S4E4: Fall Herbicide Application: Burndown and Pasture Weed Control

Recorded: 9/18/25

Have you ever harvested your crop just to reveal a major weed problem? Are you wondering whether a fall burndown is worth it or if you should wait for spring? In this episode, we chat with weed specialist Dwight Lingenfelter about fall burndown best practices, weeds that can be managed at this time, and tackling certain pasture weeds. 

Hosts: Ryan Spelman and Justin Brackenrich, Penn State Extension
Guest(s): Dwight Lingenfelter, Penn State

Links:
Fall Burndown of Weeds and Declining Forage Stands
Fall Weed Control in Pastures, Hay, and Other Forages
Burndown Herbicide Selection Before Early-fall Cover Crop Seeding
The Penn State Agronomy Guide

Photo credit: Ryan Spelman, Penn State Extension

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Transcript

Kicking Off And Team Expertise

Ryan 0:16

Welcome to another episode of the Agronomy Highlights Podcast. I'm your host, Ryan Spelman, and as always, I'm joined here with, well, not as always, because we keep changing it, but I'm joined with my lovely co-host and colleague, Justin Brackenrich. Justin, how are you doing?

Justin 0:30

I'm good, Ryan. Yeah, maybe maybe changing this stuff around. We're gonna try and keep people on their toes and a little more engaged, and maybe that'll help, right? Having kind of rotating house a little.

Ryan 0:40

Yeah, I think that's right. And and you know, you hear the saying, distance makes the the heart gro grow fonder. So you know, it'll it'll help our relationship as well.

Justin 0:51

So it's such a unique group, right? We've all kind of got something different to bring to the table and kind of a different perspective with you and your pathology background and row cropping, and mine is more fertility and forages. And Dwayne has in his practical on-farm experience and uh his relationship with forage and grain, but it's often different thoughts or different kinds of patterns and and coming to questions in what you and I have. So I I think it makes for a fun dynamic with the three of us.

Ryan 1:18

Yeah, that's right. I think it's we have a really rounded out group of expertise um between the three of us. So I I think this is gonna be great

Why Fall Burndown Matters

Ryan 1:26

moving forward. So, anyways, well, today what we're gonna talk about it it kind of follows in cue to our last episode, which is harvest du's and don'ts, right? So um, after we harvest, one of our biggest decisions we have to make before we get into the winter in the next season is weed management, right, so, um so, Justin why don't you w maybe describe a little bit more in detail what we're gonna talk about today?

Justin 1:49

Yeah, so this is kind of a um mixed bag, we're gonna call it like our fall sprain management thing, right? Uh and so like Ryan said, what about fall burndown? And for years we've talked about Marestail, and we're seeing Palmer and water hemp and chickweeds and stuff kind of getting worse. And yeah, people look at this as like, hey, it's a fall burndown, it's an expense, I don't have any crop. But if we can do a little bit of maintenance in the fall pretty inexpensively, does that set us up for a better spring control and you know, subsequently a better uh in season post-application, right? We're not fighting with as much weeds because we've kind of nipped back some of these rosettes early. So we're gonna talk about that, like when to do it, what to do, how to target, uh, and and how to manage that with cover crops. So the other big thing that we're gonna discuss, and it's kind of one of my passion projects, is just pasture hay, uh woody perennial, autumn olive, multiflora rows, uh, when to do it, how late in the fall we can do it, what treatments work best, uh, general kind of maintenance of forages to get us set up for a good spring uh moving into next summer, right? And I think it's kind of an interesting time because we've been really dry. Our grasses have been kind of tamped back some. We've seen a lot of different weeds, uh, horse nettle, kind of the weed of the year, right? And we're gonna talk with Dwight about how we can manage some of these things.

Ryan 3:14

One of the things we mentioned last episode is that uh harvest in some cases will be a little bit earlier. So given that, you might have a little bit extra opportunity to make a timely herbicide application. Um, so that's one of the things we're gonna discuss here to today. So Justin kind of mentioned that Dwight's gonna join us today, and Dwight Lingenfelder is our herbicide and weed management specialist on our team, and he's been on many times before, so he's a friend of the show, and I don't think he really needs an introduction. Um, so we're gonna kind of jump right into it. So thank you, Dwight, for for being on today. And uh with that, let's get into it.

Dwight 3:57

Yeah,

Targets: Winter Annuals And Biennials

Dwight 3:58

well, I appreciate it. So, yeah, so uh um as far as uh you know thinking about you know fall burndown and you know what what to be thinking about in terms of you know what weeds or what herbicides or other management strategies, you know, you you you think about you know this time of year uh is is a good time to spray you know a lot of these these winter annuals that will that will be starting to germinate or maybe already have germinated. Um but also there's also you know other things like perennials, you know, some of the you know perennials like dandelion, um even even like Canada thistle, some of the other ones that are really you know gonna start to take off here as we get it, you know, later into the kind of the cooler, cooler temperatures. Uh and even some biennials, you know, the rosettes some of these biennials, you know, think about some of the you know, whether it'd be uh like a thistle, uh uh like a musk thistle or a bull thistle, you know, plumeless thistle, those are all biennial weeds. Um, even things like uh poison hemlock or wild carrot, you know, those are all all you know, those those two year life two-year life cycle weeds. So any of those, you know, there are would be kind of you know targets, you know, at this time of year. You know, I think, you know, when most people think about you know fall fall burndown, they really are kind of targeting some of these, you know, more the the winter annuals, you know, things like common chickweed and mare's tail, tin bit, dead nettle, things like that, um, are are are ones that uh are really good to go after um before they um start getting too large. You know, you you think about you know something like common chickweed, and it it really thrives in kind of these cooler temperatures. You know, in fact, in some some there's been some stud studies on it done on it, and it actually can you know grow down to you know single digits from you know a temperature standpoint. So you know, even it's it's it's you know still kind of growing, maybe not be thriving, but it's still you know growing, you know, even under these real cool conditions. So that's one of those where you know if it has a you know some mild mild temperatures, you know, going into the the fall and even into the spring, it can be pretty unruly. So waiting too long, especially waiting till spring, can be a challenge to try to get it under control. So that's why you know I really suggest you know you know getting some uh control tactic on it yet, you know, this fall so it doesn't get out of out of control, or you know, even even things like you know, mare's tail, you know. So those are those are some typical weeds that um you know we're we're kind of targeting when we think about fall burndown.

Cool‑Season Grasses To Watch

Justin 6:21

Dwight, with the list that you went through, uh predominantly and and maybe all broadleaf species, are we ever really looking at fall, you know, these these post-harvest burndowns to target grass species, or is that always like a spring-fall kind of problem?

Dwight 6:36

No, that's a good point. I mean, yeah, there are definitely some some winter annual um, you know, uh grass species or or even some perennial species that we need to be concerned about. So, so uh yeah, you know, things like the brome species, you know, things like downy brome or cheat or chess, um, those are those are you know problem problem weeds that we deal with, you know, especially in small grains, but that of course they could, you know, you know, develop in a in a fallow area or after harvest. Um, you know, you things like annual bluegrass or the rough stalk bluegrass is always a a challenge. And then even even you know, ryegrass, annual ryegrass, Italian ryegrass, those are you know, it's you know pretty pretty uh you know prominent in some fields as well. And then you have the old school weeds, you know, something like excuse me, like quackgrass, you know, good perennial quackgrass. It's a cool season species, so it can really you know start taking off now in the in these cooler temperatures as well because of you know the deeper root system and so forth. So that's another species that we need to be uh concerned about too.

Ryan 7:38

So Dwight, it you know, there there's a lot of species here that that we're controlling. You kind of just mentioned some of the grass species and and then our different life cycles of some other um weedy broadleaf species. Now, do you recommend that folks be doing a burn down every year, regardless of what they're seeing in the field? Because there's probably some you know small maybe winter annuals that are just coming up. Um, or is this something where you really want to be out there scouting and deciding whether it's necessary or not?

Dwight 8:10

Yeah, I

Scout First, Then Spray

Dwight 8:11

mean that's sure. That's one of those things where I think, you know, we we're all you know wanting to practice, you know, IPM tactics. And sure, you know, just going going out and just kind of you know blindly spraying and just assuming that that you need to, you know, spray it every year, you know, it's it's it's not necessarily necessary. I think that's where we're yes, scouting, scouting first and and having an understanding about where you know what weeds have been there or maybe historically there. Um so so yes, obviously, you know, scouting, making sure, you know, what the targets are. Um because as we as we mentioned, you know, it's one thing if you're going after you know just a certain subset of broadleaves, but you know, if there are grasses in there, then obviously you're gonna need to include you know different types of herbicides um in that in that mixture um in order to target those correctly.

Ryan 8:58

Okay, so you kind of just mentioned uh the the mixture that

Go‑To Fall Mix And Costs

Ryan 9:02

you might use. So if we're trying to do a uh a fall burndown and and should we usually is that usually gonna be just like glyphosate and 2,4D combo, is that kind of still the the standard for a fall burn down in most cases?

Dwight 9:19

Yeah, so I mean uh one one of the mixtures I typically recommend, you know, for this this time of year as we're good getting over the next few weeks here is kind of a basic mix of of glyphosate, you know, and a lot of times, you know, depending on what what the formulation is, you know, typically about that quart rate, you know, it could be on a plus or minus a few fluid ounces here or there, depending on the the formulation. And then and then 2-4D, you know, probably like a 2-4D ester, probably at about a pint. And then and I I always like to include something like Metrobusin, you know, so metrobusin, uh include that probably anywhere between maybe three and five ounces. Um, and that'd be the dry, the 75% dry um flowable mixture uh uh formulation. Um and and the idea is to is to that that's a pretty good pretty good mixture for uh a good spectrum of weeds. So obviously the glyphosate will be there for you know for grasses, and then and then also it'll it'll pick up a it an a number of of different uh you know broadly species as well. Um 2-4D would be in there to help help uh improve the activity on on you know some of the the any of the species that are resistant to glyphosate. Um it has a little bit better activity on on things like dandelion, you know. So this is a good time of year to spread you know the smaller dandelion. So 24D would do a good job with that. And then you have metrobusin, that that kind of that lighter rate of metrobusin in there to help help uh complement um and pick up some of those other species and also to provide some some initial residual control um you know in in in in that that area. And and you know, in most cases, I I always try to explain that you don't want to you know break the bank on this this application. You know, it's it's really meant to be you know five to ten or fifteen dollars per acre at very most. You don't want to be out there you know spending you know twenty, twenty-five dollars an acre because the reality is you're gonna need to be out there again in the spring. You know, really this is this is to kind of get get a uh kind of a head start, if you will, on the burndown process and not let some of these weeds get too too large. Um, so so you want to at least kind of keep them at bay or or kill some of the smaller ones. But but you have a weed like marestail, for example, that has you know two different flushes, you know, so it's gonna have a fall germination phase, and then you're gonna have another spring germination phase. So this is really to help uh you know alleviate some of those problems of trying to control everything in the in the spring. And and you know, when we're thinking about products, you know, there there are other other active ingredients, you know, things like canopy or canopy EX or some of these other ones that could could potentially be used, but you know, you need to you need to start you know considering you don't want to spend so much money and assuming that you're gonna get residual all the way through um next next year. I know a lot of a lot of people will ask about you know

Rotation Flexibility And Residuals

Dwight 12:05

spraying something like prowl this time of year. Well, prowl is really not a a good good uh herbicide for this time of year. It's it's really more of a summer, you know, a spring and a summer type of a herbicide, because the activity, you know, is more more leans towards more some of those summer annual type species. So you know, just understanding the product and what what it's gonna where it's gonna fit, um, you know, can be can be important. And then on that note, you know, thinking about you know, if if you're still kind of up in the air about what you're gonna plant next year from a rotational standpoint, you know, that that's where that that basic you know mixture of glyphosate 240 and metrobusin, that allows you to have a little bit of flexibility whether you want to go to corn or beans. So if you start start spraying, you know, things like atrazine and simizine, which you could spray at this time of year, and they do have some pretty good activity on certain certain species, but then you're kind of locked into you know just planting corn the next year, you know. So, or if you start using you know higher rates of of uh you know some other other products are that are specific for soybeans, then then you're locked into soybeans. So that's where you kind of want to have a little bit of flexibility and in um the choice that you're making, you know, for these fall burndowns.

Justin 13:14

So it sounds like you know, we've had this conversation, I don't know, maybe a hundred times at this point, that like we're looking for this silver bullet or this one size fits all, you know, and that's our that's our burndown in the spring, and that's for post, right? We want one thing that we can spray over everything. And it sounds like that's just not the case for these fall burndowns either, right? Like we just unless we're sticking with like basic glyphosate 2, 4D metribus, and maybe, but like if we want to really be specific and target certain weeds, we have to know what we're going into next year to make this kind of more effective. Is that the way we should look at it?

Dwight 13:48

Yeah, well, and yeah, yeah. I mean, so obviously, you know, no knowing your your tar target, you know, that's that's obviously what we need to know. But but at the same time, too, um, as as I mentioned, you we don't want to, you know, the reality is we're gonna have to use a burn down next year, you know, in next spring, I should say. So, so you know, you know, if if if uh we're we're targeting something like Marestail, um, I I would I would, you know, you know, kind of maybe caution against something like like sharpen. You know, if you want to use sharpen now, it's one thing, but then you're probably gonna have to use sharpen again next spring. So that can get a little bit pricey. We start using too many, too many of these, these herbicides, you know, that that that you know from an expense standpoint. So I'm I'm trying to kind of balance the you know, kind of the balance the uh the aspects here, what we're what we're we're targeting versus you know being realistic about um you know the the the fact that we will need to come in again next next spring, more than likely. I mean that's to say that you know we may have it may have a good job with it, and maybe we end up with a dry, dry winter and maybe a dry spring and we don't we don't have as much of a flush next spring. But the reality is in most cases, you know, even though if you do a fall burn down with some light, you know, the kind of the these this this basic you know burn down program, you're still gonna have to come in for for some of the other other um maybe the escapes that have happened or some of the weeds that started to really take off uh more so in the springtime versus here in the fall.

Justin 15:12

So let's throw kind of a wrench

Cover Crops And Herbicide Choices

Justin 15:14

into this, right? If we're thinking about glyphosate 2,4D metribution as our standard burndow that we're gonna use in the fall, what if we want to take off our crop and then put in a cover crop? How does that change any of this, right? And I guess let's think about it first as just a cereal cover crop, just rye or wheat or tritical or something like that. And let's talk about how this may change in that scenario.

Dwight 15:35

Yeah, so if we're using more of these, I guess in this case, yeah, grass, you know, grass uh type of uh uh cover crop, you know, um, that that's where you know we do have a little bit more flexibility. Um so I so I guess you know you think about you know the aspects of of just getting the cover crop established. So so you know, what weeds would be would be there um, you know, in in you know, before before actually planting the the cover crop. Um, but then also you need to think about the potential for weeds that will come into the cover crop as well, uh, that that may need to be correct, it may need to be controlled. So that's where I think the utility of uh more of a grass, like a you know, a cereal grain, whether it's a uh rye or a wheat or even like a ryegrass, you know, you you have you have a few uh you know a few more options, especially you know, from a burn down standpoint before planting, you know, you have you have things like you know, sharpen, um, which which you know has has pretty good activity on things, you know, like mare's tail and and and even some dandelion and things like that. You can you can you know get that get that from some some utility out of that, you know, before planting, um, or even something like Liberty, you know, Liberty has a seven-day wait. Um, then you can plant you know various cover crops after seven days. So that those would be good from a you know kind of a burndown standpoint, if you will, before establishing the the that grass cover. But then in the crop, then you know, there's as I mentioned, you're gonna have things like like maristail and even chickweed and some other winter annuals that are gonna germinate uh in in amongst that grass as it's growing. So that's where you know you you have the utility of things like 2-4D or dicamba that could could potentially be used uh in that that um crop as it's getting established this fall and then even next spring. You know, I mean if if the if the um the the the uh grass of the cover crop is only maybe six, eight, ten inches tall or even a foot tall in the spring, there's still one maybe one last opportunity to spray something like 2, 4D uh in the spring before planting as well. So it just allows more flexibility. So there you're truly integrating your your tactics, you know, not only you it having a cover crop, which is a good thing, but then also you're you're allowing yourself to have some some herbicide options, unlike if you start using these these cover crop cocktails, you know, where you're um you know including some kind of a brassica and a legume and a grass and so forth. And and again again, I every time I talk about cover crops or or you know talk with groups about cover crops, you really know it need to know why you're planting a cover crop. You know, I mean if if it's if it's to have some ground cover and for weed suppression and so forth, that's one thing. But if you're trying to you know scavenge nutrients and or even improve the nutrient, you know, nitrogen or something like that, then then you you need to know why you're planting the cover crop to begin with. So so there again, as a weed scientist, you know, I'm I'm focused on you know weed control, but at the same time too, there's other other things that need to be considered, obviously, as as well. Um, you know, when when you're when you're deciding, you know, what cover crops to plant.

Justin 18:42

So we can direct people back to season four, episode one, ag innovations, and where we discuss the cover crop selector, right? The Northeast cover crop tool, where you can go in and you know follow up exactly what what Dwight is saying is you put in like these are my three goals, and it's gonna tell you what the best mix is to achieve that so that we're not just buying seeds and putting a lot of things out there that we we maybe don't know why we're doing that.

Dwight 19:07

Yeah, yeah, that's that's right. So that's where we're you know knowing what what the purpose of the cover crop is and and and uh you know having having those goals in mind before you even you know just go out there and start planting.

Ryan 19:21

So so Dwight, you you know, you mentioned some of the specialty products like sharpener. I I guess I don't know what a specialty product would be, but um when you're planting uh a cereal cover crop. Now, I just wanted to clarify here, um, you know, beforehand you were mentioning glyphosate 24D and metrobusin. I can still plant a cereal cover crop after that, right? And and how long should I wait after that application if I'm doing that?

Label Limits Before Planting Covers

Dwight 19:50

Well, yeah, I mean, so so those those types of uh products you need to be careful, especially with with something like like 2-4D, you know, that that's one where um if you look at a 2-4 label, 2-4D label in in particular, um you'll you'll you'll see that there's really not there's really not language on a label that that allows it to be used before you know small grain planting or even even like a cool season forage, you know, grass planting, because you know there's always concern for you know you know problems with with germination. So so um it it it's so so in essence, you know, according to the label, you know, that it's really not not allowed. Now we have done research on it and and we have found that you know using if you use no more than a pint of 2,4D, um and and you get about an inch of rainfall and wait, you know, 10 to 14 days, and in in most cases, you can you know get a pretty good establishment of a lot of these these grasses, um, you know, in you know, af after you know an application of something like that. So so again, you need to you need to be kind of wary of of you know what what what products you're you're working with. And then then another thing, you know, consider too is you know that this is also as a as a cover, you know. So it's one thing, you know, you even though there may be a little bit of injury, it it's not necessarily the end of the world compared to if this is more of a forage or excuse me, either a forage or or uh, you know, for for food, you know, like a food grade product of wheat, um, then then the it it kind of shoots it into a different type of uh uh scenario. Um, because then then there's always a concern about you know any residues and so forth that could be be potentially in there. So that's what I'm saying is if you have these two kind of worlds where you know you have the the the aspect of you know crop injury itself, but then you also have the the issue of of residues uh that still may be you know in in the actual you know food or feed um, you know, what what you're trying to you know trying to use that for after the fact. So so so yeah, it's it's it's it's kind of kind of one of those things where you always you know have to go back to you know the what the the rotational restrictions are and and the you know the the the time frames that need to be to be met before until you can start planting you know these different crops um you know after after these burndowns have been applied.

Justin 22:11

I think that's you know kind of a good wrapping up segue kind of a position, right? So we've we've talked about fall burndowns, uh, when we can do them, what we can do with them, uh the weeds that we need to be scouting for,

Pasture And Hay Weed Timing

Justin 22:23

right? Because this is identifying the weed to know. But what you finished on was talking about residues, right, and animal feeds and things like that. And that kind of brings us into our next topic for this fall weed management, and that's talking about pasture and hay weeds, right? And and a lot of times, and one of my favorite things in the agronomy guide, and uh one of the things that I probably give out more than I should is this calendar of the weed management schedule with pastures and hay and forages, right? I I think I tell the folks I work with, I think the biggest mistake we do is we try to manage weeds on our schedule, not theirs. And when we look at that, so many of these are done in the fall. And um, but this question always comes up, right? We're sitting here September 24th. Uh, when is too late to start managing fall weeds, or I guess stop managing fall weeds.

Dwight 23:13

Yeah, and you and as you mentioned, you know, we do have that that table in the in the agronomy guide. And in fact, it's it's table 2.6-17 to be specific if you want to look at in the the the latest Penn State agronomy guide. But um, yeah, I mean we we kind of have a a you know g general uh time frame from often time you know controlled pasture weeds. And and there again, it kind of goes back to you know knowing knowing your enemy, you know, knowing what we're we're targeting, you know, are we are we target targeting you know perennials? Um, or are we targeting you know some of these annuals and and and you know or biennials? So so there again, um, you know, if you think about you know you know a lot a lot of the weeds we're going after, you know, things like horse nettle or milkweed or dog bane, bed straw, you know, some of these these weeds that these problem perennial weeds that we're dealing with, um, a lot of those are considered warm season. So, you know, they they they come up a little bit later in the spring, then they go door go dormant a little bit earlier here in in the late summer, early fall. And and so, so you know, even if you you drive around, you know, the area, you know, your your farm or you know, road size or whatnot, and you see things like milkweed, you'll see that them some of the milkweeds already, you know, yellowing or even even brown, whereas maybe a patch right next to it is still kind of light green or or or green, you know, and and so so you know they're they're they're starting to go down. Same with the same with horse nettle, you know, that's another warm season perennial that that that you know is starting to you know have its have its its life cycle, you know, the the bulk of its growth, and now it's ready to start going dormant. And then also, you know, it's a lot of it's is still you know if the if it's still in the field, it's it's it's setting um the fruits now. So the fruits are already there, and then as soon as it sets the fruits, then it's definitely gonna start uh you know going dormant. And then and then especially with this drought we've been dealing with here the last you know several weeks, um that that's gonna force things even quicker to go into to dormancy. So um, you know, if you're out there and you you you hope to get one last spray in, you know, especially you know on some of these species that we talked about here, um I don't know, I I guess I really caution against that because I'm afraid you're gonna spend you know some of your time and effort and waste your you know kind of your return on investment there may not be what what you're expecting it to be. Now, if we have you know other species like Canada thistle, you know, that that's a cool season for an eal and that really starts to thrive here under under cooler conditions. So, you know, depending on you know the the the temperatures and the the climate, you know, even into you know say November, I mean you can you could go after something like Canada thistle, you know, well into November in some cases, you know, assuming we we don't get you know too many cold cold spells or or you know too many hard frosts and so forth. So that that's another thing. So it it's dependent upon those you know kind of climatic conditions um as well. But but you know, comparing Canada thistle versus you know horse nettle or milkweed, you know, you know, their their their life cycles are are s little bit different. So just you know knowing knowing what they're how how they grow and their their um you know optimal growth periods is gonna be very important.

Justin 26:28

And and I can say from like just now the way we're sitting uh in western southwest Pennsylvania, right, there

Warm vs Cool‑Season Perennials

Justin 26:35

is a clear difference in the visual assessment of these plants, right? And and I think if you go out and you look and they're yellowing and senescing and dropping leaves and stuff, I you know, I think that's a pretty good indication. It's not a good time to spray to target that weed, right? Um, but what we are starting to see is that greening up of some of these other cool season things. Our grasses are starting to show back up, candle thistles showing back up. And so, you know, this doesn't have to be that complicated. Walk out, scout your fields, look at them, and see what looks like it's alive.

Dwight 27:04

Yeah, yeah, exactly. I mean, that that's what uh what it boils down to again, going back to that kind of that that you know integrated approach, you know, understanding and and and and the first part of that is is scouting, you know. I would hate to see, you know, loading up a sprayer and just assuming you're gonna go out there and and and you know kill the weeds, even though you don't you really haven't you know thought through some of these, you know, the life cycles and you know the their where where they are on that that phase of of growth because they you know they go dormant and and that's the reason a lot of times we'll we'll recommend, especially with some of these warm season perennials, you know, to make sure you target them, you know, kind of you know in in that that August and September time frame because though they're they're still you know actively growing, but they're also starting to you know kind of get ready to go into good dormancy. And and and the and the target time is is that time frame when when you can spray the herbicide, and then as as the sugars in the the the plant and the leaves and so forth are starting to head down into the root system, the herbicide can get taken can get attached to those sugars and be transported down into the root system for a much better kill. So so again, but the plant still has to be actively growing. And as we mentioned, you know, you start seeing yellow, yellow, brown, or brown, tan leaves, that that plant is is well getting well beyond that that that phase of of transporting you know the the sugars down into the roots. Now it's starting to ready to go dormant, and you're not gonna get any herbicide trans transported at that when it's when they're that old.

Ryan 28:36

Yeah, so that that's a good point, and and I just want to maybe make a little bit of a clarification for our audience here, and and you can nod your head if I'm I'm right on this, but um you know, when we we mentioned that if it's going into dormancy, so maybe it's a summer annual like milkweed, that this wouldn't be a good time to spray, but if it's thistle and it's actively growing, it would be a good time to spray. Well, that milkweed, it's not to say if it's a pasture situation, you have a big milkweed problem, don't do anything. Like, that's a great point to go and mow it, right? So that it doesn't form any seed, or if it's a summer annual that's growing, will it is it past the point where it'll produce new seed at this point if it hasn't already?

Dwight 29:21

Yeah, well, so so you you're you're bringing up the the aspect of of summer annuals now. So those those are the ones that are are dependent upon seeds. So so obviously, you know, we're getting to the point now where a lot of the the annuals, um, you know, especially the summer annuals are in their seed formation phase right now. And um so so so you know it it's it's getting to the point where I I think a a good number of them are have already set their seeds. So even if you do go out there and mow, for example, um you know, whether you mow or not, the those seeds are already, already, you know, viable and and you know, probably not gonna have much much uh um you know, damage to them, you know, per se from from a seed seed rain standpoint to you know go back into the seed bank. Now having said that, you know, every situation can be a little bit different. There may be a pocket or two here and there that that

Mowing, Seed Set, And Strategy

Dwight 30:13

they're they're still somewhat green. They're not have haven't matured yet fully. And so you know so yeah, I mean I yeah if if you can mow, I'd say you know mowing would be you know obviously a a a viable you know option. And at least maybe you get 50%. I mean you know 50% you know control of those would be a lot better than letting go go to you know full full seed. And then and then you're right even with some of the perennials you know that we talked about yeah you know even like with with Canada thistle and and you know uh quack grass and some of these other cool season ones um you know any anytime you can impact them so you're forcing them to use their their res root reserves their their carbohydrates and sugars in their roots then then you're forcing them to you know deplete those so so yes I mean you know if if you're struggling with with Canada thistle you know going out there and mowing them right now is is still a a you know a viable option and and even mowing them now and then then maybe spraying them you know as we get into late October you know after they have some regrowth that could even be another another another way to uh to implement but but a lot of times we know we you we want to think about these things as as a whole strategy throughout the year not just hurry up and rush and do things right now you know we we want to make sure that we're we're doing these these timely mowings and and and you know a couple routine mowings uh like in a pasture setting for example at least a couple times during the this this the spring late spring and summer and then kind of setting those up you know to you know uh have the the herbicide be taken up you know kind of in that that late August September time frame um versus trying to do everything right now at the at the end of the season when we're kind of getting late so again it it's a a planning process um in order to set the set these things up you know throughout the season so I I also see kind of the mowing thing and when I think about mowing a lot it's often on maybe like underutilized or undergrazed pastures is having a lot of utility too and is another one of those points you can say ah that's crazy.

Justin 32:14

But if we're trying to set ourselves up for that spring spray and where I'm at there's a lot of strip ground or there's a lot of you know just kind of fallow ground and you've got weeds up there that are four feet tall um you know we might get enough snow to kind of knock that down some in the winter but this mat gets like really really intense right and so if we are trying to target spring stuff does it help us get better contact with those smaller plants and I guess in my mind it makes sense right if we're trying to spray over all of this grass there's all of these other places for that chemical to intercept before it actually makes it to the bottom and maybe that doesn't make sense but it kind of does to me.

Dwight 32:50

Yeah very much so I mean you're right because because you know the the majority of herbicides that we're using on in these these pasture pasture hayfield settings are these these uh foliar herbicides you know they're they're we they actually have to be in contact with the plant itself in order to kill so so uh um anything you can do to to um you know allow that that that spray droplet to contact that green you know tissue of the weed um you know it is is important so so yeah if you have a bunch of you know trash or residue or whatever that that's this could potentially intercept um that then it's obviously of no value then it's it's it's not killing the is it's not like a residual herbicide where you could spray it on on you know some some different uh you know the the the different organic matter and then it gets washed down into the soil after rainfalls. With these herbicides that's not that's not the case you need to have good you know contact and coverage of of the the the green foliage in order for them to have activity. So so yes just just kind of just general maintenance um of of those areas can be important too as far as you know just just mowing

Coverage, Water Volume, Adjuvants

Dwight 34:01

and and you know you know getting getting you know preparing you know for for for that utility of that spray then you know next next uh next spring.

Justin 34:10

And and so like just a context thing is if if you go out in some of these fields or all of these like really dense things and you get a tenth of an inch of rain and you stick your hand down in the bottom and see how much of that infiltrates right and that's 2700 gallons compared to us spraying at what 15 to 20 gallons?

Dwight 34:27

Yeah I mean I I I hear this this argument every once in a while you know people think well I'll just increase my spray volume to right you know 30 gallons or 40 gallons per acre and and instead of spraying it at you know maybe 15 gallons per acre and and you're right that that's that's that argument doesn't doesn't hold when it comes to when it comes to uh you know spraying things so you you you can't you know put in put enough you know herbicides you know the spray volume in order to equal anything near what what a rainfall can be so so yeah that's that's kind of a um a misconception out there just thinking increasing spray volume is going to really improve you know the control that's not the case so so what about anything we can do to improve activity right uh in the last few years I've really been pushing like adjuvants and surfactants and you know we're trying to do more with less and things are getting more expensive. Is there any advice you can give us if we are going to go out and target things like Canada thistle and some of these these cooler seasons that can help improve the activity that we are going to get yeah I mean so so I mean you're spending the money on the herbicide so you want to optimize it you know so you so you you need to you need to uh um make sure that herbicide gets into the plant um so so yes the util you the use of adjuvants you know whether it be kind of a a surfactant a non-ionic surfactant like an 8020 or 9010 um those those those have some use um or some kind of an oil you know so whether it's a crop oil concentrate or a methylated seed oil um those you know can can be recommended as well and and again you know it it it depends you know it it depends on on on the on the herbicide you know there are some of these these newer products um you know like graze on next and and uh nova graze and a few of the other ones they do recommend including some kind of an adjuvant with with um you know with with the spray in order to get the them in into the plant much better um you have other ones you know for example like 24 D and Dicamba or even like crossbow they don't really recommend those um as as as much so so it really is going to depend on on the type of herbicide um and and and looking at the label to see you know what is recommended and and we also have a a table in our the agronomy guide um that that that expounds upon you know what what are what's recommended um you know so a surfactant or an oil or whatnot or even like a liquid nitrogen or AMS or a a U UAN um so that would be one thing to uh to to make sure you look at um and again you know it it the thing about return on investment you know the the if if the companies you know are recommending it and and to to have their products be have improved performance you may you you better do it because otherwise you're gonna you know be frustrated if you if you have get a get a lack of control especially um in in these situations where you know we have under under drought conditions or you know and on where the the cuticles the the leaf the waxy tissue on the the leaf surface is kind of hard to penetrate um with just the herbicide itself so that's where the use of an adjuvant can really help you know get it through that and get it into the into the internal components of the the of the uh the the leaf tissue you know where the herbicide can do its activity because it needs to get into the leaf in order to move around the plant and do it do its control so if it's just sitting there on the leaf surface it's not going to have the effectiveness um the as as what the herbicides are designed for. Sure so maybe we can pivot here a little bit um so we've been talking a lot about some of our herbaceous weeds you know those that are winter um annuals perennials biannuals now what about woody plants so you know maybe we're talking about a pasture situation maybe it's a field crop situation and we have um some some woody woody weed issues um maybe autumn olive or multiflora rose is the fall also a good time to control those is this a good opportunity to do that yeah so with with woody species and and again you know there there's a lot of different um ones you can consider as you mentioned autumn olive multiflora rose you know another one that I get questions about routinely is porcelain berry which is a viny one you get things like honeysuckle even poison ivy you know and there there's you know kind of a a listing of of many of these other types of um exotic shrubs or or or um you know kind of these bushy type plants that that basically form a woody a woody structure to them and and you know yes I mean there there there can be some some value to going after these you know in the fall

Tackling Woody Brush

Dwight 39:18

or or even during the dormant season but again you have to know what you're doing. So so for example you know you look at some of these labels um like crossbow for example or or ones that contain triclopeer um you can do what's called these these basal bark applications or these these dormant season applications but but in those cases you really need to you know add the product to some kind of a diesel fuel or a kerosene or whatnot to help penetrate that that that uh that bark layer to get actually into the into the tissue um you know of of the of the the woody plant um so they can be you know have their own challenges you know of the of themselves to try to try to you know as you're as you're applying these um a lot of times what I'll recommend though is especially for something like multiflora rose or or some of these other ones you know they they're they're gonna leaf out again next next year and so so multiflora rose I typically recommend during the flowering stage you know like late May early June when when the the leaves and flowers are present is really one of the better times to go after something like multiflora rose um it it's uh uh you know easier to control can to spray uh the bush at that time so that's where I'd recommend something like a uh a a crossbow plus maybe a met sulfuron mixture and then just just uh if if you have a little at v sprayer that has maybe a single wand on it where you can just kind of you know just spray up and around the the the the foliage in the bush of the the uh the the woody um is probably you know just as good as just trying to go after it in at this time of year. Now you this as I mentioned there there there are some situations where you know you you can do that but I I I I just find that you know once as it has you know foliage on the leaves it tends to be a little bit a little bit um you know better way to get it into the plant um you know compared to compared to going through the bark the bark layer. And and then and another thing with lot with a lot of these woody species you know look you know there there is there is some concern about you know especially uh as they start to flower you know the things like porcelainberry and other other woodies they have these these nice flowers on them that the bees you know are attracted to so so you know finding the a correct time you know to to spray those where you're not in inner inter you know interacting with the you know the bee um activity and so forth can be can be another another time to to really um you know think about you know getting it on on the leaves but then not not too late during the flower stage. So so so so again um you know we we do have some different fact sheets here um if you're interested in in you know controlling some of these these woody species um you know some of my colleagues have put put some of those together that that that really you know spent spend some time you know going through the nuances of of controlling you know these types of of of species and but the but the reality is most of them are going to recommend some kind of a triclopeer you know that a triclopeer you know a crossbow remedy you know ones like that are in most cases pretty universal um now obviously including glyphosate is possible but but with that then then you're you're setting yourself up for you know killing you know grasses and other desirable species underneath that you know and and you know a lot of people don't want to do that so so again another it's comes down to kind of time management you know you know of you know I realize a lot of a lot of people in late May and early June are are are more concerned about other aspects of their farming operation and not really thinking about you know trying to control you know perennial weeds but um but again so you know whatever you know from from your standpoint of of you know time management you know if it's if it's easier to do it in the fall you could probably do that or the dormant season but again you putting these herbicides on it takes takes a different way of applying them you know compared to just spraying spraying the foliage in the in that that spring summertime so you you've teed me up for a whole bunch of questions so uh you know maybe I'll apologize for shooting them out this fast but uh so the first one is is you really mentioned crossbow and met sulfuron is like this combination and I want to go backwards a little bit to where we were talking about adjuvants right if you read the metsofuron it's gonna call for non-onic surfactant if you read crossbow it's gonna say not recommended um how does someone kind of bridge this gap and what do you do in that scenario if you are going to mix those two chemicals yeah well in a case like that you have to make you you you um in in a lot of a lot of cases you know something like crossbow it it doesn't necessarily say you can't use it it just doesn't it's just really not recommended so in the case like that you would you would you you would follow the the recommendation for something like metsulfuron so something like met sulfuron needs it so that's where you would include it as well. Now having said that you know that that that also could could set you up for you know if you are doing more of a broadcast uh application you know spraying it over you know grasses um your your desirable forage grasses that could could lead to some additional burning um of of the crop itself and and maybe a little bit of you know crop injury or stunting so so that that's

Mixing Guidance And Trade‑Offs

Dwight 44:30

where all all these things yes they will come into play but it but in a case like this where where we say mixed crossbow and met sulfuron you know the in and and you're gonna go out and spray you know row the rose the rose bushes then you know you you the the amount is not going to be as much on on the the whole whole uh grassy forage as well so that's where you know you want to make sure that you you're using you know the right adjuvant system to get the met sulfur on in as well but but then of course the crossbow would be be taken in in addition to that.

Justin 45:00

And I mean the reality is we've looked at a couple different options one of them is something mixed with like a fuel oil type treatment which is certainly you're gonna have some offsite damage with something like that, right? And it's gonna be uh the other option is looking at something like glyphosate and your potential is is high for any kind of dripping down and and burning around it. So you may experience a little bit of damage but when you compare the options you have using that nionic surfactant with something like those products a little bit of burning really doesn't sound too bad.

Dwight 45:30

Right. Yeah and then again that's kind of where the where you have these trade-offs you know you are you do you want to you want to kill the weed and and you know accept a little bit of uh you know crop damage for for you know a limited time um you know versus just you know can maintain your kick you know having that weed always be in there so yeah so so yeah there's always going to be a little bit of collateral damage you know with a lot of these these these situations so there's there you know we don't live in a perfect world and there's always going to be a little bit of concessions that have to be taken in order to you know can control the weeds but at the same time to maintain the area uh you know the forage area with with some some you know kind of transient you know injury that that that you know grows out of it so what about a product like spike is that that used to be more common than it is now maybe yeah I mean that that's again that's another one where that's you know what you're referring to there is a it's it's a dry it comes in a pellet um so you you do not mix it with with water um so you actually um have have uh um you know the utility of that where you you you pour out a a designated amount and then and then just kind of literally throw it underneath the the you know the the bush of the tree you know or the around the root system there um and yes it it it can be you know have have have its advantages because of that that ease of use um but also at the same time too um it it it's it's it's a herbicide that that is um pretty broad broad spectrum so we can kill a lot of the forges that we have so especially if you're using some of these on on a hillside for example and you uh you know throw a a handful of these pellets underneath the multiflora rose bush and then and then all of a sudden you get some rainfall and then there's there's the you know the that rainfall can actually leach some of that herbicide so there could be a streak of that product that you'll see you know 10 20 30 feet you know on on the lower end of that of that bush if if it's if it's on a like a hillside for example so so you can get a little bit of movement of that that product you know depending on on you know the the the physical location of that you know the the tree or the bush or the you know the the target weed in relation to the the forge. But but yeah something like that can be used. In fact I know you know a number of years ago 20 25 years ago we were working with with with with duPon at the time they were actually trying to figure out a way to um impregnate um this this met sulfur on onto

Grazing Intervals And Labels

Dwight 48:00

um just uh urea uh pellets and then and then you you um put a certain amount of the herbicide onto urea and then take the urea and just throw that the impregnated onto the urea and throw that underneath the the the you know the multiflora rose bush similar to spike but unfortunately they they never really got that optimized and and you know it it it worked to some degree but there was still some some kind of glitches with this it didn't didn't work as well as as we were hoping it to be so so yeah things like that have been been tried over the years um but but but again then a lot of times it comes back to kind of this this foliar application that that seems to be the most consistent I should say. And so then the last point I want to bring up is we've talked a lot about crossbow um one of the things to be careful with with crossbow is uh like grazing intervals right uh for the beef cattle world or or other livestock this is kind of a non-issue right um but when we start thinking about lactating dairies it's a whole different ball game right yeah and and that yeah that's very important yeah when we're dealing with with these these uh anything in a in a pasture hay setting um yeah so so uh again we have a table for that as well in the agronomy guide that it's it's a a very useful table um and and it it it provides some details on you know how long do you need to wait and after an application if you want to you know graze or if you want to hay that area and um and and you're right I mean the the biggest the biggest thing you'll notice on those tables or in in the label is the the the aspect of the lactating animal you know so you know there there are some herbicides that you know you could spray and then and then the animals can be the other you know the livestock you know can be released right back into that that area you know immediately whereas if they're but if they're lactating then you really need to wait either seven days or 14 days or 21 or whatever's on that on that that specific um listing for that that particular product. So so again that's another thing that we definitely want to make sure that we we point out as well is that just understanding you know the the utilities of making sure that you can you know have the animals in another paddock or something that hasn't been sprayed if if you have to keep them out of there um for a certain amount of time.

Justin 50:20

So for curious minds that's table 2.6-14 I don't have them on top of my head like Dwight does but I I can find them in a pinch.

Fencerows, Farmsteads, Residuals

Justin 50:30

So the last thing I want to bring up right before we kind of start to wrap up is this conversation that we have for uh farmsteads and fence rows and things like that. Right. We just talked the other day and and I've been pushing this that if we're mowing and spraying our fields but we're not treating our homesteads and our fence rows, we're really wasting a lot of time with this, right? And one of the ones that I see the worst for that is cockle burr. And where I'm at cockle burr is incredibly prominent we mow them around and then we call our cows back and what do they do is they walk the fence line and they pick up all of those cockle burrs off of them and we go through this all over again.

Dwight 51:07

Yeah.

Justin 51:08

So where do we find information? How do we handle that kind of stuff?

Dwight 51:12

Yeah and you're right you know as as the old saying you know the grass is always greener on the other side so that's the reason they're always huddling up against the uh the fence fence lines there but but yeah no again that's that's another another important area that we really need to think about when we think about overall weed management is um is is is these areas that that people tend to neglect and and fent you know fence rows and the just around you know farmstead structures and things like that where you know there's a lot of weeds that they grow up there and then and then you know there's issues with with you know see seeds being moved around you know whether it be by uh by livestock themselves or other other you know wildlife you know deer or you know um you know other rodents or whatnot that can can move these these weeds so again that that's when we think when we talk about i integrated weed management we talk about this very thing of of just pre preventing weeds from in entering an area and and and this is all part of it is to just just control weeds in in situations like this you know around fence lines and so forth um and and yeah I mean there's there's there's uh you know several different products um in fact we you know going back to the agronomy guide again we have a table in the agronomy guide and it's actually table 2.6-19 and that actually goes into all the um you know the specifics about you know what herbicides are are are available um you know for that and and then you you need to you need to be thinking about the fact that the herbicides that that are used also have to have you know grazing and haying allowances as well so you know just going out there and just you know selecting the the herbicide that has the longest you know residual um you know is is not is not necessarily the answer. So so you know on on that same same you know thought there you need to consider you know this some herbicides you know like Roundup and 24D and Dicamba um could be used, but they're not going to have any residual component to them. So that's a lot of times you would need to to um mix those with something like maybe arsenal or or there's another one called pramatol or um you know another one called resolon that have these longer residuals you know up to a few months or more um that will will control the different species under that under under that you know fin fence area. So so again things like that need to be thought about when you're putting these when it with these different different herbicide you know programs together. And then also just knowing how much to much to mix you know are you just going to make a say a one foot band underneath the the fence line or you're gonna try to do like a three foot band you know and just knowing how to calculate that you know um for for your your amount of of fence line you have or or around farmsteads or whatnot just how much to mix up you know can be can be an important aspect of of uh treating these areas as well.

Ryan 54:05

Yeah so I I think that's you mentioned a few things and and they're like calibration is important with that too right how often are people if they're using a smaller sprayer backpack sprayer and HVR calibrating and and that's going to be really important to decide your rate in in that case as well. And also consider those grazing restrictions for those products as well.

Aquatic Labels Near Water

Dwight 54:28

So I think um we can probably wrap it up there is there anything else justin that that you you want to ask yeah there was one I said earlier there were three questions and I only got to two of them right so thank you for keeping count um so when we're spraying a lot of these things Dwight and maybe this is something that's uh often they're like like a triclope or like a remedy but then there's often a similar type product but it doesn't have the water quality advisory or it gives you a little bit better ability to use that right aqua neat and and uh can you talk to us a little bit about how we make decisions or uh because I mean a lot of the times the woody stuff's growing up in the areas that we can't get to we don't put cows on we can't mow it and so it is often wet uh how do we go about kind of figuring out what to use in that that case yeah so so you're you're right I mean that that that's that's uh situation where there are certain products um that have what's called an aquatic label you know for some of these riparian areas that do have you know either either you know flowing water or maybe just uh you know kind of standing water um and and you're right you need to make sure you're using the right product because you know the the the the products are formulated you know differently you know so so if we're on kind of a terrestrial area um and there there's you know no water um you know in the vicinity of where we're spraying then then you know there's different um you know additives and so forth in that in that um you know formulation that may be potentially harmful to you know the aquatic life however that's that's where these companies they develop these aquatic labels um that that have you know slightly different um formulation that allows for utility around around these wet areas and and again that's again all to protect you know the the you know the the the habitat

Key Takeaways And Resources

Dwight 56:20

you know the you know the the various um different creatures and so forth that are in that that water body um also then it protects it from just you know the the herbicides you know flowing in different areas and causing problems elsewhere maybe downstream or to in other locations so you definitely make the need to make sure you're using products that are approved for for these types of settings um and and in in as you mentioned yeah there are you know things like 2,4D and glyphosate and triclopeer you know and several other ones have both what you know can kind of a terr terrestrial label and they also have an aquatic label. So make sure you're using the right the right product you know for the right setting.

Justin 56:58

Okay well I'm done with questions and thank you.

Ryan 57:03

No I think that's a good one though because uh we're we have no shortage of waterways and a lot of them we we're adjacent to especially in a lot of pasture settings so um I think that's an important note.

Dwight 57:15

Um cool well um Dwight anything else that that you want to get to that you haven't today or I don't think so I think we you know covered a quite a few uh different aspects and topics there of of uh you know things to think about this time of year and uh and otherwise so so I appreciate uh being able to uh chat with you and look forward to doing it again in the future.

Ryan 57:38

Yeah thanks Dwight it's it's always great I think we you're right we covered a lot here we covered kind of given any situation that you have out there whether you're harvesting a a fall crop um or you have a pasture that has some some later weed problems um hopefully there's a lot of relevant information in here for you that you can kind of get right out there and and make this decision sooner rather than later. So um I think this was a really productive discussion and has some really useful stuff in here and and I think if nothing else this is a great plug for the agronomy guide because as as Dwight was mentioning all these tables um we'll we'll have to plug the agronomy guide in the in the the bottom here in the in the episode notes because um for those of you that are really getting into weed control there's a lot of helpful tables that will help you to make some of these decisions on on what products um to use for some of these different species um so with that Dwight thank you for for coming on today we really appreciate it your knowledge is always welcomed here um and to to our listeners um we'll catch you on the next episode of the agronomy highlights podcast