A Game of 20 Questions…Diagnosing Herbicide Injury in Field Crops
February 28, 2023More Info
This session has held as part of the field crops track during the 2023 MI Ag Ideas to Grow With virtual conference. This virtual conference held February 27-March 10, 2023, is a two-week program encompassing many aspects of the agricultural industry and offering a full array of educational sessions for farmers and homeowners interested in food production and other agricultural endeavors. Sessions were recorded and can be found online at https://www.canr.msu.edu/miagideas/
the final time you're going to see them. So thank you for joining us for my egg ideas to grow with and the field crops session and particular in this one, diagnosing herbicide injuries. We want to thank our sponsors for helping with this program. That would be Michigan State University Extension and Agora Strategies, LLC. RUP and CCA sign up at the end. With that said, let's welcome Dr. Aaron. Aaron, go ahead and start Alright. Alright. Well, thanks for having me come to talk today about some of the work I do in the diagnostic lab here on campus. I've decided to call this talk game of 20 questions diagnosing herbicide injury and field crops. So first, if you're not familiar with the plant and Pest Diagnostic Lab here on campus, we are a group of plant detectives and MSU is quite lucky, I think, to have a large group of us compared to some of our other land-grant universities. Sometimes they have one or two diagnosticians and we have six full-time people working in the lab. And because we have that many people, we have people with expertise in all of the pests discipline areas. So when people send us a plant or a problematic situation, we have people who can look it over to see if there's any insect or arthropod damage or infestations. Howard Russell does a lot of insect ID. We can also have a team that can work on determining if there are any pathogens responsible for the plants poor performance. So looking for fungi, bacteria, and viruses, we have on hematologist angiotensin II has taken over the role that Fred Warner I used to have. And so that's the majority of samples that come through, surprisingly every year are nematode analysis samples. Then Angie and I worked together on plant identification. And then I specifically work on abiotic causes of plant decline, and that includes herbicide injury. And then also during the winter in the greenhouse, I'm working on screens for herbicide resistance. So people send in weed seeds of populations that are in question. And then I determine if they are resistant or not. In addition to being a diagnostician, I also teach two courses here at MSU every fall. And so if you know any students that are here, particularly in Crop and Soil Science or an AgTech, they probably have had mediums. And so we don't always just assume that herbicide is to cause. That's why rely on some of my other diagnosticians to look for signs of fungi, to look for signs of insect damage. Because sometimes we can get these symptoms confused with viruses, other diseases, insect injury, nutrient imbalances, pH, either the soil or if it's a greenhouse situation and the media where it's too high or too low. Environmental stress can mimic chemical injury and then also some cultural issues can do that as well. So I just like to put that out there. But now we will get into specific cases. I worked in the lab for, I think almost eight years now. And so unfortunately, I've collected several examples of the types of scenarios where we see herbicide injury. And so I wanna give you those with some photos that I have of these samples and then talk to you about what happened. And sometimes what we can do to prevent these things from happening. And then at the end we'll do a summary where we talk about all these things that you should be asking yourself if you think that a herbicide could be to blame. And that's why I call it a game of 20 questions. I have to be really good at taking what I see and then dissecting it down by asking the client a lot of questions. When we spray herbicides out into the environment. This is a slide that one of my collaborators, Aaron Hathaway came up with for class. But we spray the herbicide out in the environment when we're making the applications, sometimes we do have the opportunity for the herbicides and move at that time of application through drift or volatility. Ideally, the herbicide is being taken up by our target species. So either through the foliage or through the roots, depending on the type of herbicide. But then after we've made that application, there's all other kinds of Fate of herbicides and other pesticides to dealing with decomposition in various manners through the Sun microbes and chemically. And then also it can move in the environment or not moving the environment through sorption or leaching or movement with a lateral water. So this is kind of An idea to keep in mind that we're going to try and touch on a lot of these areas when we talk about these examples. The first example I have is corn, and I have a couple of examples. So I call this core number one. This came in several years ago. And what was really nice is that the sample came in and not with just plants that were symptomatic, but also it was a range of symptoms, but also some corn plants in the area that they considered to be growing well. And so we call these three types of samples, bad, medium and good. And this is what they looked like. The bad ones were pretty bad, very stunted, not a lot of root growth there. So stunting was one of the complaints. Stunted roots with brown and inhibited brace roots like we saw on that last picture, was another one of the symptoms. And then on the stocks, when we cut the stocks in half, we could see that part of that stunting that we were seeing in the photographic medium sample was due to reduced internode length compared to the good sample. And so I tried to highlight that here with these arrows. And then some of the information that we had about this area was that the, the bad and the medium corn had been treated with a herbicide called extreme. Extreme is a herbicide with two active ingredients. One is MSF up here, which is a group to ALS inhibitor, and the other is glyphosate, which we usually see in Roundup, which is EPSP S inhibitor group nine. So what's alarming about this are caught my eye is that this is not a herbicide that we think of when we think of corn because her extreme is not labeled for use on corn, I believe it's labeled for use on soybeans. Him as death appear component of that herbicide is what's causing the stunting both above and below ground and the browning of the roots and the other symptoms that we're seeing. This particular example is an example of a misapplication wear an awful labeled product was used and that's what resulted in the injury symptoms that we've seen. Another similar example. I have a couple of examples that are not field crops in here because they are too good not to use. But this was an example from this past fall from a condo complex and they had all their grass starting to die and decline over time. So these are some pictures just showing the patterns. You can see that it looks like somebody drove through this area. And what we're seeing is chlorosis, which is yellowing and necrosis, which is plant tissue death of large swaths of grass across several properties. And this condominium neighborhood, there was a clear tire track pattern that we saw in some of the areas which seemed to indicate that they're they're driving through this wet area and pulling whatever is injurious through with it. When we look at the individual plants like I have here on the right, we can see that they're dying from the growing point outwards. So if the chlorosis or yellowing is starting at that meristem at that growing point and then progressing outwards. And that's why we're seeing get worse over time. And this all happened following a herbicide application to the turf for broadleaf control with 240 Dicamba and Nico prep. Now, those three herbicides are all plant growth regulators and they are labeled for use in turf and we would not expect them to injure the turf. So something else had to be in that tank. Because we see very clearly that it follows the pattern that they use when they sprayed, even the areas where they tried to avoid things like a drainage system or different things. You can see the grass there was fine because it didn't get hit by this application. So in this particular case, the wrong, one of two things happens. And sometimes we never really know what the answer is, but the wrong product was added to the tank. We suspect it could have been something like life essay, but we don't know for sure, um, that, or the company that made this application also suspected there could be some foul play from an outside party because they did not have their equipment locked up. And either way though, the there was something and they take that was not supposed to be. So this would be another example of an off-label products. But likely they didn't know at the time they were making this application. I don t think they would have done this voluntarily. A second corn application that we have are case that we have pretty severe looking with a lot of logic, corn. And you can see it's breaking off right here at the soil surface, so the corn cord is not looking good. Overall. The lodging of the corn is happening around V4, V5. There was some chlorosis and necrosis you can see on the leaf margins and the leaf tips in this picture on the right. And what we know is applied here was a herbicide permit, which is an ALS inhibitor group two of Halo sulfur urine. And then also to 40 was in that tank mixture which is a group for synthetic ox and herbicide. So what catches your eye here is that. The stage of the corn and the application do not go together. So even though we think of to 40 as being safe, largely safe on grass species, it's supposed to be selectively controlling broad leaves. It is only save up to a certain point went on corn, which is less than 8 " tall. So at V4 and V5, this corn is well beyond that eight inch height. And so the reason you can't make those applications then is because the corn is not able to metabolize or deal with within it the 240 because it's growing so rapidly. So when it's small, That's fine. It's a labeled application. But, um, I'm calling this a misapplication because of the improper timing. If you pull up a label of 240, It will say that somewhere in the label here I have highlighted in blue towards the bottom, the directions say to apply when the corn is less than 8 " tall to avoid crop injury. So all three of these cases that I've mentioned so far are examples of direct misapplication. So the injury in these cases can be uniform across the entire treated area. That's what we saw in the three situations that I showed you. Is the result, misreading the label, maybe a misapplication by a third party. We've seen that or incorrect placement or timing of the herbicide. The other pattern we can see when were you would suspect a misapplication is I like this picture I have here on the right. We're injury is occurring in strips across the field or a lawn. So in this case, you can see that there is some cleric or bleach soybeans in just one single row, and that pattern repeats itself across the field. In this particular case, that's an example of boom overlap, which is causing an over applications so that the labeled rate, this product was fine for the soybeans. But when you have a boom overlap, then we're having the issue. And this actually was probably the result of a boom overlap the previous season because I believe the herbicide here that's causing this is loudest or Tambo try-on made to the corn that was there before. And so it created just a hot, too high of a concentration where you see this one row of soybeans. Many times. Direct misapplication is preventable. Organizing your chemical storage and proper labeling are very important. Even on our research farms, we've had instance from time-to-time where the label falls off and something gets apply that wasn't supposed to be applied and it ends up causing injury. Reviewing the label, of course, is very important. Checking for signs of plant stress prior to application. Sometimes you are more likely to see herbicide injury from a product that is labeled when the plants are under stress because their metabolism system is not working like it normally would be. The other thing to think about is ensuring that equipment is calibrated and effective positioning tools are being used. So a lot of people are moving towards the use of GPS and auto steer and all of those things. And that helps prevent some of that boom overlap a lot. But calibration is still really important to prevent over or sometimes under application to. Then keeping equipment and chemicals and locked facilities, particularly a few suspect, you have some enemies out there. And that's possible. You wouldn't want to set yourself up for that situation as much as you can help it. Okay. Moving on to a different type, herbicide injury or different source of injury. Again, I have a different example here of asparagus. I have seen somewhat similar things in field crops before, but I don't have, didn't have as good of pictures as I do for this. But this field of asparagus, this was in the springtime when they're harvesting the spheres had some spheres that are just fine like the picture on the right, all the way to the right hand side of that knife. Fair? So nice. Upright, straight spheres. And then it had some crowns that we're not emerging at all and some that were emerging with this very deformed growth. So curved spheres, some of the fronds starting to come out prematurely. And so those asparagus are not going to be marketable. So this is a big concern for this asparagus grower. So crooked or curved spheres. There were also some photos of weeds in the area. There were also showing this distortion. We see Canada thistle here on the left and some common milkweed on the right. Sometimes pictures of the surrounding really lend to the story of what's going on. So a lot of times when we get samples and I will definitely be requesting field photos. Because our lab doesn't have time to go out and do site visits. So we had those distorted weeds. And then it was reported that this injury was occurring in two distinct areas of the field. So I tried to make a little diagram of that, but along the two edges and it would taper off. And then you would see normal asparagus growing straight. The last application that was made to this field was late August of the previous year. And so the type of injury and the pattern in the field are kind of two things that tipped me off to what might be going on here. And so after some discussion with the client, the injury followed the spray path from that mid August application the previous year. And so in mid-August the asparagus has the fronds growing. And so there was some foliage there for absorption. But when they described the sprayer pass, they said that the applicator first went down that west edge of the field with one section of the boom on and then they came down the bottom south part of the field and then they turned up and drove through the field with both sides of the booms out. But now the right side of the boom was being used for the first time. And so anytime one of those sides of the booms was being used for the first time. That's where we see the injury. And so that leads us to believe that there was some spare tank contamination. They had not cleaned the booms all the way out from a product before. Now there are a couple of different products that it could be. It doesn't really matter because these asparagus are not going to outgrow this, but it could have been a synthetic oxygen like a 240 or Dicamba. It also could have been glyphosate because that can cause some of those distorted injuries sometimes in perennials too. But this is a good Example, unfortunately, of spray tank contamination. So when you have spray tank contamination, injury can occur across the whole application area or it can occur where the sprayer began treatment and then things can improve. And that kinda depends on how the tank was contaminated. If it's something that has adhered to the tank and then as being rereleased in this solution, you might have a dilute version of that herbicide being applied across the entire field. If it's something where the boom is just we're not cleaned out, like like what we saw there. Then it gets flushed out once the booms are being used. So this is a result of not cleaning out the tank booms or the mixed system. And some herbicides adhere to plastic tanks more than others and then can leach into future loads. So we know the growth regulators are, synthetic auxins are known for doing this. And also some of the ALS inhibitors like permit can do this as well. Alright, another source of potential source of herbicide injury. Here we have some pairs, and these pairs are growing in a sort of border strip along what was a cornfield the year before? It's not corn at this point, maybe it's wheat or something like that. But the injury on the pairs is showing up only on the side of the cornfield. And they're spotting on the pairs. You can see there on the fruit they're spotting on the leaves. It's concentrated on the edge near that neighboring fields. The neighboring farmer claims that the injury is scab. But when we had the rest of our diagnostic lab look at it, there's no signs of pathogens or insects related to these samples on the fruit. They were really just superficial lesions, so not scab. So to me the spotting is consistent with injury from a group 14 like a PPO inhibitor like flex star or maybe something like photosystem, one inhibitor like grim oxen, or maybe even liberty, which is in group ten. I wasn't really sure. It turns out in this scenario, the two neighboring areas, those people were related. And so they were able to get the full story of what had been applied and what was going on. So it's kinda in the middle of this family dispute, I guess. And it turns out the corn was sprayed with Roundup verdict and metro mucin. And so like I said, one of my number one suspects was a group 14 PPO inhibitor, which the component, the cephalic Venice cell component of addict is a group 14 inhibitor that lines up with the story that is drift that caused these injuries symptoms. One other example, again, we're gonna go to a different type of crop because I think it showed it. This pretty well is chrysanthemums in our diagnostic lab, we get any kind of plant that grows in Michigan. Sometimes we're looking at things from residential yards. Sometimes we're looking at things from nurseries, greenhouse industry, field crops, vegetables, you name it. So this is from Greenhouse industry and they were noticing some bleaching and stunting of the newest growth on these chrysanthemums. And here they are growing in the hoop house. You can see that sides of the hoop house or up now. And it might not be that apparent. But if you look closely at these photos, you can see that not all of the moms are insured injured. They're injured in this area here I've outlined in yellow. And you can see there's a high concentration along the edge of that greenhouse, which has the sides unrolled like I mentioned. So we have this bleaching and stunting of the newest growth concentrated along the exterior wall and then sort of tapering off as it moves in to the hoop house area. And so we also suspect that this is a case of drift. If you look closely in that photo, you can see the areas between the hoop houses is weed free. There's nothing there except dirt. So we would suspect that they are treating it with something, maybe Roundup or something like that. And these symptoms are consistent with Roundup injury on moms and that that drifted into the area. In both the case with the pairs and the moms, we saw drift and drift is off target particle movement. So actual spray droplets that are moving. And it's usually concentrated along one side of the area closest to the a place that was treated. This as we all know, I think a lot of us are familiar with drift happens when the winds are too high at the time of application. Maybe we're not using the correct nozzle selections, so maybe the droplets are not coarse enough and we're getting a lot of very fine spray droplets that are more prone to movement. And then sometimes when we have a greenhouse situation where you're moving things in through the ventilation system. If you do have a case that you suspect of being drift, there is the possibility of turning that over to MDR, the Michigan Department of Ag and rural development. They have a hotline to report suspected cases, herbicide misuse. And so they can actually send an inspector out to the site. So something that I cannot do. And they can pull samples and send those samples in for residue analysis. So they're actually testing the tissue to see if there is a particular herbicide in the tissue. Mdrd also has the capacity to pull spray records from neighboring areas. So any of these commercial applications are supposed to be keeping spray records and they have the ability to find out exactly what was reportedly sprayed when and what the weather conditions were, which is something that I don't have the authority to do. So it can be helpful in figuring things out. The only caveat there is that if they do find that there has been misuse of pesticides or herbicides, that it can result in fines. And those spines don't necessarily go to the person who saw the injury. But sometimes people don't want to go this route because they have a good relationship with their neighbor that caused the injury. Okay. Moving on to some different types of cases. This is a soybean number one, I'm going to call it. And you can see some really distorted looking soybeans here, Some cupping of the leaves and EPA nasty, which is the curling of the petioles. And you can see the pattern out in the field is pretty random. It's not all along one edge like we've seen with drift. And it's not following a spray track like we saw with tin contamination. So the roots appear to be fine, spotty pattern random. And there aren't very many other agricultural fields in the vicinity of this impacted fields. So the type of injury in the randomness to the injury kind of brings up several questions are possibilities for me, and they're not ones that are easy to pinpoint and say, Aha, yes, this is 100% what happened. But the possible explanations include the movement of a volatile herbicide of which we'll talk about in a minute. An application during an inversion layer and another field. Or maybe it was even a previous spill in the field. Ultimately, we don't know what happened in this exact case. But it looks like it encountered one of those synthetic oxen type herbicides again to 40 triglyph peer particular RAM Dicamba. So I use this case to highlight volatilization. And unlike drift, this is exposure to a gaseous state of a herbicides. So after the application to the foliage or the soil surface, sometimes herbicides can be re-released as a gaseous vapor and then that can move into areas and have some off-target impacts. So the injury in these cases, the volatility does sometimes occur in a random pattern. Sometimes we see occur along the edge of a wooded area because we get changes in temperature there. And so sometimes things dropout by big structures or wooded areas. Why does this happen? Well, some of the herbicides are prone to volatilization due to their chemical nature. And we see that a lot with dicamba, which is why we're seeing all of these different formulations trying to reduce the volatility of dicamba. This can happen when there are high temperatures. So even in the residential market, it has limitations on when people can treat their lawns because they do expect there to be some volatility if it's over 85 degrees outside. Low wind conditions, low cloud cover, and then early morning or evening applications can also lead to volatilization. Okay, soybean number two are some photos and a case that didn't come into the lab, but was submitted and seen by Dr. Christy Sprague, which is our soybean weed scientist in plant-soil Microbial Sciences. She and I worked very closely together, so she shared these slides with me. But here we're seeing similar symptoms to the last soybean where we have like distorted leaves and stunting. And you can see areas impacted out in the field or the lower lying areas. And again, this looks like a 2,4-D, dicamba type scenario. When we look at the map, these injured soybeans are Roundup ready soybeans. They are in a field right next to Roundup Ready 2 Xtend soybeans. And that extended field was planted in May and then in June they applied Engenia which is Dicamba. And the wind direction was pointing away from the Roundup Ready soybean fields. So that should be okay, right, because it's not it's not gonna be drifted over there. We would not suspect it to drift over towards the sensitive soybean field. But within two days of that application, they got 7 inches of rain. In this case. Rain is taking the very water-soluble dicamba and moved it with lateral water movement across that sensitive field. And that's the areas, the low-lying areas of that field where we're seeing where she was seeing the injury. So this is an example of when we see herbicide injury related to water movement or the watering source could also be an issue. And the injury can appear in specific areas or across an entire field depending on the source of water that was contaminated. It's the result of herbicides that are highly soluble in water. Heavy rain flow, moving soil and herbicides laterally across fields. And then this also can happen if you have a spill near surface water irrigation sources. So if you had a pond and you're treating the edge of the pond, you get something injurious in there and then you use that pond to irrigate. That's another time where we can see herbicide injury coming from a water source. Okay. Another type of injury or another method of injury here we have a wheat field that is not looking very good in the spring. Again, it's nice because this client sent us both a bad sample and a good sample. You can see from this picture of the field that there was some wheat that looked fine and some wheat that looked horrible. And so if we have those two things to compare, it's really helpful, especially if it ends up being something like a nutrient issue or something. And we have to send some tissue to be analyzed and we have a good sample from that exact site and those exact growing locations or condition. So we can compare it to, so it's an apples to apples versus comparing it to some standard. So the wheat, wheat here is not looking very good. The older leaves are necrotic and desiccated. Sometimes we had entire plant dieback. Sometimes it was more concentrated towards the older areas, but it looked like the wheat was trying to recover. We had some weeds that came in with a sample. There was some common chickweed, a winter annual weed that came in and the chickweed was looking damaged too. So that, that kind of leads you to think that it's not necessarily like nutritional thing. But something that happened to this field. The previous crop in this field was soybeans. And the they reported that it was sprayed with Zidua Pro, Roundup and Flexstar. And then another thing of note that I was able to look up is that there was really low rainfall late summer as those soybeans were maturing. And that can impact herbicide breakdown, particularly if some of some products. And I'm able to go in and pull that. And if you compare this year to the 30-year average, it was about half of the rainfall that they would typically have in the late summer. We also looked at because we had a good and bad sample, we were able to do soil pH. So sometimes soil pH can cause an issue if there's large differences and we know that our fields here in Michigan are not uniform. We do have fluctuations in pH. We also have fluctuations in soil composition. So the bad areas here or Sandier soil, whereas the good areas had more clay. And that ended up being an important part of the story. So looking at the picture of the things that were interesting were the type of damage, the Flexstar component that got applied to the soybeans and then also the low rainfall that we saw. What we suspect happened here is that the dry conditions reduce the microbial activity and that's what's needed to break down flexstar. And so it's going to make that rotation restriction, which is usually four months, a little bit longer. When I talked to Christy Sprague about this, she said when she sees this as being the most concerning, you have a dry fall following Flexstar It's when there's been an over application. So beyond the labeled rate of Flexstar or if you've used flexstar in consecutive years. So you're kind of building up what's there that the microbes are trying to break down. So, excuse me, this is an example of herbicide carryover. In this wheat field. Injury from herbicide carryover is often uniform across similar soil types or topographies. So it may not impact the entire field because like I said, most of our fields are not uniform when it comes to soil type and typography. But within that field, when it's carryover, we see it more in hotspots of pH where it's similar or areas where we see these different soil types. It can be the result of not following rotation restriction intervals. And unfortunately we do see that sometimes especially with things that have really long intervals and we have diverse crop rotations. We can see it under special soil and environmental conditions that slow the decay of a herbicide. So sometimes we've seen this. We were talking about pivots a little bit in the last talk. Outside of a pivot where the pivot does not reach, sometimes we're more likely to see herbicide carryover in those areas. We can also, as I mentioned in one of the previous examples, see it when we have boom overlap, which resulted in an over application in the previous years. Hopefully we're seeing less and less of boom overlap as our technology improves. Okay, I think this is one of the last specific examples that I have. And this one is just too good not to show you. This is tomatoes. And the tomatoes, the entire field of tomatoes is dying. I mean, this was a complete loss. And you can see the bleaching of the tomatoes at the growing point of, of them. The meristems appeared dead. There were no insects or pathogens. And we know that glyphosate was applied to this field, but it was applied before transplanting occurred. So the tomatoes were not there when they made the application, and they haven't made any pesticide applications since that time. And so glyphosate does show up in the newest growing tissue at the meristem in most plants, we think that glyphosate is going to show up as a yellowing or chlorosis in tomatoes. That actually is a bleaching. Similar to what we see with HPPD have herbicides like Callisto and Laudis. So glyphosate can do this too on particular species. So what happened in this case? We think about glyphosate as having no residual activity, no persistence in the soil because it's adsorbed to the soil particles so well. But you can see that they had raised plastic beds here and those beds must have been formed at the time of application. So the glyphosate got on the plastic and it just sits there. It doesn't photodegrade, so not breaking down from the sun. Even though it's really soluble in water, it just sits there unless there's rain events or irrigation to move it from the plastic. So this would not be a labeled use of glyphosate to apply it over these plastic areas when you're going to transplant into it without any precipitation after this application and no irrigation, these transplants were exposed in one of two ways, or maybe both ways. They could have been exposed when they were punching the plants through the plastic by root contact with the plastic. They also could have been exposed by a rain event happening after transplanting, which splashed the glyphosate up onto the foliage. So this is an example of mulch contamination or soil amendment contamination would also be similar. So when we see that we see injuries, symptoms that appear in conjunction with the use of a soil amendment or a mulch, and it doesn't have to be plastic mulch. It could be an organic mulch. We've seen this in homes where they use grass clippings. And the grass clippings were treated and they put those up by their tomatoes and then the tomatoes all twist up. That's because the grass. clippings move the herbicide back to the tomatoes and then they were injured. Tomatoes are very sensitive to herbicides. They're kinda like a canary in a coal mine. So this is a result of herbicides that are not breaking down, broken down due to their chemistry or their environment or the movement of contaminated materials near sensitive plants. So I already mentioned grass clippings is another example. We've also seen this in manure. And there are warnings about this on herbicides that are labeled for use in pastures. Some of those group 4 synthetic auxins say, it's okay to spray your grass pasture with this product to control broad leaves. But when it comes to manure management, you have to keep the manure on-site. You cannot move it because those particular herbicides pass through the animal that's feeding on the grass and then comes out in the manure and then you could effectively move that herbicide around in that way. So there's a lot of different ways that herbicides can be moved to have off-target effects. So, I want to give you a quick review of the quote unquote 20 questions. It's not really 20 questions, but it could definitely lead to 20 questions or more when you start to tease into the details of each specific case. The first is to consider the application history of the area. The pesticides used, sometimes growth regulators are used on turf or in the greenhouse industry, the fertilizers that are used. And when we're asking questions about this, we're trying to consider if it's possible there was a misapplication. There was spray tank contamination or maybe even that there was some plant stress going on that's contributing to the symptoms that we're seeing. The other thing that's good to ask about is the calibration history if that's applicable, and the use of GPS or markers to prevent overlap. Here we're looking for any potential cause to suspect over application. We also want to consider outside that field the nearby crops, plants and applications. And in that case, we're looking for anything that would point towards the possibility of drift or volatilization or temperature inversions happening from applications that were made nearby. Sometimes volatilization. It doesn't have to be a field right next door. But you can kinda get a better picture. Sometimes it's even helpful to look at the affected area on Google Maps just to see what the surrounding area looks like, to get an idea if that would be a possibility. The other thing you can look at is any amendments or materials used in the operations such as compost, manure, and mulches. Then of course, we're looking for any possibility of amendment contamination. We also see that in the greenhouse industry sometimes they will purchase field soil. And I tried to tell them that you need to consider what was actually applied to the field where you're getting that soil too because there could be some contamination that way as well. Thinking about the watering source if there is irrigation in the area, the frequency and considering precipitation events, luckily, we have a lot of weather stations around and a lot of useful weather data these days. So we can look at precipitation events. We can also look at trends and precipitation. Like I said, that one case where we saw a lot less, That's because we can easily go pull the 30-year average for that area. But in these cases we're asking these questions because I'm really interested if contaminated water movement could be an issue. The appearance of surrounding vegetation. So in a couple of these I talked to you about what the weeds looked like in the area, like in the asparagus case. That helps us indicate the timing of a potential off target issue, a pattern of exposure, and also a type of product based on the type of injuries, symptoms. So all of those things can help lead us to the answer. And so this brings me to, as far as herbicide injury goes, I get this question a lot. What can I do for you through the diagnostic clinic? As our assessments when plants come in, when cases come in, we're able to rule out other causes of injury. So that can be telling you the story, right? We can look at the plant sample and we can look to see if there's any fungi associated with it. We can test for particular viruses. We can send it in to have tissue testing done to look at nutrient imbalances. We can look for insects. So we can rule those things out. And that's helpful and pointing us down the road to the actual cause. We can also evaluate the known history of the area in conjunction with those symptoms. We can provide the MDARD contact information and then. We do not do any herbicide residue testing at MSU at a commercial level. And it's not something that we're planning to do anytime soon. It's very complicated and sometimes the results are not as telling as people would like them to be. And I'm happy to talk to people about when and when that might not be appropriate. But what we can do is provide you with a list of third-party labs that do offer residue testing. There are labs that offer it for plant tissue, for soil, and for water. Can be a costly service. But again, that's something we could talk about to determine if that's actually worth it or not. We keep this list on hand is not just for herbicides, that can be for other pesticides or other chemicals too. And then I update that list every two years to make sure that it's up-to-date. So I just updated it for 2023, so everything should be fresh on that. If you're interested in doing a little sleuthing on your own to look at what herbicide injury symptoms might look like. There's a really nice database through the University of California IPM program where you can go in and plug in a lot of different things and it pulls up pictures of known plants that have been injured by known herbicides. So you can go in and look based on the mode of action. You can look for a particular herbicide, like I have atrazine highlighted in this screenshot. Or you can just say, I want to see what any kind of injury looks like on a corn plant, or on an almond tree, or on a fir tree. It's a pretty large database and very helpful, especially for our higher use crops like field crops. When looking at, do these symptoms look consistent with what we're seeing? Could it have been this type of herbicide? So if you just Google that UC IPM herbicide symptoms it should take you to that database. And there's a lot of great pictures there for you to look at. With that. I know I have some time for questions now. Here's my contact information. I'm always happy to answer email questions or phone calls. We have our website for the lab there, which is pestid.msu.edu And then I also am fairly active on Twitter with all the weird things that come in. That I deal with in the lab. Alright, We have one question so far. So either you blew them out of the water or they're all really hungry and want us to try to wrap up early. I'm not sure which. Maybe a combination. So the first question we have right now is do you have any experience with glyphosate drift in potatoes that you could share? I don't think that I have had a particular case that has come in with that thus far. It's kinda I haven't seen everything every type of injury on every type of crops, so that's not one that I recall having seen when I do get these cases, I tried to save their photos, all the reports and things into particular folder because I like to use these examples for the classes that I teach in and when I do these types of presentations. So I don't recall having one for glyphosate drift and potato. But another good person to ask that question too, would be Dr. Erin Burns because she is our research and extension weed scientist who works on potatoes. So she may have some specific examples of that. Perfect. I want to reiterate one thing that you've mentioned a couple times, but that I found very helpful. So if anybody has anything to submit to Erin, apparently diagnosticians are like the book. If you give a mouse a cookie, except for they want a picture with everything. That is correct. We will always ask you for a picture because we're not able to go visit the site. And that's saying that a picture is worth 1,000 words is 110% true. Because you send me one corn plant. That doesn't tell me if it's just this one corn plant. And you probably wrote about it on the form, which is helpful. The more you fill out the form, the less of these 20 questions I'm going to have to ask you. But the picture, not just like far out, field scale picture, surrounding area picture and then up-close pictures too. Because sometimes those samples don't travel as well as you think they do or sometimes let's let's be real. I know it sat in your truck for a day before it got to me. So those pictures are very, very helpful and yeah, that's I, I had this meme in our lab. If you give a mouse a cookie. So if you're giving diagnostic, diagnostician a sample, they're going to ask you for a picture to go with it. Yeah. I use that as a reference for somebody when I was talking to them for sending in a sample and they said, you know, I'm never going to forget that now. So that being said, it looks like we're probably going to give you guys back some of your time. Erin, thank you so much for coming and giving this presentation. I think it helps a lot to be reminded of what some of these injuries look like.