Resources for crop disease ID
I'm Ryan Miller, Crops Extension Educator. Earlier this morning, we recorded an episode of the Strategic Farming Field Notes program. Strategic Farming Field Notes is a weekly program addressing current crop production topics. A live webinar is hosted at 8 AM on Wednesdays throughout the cropping season. During the live webinar, participants can join in the discussion and get questions answered.
Ryan Miller:An audio recording of the live program is released following the webinar via podcast platforms. Thanks. And remember to tune in weekly for a discussion on current cropping and crop management topics.
Liz Stahl:Welcome today at our Strategic Farming Field Notes session. These sessions are brought to you by U of M Extension and also generous support from the Minnesota farm families to the Minnesota Soybean Research and Promotion Council, and the Minnesota Corn Research and Promotion Council. So today's session is on resources for crop disease ID. And my name is Liz Stahl. I'm extension educator out of Worthington Regional Extension Office.
Liz Stahl:I'll be moderating today. We welcome doctor Angie Peltier. She's an extension educator on the Crookston Regional Extension Office, and we also have doctor Brett Arenz. He's the director of the U of M Plant Disease Clinic. Brett, he is unable to join us live today, so we did have that part prerecorded.
Liz Stahl:He's actually off teaching a class session that overlaps with this program. So, again, we'll turn it over to the recording. Hopefully, everything works fine with that. But, we do have Angie with us live today. So with that, I will turn it over to Angie.
Liz Stahl:And Angie, we wanted to talk with you today a little bit about this digital crop dock program that you have been leading. And, yeah. Could you just kind of start off and tell us like why did you start this digital crop dock program a little bit about what it's all about?
Angie Peltier:Sure. So thanks, Liz. We need we need to think back to 2020, and and just how derailed everything became during the pandemic. So we had travel restrictions, you know, University of Minnesota Extension. Our goal was not to go out and and be typhoid Marys around the state and infect people.
Angie Peltier:And so we we still wanted to provide the services, though, that we had always provided. And so we we assist growers. We assist crop advisors oftentimes by by making field visits. And, that just we couldn't do that in a timely fashion during the pandemic. And so we thought, well, why not go online?
Angie Peltier:Let's why not use the technology that is at our disposal? And so, the crops team, so you, Bruce Potter, all of Dean Malvick, all of our colleagues were game, and we we developed digital crop doc. Behind the scenes, we had Phyllis Bongard who's, behind the scenes in in this program as well. She made a she made it so that we have a digital platform so that people can make submissions and we can provide visual diagnosis. And so that's that's why it was started and, it's been going since 2020 now.
Liz Stahl:Yeah. So what what is a submission process if somebody wants to submit a sample?
Angie Peltier:Sure. So we've another thing we understood during the pandemic is not every producer is well versed when it comes to the web. And so we didn't want to have, a system where you needed to have a specific email address in order to make a submission. And so, a person can, in their field, if they encounter a disease, and this the the crops that we support are corn, soybean, small grains, sugar beet, and, forages. And so, if a person goes out to scout a field and realizes, wow.
Angie Peltier:Okay. Something something different is happening here, and I have no clue what is going on in my field. They can take several pictures in their field, and very easily without having to log on to anything, make a submission. So, in order to make a submission, you need to attach pictures of what you're seeing. All one needs to do in order to find Digital Crop Doc online is just search in any search engine, Digital Crop Doc, and it'll be the first thing that that pops up.
Angie Peltier:So you find the the website and then you'll find a form on that website. So along with those pictures, we're we ask several clue, We ask for context clues. So, we'll hear from from Brett Aarons in in a bit, and I I tend to think the same way as he does. In a way, it's it's a a process of 20 questions. We, we're playing a a CSI sort of game.
Angie Peltier:We need to know in addition to what we're seeing with the pictures that you capture, we need to know what else is going on in the field in order to to arrive at a a visual diagnosis. So for example, how are the symptoms distributed in the field? Are they in patches? And that, you know, a patch, especially if you think about it, patches that that are symptomatic plants that are in lower areas of the field that might be something caused by a, you know, an oomycet pathogen, for example, that tends to congregate and and be, favored by wet wet conditions, wet soil conditions. Is it evenly distributed across the field?
Angie Peltier:That could give us a clue that maybe it's it has nothing to do with the biotic cause, but maybe maybe it's something that we sprayed across the entire field. And so knowing how the symptoms are distributed in the field can help to provide us some clues as to what's going on. How are the symptoms? Arranged on the plant. Are we just seeing symptoms on the newest growth?
Angie Peltier:Oftentimes that what that's what we would expect with viral diseases. Or or is it in all old growth? Is it, towards the top of the plant only? Towards the bottom of the plant? And and getting that sort of information can provide those context clues.
Angie Peltier:Some of those answers to the 20 20 questions we're we want to to get answered, that can help to provide a diagnosis. Variety, hybrid, that can help. Knowing what what resistance is is included in your your variety or hybrid can help to narrow things down as well. When did you make your last fertilizer, insecticide, fungicide, you know, herbicide application? Sometimes we can have another example of of, you know symptoms across an entire field could be maybe we made a herbicide application that that caused some injury.
Angie Peltier:Knowing that is very important. What what was your previous crop? Knowing that, so if you if you are in a continuous corn system, that can increase your your risk of certain diseases because so many of our diseases in the state, the pathogens that cause them survive in the residue from previously infected frogs. And so if you have a lot of residue from previously infected crops and you grow that same crop over and over, that can increase our risk of certain diseases showing up. We also want your contact information.
Angie Peltier:So you don't have to have an email address, but we need to have some way, one, to provide a diagnosis if it's something that offhand is is relatively easy to provide. But if it if it isn't something that is is just kind of straightforward run of the mill, we're gonna have to to have a conversation with you to get to the bottom of it. Actually, so and I'm not gonna name names. You're anonymous, if you make a submission. But I did see one gentleman here, in the attendees today that did make a submission.
Angie Peltier:And and he was very involved in his own diagnosis because you know your field best, you know what you're seeing best. And so having that sort of conversation oftentimes is is really key to getting towards a good diagnosis for you. And then lastly, you know, you can submit up to 10 pictures. So we wanted to make it so that you don't you you weren't limited in in the number of pictures you could submit because sometimes you might wanna show the the larger patch and then slowly get closer and closer and closer, until you end up having to take a close-up very close-up shot just to show us the pattern in the field all the way down to to what we're seeing on on an individual leaf, Again, very seldom can we make a a diagnosis from that submission alone and oftentimes it will require a conversation.
Liz Stahl:So Well, and you bring up a really good point too, and that's a question that just popped up here too. Great question. So do you have any guidelines, tips, or tricks on how to take the best pictures? What should you include in the pictures since that is so key? Because again this is digital crop deck.
Liz Stahl:You're not actually sending in a sample. You're sending in pictures.
Angie Peltier:Right. Use natural lighting. That's a big one. So, that's what's so nice about this program. If you have Internet access in the field, even if you don't, you can just add add pictures to your submission after the fact as well.
Angie Peltier:But using that natural lighting in your field is really key. We want you to capture both leaf surfaces. Oftentimes, understanding what's going on really requires a look at both top and bottom. We don't want you to forget stems and and stalks and even roots. So, if you have a a wilt disease, for example, knowing whether there are lesions on the stem can help us to come up with a a cause of of that wilt.
Angie Peltier:You don't have lesions on the stem, oftentimes we'll ask you to split split the stem or stalk, split those roots, and and take a picture of that. That can help us as well. Use your zoom and don't take pictures of dead plants. That is not gonna be of use to us. It's very difficult even even in person to do a post mortem on plants because we have organisms in our fields that are called saprophytes, and they can come in after after a plant is has been killed by a a pathogen, and then and then that kind of complicates what what we see in a field.
Angie Peltier:So it's very difficult to attribute a cause when you have other other organisms moving in as well.
Liz Stahl:Well, great points. And I don't know if you said this already. Is there a cost associated with this when somebody sends in a sample?
Angie Peltier:We did not mention this. There is not. So if somebody ends up sending in in a sample to the disease clinic because we cannot arrive at a visual diagnosis, then there is a fee involved with that. But if just to use digital prop doc, there is no fee.
Liz Stahl:Okay. That's a great resource. And just curious before we turn it over to Brett here, what kind of things have you seen submitted to date?
Angie Peltier:Sure. So our first submission was pretty interesting. It came from Clay County up here near Moorhead, and a person had split a corn stalk and sent in a sample of of the internal workings of his of his corn stalk. I think it was a submission born of a person that that just hadn't seen a lot of cornstalks. So ironically, our first submission was of a perfectly healthy cornstalk.
Angie Peltier:But that's important information as well. It's important to know that your crop is doing okay sometimes too. We've seen bacterial blight in soybeans. We have had many tar spot in corn submissions, potassium deficiency in soybean, IDC, iron deficiency, fluorosis, spider mite infections, even lesion mimic mutants informed. And when it's anybody can make a submission.
Angie Peltier:It's limited to folks in in Minnesota, so we can't take those those submissions from India and and Florida that come in, unfortunately. But, you know, it's nice to know that that people have an interest in figuring out what's going on in their fields.
Liz Stahl:Yeah. This is a really great resource and, and again, we'll have the links on how to get to the Digital Crop Doc. But like you said, you can just do a search on your Internet, type in Digital Crop Doc. There's a link off of our Extension Crops website to get to this, as well. So thank you, Angie.
Liz Stahl:If you wanna hold on here, we do have the recording from Doctor Arenz, and he is the director at the Crop Disease Clinic. Because sometimes you can't necessarily figure out just from a picture. You actually need to send it in. So we did have again a pre recorded segment with with, Brett.
Liz Stahl:If you wanna run that that would be great. Well, Brett, thanks for joining us today. And why don't we have you talk a little bit about the plant disease clinic? You wanna just start with kind of explaining what you all do there and what it's all about and so forth?
Brett Arenz:Sure thing. Yeah. So the plant disease clinic is a service lab at the University of Minnesota Saint Paul campus, and it first opened in 1956 to, really, it seems, take some of the the burden off some of the plant pathology faculty who are getting a lot of requests from, homeowners, farmers in Minnesota to to diagnose plant samples. So they wanted to set up a centralized laboratory that could handle some of this. And so, at first, it was only open during the summer, run by graduate students.
Brett Arenz:In the last 20 or 30 years, I should say, it has been, become basically a year round lab. And, we're fairly small, about, 3 full time members, and we are basically just across from the state fairgrounds. If you're, you know, your listeners are familiar with that location. We, specialize in plant disease diagnosis, although we do say that we diagnose plant health problems. Because about 20 to 30% of our diagnoses are actually no pathogen found.
Brett Arenz:And so this could be a variety of other things going on. It could be a nutrient issue. It could be, some sort of environmental problem, frost damage, could be herbicide drift, things like that. So there are, of course, many other issues besides plant diseases that cause plants to look unhealthy, and, of course, the reason people are sending them to us is because they don't know. And, we really work with all kinds of plants.
Brett Arenz:I think in a typical year, we get about about 2,000 or so total samples submitted and usually representing about over a 150 different plant host species ranging from, trees, shrubs, ornamentals, annuals, crops, obviously, corn, soybean. So, really, almost anything, you can grow in Minnesota, certainly, we might see at a certain point. We also get samples from from other states as well.
Liz Stahl:Well, that's so so for a landowner or farmer, it's not only the field crops that they could send in if they got something funny going on in the yard with their trees. It all can go to the same place, and that's that's kind of a nice nice deal there. But, you know, since we're talking about samples, do you have any recommendations, like, when people are sending in a sample? I'm assuming you don't want them to just throw it in a plastic bag and send it snail mail or something like that. Do you have some recommendations on what they should do and how that should be handled?
Brett Arenz:Yeah. That's a great question. We accept samples either hand delivered here to the lab or sent in by the mail. Obviously, you know, we're down in the metro area, so, usually, the people who are hand delivering are are people who are living down here anyway. And, we do have information about how to, how to sample from plants, what kinds of things to mail in at our website, pdc.umn.edu.
Brett Arenz:I will say, though, just for some general guidelines that, typically, you want to focus on the area of concern in the plants, the the area where you're getting the strongest symptoms, and, sample from there. If possible, it's always best to supply a whole plant, so that would be above and below ground parts. For some diseases or health problems, you might have symptom symptoms in the in the leaves, for example, but the pathogen might actually be located in the roots. And so if a if a client just submitted the leaves, we wouldn't really have a way of confirming, that pathogen, unless the roots themselves were also submitted. And if if you're mailing in a whole plant, what we do recommend is, wrap the roots in plastic, and then leave the above ground parts maybe loosely, wrapped in newspaper.
Brett Arenz:You don't need to add any moisture to the situation. No wet paper towels or anything like that, because, of course, you know, things sometimes can can sit in the mail for a bit of time, and they can get pretty nasty by the time they get up get to us if they're held over the weekend or something like that. Mailing samples, usually good to mail maybe at the start of the week rather than at the end, just so that they'll get to us earlier. It's good to send living plants, so plants that have clear disease symptoms but have not yet totally died. There are, plants where that are very hard to do autopsies on.
Brett Arenz:For example, soybeans. Actually, there's a lot of soybean diseases that, can certainly cause plant, health problems during the field season, But, also, they tend to grow really well, the dead soybeans after the fact, even if they didn't cause a problem during the season. And so when people send dead soybeans in, they can be pretty tricky to know if if something is is just growing on it because the plant has died or if it actually was a problem, during the field season.
Liz Stahl:Those are your
Brett Arenz:Obviously, you know, in a lot of cases, it's not always possible to submit a whole living plant depending on the the type of plant you're talking about. Obviously, you're talking about a tree that's, you know, not realistic in most cases, unless it's a nursery sending seedlings in or something like like that. So in those cases, we oftentimes will have people send us pictures first to our email, which is pdc@umn.edu, and then we can better direct them to, what kinds of tissue would be good to collect.
Liz Stahl:Well, that's a good point. And, you know, you're talking about the whole plant, like, with the roots. Do they need to include any soil in that? You know, if there's suspecting, like, a seedling disease or something, or would you prefer keep that off of there?
Brett Arenz:Not typically. There's not a lot we can do with the soil itself. You know, so you could loosely knock off the soil from the roots, and then, you know, wrap that root mass in a in a plastic bag and tie it off. That being said, the really only thing we do with soil would be if you are asking for a nematode test, and we're trying to give a, you know, a general sort of count of plant pathogenic nematodes in a given quantity of soil. In that case, we would directly use a use a soil sample, and you wouldn't even really need to supply a a plant sample with that kind of, submission.
Liz Stahl:So you mentioned nematodes. I know that we have a soybean cyst nematode clinic, and I believe that's still going in Waseca. Correct? But so is that when you're talking about nematodes, are you talking about soybean cyst nematode as well, or are you talking about nematodes other than soybean cyst nematode?
Brett Arenz:Yeah. So basically, any other nematode other than the soybean cyst nematode. If you want soybean cyst nematode testing, you should send it to the, the lab, and it will seek at the Southern Outreach Station.
Liz Stahl:Okay. Yep. Just wanted to clear clarify that for everybody listening today. And, and is this open to anybody to send in a sample? I mean, do you have to be in the state?
Liz Stahl:Do you have you know, is it matter if you're a crop consultant or farmer?
Brett Arenz:We accept samples from anyone. And, you know, about 80%, 90% of our samples come from Minnesota. The rest come from outside, from Iowa, Wisconsin, even farther out New York to Ohio in some cases. So we do have, you know, I'll just we accept samples from a wide range of clientele, from homeowners to farmers, crop consultants, tree care specialists, professional horticultural organizations and companies, government agencies. We get samples from the MDA, from the forest service, from the DNR.
Brett Arenz:So, really just a a very wide range of clientele.
Liz Stahl:Okay. That's that's great. And then, fees, do you have, like, a fee list? Not that you have to list all those off. I don't expect you have that all memorized, but I'm assuming there's fees with this.
Liz Stahl:It's not all free probably, but, you know, maybe you have some research programs I know in the past like Dean Malvick. He's our extension plant pathologist. Sometimes he has some programs going. Do you have information about that? Or or how would a person learn more about that?
Brett Arenz:Yep. We do charge fees, with our diagnosis, and there's a it's a better list of them on the plant disease clinic website, but they range from about $50 to maybe a little bit more than $100 or so or so depending on what kind of testing is needed. $50, covers most, routine testing, examination with the microscope, things like that. If, it needs more sort of, molecular work, you know, like DNA extraction, RNA extraction analysis in that way, Typically, these are, like, viral samples.
Brett Arenz:In some cases, maybe bacterial samples that you can't actually confirm just with a microscope. Those would be samples that would be more likely to be around the $100 range.
Liz Stahl:Okay. And that kinda ties in with the next question I'm thinking of as well here is, you know, a lot of times there's there's not just one thing going on in the field. So, you know, what would you recommend if somebody's trying to diagnose a problem, and they're pretty sure they know what it is? I mean, do you see I guess, way to word this would be, do you see sometimes there's more than one thing going on, in the plants? I mean, if you're pretty sure would you still recommend sending something in just to really help get it identified?
Liz Stahl:Because, you know, again, just by visual, how how accurate can we be just by what we see sometimes?
Brett Arenz:Yeah. That's a great question. I my general philosophy is that successful disease control starts with a accurate diagnosis. There are some diseases that are fairly easy for people to diagnose themselves. You know, I'm thinking of, like, the powdery mildews, white mold on soybean, things like that, tar spot of maple.
Brett Arenz:These are things that you can pretty easily identify with the naked eye without a microscope, and you can be pretty confident in those. We and as it as it turns out, we don't tend to get a lot of those samples in the disease clinic even though they're fairly common in most years, because people can typically diagnose themselves. But for a lot of other ones, there are many diseases with, very similar symptoms, look alike conditions. Oak wilt, for example, is one of our more common, types of samples in the metro, causes leaves to kind of become marginally brown at the edges. Well, as it turns out, there's a few other things that can do that as well, including 2 lined chestnut borer, drought stress, other foliar pathogens of oak.
Brett Arenz:But, you know, if you if you just looked at your tree and assumed it had oak wilt without testing it, you might pursue a pretty costly management plan that would result in no no help or maybe would just be a waste of money because really what you're dealing with maybe was a insect problem or drought stress, for example. So certainly in situations where you are are investing money into management and time, I would really recommend starting with an official diagnosis.
Liz Stahl:Yep. Yep. Good point. And just curious, I mean, what kind of when thinking about agronomic crops, what kind of are some of the most commonly submitted diseases that you see? Just, again, just kind of a of interest.
Brett Arenz:Yeah. So, obviously, Minnesota, you know, we get a lot of corn and soybean samples. And, you know, it depends a bit on the year. Year's a little bit different. Obviously, last year, we had very dry conditions throughout most of the year, especially the later half of the year.
Brett Arenz:As a consequence, a lot of the fungal diseases, that were kinda common usually just we didn't really see them last year. And instead, we had more issues like, spider mites, for example, that can, you know, kinda get out of control with really hot and dry conditions. So with the corn and soybean, you know, there's a long list of kinda common diseases. With soybean, you know, it kinda goes through we in the roundabout this time of year, we start seeing seedlings with damping off issues, whether it's Phytophthora, phytochemryizoctonia, or, you know, maybe a herbicide issue or something like that. And then, you know, as you get into the middle part of the summer, don't see so many soybeans coming in, but then the later part, more of the late season soybean issues like, sudden death syndrome, brown stem rot, things like that.
Brett Arenz:So there's kind of a seasonality to it. Corn, you know, in some cases where it's really dry, you're not really seeing a lot of corn submissions. So it's be interesting to see if this, this moisture kind of continues through the year. But things like, northern corn leaf blight, A few years ago, we were getting a lot of goss's wilt samples into the clinic when that was kind of a, you know, a fairly new pathogen. And so, you know, it kinda depends on what's going on, what's hot.
Brett Arenz:Foreign tar spot, obviously, people are trying to figure out exactly where it is in Minnesota as it's kind of, moving around, and so that will result in us getting more samples. And then as as a pathogen kinda settles into an area, people become more familiar with it, and oftentimes, I think can kinda diagnose it themselves.
Liz Stahl:Yeah. You mentioned tar spot, and that's kinda one of those diseases where yeah. I'm sure we hope you don't have a lot of samples come in because then that means that it's more prevalent in the state. But but I'm sure you've been a big help in really helping find out, you know, yesterday actually is tar spot and because that's one that's expanding in the state here. And just curious too, do you send out reports of what you're finding?
Liz Stahl:Is that put out for general information anywhere?
Brett Arenz:So it's that's a really good question. What's of interesting about our clinic at the University of Minnesota is that we're not actually an official part of the extension, program at the University of Minnesota, which is not the case for a lot of other plant disease clinics in other states where they are actually official extension. And so I would say those kinds of clinics are more oftentimes involved in that outreach directly, sending out reports of what they've been seeing and things like that. You know, for us, we're really concentrating on the individual samples we're getting and, getting good diagnoses out and management recommendations to the people who are submitting samples. But we will also work with, the people in the DNR, with the MDA, with other extension specialists like, Dean Malvick to share the information that we've been seeing so that we can collaborate on these, you know, like, for example, the corn tar spot, situation to figure out what counties it's been found in and how it's sort of moving throughout the state.
Liz Stahl:Yep. No. That sounds great. And as we wrap it up here, is there anything else that you wanna add on before we we wrap it up today?
Brett Arenz:No. Not really. Just to say that if you have a question about something, you know, we as I as I mentioned, we can test basically any type of plant for almost any type of disease. But if you have a particular question, please feel free to email us at pdc, excuse me, at pdc@umhmm.edu, and we're happy to, to take up the conversation from there.
Liz Stahl:Alright. That sounds great. And we'll be sure to post that in our chat here today too, those website links so people can can pull that up. But, again, thanks for joining us today, Brad. Appreciate it.
Brett Arenz:Alright. Thanks very much.
Liz Stahl:Anyway, I know we're getting long on the time a little bit here. Angie, is there anything that you wanted to add, to wrap this up? Because, again, know, we're focusing on these identification tools because that is the number one thing is to get the correct diagnosis of what it is before you can actually manage that disease effectively. But anything that you wanna add here at the end?
Angie Peltier:No. Other than that, this is a a free service. Not every submission will be able to be diagnosed visually. It might require a little audience participation in having a conversation with us to to arrive at the diagnosis, but it's something that, we're able to stand up during the pandemic. We're funding, from today's webinar and, podcast sponsors as well Minnesota, soybean, Minnesota, Florida, Research and Promotion Councils.
Angie Peltier:And so, it's it's still going strong. And so, use it if if it's something that I could provide some some answers for you.
Liz Stahl:That's great. Well, thank you, Angie. And thank you everybody for attending today. And again, that's a digital crop doc. That's the free service kind of prescreens if you need to go on to the crop disease clinic or not.
Liz Stahl:That's another great resource that we do offer at the university. And again, like to thank everybody for attending today's session, and thank our sponsors, the Minnesota Soybean Research and Promotion Council, and the Minnesota Corn Research and Promotion Council.
