 Oh, and then, of course, my phone starts. A webinar. I'm so pleased that you have joined us today. We've got quite a nice crowd. Now, I hope you all had a great Thanksgiving and that you're well recovered from that. But we all know that growing in high tunnels can be quite challenging. It raises new problems that we don't normally see in the field. So the purpose of this new monthly webinar series is to address those day-to-day challenges that high tunnel growers face in the northern Great Plains. Now, as our first speaker, I'm so delighted to welcome Dr. Sally Miller. Dr. Miller is professor in the Department of Plant Pathology at The Ohio State University. She specializes in research and extension in vegetable crop diseases. And she's assembled a great team of undergrads, graduate students, postdocs, and visiting scientists that focus on researching the biology and management of bacterial and fungal diseases of vegetables. So they've got a great website that you should visit. She's got quite a bit of information out there. And I'll send you the link to her website after this webinar. But Dr. Miller has had an illustrious career and was named a fellow by the American Phytopathological Society in 2011. And she was elected the president of that society for this year. So welcome, Sally. And she's going to be presenting on identifying and managing diseases in high tunnels. Thank you. Oh, thank you, Esther. I'm really pleased to present this webinar today. It's a beautiful day here in Ohio. It's actually kind of warm and I know it's probably chillier up where you are. And I will use this as a chance to say, of course, what I'm talking about here is our or our experiences in Ohio. So there might be a bit different for you because of the differences in the climate. But I think because, again, these are high tunnels that would be quite a lot of similarities. Okay, so let's talk about disease in high tunnels. These kind of structures provide a unique microclimate for plants and pathogens. So what happens is that because you're protected, the plants are protected from rain primarily, that will eliminate certain diseases or reduce them to inconsiderate or extremely low levels. But it can because humidity tends to be higher in temperatures or higher. You may have other disease you don't see in the field. So that is one of the key things with that differentiate. So sometimes growers who've been growing tomatoes, for example, for a long time are surprised or a little perplexed when these diseases show up in a high tunnel that they have never seen before. Also, depending on number of factors, diseases can be different in different high tunnels on a single farm. Now, for foliar diseases primarily, you can use fungicides in high tunnels. We'll talk about that in a few minutes. But there are limited because of the regulations on use under greenhouses and high tunnels. You can manipulate the environment in a high tunnel to a certain extent. A lot of what we know about high tunnels, we're extrapolating from greenhouses and some greenhouses are much more sophisticated than high tunnels. So they have a lot more ability to manage the environment. But again, still there is a possibility of doing that. And primarily you're looking at moisture and humidity control. Well, let's start first with some abiotic disorders. We'll just talk about them briefly. That can happen. And so these are where you don't have a pathogen, but you still have a problem with the plant. And there are a lot of them. We see quite a few of these come into our diagnostic clinic every year from high tunnels. And again, they can be caused by a number of things. Soil condition, pH, for example. Most vegetable crops don't like to stand in water. So water can be a problem. Air pollution can be concentrated in a high tunnel. Excesses or limitations on nutrients are a very common problem. Especially, well, I say there's probably more problem in hydroponic systems where it's a lot trickier to get the nutrients right if you have good soil. It's not as much of a problem. Sometimes we can see chemical burns where chemicals or pesticides are applied. Maybe the temperature is too high. Inside that high tunnel, you can see some phytotoxicity and then genetic disorders can happen. Now this is one called edema, a problem that we see fairly often in high tunnels. And that's when you have cool overcast conditions and very humid and the soil is saturated. And what happens is the plants can't get rid of the excess water in the system. So you get these water-filled pustules that they burst and form a kind of cork over. So it's kind of a rough, quirky thing. And again, it's not a disease and it tends not to cause severe problems in the high tunnel or greenhouse. But it is rather just concerning when a grower sees that. Here's another thing that this is damage from heating systems. If there is heat being applied and maybe internal incomplete combustion, you can't get gases that cause these kind of problems. And one of the problems with that is it does look like bacterial canker. And that's a kind of scary thing. But once the heating problems are eliminated, these usually clear up. Now this, I'm bringing up herbicide damage because I'm sure most farmers are aware and extension folks of the controversies over, especially the dicamba herbicides and drift issues. And we normally see a couple of samples with tomato plants or other vegetables with what we believe is herbicide damage. And we always get help from our weed scientists on diagnosing those things. But we had quite a number. We had 10 samples, which is about 10 times more than usual, with suspected herbicide damage this spring. And most of those came from high tunnels. So there is drift. It can concentrate underneath the high tunnel if the sides have been open. So again, dicambas an issue here are 2,4-D damage. You can also occasionally see glyphosate damage that's drifted. And that's very typical. This is strawberries on the right. But this kind of bleaching on the leaves is very fairly typical of glyphosate. But there are others as well. But those are the main ones that you might see that are herbicide. And they're kind of difficult to diagnose for sure because some viruses will cause some similar symptoms. And also it's often hard to find the source because a drift can be coming from a long ways away. Okay, so let's get into foliar. The foliar disease is caused by fungi and what we call omicids like phytophthora. So one of the ones we growers tend to have a problem with is white mold. And this is a fungus called sclerotinus sclerotiorum. Usually it's not a problem in the open fields because it relies on high relative humidity. And essentially the fungus produces these black structures you see down here. And they, in the springtime or when those conditions are cool and humid and they have adequate moisture, they will produce a fruiting structure and the spores are released and then they eventually will kill a plant. So in germinate. So here's a tomato. You can see this wilting like this. And often you'll just see one plant here and another plant there. If it gets severe enough you can see quite a few dead plants inside the high tunnel. And here's the one where you can actually see the sclerotium there forming on the outside even where the red arrow is. I assume you're able to also see my moving arrow. That's correct. Okay, great, thank you. Another issue is powdery mildew. More often I've seen this in greenhouses than in high tunnels but you can't get it in high tunnels. This is a powdery mildew is a different disease than most in that it's inhibited by free moisture on the plant surface but again like a lot of others it's favored by high relative humidity. So it can really seriously cause problems if you get it in a high tunnel. Again so far we don't see it too much but it certainly can happen. It can really cause serious problems, it's difficult to control. The good thing or I wouldn't say anything good about diseases but usually it's easy to diagnose and if one catches it when it just has a few of these little colonies forming like the little white one you see there or if there are just a few and can take some action then usually reduce the relative humidity and even possibly use some fungicides. It can be gotten under control but when it gets really bad it's very difficult to control. Now but Tritis is another pathogen that really causes a problem in the greenhouse on all kinds of crops. It has very wide host range but on tomato you can get some of the symptoms here. It can kill the flowers, you can get stem cankers on fruit. It can actually rot the fruit like you're seeing here and all of this up on the calyx and the peduncle are all spores of botrytis. If you've grown anything in greenhouses for a while you've probably seen botrytis. Sometimes it causes these V-shaped lesions like this and then this is what we call ghost spot. You can see this on green fruit or ripe fruit and you see these little circles that's botrytis where basically the pathogen is kind of a weak pathogen and it got started on the fruit and then it kind of aborted the... So it won't rot the fruits but still those circles on there are making it unsaleable. So it is a problem. Again, this is another pathogen that's very much favored by high relative humidity and cool to warm temperatures but hot temperatures not so much but coolish temperatures. Then this is another foliar disease or two of them actually. I doubt that you have black leaf mold in the lower pictures. That tends to be a Southern disease but we did find it in Southern Ohio a couple years ago but this one, yellow leaf mold on the top is very, very common in greenhouses and it's very easy to diagnose because you have these yellow patches on the surface and you look underneath there are these patches of furry fungus that's growing there. It's kind of an olive green color. Okay, another one then is lape blight and this is an occasional problem. Again, I think if you... most of folks know about lape blight and that is a disease that's favored by cool wet conditions. This picture was actually taken in a greenhouse 20 years ago and the entire greenhouse was destroyed over a weekend by this disease. So if you have the right conditions, cool and wet and inoculum around and that's another issue so the inoculum is not always present. So if you have all those... sort of the trifecta of things around all the negatives you may have a problem and it can proceed very quickly. So it can be inside of a high tunnel even if it's protected from rain because if the spores blow in and land and then you can get high relative humidity and move things, things can be moved around. Okay, so then let's move on from the fungi andomyces to talk about bacteria and there are only I believe two I'm going to talk about but the first one is a biggie and that is the bacterial canker and outbreaks of bacterial canker can happen in the field and they're very common in the field or in the greenhouse or high tunnel. This is a easily mechanically transmitted disease so it can go systemic, it's in the plant's vascular system so any kind of harvesting operations or trimming plants, any kind of thing where plants are handled the sap can be moved around from plant to plant and it can become a really, really serious problem and this is a seed-borne disease but it can also persist in soil. Interestingly it does not, we don't find it in the southern United States or in tropical countries like for example in Florida or most of the tropics because it just doesn't survive very well in very high temperatures but in the temperate zones it survives very nicely and once it's introduced on the seeds it can last for a number of years in the soil. And then this is another one called tomato pith necrosis this is a different bacterial pathogen and it is very ugly what it does you can see here that it gets into the pith of the tomato stem and just pretty much liquefies it and you can see here an earlier stage of that and this is a scent, it's very common in high tunnels but it's not generally a rapidly moving thing that you'll find great blocks of plants affected this is usually one here and one there I don't really understand why that is the bacteria are common in the soil and they get into the plant when there are wounds and it is favored by cool nights and high humidity but also high soil nitrogen levels so that's where we tend to find it when there's a little too much nitrogen happening or other imbalances in the soil. Okay, let's move on to viruses and again viruses can be very unforgiving and we certainly want to keep them out of high tunnels as any tomato production system or any vegetable production so I'm going to split these up into the insect transmitted viruses and then the mechanically transmitted so primarily thrips transmitted viruses are the concern in greenhouses and the main one is tomato spotted will virus and that is primarily transmitted by western flower thrips although probably some other species may be important as well but that's the main one and there are some other gospel viruses I have a picture I'll show you another one and these are very difficult diseases because it's hard to see the thrips a lot of times they're just hiding in flowers or they're hiding and you can't find them and you'll see them so they're not controlled and then they can in fact transmit those viruses to plants and the symptoms are very severe depending on when the plants are inoculated so when the plants get a virus if they're young they may not grow out of it at all and they may be very stunted and necrotic as you'll see up here on the left you can see necrosis and curling and also some mosaic type symptoms and then you get these misshapen fruits with various kinds of spots and I'll show you in the next picture a separate TOSFO virus we call these TOSFO viruses all the related tomato spotted world type viruses and then you may also see APA transmitted viruses like cucumber mosaic virus this was on peppers but it's not so common this again is another TOSFO virus called tomato-chlorotic spot we found this in a high tunnel in 2013 in Ohio we didn't see very many kind of symptoms on the foliage but the fruits were having these ring spots and this kind of necrosis like this here's a big green spot on this one and in all these cases where we in our situations have found TOSFO virus problems it's in greenhouses where seedlings were raised near or with ornamental plants and ornamental plants are very big carriers of TOSFO viruses and also thrips so we have to be really careful we always recommend that vegetables are not produced in the same greenhouse as ornamentals of any kind because they can harbor these TOSFO viruses and the worst thing you can have is for TOSFO viruses to be introduced in the seedling stage so the TOSFO viruses can be mechanically transmitted but mostly moved around by thrips but these are mechanically transmitted viruses and they tend to be problems in greenhouses again because there's so much handling of plants and so tobacco or tomato mosaic virus very similar and I really can't tell them apart by symptoms but they can if here you tend to see a mosaic type of symptom and a lot of distortion of leaves here you can see stunting and very severely distorted seedlings leaves and other tissues on these seedlings another one is papina mosaic virus and I have to say we haven't seen a lot in high tunnels but it is a huge problem in greenhouses and you can get these kind of symptoms you're seeing here which is kind of a mottling appearance on the fruits and you'll see leaf symptoms as well and then the last one I just want to mention are viroids and they are related they're they're basically naked nucleic acids they don't have a protein coat like viruses but they are also mechanically transmitted and they can really this one's potato spindle tuber viroid and they can really destroy a system and then we have seen these or they have been recorded in greenhouses but high tunnels I haven't we haven't seen them in Ohio anyway okay so then I'll talk about soil born diseases because these are becoming more and more of a problem and a lot of that is because many high tunnels are not movable and so the same tomatoes may be grown year after year after year we had a grower in southern Ohio we had tomatoes year after year for 15 years and that's the picture you see here they finally got to the point where it really weren't getting much yield at all out of these plants they were stunted and they had all these symptoms this is pretty much an unmovable greenhouse so then we'll talk about how you might go about dealing with some of these problems obviously the easy one is to move it somewhere else to move the high tunnel but we can again we'll talk about that so why are these soil born diseases becoming more severe and I will say that in Ohio the high tunnel interest and people using high tunnels be going on for about 15 to 20 years I would say we've had greenhouse production for longer than that but the high tunnels really started emerging in the last 10 or 15 years and so we have people who have been producing without rotating for quite a while so that results in most people want to grow tomatoes because those are very high values so you don't have a lot of options for rotating to other things that are just different plant families that are just as valuable again you don't have for most free periods technically are they reduced because you can grow tomatoes for a long time and so then the pathogen populations can build up now you might also have reduced winter kills of pathogens or perhaps vectors the environmental conditions as I mentioned before can favor certain pathogens and then you won't have the reduction of these populations so here are some of the diseases that we typically see these are fusarium and verticillium wilts and they're fairly not so easy by looking here to differentiate them but you can recognize them as a wilt with this kind of discoloration in the tissue here you have the vascular tissue browning like that with verticillium you often see these V-shaped lesions on the leaves with fusarium you're going to see yellowing in general in this kind of dieback of the plants but you also often just see one side of the plant so if you can imagine that back here you see this is where all the diseases the discoloration and the stamina kind of coincides with one side having symptoms now we're also seeing quite a lot of fungal rubro complexes and so these populations where if you had a long rotations you might not see them they're kept at fairly low levels they can grow up pretty high and enough to cause some damage while also finding fun fungal disease complexes and we'll talk about that in a minute where these fungi act together to cause damage to the plants so one of the diseases I'll talk about is brown rubrod and this is caused by colototrachem cocodes which is also the causes anthracnose as you see here so anthracnose of course is extremely common on tomatoes and those tomatoes drop to the ground perhaps they're not cleaned out of the high tunnel and that inoculum goes right into the soil and eventually that causes this brown rubrod we're not sure how important brown rubrod as a yield limiting factor is at this point but we do know that it can be often found together with something that is pretty serious called corky rubrod and that's another fungus, pyronekita for us it's critical pardon? okay so let's go on then we have some other players fusarium, epithiom, and rhizectonia there are probably others as well so here are some symptoms this is pyronekita or corky rubrod you look for these cracked symptoms on the roots sometimes you'll find that also cracking in the crown when it's very serious and you can see these dark roots here that's very typical here's another one where you see these kind of bands of dark roots where they're necrotic and have been affected so if you're looking for the combination you might see and look with a hand lens you will see these little tiny black dots and that's very typical of the colichatricum that's part of the fungus structure that's growing on those roots now nematodes if you ask me a couple only a few years ago are root not nematode a problem in Ohio I'd say no we never see root not nematode but with high tunnels because the soils tend to be warmer for longer we are seeing a lot of root not nematode and in southern Ohio we see one that makes a big root knot like this and this is a southern root not nematode and in the north we'll see one that's smaller kind of galls and that's a northern root not nematode so I think that this is one that we're going to have to deal with as we go along in the future but it has really not been a problem much in the past and that being said I would say even in the field out in the outdoors we're seeing more nematode problems than in vegetables than we had seen in the past which is kind of surprising to me but interesting okay so let's go on to disease management so we love plant pathologists we love to have pyramids but this one is about IPM so essentially it's when you start from the bottom up how do you manage these diseases or manage the crops so that you limit diseases as much as possible so the major part should be prevention you have cultural practices, sanitation and you can have physical mechanical barriers for example or treatments and then biological control and chemical control should be the least used practice so clean planting materials are very keen for example bacterial canker as you saw mentioned was a seed borne there are these viruses tobacco mosaic, virus of tomato mosaic are also seed borne as is papino and the viroid so it's important to eradicate or reduce those bacterial or viral pathogens on or in the seed we have here's a I've got two websites here and this is within my vegetable disease facts website and there are videos here on how you can do chlorine treatment and hot water seed treatment and some people use acid treatment as well some people use trisodium phosphate for viruses but essentially as I'll show you in a moment the chlorox treatment will kill most of the viruses so hot water treatment is really only necessary if you have a concern about bacterial canker if that's the case because bacterial canker can be inside the seeds and the chlorox treatment will not necessarily take care of that problem what we recommend now is that if you are going to do a hot water treatment is that you also follow that up with a chlorox rinse in case you have viruses because the hot water will not take care of the viruses okay so again there are videos here and also that will give you a link to our fact sheet on that so inspect all the transplants they're going into high tunnels make sure that there aren't any diseases root diseases or foliar and take out any infective plants now another sort of foundation of disease management is the use of resistant varieties of course unfortunately we don't have resistance to everything now a lot of varieties are available they have resistance to man and mosaic virus or tobacco mosaic virus but unfortunately not all the heirlooms that people like to grow in high tunnels are not resistant let's say most of them are not resistant so I think you really have to be careful about these make sure you have clean seed when you're dealing with heirlooms and you don't have the resistance available you can check with your seed supplier one of the things I do like to say though is a lot of times a seed catalog will say something is tolerant to a particular disease and usually that means partially resistant so they'll say resistant if it's a pretty good almost immunity type of resistance but if it's partially resistant they will call that tolerant now grafting is another excellent means of dealing with some of these problems so essentially what we can do is we can take a disease resistant rootstock and graft the scion that we want onto that so a lot of rootstocks are available right now that are resistant to numerous diseases and grafting is a process that is rather specialized and it's not necessarily I mean people can pick it up you'll see down at the bottom here is our grafting guide from Ohio State University and it certainly could be done by individual growers but a lot of times you can just purchase those from propagators you can even buy them from Johnny's now they're going to cost more than grafted plant might cost $3 per plant but some of these seeds are $0.60 to $1 anyway so you might want to think of that if you have some soil-borne problems and in fact the truth is that almost all the tomatoes that are used in hydroponic the conventional greenhouse tomatoes are grafted and that's partly disease resistant because it's hydroponic they're not seeing the soil-borne pathogen that you see when you have a soil system but most of these rootstocks are also really vigorous and so they impart quite a lot of vigor to the plants and that usually translates to higher yields so when you want to select the rootstock either whether you're purchasing a rootstock or purchasing seeds or you're purchasing grafted plants you really should know what the problems you've had in your high tunnel and so you know what kind of rootstock that you should be looking at now Maxifort and Beaufort are extremely popular varieties and they have multiple disease resistance none of these are resistant to bacterial canker but they have root not nematode some of them to some forms of the root not nematode and numerous of these fungal diseases and we already mentioned the cost and then if you're doing it yourself it just takes a while to learn how to do it but once you do that it can work now there is a description of commercial tomato rootstocks that's updated annually and you can find that on the internet I'm sorry I didn't put the link there okay so the next thing is rotation and again we know that that rotation options can be limited but high tunnels can be built to be temporary structures it can be moved from one location to another and this was actually on our research farm and I can tell you that even though this is a movable structure it withheld some very high winds so I think it can they can be an option in a lot of situations obviously if you have movable structures and you want to rotate that you want to do different families although certain things like for example white mold has a very wide host range and even crop rotation won't help with that okay so you might also think about environmental management which is first of all is avoiding over watering and most high tunnels are using drip system so that should not be a problem you should really not rely on any kind of overhead watering in a high tunnel situation even if it's with a hose it's really better to have a drip system again we like to have the humidity as low as possible as you head into the evening to reduce the chance of these fungi germinating with high humidity soils should be well drained try to moderate the temperatures of course if you have experience with high tunnels it's pretty hard you have limited options which are rolling up the sides and opening up the ends some have installed fans in the high tunnels so the other thing you can do and we've seen quite a bit of success with this with growers is really to plant those I have wide plant spacing so that you really get plenty of ventilation within the canopy and that also to prune them, staking them and trellising them as well so that really you want to keep the humidity in that microclimate around the leaves and the stems as low of humidity as possible when the seedlings are being produced obviously you want to have clean planting mix and most growers or propagators are doing that and in that system if you have somebody growing for you you want to check what they're doing make sure they have clean floors and they have gravel or plastic floor covering so they're not picking up pythons or isoctonias or other pathogens pathogens can be surfaces can be disinfested to get rid of those pathogens and there are a number of options that I'm going to show you some data we have in a moment of course you use flats and you can use clean flats but they really should be sanitized so again they need to be soaked in one of these disinfectants for at least 10 minutes and then also workers need to wash their hands regularly and there should be no smoking in fact I would go so far as to say no smokers working inside of seedling production greenhouses or even in the high tunnels because tobacco mosaic virus is an extremely stable virus and it can actually be transmitted from cigarettes handling cigarettes and onto plants which we always recommend now one thing I didn't know is that you do have somebody who is a smoker obviously if they can put on a coveralls and also wash their hands and then a dip in about 50% dry milk solution will inactivate viruses on hands as well so you can dip your hands in this milk solution rinse them off and that will help as well and then obviously take care of disease seedlings now another thing is it's hard to keep a handle on the weeds that are growing in and around the high tunnels and so they can harbor insect pests and some pathogens and obviously they are going to reduce the air movement and keep that relative humidity high so weeds need to be reduced again take out disease plants and even dead in disease tissue some growers will after pruning believe that the pruned material, plant material on the ground I think it's a bad idea should be taken out and disposed of okay so here for sanitizing there are many different kinds of sanitizers, alcohols and quaternary ammoniums are very very commonly used various botanicals but they there are a couple of things you have to think about when you're choosing a sanitizer they have to have an effective with a short contact time within a few seconds preferably they should broadly be effective against viruses, viroids, bacteria and fungi not harmful to workers not corrosive or phytotoxic and economical and so it's really hard to find a sanitizer that meets all those criteria we did a couple years ago a bunch of tests on sanitizers we were looking at back to the bacterial canker pathogen botritis which we've mentioned in these viruses and viroids that we talked about so you don't need to memorize this list it's a long list here of the different things that we tried but here if you look at the results in the end so we took a little check mark for everything that worked really well and and the little parentheses around the check mark if it was sort of good but not consistently good so the best things that we found were 2% vercon which is a little bit high but it had a very high short contact time one second for clav for bacterial canker and a second as well for botritis another one that was quite good was and certainly cheap is chlorox and that was 10% chlorox and again very short contact times it was a little bit equivocal with popino but it took care of tomato and tobacco mosaic viruses and the viroids now lysol is another one that worked fairly well it needed a little bit longer contact time against botritis and it was a little bit variable against some of the virus and viroids but it was another one that's not too bad so obviously the non-fat dry milk I talked about worked fairly well against the viruses and viroids but it has no effect whatsoever on fungal or bacterial pathogens so these are something to keep in mind when you're picking out a sanitizer to use to sanitize tools, sanitize the sides of the high tunnel after the crop goes out etc so then I'll move on from sanitizers and pesticides and I think most folks are aware especially if you've been growing in high tunnels for a while that their rules for registration of fungicides and other pesticides are different for greenhouses and high tunnels than for open fields so that has to be certainly taken into account and in Ohio and all the states that I'm aware of and again you can check with your extension about your area as to what your state because the state makes this distinction is whether a high tunnel is the same as a green house so in Ohio the rules are that a green house is the same as a high tunnel or a vice versa and so the rules for green houses apply to high tunnels so for example here on this table that comes out of our spray guide for vegetable crops this one happens to be insecticides but you find exactly the same the same thing for fungicides so you'll have a group that are labeled as a green house use where the label prohibits the use in the green house and then you have one where the label is silent on green house use and again what our Ohio EPA has said is if the label is silent on green house use you can use it in a green house but that could depend on your state and you really need to check that before you use any of these and this is also only for non-restricted pesticides that really have very many restricted fungicides okay so when you're talking about high tunnels where you have products that you're allowed to use most seeds are already treated with a fungicide when they go into propagation maybe not the not the rootstock seeds but essentially it's not so critical fungicide seed treatment foliar fungicides as I mentioned are somewhat limited and then the soil fungicides are very highly restricted or they don't work so either we have not seen soil fungicides that work particularly well or by a lot there are some hydrogen peroxide based ones that are being promoted but we have not find efficacy with those bactericide treatments for the bacterial diseases generally you're talking about coppers unless some biologicals but they are not highly effective against bacterial canker or pythnecrosis the only antibiotic that's allowed on tomatoes is streptomycin that's only in transplants it's not permitted inside high tunnels so again for the vector the viral diseases like thrips there are insecticides that can be used and there will be another webinar on this kind of later on in your series so what are some other options one is organic matter so we found that in general adding organic matter is good for soil health it improves the soil microbial community structure so generally a good quality compost in a high tunnel I wouldn't recommend manures but cover crops are also a good thing in the fall when your crop goes out to put a cover crop in the high tunnel to improve and that can be however you choose what kind of crop you want survives in through the spring you can turn that under and then allow it to decompose and that will add some organic matter but a good quality compost applied in the fall is I think one of the better things you can do for your soils sometimes these organic matter amendments can cause the soils to become suppressive to diseases because it enhances the quality of the microbial communities that are there of the good bugs the good bacteria and fungi etc and nematodes and so those things can help keep populations of the pathogens under control there has been some use of biofume against mostly brassicaceous plants and these brassicas produce compounds of pathogens and you can use as a cover crop or you can add green tissues or seed meals and we don't have a lot of information on that, certainly not in high tunnels but I think that others have done some research in this area so then of course when we're talking about IPM we really like to look at bio control options but we don't always have bio control as much like there are drenches that you can apply to manage soil-borne diseases there are also others that can be applied fully or some of them are resistance inducers and will kind of boost the resistance of plants so they they're worth trying but most of these biological controls can be inconsistent and they will never I haven't seen any that give 100% disease under high pressure situations they will knock back or help the plants to maintain some health even in the presence of pathogens again just like pesticides make sure that those products are labeled for greenhouse use or that there's nothing on the label about greenhouse use or high tunnel use the labels will say greenhouse they won't say high tunnel and then if you have a problem we recommend that this Contan's product which is Coney-Aetherium Minitans, a fungus and that basically parasitizes the sclerotia and so you want to do that after you take the plant, the crop down and apply that and you may need it to apply multiple years to get those populations down and it doesn't necessarily take care of everything because those Ascosmores I mentioned that are produced by this fungus can blow into your crop from elsewhere but it will help a lot with the sclerotia killing those sclerotia that you have inside the high tunnel so if you're going to go I think we talked about this, I apologize for that I meant to not keep that one there okay so let's move on then to the other last thing I want to talk about is anaerobic soil disinfestation and that's as a means of managing diseases in the soil born diseases in high tunnels so this started off in the Netherlands probably 10 or 15 years ago and also in Japan there's quite a lot of work done there and then it's been tested in Florida, California, Tennessee Michigan and now Ohio we've been working on that a couple years here in high tunnels in open field situations so I'll go through how this works but you add an organic matter amendment saturate the soil and cover it with plastic usually around 4 weeks but sometimes longer depending on the temperature of the soil the soil is very warm you can get by with a shorter period and what happens during this process the microbes break down that carbon source they use up the oxygen because it's flooded can you be used up and they produce various kinds of acids and volatiles as well as in the liquid form and these toxic byproducts kill the pathogen a lot of plant pathogens tend not to be very they're really adapted for infecting plants they're not as well adapted to surviving adverse conditions in the soil so you will often see a general reduction in these populations so you can apply this to beds or to flat soil and I'm going to show you some data now from two sites one of them I mentioned before that had tomato production for 8 years another one had tomato production for 15 years or so and they had a bunch of different problems, verticillium root they had that pirakida or corki root rot complex with brownbrew rot as well as root knot nematode so you can see here if you just look at the root rot severity on the left then these are kind of the amendments we've been working with, the Japanese work with ethanol a lot it's very easy to apply it's a low concentration like 1-2% ethanol but we haven't found an inexpensive source of this yet so we have not really been pushing that we get just as good results with wheat bran and we also sometimes combine wheat bran and molasses and you can see here the significant reduction in the severity of root rot compared to our controls we are treated or with everything except the organic amendment in this case it's not treated at all but also uncovered so it's more like your normal practice where we see really striking results is with nematodes that destroys the nematodes here are the controls on the right so here are the three steps of ASD this is a picture from some of the work they're doing in California so incorporate the organic matter saturate the soil and put the tarps on so there are a bunch of options as I mentioned for carbon sources you want to pick something that's inexpensive so wheat bran is a byproduct obviously in California they have access to rice bran so we generally use that I have a student working on this in Nepal and he's using lentil byproducts from lentils so you can use whatever is available as an organic material molasses is also relatively inexpensive we don't have a lot of experience here with cover crops but I think that's another thing that could be very useful so the rate that we generally use is 6 to 9 tons per acre as I mentioned we use wheat bran and wheat bran plus molasses that's what we're testing so here's a greenhouse or a high tunnel we did on a small scale and here's another larger scale system that we had a soil based greenhouse in northern Ohio so again here's the wheat bran was put on the surface and then incorporated worked into a depth of 6 to 8 inches then add the molasses where it's being used and you know it probably works a bit better use a sprinkling can like this because molasses even diluted can spray up, clog up spray nozzles so then the soil is irrigated and saturated to the point where the water it begins to pond and doesn't drain and in some systems you may have to check that during that 4 to 6 week period and add more water so heavy plastic is used and again that can be the same plastic that's used you just poke holes in it when you want to plant soil temperature needs to be above 68 degrees Fahrenheit for at least the first week and again longer the longer, higher temperature and longer is better and again most of the time we've been looking at about 4 to 5 weeks so when you want to plant then you can just take the plastic off or cut holes in it allow the soil to drain and breathe and one thing I will say is that this is a very stinky process because when that soil gets anaerobic it's very smelly soil fertility should be checked because you are kind of messing around with your carbon nitrogen ratios then you can put in your chance plant and then again because you have a lot of carbon in there you want to make sure that you don't have nutrient deficiency because you might have needed some extra nitrogen that might have gotten used up or complex during this process again this is not going to destroy all the pathogens but it will knock the populations down as you saw and so I think that treatments may be needed for several years now what right now mostly we are looking at fall applications the soil is warmer in the fall than it would be in the spring so when the crop goes out then you would be applying this treatment and here is a little bonus I am just putting in at the end is that this process also kills weed propagules I have another student working on that kills all sorts of weeds especially the combination of weed bran and molasses and so here you will see one of the high tunnels we did this fall and here with the yellow are all our treated plots and these are the control plots that we are not treating here is the yellow one back here and here and you can see the difference in the weeds I didn't show the picture but we had another high tunnel where the grower had a lot of volunteer tomatoes come up and none of them came up after the ASD treatment so I think the time is about up now and that is all I want to talk about and I particularly want to thank Anna Teston who is a graduate undergraduate degree comes from the University of Minnesota and she has done this high tunnel work you can follow us and at Ohio Veggie Disease News that is my blog and again that is kind of Ohio centric but we have our fact vegetable disease facts website also high tunnel disease facts are a little specialized and then this is twitter as well so I think I can drop this exit the show now and I will take questions if there are any all right don't be shy you can certainly turn on your microphone and ask the question or else you can type it in the chat box so this is your opportunity oh here I see that we've got a couple already in the chat box so one from Mindy Grant says I didn't see spin a sad on any of the greenhouse pesticide lists any info there I will definitely be watching that webinar on insects and insecticides I'm afraid I don't really have any specific details on insecticides I'll leave that to Dr. Conyas and please do watch that one because he'll have all that he's our specialist on protected culture that's his specialty so he'll be able to tell you what you need to know and Mindy we will have Dr. Conyas on on December 11th at one o'clock so he will be speaking on managing aphids and thrips so we'll be able to ask some of our insecticide questions there and then one from Holly Moby does tomato spotted wilt virus affect anything other than tomatoes is there a topsovirus that specifically targets basil once introduced into a high tunnel can a topsovirus or the thrips that carry it winter or over season to another season okay those are good questions about the topsovirus so the tomato spotted wilt virus has a very broad host range and so it often is found in ornamental plants it can affect a lot it can affect peppers probably it can affect basil sometimes it depends on whether the thrips like basil or not so I'm not exactly sure about that but it certainly has a very broad host range and there are other topsovirus that are related that are more often found in the ornamentals like in patients necrotic spot virus but you can actually get that in a tomato plant as well so the topsovirus is if they are introduced when the plants are seedlings they can be extremely destructive and those plants just don't grow out of it and so we just won't get a crop so it's really critical in the greenhouse not have that problem about over wintering so again a lot like these many of these insect vectors or insect vector viruses they seem like everyone is different and in this case the the thrips can only acquire the virus when they're feeding as large so they eggs are laid by the female they hatch and at first I believe it's the first instar that's when they're feeding they pick up the virus and then they maintain that virus as throughout the whole life of that thrips that insect and that can transmit during its life so when it starts feeding again when it's an adult it can transmit however it does not the females do not transmit it to the eggs so essentially the eggs will go down in the larvae go in the soil and they kind of over winter there I believe Louisa is going to be the expert on this but my understanding is that over wintering should not be a huge problem with because the next generation and I think a thrips insect will allow can live 30 to 45 days so they can continue during a season to infect but I think the over wintering is less of a problem than bringing something in now again if you have perennial plants potted ornamentals of some sort and they've got thrips and the virus now that could be a way of over wintering these pathogens the virus did I answer all the questions I think you did yes great alright so we have more questions one from Tim Gainert do diseases present the same on seedlings as adult plants that's another good question because it depends we always have to say but generally the seedlings seedlings are more susceptible to diseases and so a lot of times plants can tolerate an infection when it's older so if it's infected it may be more severe now I will say on seedlings and I will say that for bacterial diseases particularly bacterial canker that may be present on seedlings without causing any disease and just what we call an epiphyte so it's kind of living on the surface and then when the conditions are right it may then or wounds occur it may get inside the plant cause diseases so in that case it's the opposite and that you may not show the symptoms when you do see symptoms of bacterial canker on seedlings they tend to be these blisters on the leaves whereas when the plants get going in the greenhouse you'll see a different type of necrosis on leaves of course bacterial canker also causes wilting and it will kill the plants next one is there another question oh yes there are would the mulch one uses for weed control whether it's plastic, fabric or straw, affect humidity and or susceptibility to soil borne pathogens all the mulches can have an effect but sometimes it's not a bad effect because even a straw mulch or a plant based mulch can reduce the amount of splashing although again inside a high tunnel you're not going to have that much splashing if you have a drip system but what will happen is that you essentially are going to keep those you're going to pretty much have your soil at a constant slightly moist state so that will affect the humidity so in generally tomatoes for example we like to see that you keep the lower parts of the plant pruned really well because then that will kind of negate any issue of a little bit of excess humidity that comes from moist soil that is coming up through the holes in the plastic for example so if you really and again the plants don't if you have indeterminate particularly indeterminate tomatoes that are growing on strings for example if you look inside of one of the big greenhouses that the hydroponics they are like a little tree with a long rope at the bottom because those stems are completely pruned so you know sometimes those those large indeterminate tomato plants that are grown in hydroponics can be 30 feet long and there will only be leaves on the top 5 feet or so or 6 feet because that's really all the plant needs so again there's no need to have to have a lot of foliage down at the bottom of the plant and it's a good idea to keep that pruned out another question here in your experience with the anaerobic soil disinfestation will this process kill all microorganisms including the beneficial ones and then if so how would you build them back up that's a very interesting question because in one that we've been thinking about it doesn't kill all the microbes it increases anything that it likes anaerobic conditions and so that's one thing also it doesn't, for example trichodermas can survive anaerobic soil disinfestation which is interesting they are not killed in that there have not been a lot of studies done but the few that have been done and this is something we would like to look into a little more too but the few that have been done we're looking at microbiome analysis for example is that generally you will have more concentrations or populations of good bacteria of some of the good bacteria at the end of the treatment but they tend to come back up to normal after a certain period of time but I think there is still a lot not known about that but they again as you see it doesn't have completely destroyed all the pathogen populations so it will reduce them but the same goes for the good microorganisms now question for you on viruses now will the anaerobic soil disinfestation help with a persistent virus like tobacco mosaic virus? I don't know the answer to that I haven't seen anybody working on that and I don't know but that would be a good idea to find out I have a student working on sclerotinia and also the student who was working on weeds in this system the seeds or the sclerotinia the sclerotinia you can bury those in little bags and take them out later and see if they're still viable so that would be a good thing to try with tissue that's got tobacco mosaic virus infection or tomato mosaic I just don't know because it's such a very very hardy virus that I don't know if this would work or not definitely very stable a question from Tim Geinert do you have any guidance or source of guidance for compost at a scale useful for a 3,000 square feet of high tunnel that might be a whole other webinar I think that's a good idea you should have another webinar on this because there are people who are more expert than I am generally I'm trying to remember how it usually puts compost on a fairly low concentration of tons per acre of less than 10 I would believe what I remember and what I've seen growers do almost looks like a dusting over the top and to work that in and again there is a lot of information out there and I did not look that up for details but again it's not a prohibitive amount that you would have to put on and again I think it's probably better to put it on every year than as opposed to putting a lot on it once any other questions well as we're doing that I'm going to share my screen here and I'll show you what we have coming up here just a moment as I so hopefully you can see can you see my high tunnel webinar series screen no maybe not not yet well I guess that's not showing up here let me try one more time here we go are you seeing it now? yes okay so I wanted to wanted to give you some dates here now we did a little teaser that Luis Kenyos will be presenting next so for those of you that had insect questions he's going to talk about managing aphids and thrips in high tunnels on December 11th at one o'clock and he's also from the Ohio State University so his talk will be a nice compliment to Sally's talk and then in January we are going to continue with Kyla Spickle from the Williston REC and she's going to be presenting on vegetable cultivar trials and we still have yet to settle on a date for that now I'm going to be sending you the various links that Sally mentioned so you'll have access to some of these fact sheets and be able to see the fantastic website that her team has developed now if there are any of you that are not on our high tunnel listserv and would like to be you can certainly email me at ester.magenis at ndsu.edu and I will put you on our high tunnel listserv and that will ensure that you know about our upcoming webinars or any other opportunities that we have in addition if you haven't done so already please visit our facebook page North Dakota High Tunnels and link to that will also be posting announcements on that alright so I'm going to stop sharing here and see if we have any more questions in the chat box will the recording be posted on the listserv or somewhere else you know we have not decided where we will be posting it we will be talking with Dr. Miller as to you know what she's comfortable with whether it's on the listserv or on our facebook page or we may actually develop a website to start posting our webinars so that whoops looks like somebody somebody is sharing their screen here let's okay well you know if we don't have any further questions we'll end for today but I want to thank Sally for her wonderful presentation we've learned quite a bit about the practical disease issues and this anaerobic soil disinfestation seems like a very promising approach so I'll share the fact sheet that Ohio State has produced on that but thank you very much we have enjoyed this and if you ever get a chance come visit us in North Dakota well thanks very much and I appreciate the invitation to speak to the group and again if you have any questions my email you can certainly share my email with people as well okay well thank you very much and I hope everybody has a good rest of the day