Plant Protection Division. Her work focuses on prevention and early detection of invasive plant pathogens that threaten crops and native plant communities in Minnesota. Thank you for joining us, Michelle. How are you doing?
Michelle Grabowski:I'm great. Thanks for having me today.
Eidan Silver:So let's, let's start with just defining plant pathologies. pathogens. What exactly are plant pathogens? Why should people care about them?
Michelle Grabowski:Well, a lot of people don't realize that just like people get sick, plants get sick too. So a person could get a cold or the flu and that's pretty normal for us. When we're talking about plants, we see things like leaf spots, branch cankers. Root rots. And all of those happen really commonly, whether we're talking about house plants, plants in a forest, or plants in our garden. Um, the pathogens that cause disease in plants are a little bit different. A lot of the pathogens that cause disease in plants are actually fungi. Um, but there are a few fungi, uh, I'm sorry, there are a few viruses, bacteria, and these tiny little round words called nematodes. Um, so all of those are organisms that are in our environment and, uh, when they come encounter a plant that's susceptible and the right environmental conditions, uh, the plant can become sick, basically. So,
Eidan Silver:and, and I'm already confused, and I'm sure you get this a lot, but plant pathogen versus plant disease versus fungi versus nematodes, there's a lot of different terms that That maybe could get confusing. So what is the difference between a plant pathogen and, say, a plant disease or plant virus?
Michelle Grabowski:Right. Uh, so the pathogen is the organism that, uh, initiates a disease and it causes a plant to be sick. The disease is usually, when we talk about plant diseases, we think about three different factors. So in order for that disease to happen, for that plant to get sick, you have to have a susceptible host plant. That means the, the plant has to be, uh, not immune or resistant to the disease. So it's susceptible, you have to have the pathogen, and then you have to have the right environmental conditions. Yeah, so right now, as a lot of gardeners are in their yards, um, one of the common diseases that you might see, um, would be spots on the leaves of your rose plant. If you happen to be a gardener who likes to grow roses, you'll notice sort of black, feathery looking spots on the leaves. Those leaves might, uh, start to turn yellow and drop off because of these leaf spots, and that's a disease. Called black spot of rose, and it's caused by a pathogen that is a fungus, and so the the fungal pathogen infects the leaves, causes these leaf spots, which is part of the disease, um, and can cause those leaves to drop. So that's how the plant gets sick, and losing all these leaves, of course, then makes it harder for the plant to store energy. You can see that plant is, uh, has reduced growth and may not bloom as nicely the next year if you have a really bad year of black spot, uh, during one year.
Eidan Silver:So, and you mentioned that there's kind of a comparison between plant diseases and human diseases and human disease can be very anxiety inducing. I know that, like, when members of my family are sick, whether it's a fever or something worse, I can be kind of scared for them. Um, so how worried should Minnesotans actually be when it comes to plant diseases in their garden? Um, for example, black spots on their roses. Do they need to be sounding the alarm and calling the MDA immediately? Or. Uh, is it maybe not that bad?
Michelle Grabowski:Um, no. So it's, it's really important to, um, not panic. Um, diseases are part of the natural environment. These plant pathogens, the fungi, the bacteria, they're out there. And many of them occur every year. Um, for example, if you look at, uh, lilac bushes, most people will notice that sort of white, fluffy, powdery growth on the leaves in the summertime. That's powdery mildew. That's a fungal pathogen causing a disease on those plants. And it doesn't seem to bother the lilacs very much at all. They did. There's really no health effect to it. So we have a lot of pathogens that our plants have grown up over the years. Um, and they have some defenses to it and are able to tolerate them. When we get more concerned about a plant's overall health is if we see major leaf loss. So if you've got a nice rose plant and it's got a few leaf spots, that's very little cause for concern. However, if you have a rose spot and there's a rose plant and there's so many leaf spots, that all of the leaves start falling out and you're losing, you know, 30 to 50 percent of the leaves. Now we start to get a little more worried that that plant, that it needs the leaves, right? It needs the leaves to do photosynthesis, to get energy. And so that's where we might want to come in and try to help that plant out a little bit more. Um, the same thing would be true if we saw a branch die, if we had an infection on a branch, um, something more significant. Um, but a lot of gardeners don't realize there's a lot we can do to, uh, help our plants maintain their health. So, for example, a lot of fungi for these leaf spot diseases, they like really moist, humid conditions. And so we've got lawn sprinklers out there, or sprinklers in our garden, and if that water is hitting those leaves and keeping those leaves wet all the time, that's creating the problem. perfect condition for those fungal plant pathogens, whereas if we can redirect those sprinklers so that the water goes to the root system and it keeps the leaves dry, then that plant has a much better chance of defending itself because those leaves are dry. It's not a great environment for that fungal pathogen.
Eidan Silver:Would you say that prevention then plays a huge role in preventing plant pathogens, or is it more about treating a plant pathogen once the plant's already infected?
Michelle Grabowski:Prevention is definitely the way to go. We want to set up environmental conditions for our plants where they're going to thrive, and part of that is choosing the right plant for the right time. place. So choosing plants that are going to thrive in your environment, not pushing it with an exotic plant that maybe perhaps this isn't the right growing zone for them. They're going to be a little bit stressed in that situation, and they'll be more likely to be susceptible to a disease. So choosing plants that are going to thrive in the environmental conditions that we have. Making sure we're using good cultural practices, so we're planting at the proper depth, we're not giving too much fertilizer or too little fertilizer, we're making sure we're giving, uh, the right amount of water because if we see, you know, drought stress, Roots can allow plants to become, you know, more susceptible, they're stressed, they can become diseased. But at the same time, if we're flooding our plants, that's when we start to see a lot of root rots. So a lot of it focuses on keeping that plant healthy and just providing it the right things that it needs at the right time.
Eidan Silver:Yeah, and I think that's a good point too, cause, cause I have plants, and I water them, and I pot them, and I do some things poorly, probably, and some things better, and I, I guess I, when they're not doing well, I don't chalk that up to plant pathology, I just think, well, I didn't water my plant enough, so it's interesting to think of it in this new lens of, well, actually, there's a disease there, and you can treat it like a disease, and watering it more on schedule, or watering it more or less, or, or, Ways that you could fix that disease instead of just saying, well, my my plant slightly worse off than it was yesterday. Um, Is there, is there a way? Or are there resources that gardeners or homeowners or farmers can go to to make sure that they are um, choosing plants that are correct for their environment and treating them in a way that with the optimal growing setting.
Michelle Grabowski:Sure. Um, I would definitely recommend that growers go to the University of Minnesota Extension website. There's a wealth of information there that they can, you can find about, uh, what plants and varieties thrive in your environment. Um, you know, what are the proper steps to take in taking care of that plant? Extension offers classes and field days. So a ton of great information there. Um, the other piece is also talking to your plant supplier. So if you are going to a nursery, those little tags that are hanging on the plants always list information, um, that talks about what horticulture zone it's going to grow well in. Whether it wants full sun, partial shade, um, you know, how much moisture it can tolerate. So there's a lot of information, um, on a plant tag, on a seed packet. And then part of it also is getting to know your own yard. So have you paid attention to how many hours of sun your front yard gets? Um, a lot of us don't necessarily pay attention to that. And so, taking a little bit of time to think about that. The to look at that space you want to plant in and checking in at a couple times of the day to see just how long it is staying sunny or maybe digging a little bit and, you know, watching it after a rain. Did it drain? Well, or is it really heavy and wet for, you know, days after? So you can get a lot of information just by observing your own environment.
Eidan Silver:That's awesome. So, uh, check with you and extension resources. There's plenty online and in person. Mm hmm. Check with your plant supplier for information about hardiness zones and other appropriate plantings for your area. And then maybe be a little bit more mindful about the environment that you're actually planting your plants in, right?
Michelle Grabowski:Perfect.
Eidan Silver:It's not as hard as it seems at first, but it can be intimidating, for me at least, when I think about, like, my personal garden. Because I don't sit out there and count plants. How many hours of sunlight my garden's getting, but it probably wouldn't be that hard to just write down, you know, when the sun is rising there and when it's setting, so it's, it's helpful advice for sure. Um, and I, I know that we're kind of broaching on your work with the MDA, but I want to take a step back and talk about, um, your experience with plant pathology in general, because it's a very interesting field and sounds like a very broad field. So how did you get into it? How did it get you to where you are today, where you're able to give us the wonderful advice that you're giving us now?
Michelle Grabowski:Um, well, I always enjoyed being outdoors, and I knew that I wanted to go into the life sciences, uh, because I just found it fascinating the way different people, Plants and animals and microorganisms interacted together, um, and plant pathology seemed to have a lot of those different factors. It has the effect of the environment, the, the plant, um, the, the organisms and how they move and interact with one another. Um, so I actually had gone to school, um, to study botany and was really interested in plants. And my very last year of my undergrad degree, I went to, to Nepal for an overseas study, and we were learning a lot about the agriculture in Nepal, and I remember being on a hike and seeing this very small farm, um, and the people were growing food that they were going to directly feed to their family. And it was a wheat crop, and there was a number of the heads within the crop that were covered with a fungus, a smut fungus.
Eidan Silver:Interesting.
Michelle Grabowski:And it was the first time that it really hit me how important it was. That this was this family's food for the upcoming year, and that by losing those seed heads that it was significantly going to impact what they had to eat that year. And so I really became interested in learning more about, you know, this interaction and wondering, you know, what could people do to maximize the food that they get and make sure that they have healthy food to give to their families, um, and fit into this, um, Ecosystem idea, too, of looking at the environment and the different organisms and their interactions, and yet it was a very, um, applied way to use that science, um, to actually help people and help, hopefully, the world in a better way. So, um, it's one of the things that I really love about my job is I can take science and I can take some of these studies, um, that seem very academic, but you can take them and apply them to real things that are happening right here in Minnesota, um, and use them to help people. people, whether it's talking about helping our natural forests, helping people in their landscapes or helping our farmers.
Eidan Silver:Yeah. And when I think about plant pathology and maybe the root rot on my knee on Pothos, I don't necessarily make that connection, but it is a helpful reminder that plant pathology can be a really important part of the general health of communities, even that's something that we hear a lot. Uh, When it comes to agriculture, it has a surprising connection to quality of life for people, even when you might think that you're removed from the lives of plants. So, that's awesome to hear and you're definitely making me consider a career change. Um, So, but that is also a good segue into talking about your work with the MDA. You mentioned, um, being able to take some studies and, Consider the practical applications of them to help people out in the world. So what are some ways that your role, uh, and, and your, your job at the MDA contributes to invasive plant pathogen management?
Michelle Grabowski:So one of the things that we do every year, um, that is really important is we do early detection surveys. Um, where our team goes out and we actively look for plant pathogens as well as insect pests that could potentially move into Minnesota and be a threat to either agriculture or our natural ecosystems.
Eidan Silver:Prevention, prevention, prevention.
Michelle Grabowski:That's right. And we want to find, uh, Um, a disease problem before it becomes widespread and well established. Because if we can find it when it's a very small area, we're much more likely to be able to maintain it and control it. And if we can't completely eliminate it, at the very least, we could slow the spread. We could learn more about it, um, and we can monitor how it's moving and, um, get, provide some information to growers and how to help their plants if this new issue is emerging.
Eidan Silver:That gets back to an important part of working for the Department of Agriculture, I think, which is that reporting finds of plant pathogens or things that don't look normal maybe in your Environment can be really important because there are experts like you who can come out and help with invasive plant pathogens or invasive species in general But if you don't report them, then you don't know to come out and take a look and to contain those things so Is there a way, uh, that people can report what they think are invasive plant pathogens in their yard or crop or garden?
Michelle Grabowski:Right. Yes, um, definitely. So, um, I would actually take a step back and say, let's say you found something in your yard or in your landscape or maybe you've been hiking in your local woods and you see something of concern. Um, there's a couple different things that you can do. Um, you can go ahead and look online. The extension website does have a link. We do have a lot of information about what are diseases and insects that are common, and we do have some common diseases and insects that can be a little startling when you first see them, but there's a lot of information about them online. Um, you can also go to the University of Minnesota Plant Disease Clinic. Um, they will accept plant samples where you would actually bring in, um, Um, part of the diseased plant, whether it is a branch that seems to have an infection on it, some leaves with leaf spot, or even the whole plant itself, um, and they will actually, uh, do laboratory analysis to determine if there is a pathogen in that plant material that you brought in, and then help you find some resources to deal with that. When you want to reach out to the MDA is when you've seen So if you've started to look at some of these common issues and what you're seeing looks very different, or perhaps as you're looking for common things, something comes up that has a warning flag on it and says this is invasive, this is unusual, please report. Um, and in that case, the Minnesota Department of Agriculture does have a website called Report a Pest. Um, and it has a place where you can take photos, you can enter your photos. You can add a description about what you're seeing, where you've seen it, um, and that will come to my team, um, as email. And we will look at all the information that you've provided, um, maybe reach out back to you to ask for more information. In some cases, if we suspect it isn't invasive, we might come out and take a sample so that we can verify if it is that pathogen of concern or not. Um, and at the very least, we can provide you more information about what it is that you might be looking at.
Eidan Silver:That's really interesting, and it's interesting to me because I think of Google as this all powerful tool, and if you think something looks amiss, maybe don't go to the UMN or don't go to the MBA, MDA, just look it up on Google and find a picture of what you think it is. But it's important to remember that Google doesn't have all the answers. It certainly doesn't have answers tailored to your situation, and it definitely doesn't have the resources that we do. I'm curious when you talk about maybe going out to a site, uh, that you think has an invasive species and you're taking a sample, what actually happens on the back end of that? Do you take that back to some lab and look at it under a microscope or how does that process work to actually get from, you know, This might be an invasive species too. Oh, maybe we have a problem here that we need to solve.
Michelle Grabowski:Right. So that's a good question. Um, when we're talking about plant diseases, the, the pathogens that cause plant disease are microorganisms. They're too small to see with the naked eye. So we may be able to see some fungal structures on a leaf. We may be able to see a little bit of bacterial ooze, but often that's not enough. for us to 100 percent say, Yes, I feel confident this is this organism. And so we do have a lab here at the Minnesota Department of Agriculture, and they run a variety of different tests. There's tests that you would run for viruses and bacteria, and you might use microscopy to look for fungal structures. So there's a whole wide range of tests that can be run in our lab.
Eidan Silver:And microscopy is Like fungal microscoping, is that the general
Michelle Grabowski:microscopy is just using a microscope to get a closer look at what's going on on the plant. So sometimes if you saw like a leaf spot on a leaf, you could cut up that leaf and put it on a slide and put it under a microscope and you could actually see. Bacterial ooze coming out of that leaf, um, and that won't tell me which bacteria it is, but it does tell me that there's bacteria there. And so that's a good start, and then I can go to the next test. However, I might look at that and see some fungal spore producing structures and some really cool looking, uh, fungal spores. And sometimes based on just the, the size and the shape of those spores, I can identify which organism it is.
Eidan Silver:So you made some really good points about the importance of staying vigilant and looking for these plant pathogens. Are there any specific invasive plant pathogens that Minnesotans should look out for in their fall landscapes?
Michelle Grabowski:Sure, um, there's actually two plant diseases that we would really appreciate help from, uh, Minnesotans. As far as looking for them as they're cleaning up their yards and gardens this year, um, one of them is a disease called red star rust, and it's an invasive fungal pathogen. The scientific name of the fungi is Gymnosporangium yamadae, um, it's a mouthful it is, and that's why we usually go with red star rust. It's a lot easier to remember, um, That is a disease of, uh, crab apples and apples. And then, uh, part of its life cycle, it actually takes a jump and moves over to junipers. So, we have multiple plants in our landscape, um, that could become, uh, infected with this particular fungal pathogen. And where you'd be looking for it in the fall It would be on the apples and the crab apples. And it's a pretty easy disease to spot because it causes a leaf spot and the leaf spots are often bright, bright red, or they're yellow and orange with a bright red border. So they really pop out in the landscape, whether you're looking at the canopy or you're looking at leaves that are on the ground. And if you saw something like that, we would want you to take a little bit of a closer look at it. And flip that leaf upside down, and on the bottom of the leaf, you will see, um, if it is the red star rust, little, it looks like, almost like little bristle brushes. They're little beige structures coming out, and that is actually structures created by the fungus itself to release spores. Wow. And if you rub your thumb on it, you might be able to see some powdery, reddish brown spores. And that's how the fungus releases spores at the end of the season. everyone. to go travel to the juniper bushes, um, where it'll start the infection. It'll actually spend the winter time on the juniper and then move back over to the apples and the crab apples next spring.
Eidan Silver:That's interesting. And is this another one where, say, you find the red spot and you think you found the bristle brushes and the spores. Is that something that you could also use report a pest to report if you're not sure?
Michelle Grabowski:Yes, that would be, uh, a perfect opportunity to, uh, share this information with the Minnesota Department of Ag. You would want, we would be asking for, uh, Minnesotans to take a picture of what they're seeing. Um, ideally a picture of the, the top of the leaf to show the leaf spot and maybe the bottom of the leaf to show that sort of bristle brush fungal structures and go look for report a pest on the Minnesota Department of Ag website and you could load those pictures, give a description of where, um, the, the disease has been seen and what you're observing on your plant and send that in to the Department of Ag.
Eidan Silver:Okay. Well, that doesn't sound so hard when you put it like that. Um, I gotta be honest though, I think my reaction initially if I did not know about Red Star Rust would be like, Oh, these are some pretty colors on my, on my trees. So, um, is it, is the tree actually in pretty dire straits if I'm seeing those red spots? Or do I need to, or do I not need to be worried about the, uh, longevity of that tree?
Michelle Grabowski:So at this point, we're still learning about red star rust and its impact on crabapple and apple trees here in Minnesota. Um, this is a, a fungus that was originally described in Japan, Korea, and China. And it was first found in Minnesota in 2022. And we know that where it occurs, um, in its native range, There are some apple trees that when they become infected, they will actually drop their leaves. And so that is a more significant impact on the health of the tree, because it needs those leaves, um, in order to do photosynthesis and produce a good crop. But because the fungus is new to Minnesota, What we don't know is we don't know how Minnesota varieties like Honeycrisp and Sweet Tango and all of our favorite apples, as well as all of our favorite crab apples in the tree, we don't know how they're going to respond to this new fungus. So at this time, we're still doing some observation and some research work with the University of Minnesota. To learn more about how the varieties here in Minnesota are going to respond to this new fungus and whether it's going to be a pretty leaf spot that, uh, is just kind of a minor irritation to the tree or if it is something that in certain varieties causes those trees to drop their leaves in which case we would want to take, uh, more steps in order to try and manage that and reduce it.
Eidan Silver:Well, we'll stay tuned for your updates on that. Maybe we'll have to have you back on the podcast to give us some concrete info about it. Okay. Um, and then you mentioned there was a second disease that also the M. D. A. could use help with looking out for in the fall.
Michelle Grabowski:Right. Um, so another disease we're looking for is called boxwood blight. Um, boxwoods are pretty common landscape shrubs. Um, they have, they're an evergreen shrub, so they keep their leaves year round. Um, but they don't have a needle. They have a small little round leaf. Um, they're pretty common in the landscape. And boxwood blight is a fungal disease that causes a leaf spot on the plant and it also causes those leaves to fall off. So if gardeners were out in their yard cleaning up for the season and noticed either bare branches on their boxwoods or a pile of leaves at the base of their boxwoods, that would be an indication that maybe there's a problem with that plant. Because we would expect that boxwood to hold on to its leaves all winter long. So if you're seeing those bare branches sticking out, you're seeing a bunch of leaves piling up at the base. Um, the best thing to do would be go check out that plant up close. Um, preferably grabbed some of those branches and open up that canopy and look inside again. It's caused by a fungus and they like that humid, shaded environment. So you're more likely to see some of those symptoms on the inside. inner part of that plant, and you'd want to take a look at the leaves and see are there any dark sort of purple y brown spots, um, and then look at the stems themselves, especially if you have stems where the leaves fell off. Are there black to purple y black sort of lines, like someone was drawing on your stems with a sharpie, um, that actually, um, often looks like someone's just kind of been adding some color. But it's not. It's actually an indication of where that infection is. And so again, this would be a great opportunity, um, if you could take some pictures, so take a picture of the whole plant to show, look, I've got some leaves falling off, I've got some empty branches, maybe take a close up if you're seeing those black lines on the stem, and another close up of some spots on the leaves, and send that in to report a pest with a little information about where you're located, um, Um, this is, uh, a disease that's causing a lot of problems, particularly out east, where they have, um, a lot of historic sites with really big, very old boxwoods that are, um, losing their foliage and really suffering from this disease. And we've seen it in several neighboring states, but it has never been reported yet in Minnesota. So it is one that we're on a lookout for, because we know that it is in the United States and it can get moved around. On plants that are being moved from place to place.
Eidan Silver:Okay. Well, I'll keep my eyes out for you And this might be kind of an ignorant question, but it sounds like a lot of the diseases you're describing are Signified by symptomatic spots on the leaves of the tree Is that one of the more common ways you can identify something wrong with trees or? What are the general symptoms you should look for outside of spots?
Michelle Grabowski:That's a tricky question because every disease has a little bit different symptoms. Um, these two happen to have a leaf spot phase to them. Um, that's simply how they, those particular pathogens work. Um, and fungi, we often see fungi. fungal leaf spot diseases, um, where spores can get moved around on the wind or splashed around on rain and irrigation and get moved into new leaf spots. Um, but there's actually a lot of different ways that pathogens can infect. So we do have some pathogens that live in the soil and will infect in the roots, um, and start rotting off all of those small little fibrous roots that the plant needs to pull up water. And so then we wouldn't see spots on the leaves, we would see leaves that are wilting, plants that are really struggling, and those can be really tricky 'cause it's easy to mistake that for drought stress, or maybe this plant needs fertilizer. Maybe the soil is wrong and you really have to dig up the plant and see that something's going on in the roots. Um. We have other, uh, pathogens that can get right into the vascular system of the plant. Um, so, uh, a famous case, actually a couple that are common in Minnesota, um, is Dutch elm disease. So, that's a, a fungus that gets in and it actually blocks the vascular tissue of the plant. So, the plant can't move water and nutrients up through its tissue and it causes it to wilt and die. Like,
Eidan Silver:the fungus grows in the tissue itself? Is that what's blocking the tissue?
Michelle Grabowski:Um, yes, in the case of Dutch elm disease, it's a combination of the fungus itself being right in the vascular tissue and then the tree making a failed attempt to block the fungus from moving up and down its vascular system. So it'll actually try to close off. The, um, the vascular tube where the pathogen exists, and because our, because that's an invasive and our Native American elms don't have good resistance, that resistance response is often too late. And so by the time it blocks it off, the pathogen has already moved, but now it's cut off this flow. Um. And so, as, as many people know, Dutch elm disease was devastating in the United States. Right. And it was an invasive that was brought in on, um, logs back in the 1930s that were intended for use in furniture making, um, and the pathogen was able to get out. And because our native elms here, uh, in the United States had never been exposed to this fungus, they had no defenses against it. And so, it's estimated there's over 77 million. Elm trees that have died because of that invasive fungal disease.
Eidan Silver:And it's a good example of you don't always need to be alarmed if you find a plant pathogen, but there can be high stakes associated with them under the right conditions.
Michelle Grabowski:That's right.
Eidan Silver:Um, well, let's, let's bring it back to, um, what everyday Minnesotans might encounter in gardening or their crops in the fall. Do you have any advice for best practices when it comes to cleaning up and disposing of plant material in the fall?
Michelle Grabowski:Sure. So, For the majority of diseases that occur in a lawn and in a landscape, they're native or they're established here, um, and they're not a concern. If you do suspect you have an invasive, before you clean that plant up, we would really want you to reach out on Report a Pest to the MDA because there may be special conditions. Uh, precautions that are needed in order to clean that infection up in a way that it doesn't spread. Um, but for your everyday plant diseases, the powdery mildews, the tomato leaf spot diseases, things like that, that happen every year in our yards and gardens. Um, a lot of those can go right into either your backyard compost or, um, municipal compost. Um, the heat that's generated in the compost will help to, uh, break down that plant material and it'll actually kill a number of those pathogens. Um, there are a few that are tough enough to kill. To make it through, but if that compost actually gets really hot, um, which a lot of municipal composts do, um, it's a sufficient enough to kill those pathogens. So the, the compost material comes out clean, uh, backyard compost often don't get that hot. So if you are concerned, let's say you've got a lot of, uh, leaf spot disease on your tomatoes this year, and you put that in your compost, maybe next year, don't use that compost in your vegetable garden. Put it under your, uh, Um, dogwood bushes or something like that, um, because it is important to remember that most plant pathogens, they have somewhat of a specific host range. So a pathogen may infect tomato and pepper and potato because those plants are closely related to one another. It's pretty tricky for a pathogen to be able to infect a tomato plant and also an oak tree because those are very different plants. Um, so you can think about doing that as well. Um, sometimes even Even just, um, so leaf spots on trees, things like apple scab on your crab apple tree, um, mulching that with a mulching lawnmower, um, brings it down into the soil. And that's where the soil microorganisms, those composting organisms that naturally occur in our soil, will actually start breaking down that plant material and reduce the pathogen's ability to survive from one season to the next. So in general, if we can get that material composting, we can get those composting microorganisms doing their job, that's going to be a good way to slow down the pathogen's ability to spread.
Eidan Silver:Hmm. I never had so much appreciation for composting organisms until you just said that. Um, so those are a couple ways that we as people can, um, prevent plant pathogens from spreading. One of the things I'm curious about is, what about natural conditions? I know you mentioned that making sure natural conditions are right is a good way to prevent disease from emerging in the first place. But, when I think about Minnesota, one of the first things I think about is winter. And if I'm not careful, that winter kills me, right? So, my assumption would be that we could rely to some extent on the, uh, Harsh conditions of Minnesota winter to kill some of these plant pathogens. Is that the case or Can we not rely on that?
Michelle Grabowski:Um, I would not rely a hundred percent on that winter can be helpful in knocking things back But many pathogens have evolved strategies in order to survive Through harsh winter, um, being sheltered in that plant material that they're they've infected during the growing season is one of the ways that they can survive winter, which is why that composting process and the kind of shredding and breaking stuff down and getting it into the soil is really helpful in reducing that survival. So, yes, cold can be a little bit helpful and it will knock things back. I would never count on it to It's not
Eidan Silver:a replacement?
Michelle Grabowski:A hundred percent, yeah. Okay. Clear out those pathogens. So I
Eidan Silver:can't just cover myself in plant material and hope that that gets me through the winter?
Michelle Grabowski:Nope.
Eidan Silver:Okay. Um, well, any, any other advice for gardeners or farmers or, um, anyone in Minnesota really who's looking to prevent the spread of plant pathogens?
Michelle Grabowski:I think the important thing is start out just being observant and curious. So, when you're in your garden and you see something, you don't have to hit the panic button right away, but do a little investigation and figure out what's going on. So, taking pictures, submitting that into the MDA, um, It's looking at extension websites to learn how to identify something or sending it to the plant disease clinic. The more you know about what is going on in your landscape, in your farm, in your garden, the more you're going to be able to set up the conditions for success for your plants. So if you don't know why your plant is wilting, but you submit a sample to the clinic, You may find out that the disease your plant has is verticillium and that there's resistant varieties. And so next year, when you're selecting which tomatoes to plant, you can choose the ones that are resistant to that pathogen and not have a problem. So having that mindset of, um, I'm curious, I'm going to find out what this is. You know, maybe you'll come to a point where you learn it's, it's powdery mildew. It's not that big of a deal and you don't have to worry about it. Now, you know, and you don't have to worry, um, or if you find out it's something that needs a little more management or involvement by knowing what is going on and what disease that is, then you can actually find good information about what's going to be really helpful rather than just kind of guessing at what, what might be a good strategy.
Eidan Silver:What a great plug for this podcast, too, because we'd be happy to satisfy that curiosity when people like Michelle come on and give this great information. It's called Smarty Plants for a reason, right? Um, well, I want to end by asking maybe a lighter question then. Um, do you have any fun stories related to your history in the field, uh, or plant pathogens in general?
Michelle Grabowski:Um, so a lot of the pathogens are really fresh. fun looking. Um, and, uh, I guess the, the one we talked about, the red star rust, that comes from a group of fungi in our, uh, some of them are native here in Minnesota, including cedar apple rust and hawthorn rust. Um, and one of the things that they do is on junipers, Um, they start an infection, it causes a round little woody growth called a gall, and those aren't all that exciting to look at. But then they do this very surprising thing in the spring where we get a rain event and all of a sudden these gelatinous orange tentacles come out of these round woody galls. And on cedar apple rust, the gall can be up to an inch across and you get these really long orange tentacles. And I've had people asking, you know, there's. aliens in my tree or, you know,
Eidan Silver:I'm picturing like an octopus emerging from the trunk.
Michelle Grabowski:So I've actually been out with some of the MDA field staff and we were looking for certain diseases, in particular for some of these rust diseases that occur on the juniper. And one of the staff was a few plants over from me and I heard him say, well, What in the world is that? And I was like, right away. I was like, yep, he found it. Walked over and sure enough, it was a Hawthorne rust gall. And it looked like this big, bright orange jelly star in the tree, um, with these orange So it's, it's actually fungi that's growing out of it. But they're really bright orange and they look gummy and they're kind of gooey. And, um, so they're always just kind of fun to see first thing in the spring.
Eidan Silver:I can't tell if that sounds like the grossest thing I've ever heard or like something that I would want to eat for dessert or something. Um, well, that's at least one plant pathogen that maybe I could identify now.
Michelle Grabowski:That's right. And, and Oops, I was going to say, go out and look for him now, but it's fall. Go out and
Eidan Silver:look for him next spring.
Michelle Grabowski:Next spring. That's right.
Eidan Silver:Well, I really appreciate you taking the time to speak with me today, Michelle. It was great to have you.
Michelle Grabowski:It was great to be here. Thanks.
Eidan Silver:All right. This has been Smarty Plants, a podcast from the Minnesota Department of Agriculture. Our producer is Brittany Raveill. Our editor is Larry Schumacher, and I have been your host. Eidan Silver. You can learn more about pests and other invasive species that affect our environment at www.mda.state.mn.us/plants-insects. And while you head over to our website, we'll be working on the next episode of Smarty Plants. See you there.
