 Okay, so that brings me to our speaker today. Jesse Ostrander received his master's degree from Kansas State University in 2014 and he worked for the Kansas Department of Agriculture's Plant Protection Program as a Plant Protection Specialist-slash-Nursery Inspector from 2012 to 13. And we're very fortunate to have Jesse with us He's at the Plant Diagnostic Laboratory and he's been in that position since July 2013. So with that I thank you for being with us and take it away Jesse. Okay, thank you Julie for the introduction and for correctly pronouncing my name. And I just want to thank everyone else for their interest in my talk today about common diseases in the garden. When Julie asked me to do this, I was told that there'd be a wide range of experience in the audience ranging from some master gardeners to maybe some garden enthusiasts and possibly even some of you might be just starting your interest in gardening. So hopefully some of you might find some of these topics familiar and may recognize some of the diseases they'll talk about today for yourself and then some others of you might this might be your first exposure with some of these things. So the goal of this talk today is just to expose everyone to what these diseases look like. All of the things I'm going to talk about today are listed here and these are all problems that I have received samples of or have helped local homeowners with in my time here at the Plant Diagnostic Lab. So hopefully I'm going to provide you with some level familiarity and some management options beyond just using fungicides, especially since fungicides don't work for any of these problems except those the blights and anthracnose and septoria. And so my talk today will be focusing on diseases of solenaceous and cucurbit plants as they tend to have the most enthusiasm for those crops. So with that I'm going to start off talking about blights of tomato and potato. There are two different blights. One is called early blight and the other is called late blight. Early blight is caused by a fungus. There are two different species. One was named for its characterization on tomato and the other on potato. But both species can affect either crop and it's a pretty easy to identify disease. Probably the easiest one I'm going to talk about today. It produces large easy to see lesions on the leaves and as you can see in that picture they have concentric rings kind of a bullseye pattern. So that's going to be something that's fairly easy to recognize. This pathogen obviously can affect leaves. It's very common. I've been lucky enough not to have this in any tomatoes. I've grown but friends and other people I've talked with who use community gardens or if you just grow a large number of tomato plants I usually only grow about five or so. But if you grow quite a few it's going to be very likely that you're going to get this pathogen. And as this name suggests it does occur earlier in the growing season. It can also affect stems and on stems you'll see these sunken cankers and eventually those cankers will expand to girdle the stem and the portion of the plant upwards from that infection will die. It can also affect both the tomato fruit and the tubers of potatoes. So you can see some of the damage there on the tomato on the tuber potato. That tissue is just going to turn kind of a dark brown and it will die. So with every disease I'm going to talk about I'm also going to provide some management options and the idea with these management options are they all kind of go back to this theory of the disease triangle. So as plant pathologists we always look at the disease triangle. The theory here is that the total amount of disease is going to be based on all the different components of a disease coming together. So to have a disease you need to have a susceptible host. You need to have a pathogen that can affect that host. And then you need to have environmental conditions conducive to disease. And I'll come back to this when I give you some management options here. So how do you manage early blight? You can manage early blight through sanitation, buying quality seed that is free of the pathogen, moving your planting site. If you have a large number of tomatoes and you're seeing this pathogen year after year the spores will persist in the environment. So planting your susceptible hosts in a new location will remove them from those infective spores. Also the next three items are looking at reducing the moisture levels. And then we could also pick hosts that are less susceptible. So if we kind of break these things down those first three components are looking at reducing the total abundance of the pathogen. The next three as I mentioned are looking at reducing the moisture. So that's helping with the environment. The mulching actually does two things. It actually can also reduce the abundance of the pathogen. If you put mulch down it acts as a barrier between the soil and the plant. So it can reduce the amount of humidity, but it can also prevent the spores from being splashed up onto the plant. So that could have kind of been put in either category. And then host resistance is going to reduce susceptible hosts. I've also included a list of some varieties that are less susceptible to early blight. So if we bring that triangle back in you can think of if we're reducing the abundance of the pathogen that's going to make that left side of the triangle smaller. And then if we reduce the environment that's going to make the right side smaller. And then if we reduce the hosts it's going to make the bottom of the triangle smaller. So we're just going to result in a much smaller triangle which is going to theoretically reduce the total amount of disease. It's a pretty good theory though because it does work. Some other things that you can do would of course be chemical control. So there are some, there are actually a lot of fungicides available for this pathogen, but few are available if you do not have a pesticide applicator's license. So the ones that I've listed here are all products that I found on Home Depot's website that were listed for control of early blight. The one that I would personally use would be chlorothalonil. And the product name is on the right hand side there. So first we have the fungicide AI, that's the active ingredient, not artificial intelligence. So the active ingredient is chlorothalonil. If you apply chlorothalonil it's going to protect your plant for up to 14 days. And then a product name would include dacanil or funginil. And these are usually in little spray bottles, mancoseb and manneb or other fungicides that you can find. Those target the membrane of the fungus. And the other two listed on there you can also find. So the bacillus is, if you're wanting to be organic, that's something that's a natural, it's a bacteria that is antagonistic to the fungus. So that's it for early blight. Late blight is the other blight that can affect tomatoes and potatoes. It's caused by a fungal-like organism. So it's not actually a fungus. Phytophthora infestans is its name. It's not quite as easy to identify. It doesn't have that nice characteristic, obvious, bullseye pattern lesion. In the photo that I provided here, you can see there's just kind of a diffuse browning on the stems. Eventually it will kill the plant, but at first you'll just see a diffuse browning. And if the humidity is high enough as it was in this photo, those infected areas are getting a fuzzy appearance because the fungus or the fungal-like organism is producing infective spores. This pathogen is historically significant. It was the cause of the Irish potato famine in the mid-1800s, and it can be immensely destructive. And as its name indicates, it does usually occur later in the summer, although it does cool wet periods as well. And so it can affect the leaves, the stems, as well as the fruits of tomato and potato. It can also infect hairy nightshade, a weed, so it can overwinter on hairy nightshade. Here's just another image of it infecting a stem. And here are some tomatoes and tubers that are infected. They look pretty bad. You obviously wouldn't want to eat those tomatoes at that point. And if you cut open the potato, there's quite a few pathogens that can create necrosis and potato tubers, but late blight has a very granular-like appearance, almost looks sandy. And this photo doesn't maybe do it justice, but also has a salmon color to it. Looks a little bit more orange in this photo. I like this photo because you can see the granular texture of the infected tissue. So where does this pathogen come from? It actually doesn't like to overwinter well this far north. It is an obligate parasite, so it needs a living host to survive. And so the combination of how cold it gets here and how long the winter is, usually there's no starting inoculum out in your garden, but it does get spread with tuber seed pieces. You could also purchase a tomato or potato transplant grown in a greenhouse in another area and introduce that into your garden for the season. And to a lesser degree, spores are able to travel north from southern states. These fungal-like organisms are more reliant on water to move as opposed to wind, so they don't travel quite as readily, but they can move through the environment. So what will you do to manage if you see this pathogen? You're going to want to destroy any residue by burying it or removing it from the area or burning it. Whenever you bury a pathogen, it is introduced into the soil, and if you have healthy soil, there's going to be a lot of organisms that are antagonistic to it, so it breaks down faster. If you do have a plant with this pathogen, you're going to want to immediately remove it from your garden to prevent it from spreading to other plants. And then controlling any volunteer plants, probably less of an issue here. That would definitely be helpful in a southern state where plants could potentially grow 12 months of the year. That's obviously not the case in North Dakota. And then also controlling those weedy host. Again, those are more southern control recommendations for more southern areas. Also, if you like to save your own seed, if you've had this pathogen, you're definitely going to want to think twice about that. So try and use certified commercial seed. If you do save your seed, you could wash or heat treat it, and I'll talk a little bit more about that later. And then just inspect transplants at garden centers for any signs of infection. So I showed you some stem lesions on the leaves. You'll see this kind of diffuse browning. It often starts at the margin of the leaf, and it'll cause the leaf to constrict. So we have leaves with varying degrees of infection here, and you can even see it traveling down the stem from some of the infected leaves. And you won't necessarily see the fuzzy-like appearance unless the humidity is very high. What can you do to manage it? So there is another... Well, I've already given you some tips there on that earlier page, but some additional management tips would include host resistance again. So there's quite a few. These are tomato varieties. I didn't give a list of potato. Also for chemical control, chemical control is going to be a little bit different. The chlorothalonil will work for late blight as well, but it will not. The manneb and mannexab will not, because they target the fungal cell membrane, and the cell membranes are different on this pathogen. So if you're ever wanting to see an inclusive list of chemical control options, Purdue release is a really good resource called the Midwest Vegetable Guide. And I provided a link there. And so you can find your crop and then it'll have a list of different pathogens and available fungicides. And they release... They update that every year. And so that way you'll see the most up-to-date recommendations for those fungicides, because resistance does develop or the EPA might limit what can be sprayed on different food products year to year. So it's important that you reference something that's kept up-to-date. So another fungal pathogen of tomato and potato would be anthracnose. It's caused by the fungus colliotracum cacodes and other species of colototracum. It can also cause black dot on potato. And while all of the colototracum species have a wide host range. So up to 68 different weedy hosts can serve as alternative hosts. Only colototracum cacodes can persist in the soil in these structures called microsclerosia. And so this pathogen can be quite destructive. It primarily affects ripening fruit. It can affect tubers though, producing a black dot disease. And what's difficult with this pathogen is that the fruit could be infected very early season. The spores will land on the not yet developed tomato and they can just barely penetrate the epidermis and then they'll just kind of hang out and wait until the tomato is well ripe. So that can make fungicidal control difficult because your tomatoes could be infected but you won't see any evidence of this. So should you be spraying all season in anticipation of having an anthracnose problem or should you wait and at that point it's too late. I would recommend if you've never seen this in your garden not to spray fungicides and if you have seen it before then you can make your own decisions for that because if you do harvest the fruit regularly and consume it in a timely manner this won't be a huge problem for you but if you have a lot of tomatoes that maybe you store for a few weeks after harvest or sometime this can lead to storage rots quite rapidly. So the symptoms that you're going to see is once the fungus becomes active on that ripened fruit you're just going to get a collapse of tissue under the epidermis. Eventually the epidermis will split and it'll really take off. You'll see a lot of black mycelial structures and then over time the fungus will start producing some spores and those spores are kind of a salmon color as well. Then on potato the black dot pathogen it's named black dot because you can see little black dot like fruiting structures but the actual tuber symptoms are more diffuse almost like a bruising and then a collapse of the tissue. So what can you do for this? Well it's soil borne so moving your plants to a new location is key to management if you've had this problem for several years and mulching will also help with this since those structures are surviving in the soil. Avoiding overhead irrigation will help the plants dry out so that's pretty much a common theme here the overhead irrigation. You want your plants to stay as dry as possible it's going to help with basically every disease that I'm going to talk about today. Controlling weeds is going to be really important within Thracnos just because there are so many different species that it can survive on. Removing the fruit regularly is going to prevent any overripe fruit from producing spores and reintroducing those into the environment. And as I kind of alluded to earlier fungicides can be effective but you're going to really have to apply those periodically because fungicides are and I meant to mention this earlier you we really only want to use fungicides to prevent infection we don't ever use them to cure so you need to get those fungicides on there before the fruit isn't infected and that can be hard to do since you won't see any signs of this maybe developing until later in the season. For host resistance slower to ripen cultivars are somewhat resistant just because it gives you more time to get them out of the garden and use them and when those do become infected they produce smaller lesions and they develop slower and so there's less spores that are going to be introduced into the environment. The last fungal pathogen I'm going to talk about is septoria and that can be very destructive to foliage it doesn't usually affect the fruit directly but if your plant's losing a lot of its leaves it's not going to have any tissue to produce photosynthates and so that's going to result in fewer fruits lower quality fruits and so this can affect all vegetative parts of the plant and we can see a leaf there that has a pretty severe amount of damage from septoria you want to look and see what the lesions are going to look like earlier in the season they're pretty small and they're characterized by having a gray center with a dark border and if you have good eyesight you'll be able to see these little black threading bodies in the middle of the lesions if you need any assistance you can always see those very clearly with a hand lens the lower leaves are usually affected first because again this pathogen is going to be in the soil so it's going to affect the lower parts of the plant that may be coming to contact with the soil or let rain water splash up and the lesions are usually pretty small one to three millimeters in size as I mentioned they have that dark margin with a tan gray center and they could have threading bodies visible so I just told you that the lesions are small and I'm showing these huge lesions but these are uncharacteristically large sometimes you see things that aren't perfectly textbook just depending on different environmental factors and host pathogen interactions I like this photo because you can very clearly see the little black threading bodies in the middle of the lesions infection centers and if we look at those really close when it's nice and humid out you'll see the spores being released in these mucosal matrix coming out of the structures called picnidia so as I already mentioned the pathogen will spread upwards and heavily infected leaves will turn yellow and then eventually they could turn brown and fall from the plant and I'm time out the whole leaf so not just where the infections are as the leaf becomes more heavily infected the whole leaf might turn yellow and then brown and then be cast from the plant so the primary noculeum again it can be seed borne on the coat of infected seeds could just be an old plant debris can survive on some solinaceous weeds and then it's been it's been shown through experiments that just random equipment out in the environment such as pots, plant stakes other gardening equipment can be a reservoir for spores and then once it's in the environment it's just spread there from rainfall, wind but especially if you or a pet or even insects are moving through the foliage of the tomato plant when it's wet that's really going to spread any infections that you have throughout your crop so what can you do if you see this? well there is no host resistance available for this pathogen but you can move the plants to a new location again I know that's a luxury many people might not be able to afford but if possible moving your plants to new locations periodically is just great all around decision for you to grow in your garden even moving them for just one year can help with managing this pathogen but two years is recommended you can also control those alternate hosts or just clean everything up clean your pots clean your plant stakes clean your tools and there are fungicides available as well so chlorothalonil again is a really great tool I did mean to talk a little bit more about chlorothalonil when I first introduced it so chlorothalonil is a really broad spectrum fungicide and it also works on fungal-like organisms it's pretty toxic but it has a short short life span out in the environment it breaks down pretty quick part of what makes it toxic is it's highly reactive so it reacts and breaks down pretty fast if you do treat anything with this clean it very thoroughly if any produce gets chlorothalonil on it also when you're treating plants chlorothalonil again I already mentioned this but you want to treat the whole plant not just what's infected and you also want to get the underside of the leaves as well because this product does not go into the plant it would actually kill the plant if it was absorbed into the plant it's formulated to remain outside of the plant and coat it so only the areas that are coated with it are going to be protected so you'll want to spray the underside and the top of all parts of the plants so that's all I'm going to mention for fungal diseases and in general whenever you're trying to manage those diseases it's really best if you try and do those non-chemical controls and if you can achieve control with those awesome if you can't then it might be a good idea to start thinking about using some fungicide now I'm going to talk about bacterial diseases of tomatoes I'm going to talk about what all three of them look like and then I'll give general management for all of them together there's three different bacterial diseases spectral cankers pretty rare it's so destructive that there is a lot of mandatory testing that goes on to make sure that that's not being introduced or spread around through seeds and transplants and then bacterial speck and spot do occur more frequently but they're less damaging the symptoms of bacterial canker will depend on the age of the plant so if the plant was or well the dependent that on the age of the plant when it was infected so early season infection systemic infection from seed or infected transplants systemically infected seeds might just die they might just show poor germination if they do happen to become established they'll show blistering on the petiole and browning of the mid vein but they could remain asymptomatic which is why this pathogen is tested for regularly to prevent it from spreading since visual inspection alone is not sufficient so here we can see actually six transplants and the middle one in the top especially its topmost leaf there in the middle is showing a little bit of off-color and curling and that's actually all the symptoms that you might see for a infected plant if the plant does end up getting planted and developing later in the season you may see some interesting symptoms such as one half of a leaf or half of a stem will die this is a clavibacter bacterium and it moves through the vascular tissues so the water and sugar conductive tissue and because of that it might only move up through the vascular tissue on that side of the stem so that's why you're seeing that somewhat crazy looking symptom but it makes sense when you think of the plant as a series of pipes or tubes if you do cut into that stem you will see that the interior stem tissues have brown vascular tissue and the stems may develop a canker and split open and the whole plant will wilt and as I mentioned this pathogen is very severe it only takes one out of 10,000 plants to be infected to create a serious epidemic so here's a photo showing an infected plant stem that's been cut into and we can see the browning and death of those vascular tissues on the fruit you'll just see small white spots I think we can all notice them here but they're going to be much more noticeable as the fruit ripens and you see the contrast they're just little white blisters so moving on to bacterial spec these are small round smooth lesions that occur on the leaves and each lesion can be seen on both sides of the leaf so they just kind of cause all the tissue different tissue levels to collapse in and they will generally have a chlorotic halo and many lesions will cause an entire leaf to turn yellow on the fruit the lesions are smaller than they are on the leaves and if they are produced early in the season the lesions will come sunken in as the rest of the fruit continues to expand but those areas with the lesions just kind of stay and this could be confused with septoria because the lesion size are somewhat similar in the way that a heavily infected leaf will show just overall chlorosis and can be cast from the plant one thing that you might notice if you have a good eye and looking at this is that I think actually that leaf might have a few septoria lesions there in the middle towards the leaf tip but overall most of those bacterial spec lesions are just totally dark whereas the septoria lesions have that color different the light gray center with the dark border and also you will not see any of the little black fruiting bodies on bacterial spec so those are some things you can look at and it's important to be able to tell the difference because if you have septoria a fungicide will help if you have bacterial spec it will not and here we can just see some of those specs those infected areas on fruit it's important to mention that none of these bacterial pathogens are going to harm us if we were to eat that fruit for the most part especially with bacterial spec they just cause that fruit not to look as good sometimes if these are grown commercially they can still use the fruits for some production such as making them into catch up or something along those lines but at a fresh produce you know supermarkets produce section that would not be high enough quality to be sold in that setting so the third one here is bacterial spot as the name might suggest the infection the lesions are going to be larger they're more distinct on vegetative tissue later season the leaves might just have a generally scorched appearance and it could be confused with other fungal pathogens when first forming especially early blight it has a similar infection lesion and size and somewhat shape to bacterial spot the chlorosis will eventually become extremely diffuse even compared to bacterial spec just well you'll see in a moment when I show you an infected plant in the next slide so with this disease there are actually four different species of xanthomonas that can infect tomato and create bacterial spot and one of the four species will create a shot hole like appearance so instead of seeing the lesions you'll just see a missing area where the infected tissue has fallen out of the plant so that might be something to keep in the back of your mind if you're growing and you see shot hole in your tomato plants mature lesions on the fruit are scab-like so you can see this causes quite a bit of damage to the foliar tissue of the plant and on the fruit those lesions are kind of quirky and scab-like when they are mature so what can you do for these diseases well it's a good idea to confirm them they're pretty easy to confirm with some microscopy or culturing so fungicides won't help though so it's best to know which pathogen you have so you can avoid using an ineffective product also buying only clean certified seed that's more important I mean it's important with all these pathogens but especially with bacteria they tend to be seed transmitted so seeds sold from a professional supplier should have been tested free from both the clavibacter that causes the bacterial canker and the xanthomonas species that cause bacterial spot and they should have been washed or heat treated to remove other bacterial pathogens if you do want to save your own seed you can always either wash it with a bleach solution or you can put it in 120 to 125 degree water for 25 minutes for tomatoes of course at any first signs of this patch and immediately stop any overhead watering that's going to spread it like crazy so you definitely don't want to be using overhead irrigation system removing any heavily infected plants or even parts on a plant will prevent bacteria will ooze out of the infected areas of a plant so that it can be washed off and find new tissue to infect also only handle plants when they're dry if you have any bacterial diseases and you should also be cleaning tools or your hands between plants so I'm not saying you need to be out there constantly washing your hands and your tools if your plants look healthy just if you have some of these pathogens and then removing all the debris at the end of the season it's going to prevent a source of inoculum for the next year and so that works for all bacterial diseases of tomato so that's that pretty much sums up the pathogen specifics to the solenaceous crops now I'm going to talk about a couple of pathogens that affect well really I'm going to talk about bacterial wilted curbits and then I'm going to talk about viruses that can affect both cucurbits and solenaceous so bacterial wilted curbits I think I've only seen this twice but does occur here and it's caused by yet a fourth type of bacteria erwinia species the erwinia cannot actually survive in the environment but it does over winter and the cucumber beetles gut and then it's spread by their feeding activity out in the field cucumbers and muskmelons are the most susceptible to this so it usually will kill them if introduced pumpkins and squash are less affected they will show some symptoms but they might not die or at least not with the same amount of erwinia being introduced to them and watermelons are not affected so that's good news although I don't think there's too many people growing watermelons oops sorry I hit the back button there I know watermelons are a bit difficult to grow this far north but if you do decide to grow watermelon they won't be affected by this pathogen so what are the symptoms you're gonna see well the leaves will just start to dull they'll get kind of an off color a darker green to gray and then the plant will start to wilt during the day but it will still recover overnight so what's happening is that bacteria is clogging up the water conductive tissue so the plant can recover during the cool night but it will wilt during the day even if you water it eventually that tissue will become plugged up to the point that even with the night period to recover the plant will still will not recover and it will have a scorched appearance to the leaves and then eventually the leaves will die and then the whole plant can wilt and die depending on how the beetles are feeding where they're feeding on the plant it might only affect a single runner or some runners of the vine or it could affect the entire plant so we can see just the total wilting of the plant there with the runner in the background is still healthy other thing you're gonna do to confirm if you have this pathogen is you can look for those cucumber beetles you can look for their feeding injury on the leaves shown there on the right or the beetle themselves I already showed both the beetles but there is a 12-spotted beetle as well as a striped beetle you can also look on the underside the leaves for their eggs and if you have any questions about confirming if you have cucumber beetle we do have an entomologist here in the lab that would be happy to help you out if you wanted to send in a sample or send in a photo to the Plant Diagnostic Lab and then the confirmation of the disease though would actually be the bacteria in the tissue of the plant it isn't impossible to have cucumber beetles and not have or yeah you could have cucumber beetles and not have them introduce their winea bacteria most of the time though they are introducing that but if you cut into the stem and kind of pull the plant away touch the cut pieces and pull them away you'll see this gummy strands formed by the bacteria they produce sugars and that's actually what clogs up the vascular tissue is those sugars make it sticky and they stick inside of the plant so really you're going to want to control the insects though you can't do anything for that plant it's it's gone or if it's infected depending on the size of your operation you could just pick the insects off there are insecticides available but they do harm pollinators and of course we're always going to protect our pollinators and we're all made very aware of the dangers pollinators these days if you do decide to use insecticides there's seven in permethrin based that are toxic to bees but if you do later day applications when the bees aren't active that will help it get absorbed into those plants and not be in the environment to harm the bees you could also use other plants to pull them off of your cucumbers and melons but personally I'd prefer to have the zucchini so I don't know if I would go that route but that's an option for you and then of course you're going to remove any plants showing signs of infection so if you see any day wilting in spite of watering and then it recovers at night go ahead and remove that plant as best and again just don't use a fungicide for this pathogen that's not going to be effective at managing either the beetle or the bacterium so we talked about some fungal pathogens and some bacteria the last group here are viruses so solinaceous and cucurbit plants can get many of the same viruses some common ones that are well documented are tobacco mosaic virus tomato spotted wilt virus cucumber mosaic virus potatoes also if you get potatoes from the seed obviously you're not going to have a chance to see their foliage before you plant them they have there's a high level of incidence of potato leaf rule and potato virus y and potato plants and those are spread by vegetative propagation I'm just going to kind of treat viruses as a group here I'm not going to go through each one as you've probably noticed we don't have a ton of time left to do that so what are you going to see if you have a virus? well chlorosis is a common sign of viruses when we talk about tobacco mosaic cucumber mosaic we're talking about the mosaic pattern of the chlorosis and the healthy green tissue so sometimes it can be maybe a little difficult to tell a viral infection apart from a nutrient deficiency one way to tell is with nutrients usually depending on if the nutrients mobile or immobile the older leaves are going to look more affected the new leaves will look healthier or vice versa a virus will be more sporadic throughout the plant also with nutrient disorders usually the veins will remain green and the intervainal tissue will be yellow or vice versa whereas you can see how random like the chlorosis is that's actually a picture of a chikurbit with cucumber mosaic virus so it's not going to follow those patterns of the nutrient deficiency leaf distortion can also occur and to some degree that could be confused with chemical herbicide spray damage so ask yourself you know what makes sense if you're in a heavily urban area and you have a small yard with a fence up and you haven't applied any herbicide chances are you're not getting any drift right but if you're out in a more rural area where spray activity is going on might be more difficult to determine on your own if it's a herbicide or a viral infection so here's a tomato plant and it also has cucumber mosaic virus and it looks a little bit different than that chikurbit that we showed so plant viruses are typically named for the host that they are first discovered on and the symptoms that they produced on that host different hosts or even different cultivars or even different varieties of that host as well as other variables such as how long has the plant been infected what other stress factors does that plant have in the environment is it healthy in spite of besides that virus is it healthy or is it also experiencing a nutrient deficiency or drought stress those are going to make it look a little different so that's why it can be somewhat difficult to determine if you have a virus or not it's pretty easy if you see cucumber mosaic virus in a healthy susceptible cucumber plant but it can be more difficult and some of the many other hosts that are susceptible and then some viruses will also include necrosis so here we have a tomato leaf with tomato spotted wilt virus and that's a very severe virus that will result in the whole death of the plant eventually but at first you'll see spots and the plant will start to wilt and then over time that the leaves usually first will turn necrotic and then the plant will just lose all of its leaves and the stems will wither up and die and of course how fast it does that it's going to depend on how healthy is the plant otherwise you know if you're watering it if you're reducing all of those stress factors it might withstand that virus for a very long time maybe even the rest of the season but if there's other stress factors involved that plant's going to succumb to that virus much quicker so overall plants with viruses are just going to be unthrifty they're going to probably be stunted grow slower they're going to fail to perform they might still produce some fruit but it might be smaller and it can be hard to identify a virus because as I already mentioned there's so many different factors that can contribute to how that virus is being presented on that plant what are the symptoms on that plant so it is a really good idea to get confirmation of a virus some viruses are spread by insect vectors others can be seed-borne so confirmation is going to help identify the origin of the virus and provide you with specific management tools and the Plant Diagnosis Lab is able to identify a lot of the common viruses that are found in the landscape in North Dakota any produce produced on these plants will still be safe to eat but they might not taste very good since the plant was sick so here's just a nice image of cucumbers that have varying degrees of severity of cucumber mosaic virus so none of these viruses are going to infect us our immune system is pretty amazing compared to a plant and these viruses aren't going to do anything to you nor do they have the correct receptor proteins for you but you still might not want to eat the produce just because you might want to spend your time eating something that tastes a bit better so that's really it for the different pathogens we're going to talk about perhaps you think that was more than enough as I had mentioned my goal here was just to kind of expose everyone to the different pathogens we didn't go too in-depth into any specific one I do want to wrap up the talk looks like I have a few minutes left just to talk about some abiotic disorders that might look similar to some of the things we talked about today so herbicide damage as I mentioned can also cause leaf distortion and solonaceous plants are extremely sensitive to herbicides potatoes especially you could get a very low level of dicamba or other growth regulator that could hit your garden all the other plants will look fine and your potatoes will look absolutely crazy tomatoes are the next most sensitive in general but they're quite a bit less sensitive than potatoes and the source of the herbicide could be from several different things if you do manure amendments there are some growth regulator herbicides they apply to forage selective for dicots that cattle will eat and it will remain stable through their gut and persist in the manure and can be introduced to your garden that way and depending on the rates it might be low enough that no other plants are affected but your potatoes again kind of go crazy so here's some examples of that with the leaf curling and the puckering and so potato plants with PVY leaf roll and potentially even cucumber mosaic could also have some leaf distortion so just something to keep in mind and then if you've ever grown tomatoes I'd be very surprised if you're not aware of blossom in rot but I just wanted to kind of go full circle here and remind you that there are other things that can cause rots of your tomatoes and even though in these photos we show it coming from the petiole down you can get infections on other parts of the tomato so you might not necessarily want to assume that your problem is just blossom in rot but of course if you're doing container gardening blossom in rots exacerbated by not just a lack of calcium but also with the plants experience very dry and then wet and then dry alternating conditions it just makes the plant unable to utilize calcium even if it's present and will result in that blossom in rot the collapse of those tissues because they don't have enough calcium for their cell wall so with that holy cow I ended on the minute I'm quite proud of myself so so with that if anyone has any questions I might have answers all right well we have five questions that have popped up oh okay I try to should I look at those now I'll just say them out loud and they're also in the chat so Becky asks does crop rotation count as moving plants to minimize pathogens oh absolutely yes yeah that's the whole idea with crop rotation on larger scale agronomics and then you can do that on a smaller scale in your garden I would say the one thing to think about is if you if you have your plants kind of organized into different blocks and the block is sharing a border with where they were the previous season that's probably not sufficient you want to actually have some you know some space there what the exact minimum you know number of feet or whatever that you need to space them apart I don't have a specific number there but the more the better all right thank you I posted a comment myself this is Julie we have some resources from other states for you available on the Field to Fork site and also a certificate so that's just a reminder that you can click back to Field to Fork and you'll be able to pull open some other resources so Judy asks if a plant is asymptomatic of bacterial infection how do you detect the bacteria well you probably wouldn't but there are PCR tests so through the USDA and sometimes they'll partner with labs that will have to adopt their protocol but they'll just randomly select plants in a greenhouse bay for example and or the seed of those plants and test them for the presence of the DNA of that bacteria I do similar testing on potatoes for bacterial diseases so I can't give you the exact details but yeah basically they do diagnostic monitoring to prevent it from being spread all right so here's your next question you mentioned heat treatment in water at a certain temperature how about dry heat or how does that affect seed viability I would presume the dry heat would not be preferred to wet for potentially a number of reasons I think the wet is probably going to be more effective because rather than air you know you have a more solid substance coming into contact with the bacteria so it's going to always be more effective I've not really read anything either way about dry heat I've only ever heard of people using the the wet heat all right here's another question do pathogens arise if seeds are stored and used in future years I'm sorry you got really quiet towards the end of that question okay let me try it again do pathogens arise if seeds are stored and used in future years well the path is either going to be there when the seed was collected or it's not so it could remain on that seed even if you hold it for more than one year yes but it's not going to spontaneously arise on that seed it was either on that seed when you collected it or it wasn't all right and from Lucinda for blossom rot does adding eggshells to soil help or what else can we do um the biggest thing you can do is try to keep your tomatoes appropriately watered eggshells can help the problem with organic amendments like that is just that they take time to break down so a non-organic form of calcium that's immediately bioavailable is going to more quickly and readily but if you're adding eggshells every year as a form of maintenance that can certainly be effective so it's kind of the two-step combo but even if you add calcium you're still going to see blossom and rot if you allow the plant to become water stressed and another question just popped up you're doing great Jesse does cool storage of seeds affect pathogen viability uh no the the pathogens are able to survive out in the landscape through winters so they're going to be fine if you cool down the seed again if the only one we talked about today was phytophthora infestants and it would um it would not survive at colder temperatures but it's it's not seed disseminated anyways it needs a living host so okay does anyone else have any questions you want to type in we have a few minutes left I was interested in your comment that the plant diseases that some of the ones you were showing us do not affect us what is your what's your thought on cutting off those diseased parts of fruits of the plant and like eating the rest of it eating the rest of it well that's what I do well I would say so some fungi can I don't really want to get in this too deep but there are some allergic reactions to different things especially with fungi you know when we hear about like home molds and things they affect people differently same could be said of anything on your produce so there's not zero risk there that something could be produced that someone would have a reaction to personally if it's heavily fungal rot I throw it away but if it's a small spot like you're just seeing that first photo of anthracnose where you get that kind of localized water soaking but you're not seeing any of that black growth or that the skin hasn't cracked open I cut those parts off and eat them in the world of food preservation we usually say preserve the best and eat the rest yeah there you go all right well I think that brings us to the end and I really want to thank you Jesse for doing this and maybe we can do it again okay well actually it was pretty fun so thank you for giving me the opportunity to do it and thanks everyone for being here we have three more of these wednesday webinars left in our series so join us next week for pollinator gardens