 Okay, everybody out there, let's get going here. Segment two of our North Dakota State University Spring Fever Garden Forum, and now we're going to shift gears and talk about the battle against diseases. And the diseases are out there. They will attack our landscapes this year. So luckily we have Dr. Jared Maboulis, an extension plant pathologist who teaches tonight a little bit about how to prevent the problems, how to spot the enemy, and then how to protect our plants. So let's welcome Jared to the forum. We actually just changed the mic here too, so please let us know if things aren't working out at the various places in the state. So Tom asked me to come and speak to you about diseases, and he warned me not to depress you, and then he proceeded to do that. So hopefully everything will be on an upswing from here. And what I really wanted to do was basically give some general tips about ways you can manage your diseases in your gardens or in your turf grasses or in your trees. Basically things you can do that are really simple at the beginning of the growing season to try and prevent disease from becoming a problem. Before I do that, I thought I would show you certain pictures of some diseases, more to give you an idea of things to look at and things to keep your eyes on. So here we have something which is obviously a problem. We have two begonia plants. We have one nice, happy, healthy begonia plant and one that's wilted and dead and fallen over. This is obviously going to be a problem. If your begonia plants all look like that, you're not going to be very happy and you're going to want to do something about it. And here's another example of a disease. This is a plum pocket disease. Basically, it's a fungus that attacks the fruit on these plum trees and causes them to shrivel up and die and basically looks like this, something that you obviously aren't going to want to eat and isn't going to taste very good. Those are two examples of diseases that you might consider to be really important in your landscape plants. And now I'll show you an example of a disease that's really common in North Dakota, but probably most people won't really worry about in their landscape plantings. And that's a leaf spot of poplar. So most people who have poplar trees either in shelter belts or in their backyard will notice these little gray or black spots in the leaves. If it's a common disease, it's all over the place, not really going to cause a problem. And then the last one I want to highlight here is something that I'm sure everyone is familiar with in North Dakota and that's snow mold. So pretty much every spring when the snow melts, if there's been enough snow for a long enough period of time, you're going to have some snow mold that's growing on your lawn. So these are examples of rare diseases, common diseases. You'll probably disturb you and you want to do something about it in the landscape and diseases that you don't really care about too much. And I think the thing that's really important to keep in mind here is that what you decide to do about your disease or the disease problems you might be having is largely up to you. So some people might be bothered by after plants having these little black spots on the leaves and other people might not be. So the decisions on the types of things you want to do are in a lot of cases up to you as the person taking care of that garden or that plant. One more disease or common thing that you might see, especially if you're in the wet soils we have in North Dakota is something called damping off. So that's basically when you're planting seeds into really wet soil in the spring and the seeds never germinate and emerge. So you can imagine that damping off is a common problem, maybe not this year but in other years in the state because of the soil moisture issue. Now one thing, there's a lot of specifics in plant pathology. There's scientific names for these diseases and these little structures you have to look for and these little structures you have to look for. And people tend to get frustrated with all the details. And so I'm not going to spend too much time talking about that today. And what I really want to do is highlight the importance of some general concepts. And one is to think about how diseases occur. And this is a really common thing used by plant pathologists. It's called the disease triangle. And there's three sides to this and they're labeled on here. So you have to have a pathogen, something that causes a disease, a host. So a plant that becomes infected with that pathogen and then the environment. And you need those three things to come together at the right time in order for disease to occur. And so when you're thinking about how to best manage diseases in your landscape, it's a really useful tool to kind of think about these things. So you think to yourself, okay, well I have a problem with apple scab, let's say. What can I do to either the pathogen to the apple scab fungus, the host, the apple trees or the crab apple trees that it's causing a problem on, or the environment? And that's kind of the general way I'm going to approach the rest of this talk today. It's talk about things that you can do to either the host, the pathogen, or the environment in order to limit the amount of disease that occurs. One other thing I want to mention about this, and this is kind of maybe a little bit of an odd thing to mention, but what I always try to do is think of myself as a fungus whenever I'm trying to come up with a plan for how to control a disease. Fungi in general, like coolish temperatures and lots of moisture. So if you can do things to limit moisture and increase temperatures, that helps in most cases. You know, a really good example, something that Kathy just mentioned, was the pruning of trees to open up the crowns. You can open up the crown that allows air movement through, the leaves will dry off, and things like apple scab will be less of a problem. So here are the four main things that, four words that I think you should keep in mind when trying to control diseases. So avoidance, protection, eradication, and exclusion. Those are four things that you can do to try and limit the amount of disease that there is on the landscape. And I'm going to go through examples of all of these disease control strategies. And at the end, what I'd like to do is kind of talk about how you can use these in combination to limit the amount of disease that occurs. So the first one, avoidance. You know, this is probably one of the easiest things to do. You know, here's a perfect example. I mentioned damping off earlier. One way to avoid damping off is basically to avoid planting in really wet soils. So rather than planting, you know, a couple of days ago when everything was bare, or when, you know, the puddles are still in your garden, you wait until the soil is kind of drying out, the water's drained down through the soil, and you can plant your seeds then. And then you're less likely to have a problem with damping off. The other thing that's really important to keep in mind is most of these plant pathogens produce the spores that cause new infections in the spring. So it's really at the beginning of the growing season when you can do the most to limit the amount of damage that these diseases can have. The other thing to think about with avoidance is if we think of these two examples we have here. So these are two really common diseases you have on, sorry, I'm not sorry, it's going to be on your right or on your left. I'll be in the video world. But you have a powdery mildew of squash, and then you also have powdery mildew on lilacs. So these are really common diseases. I'm sure everyone has seen them. They're called fungi, and you usually see them at the end of the growing season. And this is a really good example of something that even though you might not like all the white spots all over your plants, you probably don't need to worry about. It occurs so late in the growing season that it's not going to affect, at least in North Dakota, it's not going to affect the fruit that's produced or hurt your lilac bushes. So there's all sorts of ways to think about this disease and whether or not you need to actually do anything about them. The next thing I want to talk about is protection, ways to protect your plants. And obviously the most common way to protect your plants or people would commonly think of is to use some sort of pesticide. And I tend to lean towards more what Kathy was mentioning earlier, and to try and use organic control or try and limit the amount of pesticide that's applied in our gardens and in our landscape planting. And so I tend to use that as a last resort. But as Kathy mentioned with the spotted ring desoscelia, there are certain diseases where you might just have to spray something in order to control them. One thing though that's really important, and this gets back to thinking about pretending that you're a fungus or pretending that you're a plant pathogen, is basically to allow the plant surfaces to dry off. So here I have a picture where you have a bunch of trees on a boulevard and the irrigation water is spraying those trees. So basically what that's doing is allowing the leaf surfaces and the stems to stay wet for a long period of time. And fungi really like those wet surfaces. And that basically increases the amount of potential disease that there is. And you see this quite commonly where people are irrigating their lawns and they have spruce trees. And they spray those spruce trees at the same time as they're irrigating their lawns. And if they do that in the evening, then the spruce trees will basically stay wet all night. The fungal spores will land on those spruce trees and cause potential problems. So those are, you know, when I talk about controlling the environment, it's kind of, you can be uncertain of ways to do it, but this is a good way that you can do it. You know, you can avoid all this excess moisture on your trees. The same is true whether it's the lawn or plants in your garden. And one thing also I want to highlight here is that if you do make the decision to use a fungicide or use a pesticide in order to control the problem, you really want to be careful to read the label and be sure that you're using it in the correct way and on plants that it's labeled for use. The next thing I want to talk about is eradication. And I'm a big fan of eradication because this is probably the simplest, most straightforward thing you can do. Basically getting rid of any of the dead plant material in the fall or in the spring before things start to bloom. So perfect example, rake up the leaves in your lawn. I don't really like raking up leaves and I know lots of people don't necessarily like raking up leaves, but that's one of the best things you can do to control disease. Because if you think about something like apple scab, which is all over the leaves and all over the fruit, they fall off, land on the ground, they're under the snow all winter, and in the spring they produce spores that cause new infections on your crab apples or on your apple trees. The same is true of branches, dead branches on trees. You want to be sure to prune those off and get rid of them. In your garden, you want to pill under all the dead plant material. That's a really good way of eliminating problems from the start of the previous year and protecting them from moving forward into the next year. So I know any of you who have kids, kids' rooms are never clean. You don't want your garden to look like your children's room. That's a good pointer. Here are some examples of a few diseases that this can be really, really important for. Any of the diseases that are canker diseases, so they infect the branches and main stems of trees. You want to cut out those cankered areas and basically get rid of them. Apple scab, as I mentioned before, is a really good example. Basically get rid of all the dead leaves in the fall or at the very least in the spring before things start to flush and start to bloom. And basically any disease that impacts the leaves of plants or trees, you just want to get rid of that dead plant material. That's one of the best strategies you can do. They basically prevent the problem from starting in the first place. Some other things to point out here. So you'll notice here there's a big stack of firewood underneath a couple trees. Well, that's alum firewood, and those are alum trees. And those alum trees were killed by, or Dutch alum disease, which is spread by a beetle. So the point I guess I'm trying to make here is if you do remove dead branches or cut down a tree, get rid of it. Don't leave it in your yard. Don't stack it underneath a tree of a similar species. Get rid of it. If you want to keep it for firewood, that's fine, but don't stack it directly below alum trees if you cut up an alum tree that was killed by Dutch alum disease. The same thing is true for composting. So if you have infected plants from your garden, you don't want to use those plants in the compost because a lot of the fungi that cause these diseases produce resting spores, which can survive in these compost piles. So you can imagine you have this really nice garden, a couple of the plants are infected, you harvest all that material, you compost it, and then the next spring you spread it all over your garden, which is spreading those spores all over the place. So that's something that's really important to keep in mind. It's a good idea to compost, but you want to try and minimize the infected plant material that you use in that compost. The last point I want to talk about is exclusion. And this is another really good strategy, which is basically when you buy your plants, whether you're buying them at Home Depot or at a garden store or ordering your plants online, you want to make sure that they're disease free. So you don't want to bring infected plants to your garden. So there are a couple of examples here. I have bags of potatoes. Potatoes are a really good example of a certified seed program. So it'll say on that bag, if those potatoes are disease free. And when that's there, you know it's safe to plant them and you're not going to be introducing a disease into your garden. The second example here is a downy mildew fungus, which has been recently identified in Minnesota and present all over the U.S. And this is a really good example of something that I mentioned about the composting. So this downy mildew fungus grows on the leaves and at the end of the growing season it produces a spore that can handle high temperatures, no moisture, really cold temperatures, basically is able to survive in the soil. And so if you were to plant the same plant in that location again the next year or if you were to use those dead plants as compost, then you would potentially be spreading this disease. So the last thing I want to talk about before I go through an example of how we can use these different approaches is integrated pest management. So you might have heard people talking about this in an agricultural kind of system. Well the same thing can be applied in your garden. And basically integrated pest management or IPM is using a combination of avoidance, protection, eradication and exclusion to limit the amount of damage there is to the plants by different pests and different fungi while minimizing the environmental impact and the cost of controlling the disease. So you know if you think about it you can use combinations of eradication, cleaning up your leaves and potentially applying a pesticide at reduced time periods or sorry less frequently to limit the amount of disease you might have. So we're going to talk about cedar apple rust or juniper apple rust as an example of one of these diseases where we can apply these different strategies for control. So here we have two pictures. You have leaves of an apple tree or probably a crab apple tree with these yellow spots on them. So those spots are caused by the fungus. You can also see those spots on fruits. And then you have a picture of junipers where you have the fungus growing on those junipers. And anyone in the spring who has seen these orange jelly-like structures hanging off their juniper plants which I think are really neat but other people don't necessarily think so. Tom shaking his head are the other sign of this disease. And like Kathy said earlier this disease basically cycles between the juniper and the rosaceous host. So not only are apples susceptible to cedar apple rust but any plant in the rosacea family is susceptible to cedar apple rust. And so basically what happens in the spring those jelly-like structures come out of the cedar or juniper tree. They release spores. Those spores travel through the air and they land on susceptible apple or rosaceous host. So that's kind of what you see here. And then basically at the end of the growing season the fungus produces a second type of spore which will reinfect the juniper or the cedar plant. A lot of the time you can see so those jelly-like structures are only visible in the spring when things are really wet. They dry up and fall off but what you can see are these woody galls which is on the lower side of the screen underneath the word juniper. Those woody galls are present on the juniper plant all year long and you can see them. That's what produced those orange jelly-like structures. So how can we use these different IPM these different approaches we talked about the avoidance, eradication, exclusion and protection to limit the amount of problems caused by the growth of the plant. One of the ways you can do it and some people think this is a good idea and I'm not sure how effective it is but it's basically to remove one of those hosts. So if you don't like your juniper plants get rid of the junipers. If you don't like your apples which is probably the least likely choice people make then you can get rid of your apple plants. This might work but you have to remember that these spores are spread through the winds and so if your neighbor has a bunch of junipers they might and you've gotten rid of your junipers those spores are going to spread from those junipers onto your crab or your apple trees. So it's really important that unless you're willing to go into your neighbor's yard and kill all their juniper plants too and so on and so on that it's not necessarily that effective a strategy. Another approach which I know people grown at is those little dolls you see on the junipers you could prune those off. So that's getting into the eradication side of things. Once again, that's probably not going to be the most effective for the same reason that removal of the junipers wouldn't have been that effective. This disease can still spread from further away. There is the possibility in terms of protection to apply fungicides to control this disease. Now there are fungicides which are labeled for use on the rosaceous posts so on the apples and on the crab apples but I'm not aware of this time of fungicides that are labeled for use on the juniper plants. And then the final thing I want to talk about is basically the use of resistant cultivars. So there are resistant cultivars of both the apple and the juniper which you could plant in your landscape if you're developing a new planting. So that's something that's also an option and probably one of the better choices in this scenario for trying to control this problem. Now the one thing as I mentioned earlier is that you don't necessarily have to think of this as a problem. I like all this stuff on my junipers and on my apple trees. I think it's interesting to look at. I wouldn't necessarily do anything about it but I know that's not necessarily true of everyone. So that's pretty much all I've got for today so I'd be more than willing to answer any questions that you have. Okay, thank you Jared. Got a few questions and people keep in comment. You talked a lot about cedar apple rust. Do you know how far can these spores travel in the wind? How many neighbors down the block do we have to worry about? In order to... You have to worry about a lot of neighbors down the block. I'm not sure the exact distance is but most of these fungi that are spread by wind can travel miles so it's not a short distance. That's why I really kind of think that even though people suggest removing the alternate hosts or removing the junipers, for example, it's probably not going to work. Thank you. What's the best time of year for cutting out Cytospora canker on spruce? That's a really good question. I'm taking a second to think about it. Largely because I would say as soon as you see it, I think that's probably your best approach. So as soon as you see the Cytospora canker on the spruce, you probably want to cut that branch off. And whenever you're pruning spruce, I think the best approach is you want to prune it right back to the main stem. You don't want to prune just the end of the branch off. So you'd prune the whole branch right up to the trunk of the tree off to do that. Do you have any recommendations on how we can manage snowmold on turf? Yeah, I think the best approach for managing snowmold in a landscape type setting is basically user rape when you see it in the spring. Most of the time when the snow melts, if you have snowmold underneath and you rake it to just basically break up that mass of fungus that's growing there, you're not going to have a problem with it. You know, the grass might get knocked back a little bit early on in the growing season, but it'll recover. Snowmold generally is a problem when you don't do something about the matted hyphae and mycelium growing on the surface of the grass. You don't want to rake it out there and rake that up as soon as the snow is melted and the soil and the turf's a little bit dry. I think you won't have too much of a problem with it. Thank you. A question on Dutch Elm disease. This person says, I thought it's a big no-no to burn elm trees with the bark on since it will spread Dutch Elm disease. Is that true? I think maybe the way to think about this is that when they talk about the bark on the elm logs, the beetles need that bark on those elm logs in order to survive. So if you remove the bark and have that wood piled there, you'll be all right. It's just basically the wood drives out and any beetles that are there would die or they are actually present in the bark and not in the wood of the tree. So I think that that recommendation has to do with the storage of the wood. I hope if I can clear that up anymore. I think burning the wood itself will not spread that stuff. No. How about for the potato packages, how can we tell if they're disease-free? The potato packages will usually say it's certified seed. So they'll be somewhere on there and it'll say this is disease-free. And with potatoes, viruses are usually the biggest problem and they'll be a note on the bag that says this is certified seed that there's no viruses present in them. Here, how can we get rid of mushrooms in the lawn? That's a really good question. So there are a whole bunch of different kinds of things that produce mushrooms in the lawn. I think fairy-ring is probably one of the most common ones that people think about. There are things you can spray on your lawn. They don't work particularly well. And so I basically just recommend the same thing with a rake. You just kick them or you rake them up and get rid of them. That's probably the best approach. Usually the reason those mushrooms are being produced in the lawn is there's a piece of wood buried underneath there and it's actually the mushrooms growing from that piece of wood that you see on your lawn. So I mean, chances are I think you just pick the mushroom and get rid of it. Jared, black knot disease on cherries. Is it possible to get rid of it? It's been there for two or three years. Black knot is a little bit tricky disease to deal with and that's because it has a two-year life cycle. So it causes spores get spread through the air in the spring. It lands on a cherry tree and it takes two years before you actually see the symptoms developing on that cherry tree. So what you actually are pruning off when you prune off those black knots are symptoms that are two years old. So normally what happens is people prune everything off their tree. They get rid of all those black knots and then all of a sudden it shows up again next year and they're upset. Well, why did I prune the tree when the black knots are coming back again? And usually what they find is if you keep pruning that for two to three years then you can limit the amount of disease, reduce the amount of disease that's there. But it's virtually impossible to get rid of black knot entirely. Is scarlet uses great leaves as a mulch in the flowerbed in this winter protection? Is this a bad idea because of the risk of spreading disease? That's maybe a tricky question. The reason I say this may be tricky question is it depends on first of all if those leaves were infected. So I would say if you've got a crab apple you're saying they're mulch leaves. If you've got a crab apple you probably don't want to spread them close to your crab apple tree if they have apple scab on them. But if they're elm leaves it probably doesn't matter at all. Usually mulch leaves, especially if you turn them into the soil are going to decompose and it won't be a problem the next year. Yeah, just don't use disease leaves. Yeah. How about anybody in Fargo have any questions? We've got a very quiet group here tonight. There's a few questions out there on insects I'm going to spare Jared of. Here we go. Now we're shifting to rhubarb. Again, really after a good start in spring, on the end of June they start getting rust and then the leaves will start dying and sterling up. First of all, how about using dish soap on them in spring? I actually don't know anything about rhubarb rust. But I would think that applying dish soap, if you need actually spraying them on the leaves, I don't think that that actually would necessarily do anything. Probably you would just make the surface of the leaves wet and actually potentially make the situation worse. It's a cleaner rhubarb, but dish soap is not a fun to site. They will not do the job. What do you recommend for controlled plum pockets? That's a good question. I actually don't think I could answer that question right now. I'm not sure of the best way to control plum pockets. Just do your best to pick them up. Sanitation, right? You're talking about eradication. Good sanitation is always a good start. This person has astral yellows on petunias spread by leaf hoppers. Someone in the audience, I think that probably is the best approach. The leaf hoppers, I'm sure there is a label that's designed for their control. But I think the issue with astral yellows is probably the best thing to do is just remove the plants. Anyone has questions? Otherwise, any questions on diseases? These are excellent questions. Any questions on diseases? I tell you why. Why don't we just take a break now? Take a five-minute break. Thank you, Jared, for your excellent presentation. Thanks for the excellent questions out there, everybody. Let's take a five-minute break, and then we're going to talk about planting trees.