As many of you have probably heard, or even having your fields, you might have pig weeds and you might have some of our more serious pigweed like Palmer amaranth or water hammer. And this session is designed to teach you how to distinguish between not only those two pigweed species, but others pigweed species that may be common in your field. So before we get started, I just wanted to talk a little bit about a few botanical terms. The first one is over. Now that's just a fancy term we use for a leaf that is egg-shaped. Next thing I want to talk about is the petiole, which is this stock like appendage at the leaf, at the end of the leaf attaching to the stent. Now that I've gone over that, I've taught you something. So when you fill out your evaluation forms, be sure to mark that you learned something. Alright, so why am I talking about pig weeds? Why are they important? This is a list of the top resistant weed species in the world by number of sites of action they're resistant to. And if we take a look, Amaranth is pulmonary Palmer amaranth. Amaranth has tuberculosis, water hemp, and Amaranth is hybridise, are all in the top ten, with Palmer amaranth being resistant to up to nine modes of action in the world, water hint being resistant up to seven modes of action. And smooth pigweed being resistant to six modes of actions. So what species of pigweed you have will definitely depend on the management strategy you need to take to control this species. So to start out with, I'd like to play a little game. Now, you people in the front are actually being rewarded for sitting up front because you're not going to have to move. Those of you in the back. Each of you should have a card on your table. One of these cards, you should also have a sheet of paper that says either smooth pigweed, red group pigweed, water hint, Palmer, amaranth, or live at amaranth, one of those six species. So stand up, take your card and go to the table. You think that your weed is Just going off the picture. Don't worry about the plants. Can make a quick guess. I gave you one more minute. We started out with All right. Time's up. Go ahead and sit back down wherever you can find a spot. Time. You sit back down wherever you have a spot. Alright, so raise your hand if you change seats. Raise your hand if you actually change seats. Alright. Now raise your hand if you move to the correct seat. Alright, so a lot of you are wrong. And as you can see from these pictures, these pictures up here, it's really hard to distinguish something just by looking at a single characteristic such as the leaf. Sometimes it's the tail, tail feature. Sometimes it can get a little bit more complicated, which is why when you're looking at pigweed, you need to look at more than one feature of these plants. So let's first start with pigweed seedlings. All are similar in shape. I'll I'll kinda look the same, especially when you get are just at that codon lead and stage and the caudal Edens are what we refer to. As There we go, the seed leaves. These are the caudal lesions. And they can be different from each of these six species that I'll be talking about. E.g. we're talking about smooth pigweed here and red root pigweed here. These two species are very hard to distinguish when they're at that young growth stage. But the caudal Laden's first both smooth and red root tend to have these kinda long, longer, linear caudal lesions. Now for Palmer amaranth, not a good picture here, but those codons leanings are a little bit broader. For water hemp. Notice here those cauda leans kinda have an orange shape to them. Water hemp leaves, those first true leaves, they're going to be long and they're gonna be linear. Now, once these plants mature, a good characteristic for distinguishing a lot of these species is the presence of hairs on the stem. Each of you should have a smooth pigweed plant on your table. If not, somebody can pass one back to you. Everything is labeled. Look for look for hairs around that upper surface on the upper part of the leaf. That's a good indication that it's either smooth pigweed or red root pigweed. Smooth pigweed and read root pigweed can be hard to distinguish from each other at this stage. In general, rhetoric, pigweed will have more hairs on the stem than smooth pigweed does. More and more as kind of a subjective term, especially when you're looking at look at these two pictures. Yes, the one on the left appears to have more hairs on the stem, then the smooth pigweed on, on the right. But when you're actually looking at these in the field, can be harder to distinguish. But what we do know is if there are hairs on the stem, it is not Palmer amaranth, it is not water hammer. It is not spiny amaranth and it is not live it amaranth. So no hairs. It's either livid, Palmer, spiny or water hemp. Now, just pay attention to the fact that the stems have no hair color. The coloration of the stems can be deceiving because all of these species, yeah. Alright. Alright, better. Alright, so don't pay attention to the color variation on the stem because water hand Palmer amaranth, they can have anywhere between green to red stripe stems. But if you notice, you know, Palmer amaranth here, the flower here, and spiny amaranth. What's the key difference between the bottom of the leaf axle hit flower here and here between Palmer amaranth and spiny amaranth. The spine that is the key distinguishing feature between these two species, Palmer amaranth will not have that spine coming off the leaf axle. Next feature can be a little bit more complicated. The leaves and the petioles. In general, you know, red root pigweed and smooth pigweed. They're going to have this more pronounced, the nation. And they're going to have these wavy margins on their leaves. And generally shorter petioles. Spiny amaranth, little bit in-between, little more glossy appearance. Does tend to have longer petioles and either smooth pigweed or our red root pigweed. Water hint in general, is going to have long linear leaves. And Palmer amaranth, it's going to have that long petiole. Nothing about smooth pigweed and red root pigweed shapes in general, they're going to have innovate shape, that egg shape, same as spiny amaranth Palmer amaranth tends to have more of a diamond shape to innovate shape depending on what you're looking for. Now, as I, as I mentioned, Palmer amaranth, it's going to have that long petiole. And how many of you have ever heard me talk or ever been with a scene of pigweed? Id gathers had someone talk about Palmer amaranth and say, if the petiole is longer than the leaf, It's Palmer amaranth. Yes. That's a good distinguishing feature. Sometimes. Now, like all plants, the leaf morphology of Palmer amaranth can be affected by things such as not being watered or the temperature is being too high. All of these pictures here are Palmer amaranth ranging from no to ranging from temperature and moisture stress. So as you can see, not all of those petioles are long and not all of them are going to be longer than that leaf. If you take a look at the Palmer amaranth on your table, you'll notice that not all of those leaf petioles are going to be super long. However, most of the leaf petioles at the bottom of the plant, those outer leaf petioles, We're gonna be a telltale sign that it's going to be Palmer amaranth because they will be, in general longer than the leaf. Just be aware when you're scouting. These don't rely on just long leaf petiole to be your only diagnostic feature for Palmer amaranth? Nothing about Palmer amaranth we usually talk about is having a watermark on the leaves, kind of a V-shape. Sometimes they're purple. Is anyone here have a Palmer amaranth plant with a watermark on their leaf. Alright. That's a good distinguishing feature for Palmer amaranth two, but unfortunately, Palmer amaranth isn't the only species that has a watermark honestly for can have a watermark on its leaf. This is spiny amaranth. Notice it also has that kind of purplish thumbprint watermark. So what's the best distinguishing feature between Palmer amaranth and, and spiny amaranth, again, having that spine on the leaf. Both of these are going to have smooth stems. They have the potential to have watermarks. And I've seen spiny amaranth and some really long petioles. Seed heads. All of these look like pigweed seed has. A lot of these may be indistinguishable, but there are some key differences. When these plants start to flower. Now, starting with the red root pigweed seed head. In general. You see that? See Ted. And you see the seed head. That's smooth pigweed. During their vegetative stages, again, these are very hard to tell. Apart. Both have leaves with wave he marches both have hairy stems. But this red root pigweed, that seed heads gonna be more stuff, more stumping, more compact compared to the smooth pigweed. That's going to be more branched. The spiny amaranth seed heads gonna be a lot shorter. It's not gonna be as tall as what we see from water hemp or Palmer amaranth. Water hemp and Palmer amaranth are gonna be this two species that you see most putting out that longer seed head, generally over a foot-long. What's another distinguishing feature that Palmer, amaranth and water him have with their flowers and their seed heads. Could anybody tell me? They are dioecious, which means they produce male and female flowers on separate plants. For water hemp, which is this species. On the left. Both the male flowers and the female and the female flowers are going to produce relatively soft seed heads. For Palmer amaranth. Species on the right. This male flower is going to produce a nice soft seed head. While the female flower is going to produce sharp, very sharp practice. If you're pulling this polymer from your field at the end of the season, you will definitely know whether or not you have a male Palmer or you have a female Palmer. Another key difference in Palmer, amaranth seed heads and water hemp seed heads are the way the flowers are structured. If you look at this female water hemp seed head, notice that these flowers have a little bit more separation in them. And know Brex versus that female flower. Notice how all of those structures are compact, basically stacked one on top of another with these sharp breaks. So does anyone have any questions so far? Alright. Just to go over these again, water hammer. And as I go through this, feel free to look at all the plants on your table. Notice that those water hemp plants, in general, the leaves are gonna be long, they're gonna be linear. Sometimes they can be oval-shaped again, that's all part of environment. The stems, no hairs, green to red striped seed heads are going to be taller, one to 2 ft long. They're not going to have any brackets, they're not prickly and water hand, it's going to be one of your taller growing plants in the field, up to 10 ft tall. Palmer amaranth, again, leaves will have a more overweight to a diamond shaped appearance in the field. There's a potential that they could have that watermark on them. Again, it's not the only distinguishing feature. Usually. They'll have long petioles. Petioles that are longer than the leaf. No hairs on the stem. Nother get good key identifying feature for if you have Palmer amaranth is the present. This little hair on that leaf tip notch. That can be a very important distinguishing feature. If you have a weed that looks like water hemp, you're not really sure It's water hammer. But you're not really sure It's Palmer either? Water him, he usually doesn't have that here on the leaf tip. And again, Palmer amaranth is one of those other species that grows to be very tall, especially when not competing with anything else. Spiny amaranth. The leaves, again, they're gonna be egg-shaped over a longer petioles. Know Harrison that stem. The seed head of spiny amaranth, the male and the female flowers are on the same plant. The male flowers tend to be at that terminal spike here, while the female flowers tend to be located at the stem axles and spiny amaranth. Not very tall, grand plan, only up to be 5 ft. Another species that we see in the area's not much of a problem, is live at amaranth and I didn't cover, talk a lot about live in amaranth at the beginning because the distinguishing features of livid Amaranth are very easy. It's basically, you're only pigweed species where you kinda have that huge notch and that leaf, know Harris on the stem. All the male and the female flowers clustered together. And very short plant, only about two to 3 ft tall. Red root pigweed and smooth pigweed. No. Leaves tend to be oval to diamond egg, egg-shaped way the leaf margins, very prominent venation. You can see how deeply cut those veins are into the plant. Stems have many fine hairs, more so than pigweed. The undersides of the red root pigweed, please. We'll tend to have hairs. The seed heads again, they're going to be short, stubby, and compact. With this plant reaching about three to 6 ft tall. Smooth pigweed. Those leaves again oval, the diamond shaped, wavy leaf margins, hairs on the upper stem. They're not going to have that same type of hairs that rhetoric pigweed had. Again, short, shorter plant three to 6 ft tall. The seed heads again, they're going to have a more branched appearance. They're not gonna be as stubby. So again, it's important key identifying traits of pigweed species. This, There's sums everything up and the table. All of these features are very important for distinguishing these pigweed species. And these aren't the only pigweed species. And the country or even in the area. I just chose the six and I see the most. So leaf-shaped. Remember, water. Water hymns usually going to have that long linear leaf making an indistinguishable between most other species. The petiole to leaf ratio, Palmer amaranth, that longer petioles usually going to be a good giveaway as long as you're looking at those lower lease and always check the entire plan. Just don't rely on new growth when you're identifying stems. Very important key feature, smooth pigweed, Frederick period pigweed, not going to have any Harris on their stems are more problematic. Pig weeds are gonna be the Palmer and the water hammer. Those are the ones that grow to be the tallest male and female flowers and see him just remember that water can and Palmer going to have male and female flowers on each plant. Palmer is the one that you don't want to pull the female flowers because you'll perked your hand. Trust me, I know it's not fun pulling Palmer out with bare hands. I do recommend you always using leather gloves when you pull pigweed. And another feature is going to be resistance because again, this is going to determine how you manage this species. On this bottom row, I have pigweed resistance in the US. And notice that we have a lot of resistance with Palmer, amaranth and water hint, basically resistant to most of our post emergence sites of action. This does include glyphosate or ALS inhibitors are grouped for inhibitors dicamba and to 4D among others. But fortunately, here and the Mid-Atlantic and Delmarva, what were, we, were still only seen resistance to our group two or ALS inhibitors and our group nine or glyphosate. Notice we don't always have resistance and smooth pigweed, red root pigweed and live it amaranth as well. But we do not yet have glyphosate resistance, resistance to liberty or resistance to 4D. Any questions so far? Alright, so next I just wanted to cover a little bit about lookalikes because these can be a little bit harder to distinguish, especially at younger growth stages. So one of these is Eastern Black Knight shape. Now, Eastern black night shade compared to smooth pigweed. Once it gets up there, it's going to have a more sawtooth leaf margin. It's also going to have a purplish cast on that underside. Not all of these pictures are Eastern black night shade. That smooth pigweed that also has a purplish cast. And when these plants are younger, they can be very hard to distinguish. However, when you're comparing Eastern Bloc night shade, smooth pigweed, usually the first true leaves as the smooth pigweed, there's gonna be a little bit more rounded. Whereas the first true leaves of Eastern black night shade, they're going to come to a point as that plant gets bigger, of course, a lot easier to distinguish between Eastern black night shade and smooth pigweed or any of those pigweed species, species is going to have a more branched appearance. And eventually you'll start to see berries on the plant which smooth pigweed does not produce, or any of the pigweed species for that matter. Another species that can look like a pigweed, Palmer pigweed is Virginia copper leaf and you might see that intermixed with a lot of things. I saw a lot in our watermelons this past fall, just based on that kind of canopy architecture and that almost Rosetta light pattern which Palmer amaranth can path. But again, notice the differences. The leaf margins whereas smooth pigweed Palmer, amaranth, they have wavy or entire leaf margins. You can almost see a little bit of duration. And those virginia copper leaf plants, Virginia copper leaf also doesn't get nearly as high as the pigweed species. And their flowers look nothing like those pigweed species. Common lambs quarters can also look a lot like our pigweed species, especially when it's at seedling stage. However, notice that those seedlings, It's common lambs quarters, have a little bit of a grayish cast to them. Smooth pig weed seeds, Palmer amaranth seeds do not have that small grayish cast to them. Another one I just threw in there, curly dock. Why did I throw curly dock in here? Because if you're driving by your field, you might see something that looks like a cluster of Palmer amaranth seeds. Drive a little bit closer. Notice it looks nothing like Palmer amaranth. Curly dock usually has that Rosetta pattern. And you'll see curly dock lot earlier in the season than you will Palmer amaranth. Any questions so far? Alright, let's see how we're doing. I'm going to put a picture up. And someone raise your hand or just shout out the answer. Tell me what you think it is. Any guesses? Livid, alright. Yes, that is living in amaranth, as I said, very easy species to identify. Those nice, decent, deeply notch leaves. All right, I have a different name. It's also called Purple amaranth. Prostrate pigweed that looked a lot like that. Prostrate pigweed does look a lot like that. It does have a, a, does have a prostrate a lot lower. And the leaves tend to be a lay person. Yes. How about this one? Where do you think? Alright, raise your hand if you think it smooth pigweed. Raise your hand if you think it's Palmer amaranth. Palmer amaranth. Again, pictures can be deceiving. You can kinda see long leaf petioles, but you can't tell from the picture. You can see a water mill mark. It's difficult to tell from that picture, so it's important to get out into your field and scout. How about this one? Water hand? Yeah. Why is it water hemp? Because it has those long, narrow leaves, a key feature of most water hemp plants. How about this one? Correct. It is Eastern black night shade. A seedling stage again, look a little bit like a pigweed. Notice those first, again, those first true leaves tapering out to a point. Why do you think it's spiny amaranth? Yes. You're correct, but why do you think it's funny M or N bond right there? That my fields, my bare feet. And therefore, yes, it is spiny amaranth and you can see some spines on those pictures. About that one. It is Virginia copper leaf. Alright. Here's that smooth pigweed. Relative they're smooth or red root pigweed. I didn't really check when I took this picture. And it's one of those two. The important thing it is not Palmer. Alright. What's this one? What's this one? Brian Very good. It is spiny amaranth. Again, a little more difficult to tell from this picture. Not very good. Like a lot of the pictures I get. But he can kinda see some of the spines in here. What about this one? Who thinks it's red root pigweed? Alright, trick question. There are actually two to pigweed species in this picture. One to the left, that is red root pigweed or smooth pigweed. The one to the right, that is Palmer amaranth. Now notice, notice the difference in not only the leaf-shaped, the leaf color, but notice that that Palmer amaranth, a lot taller than that smooth pigweed. Palmer amaranth is a very pesky. We'd not, just because it's resistant, because it grows very quickly. Under optimal conditions, the heat of the summer, it can grow about an inch a day, and it can grow anywhere. This picture was actually taken in downtown Salisbury. Show up alone at home or kitten? Or is it later? You can see it in later stages. Alright, I think this is the last one. Photo is Palmer but doesn't reach has a short patio, but it kinda has a more of a linear leaf shape. So how many of you think this might be Palmer? How many of you think it's water? And congratulations to those of you who said it was Palmer amaranth. Again, this was taken asleep was taken no front probably from the upper portion of the plant where that petiole, those petioles haven't elongated as much. But if you notice at the leaf tip here, there is that hair. I also know that this is Palmer amaranth because I had the plants from this particular field genetically tested and it came back, Palmer amaranth. So that's a sure-fire way to make sure you have the right pigweed species. It's just going to cost you about 100 bucks to send the sample off. How about this one? Either? Short stumpy branches, red root pigweed. This one. It's Palmer amaranth. Think this is my last one. Water hammer. Notice that that's the longer seed head, but notice there's a little bit, a little bit more separation in those flowers. So very good. Hope you all learned something today. Just wanted to touch on management quickly. Again, a type of pig weeds when determine what type of management you have. What we've done a lot today, here is learn about prevention. Scouting. What pig weeds do I have in my field? What do I need to plan for next year? What kind of chemical control programs do I need to use? Alright, so hopefully everybody has learned something. And by this time next year when you're driving by your soybean fields, at your client's soybean fields, you can determine whether or not all these seed heads popping up our Palmer amaranth or not, correct. Everybody not drop. I just showed you how to identify these plants before they set seed. When these plants set seed, they're too big to sprayed with herbicide. By the time you get to this, there's nothing that you can spray on them. It's going to be effective. Even with some of our stack soybean traits. Dicamba to 4D and list liberty. You cannot spray Liberty, passed R1. You can only spray to 4D up through R1. And you cannot spray Dicamba after June 30th. So there's nothing you can spray on these plants that are going to kill them. You cannot put paraquat and a wiper bar and go over the plans to try to kill them. See deep I can't put paraquat and y-bar bar, right? Okay. No. Yeah. There's nothing you can do to be able to control these. If you went to Linz talk lash? Yes. Alright. Yesterday, she did talk about having that we'd electrocution system that is a good fit for collar pigweed species. If you have that Canopy Height, give differential. But again, you still want to target these weeds before they flower, before they set seed. And if you do, hopefully get them early in your field, looks like this. Next year. I think we have still have a little bit more time. When did give you all plenty of time just to go over those plants in front of you. Look at those distinguishing features, their leaves, their stance, feel free to take pictures of the plants. Here is my contact information. If anybody has any questions, I'll be right here.
2022 Crop Management School - Kurt Vollmer
From Robert Diiorio December 02, 2022
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