March 12, 2025 • 33 mins
This week we have Dr. JD Green on the podcast to cover everything Johnsongrass. He covers the history of Johnsongrass and how to manage it. Available now!
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Unknown (00:00):
Music.
Sarah Lancaster (00:07):
Welcome back to the war against weeds podcast.
This is Sarah Lancaster,extension weed management
specialist at Kansas StateUniversity. I am here today with
co host Alyssa Essman, howdy.Alyssa,
Alyssa Essman (00:19):
howdy Sarah!
Sarah Lancaster (00:21):
and we have an awesome guest with us today. Dr
JD Green, we have coerced himinto coming out of retirement to
talk to us today about a weedthat is, I guess you could say,
near and dear to him. We'regoing to talk about Johnsongrass
today with Dr green, so hello.JD.
JD Green (00:44):
Hello Sarah, hello. Alyssa, thanks for having me on
today to talk about one of theplants that's been in the
background of what I've done forthe last 40 plus years.
Sarah Lancaster (00:57):
We all have a weed that gives us job security.
Must have been one of yours,right?
JD Green (01:02):
Absolutely, absolutely, from my graduate
school days all the way throughmy professional career.
Sarah Lancaster (01:10):
So that's a great kind of segue into
formally, more formallyintroducing you to the audience.
JD, what was that position thatyou've recently retired from?
And kind of how did you get tothat point?
JD Green (01:23):
So I did recently retire from the University of
Kentucky, where I spent 38 yearsas the extension weed scientist
located on the camp main campusthere in Lexington. I was very
fortunate to be able to start myactually, my my undergraduate
degree at the University ofKentucky, and then spent a few
(01:44):
years in Oklahoma before I cameback to University of Kentucky
and started my professionalcareer.
Sarah Lancaster (01:50):
So you have lived in the South, which is
where we tend to think aboutJohnsongrass being more a little
bit more problematic. So thatmakes sense, all right, so let's
dig into kind of the topic athand here. JD, what are some of
the identifying features forJohnson grass?
JD Green (02:09):
First and foremost, we have realized that Johnson grass
is a warm season perennial as awarm season grass, so it's
habitat is more associated withthe what you might say
subtropical to tropicalenvironments where it does, does
best and grows best. It is agrass that can get six to eight
(02:30):
foot tall. Kind of grows as abunch grass. Some of the key
identification characteristicsit has no hairs on the leaf and
or the stem. So no part of theplant that is is hairy, somewhat
of a membranous legal or it ismembranous, but it can be a
little bit jagged towards thetip of that and then it also has
a prominent mid rib on which itcan can be identified with.
(02:55):
There are some things that aresimilar with other grasses. It
is a sorghum species, althoughit's the perennial perennis
sorghum, so other sorghums canbe confused with when they're in
the younger growth stages. Andthen I had a case just a couple
years ago where a producer wasconcerned about his lack of
(03:16):
Johnson grass control in corn,and when I went out and looked
at the field. The grass wasstill in some of the seedling
stage and the the season, Ilooked at it and turned turned
out it was fall panicum. Sothere are some other weedy
grasses that it can be confusedwith, as well as volunteer corn.
(03:36):
When corn is in that young,vegetated growth stage, you can,
you know at first glance, butwhat you have to look for with
Johnson grass is it's aperennial, so that then, only
does it reproduce by seed, whichare very long lived in the soil,
but also it produces theseunderground stems called
rhizomes. And if the plant hasmuch development at all, if you
(03:59):
if you dig it up by the root,you'll find those very prominent
rhizomes to help identify it.
Sarah Lancaster (04:06):
Johnson grass will start producing rhizomes
when it's like, six or 12 inchestall, like, really quite short
for what I or what I would thinkwas short. Oh
JD Green (04:15):
yes, within four to five weeks, it can do that. It.
It doesn't take long before theinitial rhizome from a seedling
plant, or it's a plant comingfrom a rhizome, and fairly
quickly, will produce newrhizomes. So
Sarah Lancaster (04:30):
it is easy to confuse it with other plants,
especially, you know, I kind ofstart with that white midrib. Is
that kind of key indicator,right? And then gotta go from
there sometimes. So right? Youtalked about Johnson grass being
a c4 plant we mentioned kind ofmostly being found in the South.
What else do we need to knowabout where to find Johnson
(04:52):
grass?
JD Green (04:54):
So Johnson grass, apparently has been found
throughout most of thecontinental US. I. Perhaps Maine
and some of those north, farnortheastern states, it's not
there. But when you think aboutJohnson grass, as you mentioned
earlier, we primarily find it inthe southeastern quadrant of the
US, where it's most prominent,and becomes more much more
(05:17):
problematic in that area of thecountry. But even Southern
Illinois, southern Indiana, andI suspect Alyssa and southern
Ohio, it can also be be there inSarah, maybe you find it in
Kansas, in some areas where itcan be problematic as well. So
when I think about Johnsongrass, I kind of think of as a
southern weed, but it doesextend a little bit more into
(05:39):
the northern areas of the othercountry.
Alyssa Essman (05:43):
Yeah, we definitely hear about Johnson
grass. And honestly, somethingwe're hearing about more in
recent years, I was kind ofexcited. We had this episode on
the docket. Actually, my firstundergrad research project was
examining a Johnson grasspopulation for glyphosate
resistance. But as we as we talkabout some of these identifying
characteristics. JD, I'mcurious, do most of the
(06:03):
populations that you get callsabout or have dealt with, are
they from the seedling stage? Iguess my perception is most
often it's those rhizomaticpopulations that are really
problematic. Is that yourexperience? I
JD Green (06:15):
think in most cases, the problem has got to the point
where the rhizomes are beingproduced for a year, a few years
before people recognize thatthey have a problem with Johnson
grass. So yeah, more often thannot, there are rise and zone
plants out there in situationsI've dealt with over the years.
(06:35):
Yes, there'll be some seedlings,but the rhizomes, if you look,
you don't have to look too far.You can find the evidence of the
rhizomes.
Sarah Lancaster (06:45):
So that ties into kind of the thought that I
was wondering about. JD, itseems like when I get questions
about Johnson grass, it's in aless disturbed setting, like my
corn and soybean folks aren'tnormally the ones calling me
with questions about Johnsongrass, is that? Is that accurate
for your part of the world?
JD Green (07:06):
No, I don't think so, per se. I mean it, it was just
as problematic back in my earlyyears, when we did a lot more
conventional tillage as it isnow, when we do less tillage,
and we also find it out intoforage crops, pasture field or
(07:28):
hay fields and perf, non cropland areas that are not
disturbed at all. So I think,from my perspective, is probably
in all those differentenvironments that it can can
survive in
Sarah Lancaster (07:44):
all the above.
JD Green (07:45):
All the above? Yes.
Sarah Lancaster (07:48):
So I think now would be good, probably, to talk
about, like, how did Johnsongrass get here? Because I think
that also plays into, like,where we find it, why it's a
problem.
JD Green (08:01):
yeah, yeah, certainly. So I think there's some
interesting history on howjohnsongrass ended up in the US,
from what I've been able todiscern. And there was a
publication by Dr ChesterMcWhorter, who did a review of
the introduction and spread ofjohnsongrass in the US back in
the 70s, I think it was, and hedid a great job of of trying to
(08:24):
track down specifically how itgot introduced into the US. And
I take from that, from thatwork, that it's not real clear
specifically when it may havefirst arrived in the US, but
sometime in the 1830s would havebeen when, when some plants were
brought into the US. But theprobably more interesting fact
is it was about 1840s thiscolonel, William Johnson, had
(08:49):
collected some seed from SouthCarolina and brought it to his
farm over in Alabama to start itas a forage crop, and that's how
the name is. Became notoriouswith Johnson, named for Colonel
William Johnson, who brought itinto Alabama and began to
propagate it and promote it as aforage crop in that that part of
(09:10):
the country and some otherinteresting tidbits. Is prior to
that this, this plant was calleda lot of different names, gana
grass, Egyptian millet, Arabianmillet, are a few of the names
that I came across, as well asbankruptcy grass. And then, of
(09:30):
course, there's been a few othernames associated with this plant
over the years that I don'tthink we need to mention, just
because of its ability to thriveand survive and and all these
different environments in whichyou can find it, and kind of
dominate these areas once itgets well established and it's
not dealt with in a timelymanner and efficient manner. So
there's some interestinghistory, I think, and and how
(09:51):
this plant is thought to arrivein the US. Yeah. As a side note,
it's kind of interesting to methat, as I've. Worked in the
weed science discipline over theyears. You know, some of the
plants that we've spent the mostenergy and most resources and
expense to control have beenplants that were intentionally
introduced. And you go rightdown the list, and Johnson grass
(10:14):
is on my list. You hear a lotabout kudzu and some of those
others, but, but Johnson grassis definitely was a plant that
it depends on who you weretalking to, is whether it was a
good, a good introduction, orit's been a despised
introduction. And I think mostpeople are on the fence that
despise in the plant, but, butthere are a few people out there
(10:35):
recognize it's that does havesome value as a forage. So,
yeah, I
Sarah Lancaster (10:39):
wondered if you wanted to talk a little bit
about kind of the cautions ifsomebody does choose to use
Johnson grass as a forage, like,why was it introduced as a
forage? What are some of thelimitations there? Well,
JD Green (10:53):
they're very they're very similar to the other
sorghum species, the foragesorghums that are being utilized
as forage crops it had does havegood value. It grows quickly,
easy to establish, and itprovides adequate nutrition for
for animals to graze during thesummer months. The major
precaution is, if you'regrazing, it is if it if you get
(11:18):
frost or some other major stresson the plant, you can get a
toxic compound in the plant thatcan be deadly or be problematic
for for animals to graze. Sooutside of those windows, it's,
it's, it's, it's a good, goodplant for grazing purposes. You
know, you've just got to be,gotta be cautious about how
(11:39):
you're grazing and when you'regrazing, as far as it showing up
in silage and other haylage typeplants, my understanding is the
comp the toxic compounds, breakdown pretty quickly once they go
through that process. So it'sit's not as problematic in those
scenarios.
Sarah Lancaster (11:55):
Okay, so we know that it can be a problem.
Most folks don't want to grazeit. So how do we try to control
it?
JD Green (12:05):
Well, let me back up a little bit on that control
question, because when I firststarted in the Weed Science
arena, back in the late 70s,early 80s, Johnson grass, at
least for Kentucky, was, was theone of the most prominent weed
problems we dealt with, both incorn and soybeans. And it, it
(12:29):
was sort of the top of the listof drove a lot of weed
management programs that that wehad in place, if you had corn,
trying to grow corn, where youhad Johnson grass, we use
products like eradican andSutan, plus that you don't hear
about anymore. Those were twothyrocarbamic tape products that
had to be incorporatedimmediately into the soil before
(12:52):
planting, because they werevolatile compounds, and they
quickly lose them as a gas insoybeans. We had products like
treflan Prowl, a few other otherthe yellow compounds, if you
will, we could use, but youknow, most of those herbicides
target seedling plants. Theydidn't do as well on rhizomes.
Of course, the other thing thatwas used is tillage, trying to
(13:16):
do what you could to break upthe the rhizomes and control the
plants that were up and growingbefore you planted some in crop.
Tillage was used as as well inthat regard also. So when I did
my my graduate work at theUniversity, taking on my
(13:38):
masters, I was looking at tryingto extend the length of control
we could get out of things likethe radicand to suppress the
microbial degradation process sothat it would last longer in the
soil. And yeah, we saw some somepositive results, but they
weren't great in that regard.Another technology being used at
(14:00):
that time was some of the firstselective tools for weed
management, and that was the useof glyphosate through rope wick
applicators, particularly insoybeans and in down south and
cotton production areas, whereyou would load up a high
concentration of glyphosate onthese rope wicks and wipe it
across the field where thegrass, the Johnson grass, was
(14:23):
above the canopy of the crop.But then the 1980s we had the
introduction of what you mightcall the selective post grass
herbicides, products that peopleare familiar with. Well, the
first one was post, thenfusillade, and then we had
select, known as clethodim,that's under sold on different
(14:44):
names now, as well as a sure andthose were were fairly effective
for selected control we coulduse only in our broadleaf crops,
particularly soybeans andcotton. Again, is where that
those products could be used,and they really moved us a. Step
forward in controlling some ofour grassy weeds, like Johnson
grass, as well as other weedygrasses. And then 1990 we had
(15:09):
the introduction of accent andbeacon. These were two als type
herbicides that for the firsttime to be able to selectively
control a weedy grass, such asJohnson grass out of a crop,
which is a grass. And to me,that's probably one of the one
of the key milestones in weedmanagement that's occurred
(15:29):
during my career, was theintroduction of herbicide
technology that was thatselective to take grasses out of
out of grass. And certainlybetween that technology in the
the selective post grassherbicides we had for soybeans,
was a leap forward incontrolling weeds like Johnson
grass. One of the reasons I saidthat that that was so
(15:54):
significant for the accent beingintroduced or nickel software on
be introduced, is it changed,our tillage patterns. Before
then we had we were had to dosome type of tillage to plant
corn where Johnson grassoccurred again, because we
needed to incorporate thoseherbicides into the soil. But
once we had those products onhand, then allowed us to do more
(16:16):
continuous no till production,even between crop rotations
where we had corn and soybeans,we could, we could then stay
into a more continuous no tillenvironment for producing those
major crops. Of course. Theother major change was the
introduction of the roundedready crop technology, where you
(16:37):
had a product like glyphosate,which is highly effective on
grasses such as Johnson grass.And we went to this, this era
that lasted for a short periodof time. Now that we look back
on it, we had these cleanfields. I mean, we really
cleaned up some weeds. Andagain, with Johnson grass being
so dominant in a state likeKentucky, when you could drive
(16:58):
down the road and not see thatthose kind of weeds out in the
field. You know that was, thatwas real progress on the wheat
weed control front. Now,unfortunately, as we've gotten
into more recent time, I'mgradually seeing more and more
increase of Johnson grass backin some of our fields, our our
crop fields. And I don't Are youy'all seeing the same thing
(17:20):
showing up in soybeans thatwasn't there even 15 years ago.
Alyssa Essman (17:26):
Yeah, we're seeing some of that towards the
southern portion of the state,for sure.
JD Green (17:31):
But I've been kind of watching that over the last, oh,
10 to 15 years or so, especiallyas to seeing more populations
Johnson versus and it's not likefields are over, overrun by by
the johnsongrass, but it youhave pockets of in the out in
the field. And some of mythoughts as to why we're seeing
that is that, I think as we wentto tank mixing more of the
(17:56):
synthetic oxen herbicides, andwe started targeting more things
like water hemp and Palmer,other problematic weeds, or
herbicide resistant weeds, andwe're taking we reduce the
activity of our grassherbicides, and particularly
glyphosate in that case. So Ithink that's one reason. The
(18:16):
other thing is that the emphasiswasn't necessarily on Johnson
grass control. So we developedour programs. We weren't
thinking about Johnson grass hasbeen an issue. So, so we might
leave out that post grassherbicide. And some years since
we, you know, we wouldn't seemuch of it. And the other, the
other piece to that is thetiming, just like with any weed
(18:37):
control program, the timing ofwhen we make those applications.
But some of the problems thatwe've seen were some escapes. Is
where we were spraying early andwhen the plants young and
earlier growth developmentstages, like I've seen with a
lot of perennial species, whenyou spray them early, you don't
always get the best control. Theweather conditions are not good
(18:59):
for good uptake. The plantsyoung, it's spending more energy
producing top growth, and not somuch to the root system of the
plant. Which brings us to thethe other possibility of, what
about are we developingherbicide resistant populations
in in these fields as well? Justto kind of give a background,
(19:20):
though, and of course, the majorconcern is about resistance to
glyphosate. We have yet beenable to, we have not been able
to document glyphosate resistantjohnsongrass In Kentucky,
because we could take some ofthose plants that were sent to
us or go back to the field wherethe problem was and go re spray
them, and we could kill them. SoI think that's reason, I say
(19:40):
some of these other issues areplaying into that as a reason
why the control was is beenlacking in some lot of these
situations we've dealt with. Butit wouldn't surprise me, it's
out there. It could be out therebecause there are the first case
of glyphosate resistant Johnsongrass, I think was in Argentina.
Yeah, and then states likeMississippi and I think Arkansas
(20:04):
and maybe Louisiana, thosesouthern count of states, and
I'm maybe even Tennessee, WestTennessee, have reported that
they have some resistant Johnsongrass. But again, we have not
been able to document that inKentucky, with the with the
sampling that that we've done,the cases we've looked at, what
we have documented, however, isprobably the first case of
(20:28):
resistance in Johnson grass thatwe observed was with fusillade
back whenever it first was puton the market, and then it was
primarily used for two or three,you know, several years in a row
on in soybeans, where we hadsome resistance that that showed
up. It was a very smallpopulation. And then with some
changes in other technology,that's that sort of went away in
(20:50):
itself, then, then when accentstarted to be used in the 1990s
about 10 years later, I got acall to go look at a field in
the southern part of the state,for lack of control, with
accent. And I did some fieldwork, and then some greenhouse
work. And not on that field, butanother field as well. In this
(21:12):
particular case, this was agrower that started using he was
a he produced silage corn andwheat. He was kind of a corn
wheat rotation dairy producer,and he had been using accent
year after year after year. Andnot only was it that population
resisted by accident, but alsosome of the other ALS
chemistries as well. Then fromthere, the most recent cases
(21:38):
I've gotten involved with wasonly about four or five years
ago, back in 2221 22 we havesome areas in the state that are
producing non GMO corn for thebourbon industry, and so they're
trying to stay away from usingglyphosate as a, as a, as a
herbicide in those thoseprograms as a post treatment. So
(22:01):
they've gone back to use anaccent and some of these other
herbicides. Well this particularcase, we did field trials. We
did confirm we had some accidentresistance in that field, but
also looked at select as well asassurers. And in this particular
field, there is evidence thatnot only do we have the
(22:23):
population resistant accident,but also the group one
herbicides, the the thoughts,but not the DEM. So it was as
did not control it very well,but, but clethodim Or select was
still, still effective. Sothere's some interesting
dynamics that's going on there.Both when I was investigating
(22:44):
that case, the next year, wewent out to collect some seeds,
or molecular biologists couldstart doing some work on that,
and we went to a field of cornthat, to me, looked exactly like
what I was dealing with back inthe early 1980s I mean, just
fields covered. You know, fieldsjust dominate by Johnson grass,
and you're hard pressed to findthe corn. So it's disheartening
(23:07):
in some ways, that we've come sofar, but yet, there's evidence
that we may be regressing backto dealing with the with the
problem. We'd like Johnson grassin
Sarah Lancaster (23:18):
the case where you have non GMO corn. So
glyphosate is not an option, andyou've got resistance to the two
kind of main tools. What wasyour recommendation there? JD,
going quote for that armor goingforward.
JD Green (23:32):
Well, this particular farm is a pretty good sized farm
operation. They farmed several1000 acres, so they've got the
problem also spreading it aroundthrough their equipment and so
forth as they as they go farm tofarm, I think the answer is
they've got to change up thesystem. They they will not be
able to continue that approachlong term. They can probably
(23:56):
keep it at bay by, by using thecrop rotations of having
soybeans in these corn fields,you know, ever just like it's
kind of way we were back inbefore, before we even had
accent, you know, we were using,we can, you know, stay in
soybeans for two or three yearsand then come back to corn and
try to knock down thepopulation, and then then come
(24:19):
back and plant your non GMO cornin those fields. So, so I don't
have a strong answer to that atthis point, other than you just
going to have to shift up andjust admit that there are fields
you're going to have to plantsome traded crops that allows
you to use the full tool, rangeof tools we've got to work with.
(24:40):
As you all know, I don't thinkI'll see much new chemistry
that's going to tackle thatproblem for us immediately
anyway, so I'm going to figureit outeventually.
Alyssa Essman (24:51):
To my knowledge, also have not confirmed
glyphosate resistance, but Iknow we get reports of control
issues, and I know you mentionedthe synthetic auxins. And I also
want. Wonder if you know howmuch we're relying on
glufosinate. Post, do you thinkthat's reducing control with
glyphosate in some instances too?
JD Green (25:09):
That's a good point, yes, where we're trying to use
glufosinate instead ofglyphosate, the glufosinate is
just, which is basically libertyis not as effective on Johnson
grass and other grasses as asglyphosate would be. So, yeah.
So we get those failures with,you know, you burn it back, it
(25:33):
looks like you've got someinitial activity, and then
within weeks, it's gone. So orit comes back, is what I'm meant
to
Sarah Lancaster (25:44):
So going forward, what do you think the
answers might be, if we thinkabout the tools that we have and
maybe some of the tools thatcould be coming, what do you see
as the future for Johnson grass management?
JD Green (26:01):
Well, we we have some good tools that are still
working for the most part. Wejust need to use them in the
right way, in the right timing,and not rely just on the one
tool in the box to to get thejob done. So I think we just
(26:22):
gotta, gotta be conscientious ofof being diversified in our weed
management program. And I thinkthat's the main message that
we're trying to get across asweed scientists, that it's, it's
gotta be a variety of tools. AndI won't mention another scenario
where I've gotten a lot ofJohnson grass questions in the
(26:43):
past 15 plus years, is Johnsongrass in grass hay fields? You
know, we're back to not having aherbicide tool that works in
that situation. And most of ourgrass here in Kentucky is cool
season grasses, things likeorchard grass and tall fescue
and so forth. There are noherbicides that we can apply to
(27:08):
a grass hay field that's goingto be fed to cattle. Now, the
non crop folks have some toolsthat they can use, but they're
not approved for use inpastures, and probably because
of the chance of risk of injuryto the desirable species is one,
one reason for that. Now, coolseason grasses, like Bermuda
grass, they do have a couple ofproducts that that can help them
(27:31):
on Johnson grass down south inthose environments, but I bring
that up in hay fields from thestandpoint it's been one more
frustrating scenarios for me tocome up with answers for,
because I don't have any goodanswers. But the things I talk
about is you've got to dosomething different. Your hay
production system is propagatingJohnson grass. Now, once you get
(27:52):
a get a pocket started, how manytimes do you roll through that
field to cut it, to rake it,tether it, and then front
probably run the baler throughthe field. You're just moving
stuff around, particularly thoselater season cuttings that we
have with Johnson grass is inits full reproductive stages of
(28:13):
growth. So my main message isyou've got to do something
different, and that may meantaking that field out of
production for a few years. Ifit's a field that could grow
grain crops, use that as your asyour your tool. Now we have some
producers. That's not an optionfor them, very logically. And
(28:34):
the other is, I can go ahead andproduce hay for the first
cutting, but let's turn it intopasture field, because where you
continuously graze pastures,Johnson grass is basically, you
know, animals are continuouslygrazing. In fact, I hear a lot
of people tell me, cattle preferto graze Johnson grass over the
(28:55):
other grasses that are outthere. But again, going back to
our earlier conversation, you'vegot to be you gotta manage that.
We get late in the season andand it comes time where we're
going to start transitioning tothe fall of the year and frost
happening. We need to get thoseanimals off of there so, you
know, the exposure standpoint.But, but to me, as an example,
the grass hay scenario was, is,is, it's there are. There's no
(29:20):
good answers for other than thatbasic principle for weed
management overall, we have todo different things so you can't
rely on one tactic time aftertime and expect to be
successful.
Sarah Lancaster (29:33):
Think that is a great summary of weed control,
but it's kind of nice to takethat kind of big art from kind
of the beginning of your careerto today. JD, and just thinking
about how things kind of what'sold is new again, right? Kind of
back where we started and soabsolutely. So. Alyssa, did you
(29:54):
have anything that we maybemissed talking about today? Nope.
Alyssa Essman (29:58):
The only other thing that came. To mine was
brought up right at the end, youknow, the grazing and and, or
mowing, or, you know, those kindof non chemical control options
that he touched on there. Ithink it's another tool,
Sarah Lancaster (30:09):
yeah, I mean, it's, it can be a tough space.
It's interesting for me to hearyou talk about Frost being the
major concern, because we getconcerned about Frost, but we
also worry a lot about droughtstress,
JD Green (30:20):
right? I guess yes, because that
Sarah Lancaster (30:23):
triggers all of those, those stress responses
JD Green (30:26):
that, yeah, they can be at the same concern under
under drought stress as well.Yes.
Sarah Lancaster (30:33):
So, all right, did you have any closing
thoughts, JD, anything that Ishould have asked you, but
didn't you know, not
JD Green (30:39):
necessarily, but I mean, this has been a good
opportunity for me to comeopportunity for me to kind of
reflect back on my my careerworking with, when with one
particular weed. That's not thatI've spent my whole time working
on Johnson grass problems, butit's was one of the key weeds I
worked with, specifically when Ifirst started my career, and
then as I've wrapped up anddealt with this last case of
(31:04):
potentially multiple, multipleresistance and it, and what is,
you know, you ask a key questionthere. So what do we do when we
run into that? And, and I'mgoing to actually just just jog
my memory, is when I was doingthe my initial work with accent
(31:24):
documenting the accent resistantpopulation back in oh, about
2000 or so. We finished up thatproject. The county agent I was
working with this one RoundupReady corn was just being
introduced for use, and he and Iwere just having a nice little
discussion and saying, Well, youknow, the roundup pretty corners
(31:46):
probably gonna solve this, thisindividual's problem. But he was
very insightful. He says, so howlong would that last? Getting at
the fact that, you know,ultimately, we may have
resistance there as well. And aswe've discussed here today, you
know, we don't have itdocumented yet in Kentucky, but
(32:07):
there are states around us inwhich they are already starting
to find some resistance thatthat they can confirm, and as
much as which beginning to showup these populations, I think it
could be a matter of time beforewe want to have a document
again. Documented case for forour state, and perhaps other
states like yourselves in Kansasor Ohio, where, wherever. So I
(32:30):
hope not soon, but keeps us,keeps us in our careers,
Sarah Lancaster (32:36):
job security, and you know, nothing like a
weed to keep a person humble.
JD Green (32:41):
Absolutely, absolutely.
Sarah Lancaster (32:44):
So hey, thank you JD, for taking time to kind
of polish off all the some ofthe points of your career and
for talking with us today. Weappreciate it. We also
appreciate folks listeningtoday, and we hope you'll join
us again next time.
(33:09):
Thanks for listening to the waragainst weeds podcast. We
appreciate support from thenorth central Integrated Pest
Management Center and thecollaboration with the Crop
Protection Network. At cropprotection network.org, you can
find this podcast, otherpodcasts, and a variety of other
(33:30):
pest management resources.
Music.
Sarah Lancaster (00:07):
Welcome back to the war against weeds podcast.
This is Sarah Lancaster,extension weed management
specialist at Kansas StateUniversity. I am here today with
co host Alyssa Essman, howdy.Alyssa,
Alyssa Essman (00:19):
howdy Sarah!
Sarah Lancaster (00:21):
and we have an awesome guest with us today. Dr
JD Green, we have coerced himinto coming out of retirement to
talk to us today about a weedthat is, I guess you could say,
near and dear to him. We'regoing to talk about Johnsongrass
today with Dr green, so hello.JD.
JD Green (00:44):
Hello Sarah, hello. Alyssa, thanks for having me on
today to talk about one of theplants that's been in the
background of what I've done forthe last 40 plus years.
Sarah Lancaster (00:57):
We all have a weed that gives us job security.
Must have been one of yours,right?
JD Green (01:02):
Absolutely, absolutely, from my graduate
school days all the way throughmy professional career.
Sarah Lancaster (01:10):
So that's a great kind of segue into
formally, more formallyintroducing you to the audience.
JD, what was that position thatyou've recently retired from?
And kind of how did you get tothat point?
JD Green (01:23):
So I did recently retire from the University of
Kentucky, where I spent 38 yearsas the extension weed scientist
located on the camp main campusthere in Lexington. I was very
fortunate to be able to start myactually, my my undergraduate
degree at the University ofKentucky, and then spent a few
(01:44):
years in Oklahoma before I cameback to University of Kentucky
and started my professionalcareer.
Sarah Lancaster (01:50):
So you have lived in the South, which is
where we tend to think aboutJohnsongrass being more a little
bit more problematic. So thatmakes sense, all right, so let's
dig into kind of the topic athand here. JD, what are some of
the identifying features forJohnson grass?
JD Green (02:09):
First and foremost, we have realized that Johnson grass
is a warm season perennial as awarm season grass, so it's
habitat is more associated withthe what you might say
subtropical to tropicalenvironments where it does, does
best and grows best. It is agrass that can get six to eight
(02:30):
foot tall. Kind of grows as abunch grass. Some of the key
identification characteristicsit has no hairs on the leaf and
or the stem. So no part of theplant that is is hairy, somewhat
of a membranous legal or it ismembranous, but it can be a
little bit jagged towards thetip of that and then it also has
a prominent mid rib on which itcan can be identified with.
(02:55):
There are some things that aresimilar with other grasses. It
is a sorghum species, althoughit's the perennial perennis
sorghum, so other sorghums canbe confused with when they're in
the younger growth stages. Andthen I had a case just a couple
years ago where a producer wasconcerned about his lack of
(03:16):
Johnson grass control in corn,and when I went out and looked
at the field. The grass wasstill in some of the seedling
stage and the the season, Ilooked at it and turned turned
out it was fall panicum. Sothere are some other weedy
grasses that it can be confusedwith, as well as volunteer corn.
(03:36):
When corn is in that young,vegetated growth stage, you can,
you know at first glance, butwhat you have to look for with
Johnson grass is it's aperennial, so that then, only
does it reproduce by seed, whichare very long lived in the soil,
but also it produces theseunderground stems called
rhizomes. And if the plant hasmuch development at all, if you
(03:59):
if you dig it up by the root,you'll find those very prominent
rhizomes to help identify it.
Sarah Lancaster (04:06):
Johnson grass will start producing rhizomes
when it's like, six or 12 inchestall, like, really quite short
for what I or what I would thinkwas short. Oh
JD Green (04:15):
yes, within four to five weeks, it can do that. It.
It doesn't take long before theinitial rhizome from a seedling
plant, or it's a plant comingfrom a rhizome, and fairly
quickly, will produce newrhizomes. So
Sarah Lancaster (04:30):
it is easy to confuse it with other plants,
especially, you know, I kind ofstart with that white midrib. Is
that kind of key indicator,right? And then gotta go from
there sometimes. So right? Youtalked about Johnson grass being
a c4 plant we mentioned kind ofmostly being found in the South.
What else do we need to knowabout where to find Johnson
(04:52):
grass?
JD Green (04:54):
So Johnson grass, apparently has been found
throughout most of thecontinental US. I. Perhaps Maine
and some of those north, farnortheastern states, it's not
there. But when you think aboutJohnson grass, as you mentioned
earlier, we primarily find it inthe southeastern quadrant of the
US, where it's most prominent,and becomes more much more
(05:17):
problematic in that area of thecountry. But even Southern
Illinois, southern Indiana, andI suspect Alyssa and southern
Ohio, it can also be be there inSarah, maybe you find it in
Kansas, in some areas where itcan be problematic as well. So
when I think about Johnsongrass, I kind of think of as a
southern weed, but it doesextend a little bit more into
(05:39):
the northern areas of the othercountry.
Alyssa Essman (05:43):
Yeah, we definitely hear about Johnson
grass. And honestly, somethingwe're hearing about more in
recent years, I was kind ofexcited. We had this episode on
the docket. Actually, my firstundergrad research project was
examining a Johnson grasspopulation for glyphosate
resistance. But as we as we talkabout some of these identifying
characteristics. JD, I'mcurious, do most of the
(06:03):
populations that you get callsabout or have dealt with, are
they from the seedling stage? Iguess my perception is most
often it's those rhizomaticpopulations that are really
problematic. Is that yourexperience? I
JD Green (06:15):
think in most cases, the problem has got to the point
where the rhizomes are beingproduced for a year, a few years
before people recognize thatthey have a problem with Johnson
grass. So yeah, more often thannot, there are rise and zone
plants out there in situationsI've dealt with over the years.
(06:35):
Yes, there'll be some seedlings,but the rhizomes, if you look,
you don't have to look too far.You can find the evidence of the
rhizomes.
Sarah Lancaster (06:45):
So that ties into kind of the thought that I
was wondering about. JD, itseems like when I get questions
about Johnson grass, it's in aless disturbed setting, like my
corn and soybean folks aren'tnormally the ones calling me
with questions about Johnsongrass, is that? Is that accurate
for your part of the world?
JD Green (07:06):
No, I don't think so, per se. I mean it, it was just
as problematic back in my earlyyears, when we did a lot more
conventional tillage as it isnow, when we do less tillage,
and we also find it out intoforage crops, pasture field or
(07:28):
hay fields and perf, non cropland areas that are not
disturbed at all. So I think,from my perspective, is probably
in all those differentenvironments that it can can
survive in
Sarah Lancaster (07:44):
all the above.
JD Green (07:45):
All the above? Yes.
Sarah Lancaster (07:48):
So I think now would be good, probably, to talk
about, like, how did Johnsongrass get here? Because I think
that also plays into, like,where we find it, why it's a
problem.
JD Green (08:01):
yeah, yeah, certainly. So I think there's some
interesting history on howjohnsongrass ended up in the US,
from what I've been able todiscern. And there was a
publication by Dr ChesterMcWhorter, who did a review of
the introduction and spread ofjohnsongrass in the US back in
the 70s, I think it was, and hedid a great job of of trying to
(08:24):
track down specifically how itgot introduced into the US. And
I take from that, from thatwork, that it's not real clear
specifically when it may havefirst arrived in the US, but
sometime in the 1830s would havebeen when, when some plants were
brought into the US. But theprobably more interesting fact
is it was about 1840s thiscolonel, William Johnson, had
(08:49):
collected some seed from SouthCarolina and brought it to his
farm over in Alabama to start itas a forage crop, and that's how
the name is. Became notoriouswith Johnson, named for Colonel
William Johnson, who brought itinto Alabama and began to
propagate it and promote it as aforage crop in that that part of
(09:10):
the country and some otherinteresting tidbits. Is prior to
that this, this plant was calleda lot of different names, gana
grass, Egyptian millet, Arabianmillet, are a few of the names
that I came across, as well asbankruptcy grass. And then, of
(09:30):
course, there's been a few othernames associated with this plant
over the years that I don'tthink we need to mention, just
because of its ability to thriveand survive and and all these
different environments in whichyou can find it, and kind of
dominate these areas once itgets well established and it's
not dealt with in a timelymanner and efficient manner. So
there's some interestinghistory, I think, and and how
(09:51):
this plant is thought to arrivein the US. Yeah. As a side note,
it's kind of interesting to methat, as I've. Worked in the
weed science discipline over theyears. You know, some of the
plants that we've spent the mostenergy and most resources and
expense to control have beenplants that were intentionally
introduced. And you go rightdown the list, and Johnson grass
(10:14):
is on my list. You hear a lotabout kudzu and some of those
others, but, but Johnson grassis definitely was a plant that
it depends on who you weretalking to, is whether it was a
good, a good introduction, orit's been a despised
introduction. And I think mostpeople are on the fence that
despise in the plant, but, butthere are a few people out there
(10:35):
recognize it's that does havesome value as a forage. So,
yeah, I
Sarah Lancaster (10:39):
wondered if you wanted to talk a little bit
about kind of the cautions ifsomebody does choose to use
Johnson grass as a forage, like,why was it introduced as a
forage? What are some of thelimitations there? Well,
JD Green (10:53):
they're very they're very similar to the other
sorghum species, the foragesorghums that are being utilized
as forage crops it had does havegood value. It grows quickly,
easy to establish, and itprovides adequate nutrition for
for animals to graze during thesummer months. The major
precaution is, if you'regrazing, it is if it if you get
(11:18):
frost or some other major stresson the plant, you can get a
toxic compound in the plant thatcan be deadly or be problematic
for for animals to graze. Sooutside of those windows, it's,
it's, it's, it's a good, goodplant for grazing purposes. You
know, you've just got to be,gotta be cautious about how
(11:39):
you're grazing and when you'regrazing, as far as it showing up
in silage and other haylage typeplants, my understanding is the
comp the toxic compounds, breakdown pretty quickly once they go
through that process. So it'sit's not as problematic in those
scenarios.
Sarah Lancaster (11:55):
Okay, so we know that it can be a problem.
Most folks don't want to grazeit. So how do we try to control
it?
JD Green (12:05):
Well, let me back up a little bit on that control
question, because when I firststarted in the Weed Science
arena, back in the late 70s,early 80s, Johnson grass, at
least for Kentucky, was, was theone of the most prominent weed
problems we dealt with, both incorn and soybeans. And it, it
(12:29):
was sort of the top of the listof drove a lot of weed
management programs that that wehad in place, if you had corn,
trying to grow corn, where youhad Johnson grass, we use
products like eradican andSutan, plus that you don't hear
about anymore. Those were twothyrocarbamic tape products that
had to be incorporatedimmediately into the soil before
(12:52):
planting, because they werevolatile compounds, and they
quickly lose them as a gas insoybeans. We had products like
treflan Prowl, a few other otherthe yellow compounds, if you
will, we could use, but youknow, most of those herbicides
target seedling plants. Theydidn't do as well on rhizomes.
Of course, the other thing thatwas used is tillage, trying to
(13:16):
do what you could to break upthe the rhizomes and control the
plants that were up and growingbefore you planted some in crop.
Tillage was used as as well inthat regard also. So when I did
my my graduate work at theUniversity, taking on my
(13:38):
masters, I was looking at tryingto extend the length of control
we could get out of things likethe radicand to suppress the
microbial degradation process sothat it would last longer in the
soil. And yeah, we saw some somepositive results, but they
weren't great in that regard.Another technology being used at
(14:00):
that time was some of the firstselective tools for weed
management, and that was the useof glyphosate through rope wick
applicators, particularly insoybeans and in down south and
cotton production areas, whereyou would load up a high
concentration of glyphosate onthese rope wicks and wipe it
across the field where thegrass, the Johnson grass, was
(14:23):
above the canopy of the crop.But then the 1980s we had the
introduction of what you mightcall the selective post grass
herbicides, products that peopleare familiar with. Well, the
first one was post, thenfusillade, and then we had
select, known as clethodim,that's under sold on different
(14:44):
names now, as well as a sure andthose were were fairly effective
for selected control we coulduse only in our broadleaf crops,
particularly soybeans andcotton. Again, is where that
those products could be used,and they really moved us a. Step
forward in controlling some ofour grassy weeds, like Johnson
grass, as well as other weedygrasses. And then 1990 we had
(15:09):
the introduction of accent andbeacon. These were two als type
herbicides that for the firsttime to be able to selectively
control a weedy grass, such asJohnson grass out of a crop,
which is a grass. And to me,that's probably one of the one
of the key milestones in weedmanagement that's occurred
(15:29):
during my career, was theintroduction of herbicide
technology that was thatselective to take grasses out of
out of grass. And certainlybetween that technology in the
the selective post grassherbicides we had for soybeans,
was a leap forward incontrolling weeds like Johnson
grass. One of the reasons I saidthat that that was so
(15:54):
significant for the accent beingintroduced or nickel software on
be introduced, is it changed,our tillage patterns. Before
then we had we were had to dosome type of tillage to plant
corn where Johnson grassoccurred again, because we
needed to incorporate thoseherbicides into the soil. But
once we had those products onhand, then allowed us to do more
(16:16):
continuous no till production,even between crop rotations
where we had corn and soybeans,we could, we could then stay
into a more continuous no tillenvironment for producing those
major crops. Of course. Theother major change was the
introduction of the roundedready crop technology, where you
(16:37):
had a product like glyphosate,which is highly effective on
grasses such as Johnson grass.And we went to this, this era
that lasted for a short periodof time. Now that we look back
on it, we had these cleanfields. I mean, we really
cleaned up some weeds. Andagain, with Johnson grass being
so dominant in a state likeKentucky, when you could drive
(16:58):
down the road and not see thatthose kind of weeds out in the
field. You know that was, thatwas real progress on the wheat
weed control front. Now,unfortunately, as we've gotten
into more recent time, I'mgradually seeing more and more
increase of Johnson grass backin some of our fields, our our
crop fields. And I don't Are youy'all seeing the same thing
(17:20):
showing up in soybeans thatwasn't there even 15 years ago.
Alyssa Essman (17:26):
Yeah, we're seeing some of that towards the
southern portion of the state,for sure.
JD Green (17:31):
But I've been kind of watching that over the last, oh,
10 to 15 years or so, especiallyas to seeing more populations
Johnson versus and it's not likefields are over, overrun by by
the johnsongrass, but it youhave pockets of in the out in
the field. And some of mythoughts as to why we're seeing
that is that, I think as we wentto tank mixing more of the
(17:56):
synthetic oxen herbicides, andwe started targeting more things
like water hemp and Palmer,other problematic weeds, or
herbicide resistant weeds, andwe're taking we reduce the
activity of our grassherbicides, and particularly
glyphosate in that case. So Ithink that's one reason. The
(18:16):
other thing is that the emphasiswasn't necessarily on Johnson
grass control. So we developedour programs. We weren't
thinking about Johnson grass hasbeen an issue. So, so we might
leave out that post grassherbicide. And some years since
we, you know, we wouldn't seemuch of it. And the other, the
other piece to that is thetiming, just like with any weed
(18:37):
control program, the timing ofwhen we make those applications.
But some of the problems thatwe've seen were some escapes. Is
where we were spraying early andwhen the plants young and
earlier growth developmentstages, like I've seen with a
lot of perennial species, whenyou spray them early, you don't
always get the best control. Theweather conditions are not good
(18:59):
for good uptake. The plantsyoung, it's spending more energy
producing top growth, and not somuch to the root system of the
plant. Which brings us to thethe other possibility of, what
about are we developingherbicide resistant populations
in in these fields as well? Justto kind of give a background,
(19:20):
though, and of course, the majorconcern is about resistance to
glyphosate. We have yet beenable to, we have not been able
to document glyphosate resistantjohnsongrass In Kentucky,
because we could take some ofthose plants that were sent to
us or go back to the field wherethe problem was and go re spray
them, and we could kill them. SoI think that's reason, I say
(19:40):
some of these other issues areplaying into that as a reason
why the control was is beenlacking in some lot of these
situations we've dealt with. Butit wouldn't surprise me, it's
out there. It could be out therebecause there are the first case
of glyphosate resistant Johnsongrass, I think was in Argentina.
Yeah, and then states likeMississippi and I think Arkansas
(20:04):
and maybe Louisiana, thosesouthern count of states, and
I'm maybe even Tennessee, WestTennessee, have reported that
they have some resistant Johnsongrass. But again, we have not
been able to document that inKentucky, with the with the
sampling that that we've done,the cases we've looked at, what
we have documented, however, isprobably the first case of
(20:28):
resistance in Johnson grass thatwe observed was with fusillade
back whenever it first was puton the market, and then it was
primarily used for two or three,you know, several years in a row
on in soybeans, where we hadsome resistance that that showed
up. It was a very smallpopulation. And then with some
changes in other technology,that's that sort of went away in
(20:50):
itself, then, then when accentstarted to be used in the 1990s
about 10 years later, I got acall to go look at a field in
the southern part of the state,for lack of control, with
accent. And I did some fieldwork, and then some greenhouse
work. And not on that field, butanother field as well. In this
(21:12):
particular case, this was agrower that started using he was
a he produced silage corn andwheat. He was kind of a corn
wheat rotation dairy producer,and he had been using accent
year after year after year. Andnot only was it that population
resisted by accident, but alsosome of the other ALS
chemistries as well. Then fromthere, the most recent cases
(21:38):
I've gotten involved with wasonly about four or five years
ago, back in 2221 22 we havesome areas in the state that are
producing non GMO corn for thebourbon industry, and so they're
trying to stay away from usingglyphosate as a, as a, as a
herbicide in those thoseprograms as a post treatment. So
(22:01):
they've gone back to use anaccent and some of these other
herbicides. Well this particularcase, we did field trials. We
did confirm we had some accidentresistance in that field, but
also looked at select as well asassurers. And in this particular
field, there is evidence thatnot only do we have the
(22:23):
population resistant accident,but also the group one
herbicides, the the thoughts,but not the DEM. So it was as
did not control it very well,but, but clethodim Or select was
still, still effective. Sothere's some interesting
dynamics that's going on there.Both when I was investigating
(22:44):
that case, the next year, wewent out to collect some seeds,
or molecular biologists couldstart doing some work on that,
and we went to a field of cornthat, to me, looked exactly like
what I was dealing with back inthe early 1980s I mean, just
fields covered. You know, fieldsjust dominate by Johnson grass,
and you're hard pressed to findthe corn. So it's disheartening
(23:07):
in some ways, that we've come sofar, but yet, there's evidence
that we may be regressing backto dealing with the with the
problem. We'd like Johnson grassin
Sarah Lancaster (23:18):
the case where you have non GMO corn. So
glyphosate is not an option, andyou've got resistance to the two
kind of main tools. What wasyour recommendation there? JD,
going quote for that armor goingforward.
JD Green (23:32):
Well, this particular farm is a pretty good sized farm
operation. They farmed several1000 acres, so they've got the
problem also spreading it aroundthrough their equipment and so
forth as they as they go farm tofarm, I think the answer is
they've got to change up thesystem. They they will not be
able to continue that approachlong term. They can probably
(23:56):
keep it at bay by, by using thecrop rotations of having
soybeans in these corn fields,you know, ever just like it's
kind of way we were back inbefore, before we even had
accent, you know, we were using,we can, you know, stay in
soybeans for two or three yearsand then come back to corn and
try to knock down thepopulation, and then then come
(24:19):
back and plant your non GMO cornin those fields. So, so I don't
have a strong answer to that atthis point, other than you just
going to have to shift up andjust admit that there are fields
you're going to have to plantsome traded crops that allows
you to use the full tool, rangeof tools we've got to work with.
(24:40):
As you all know, I don't thinkI'll see much new chemistry
that's going to tackle thatproblem for us immediately
anyway, so I'm going to figureit outeventually.
Alyssa Essman (24:51):
To my knowledge, also have not confirmed
glyphosate resistance, but Iknow we get reports of control
issues, and I know you mentionedthe synthetic auxins. And I also
want. Wonder if you know howmuch we're relying on
glufosinate. Post, do you thinkthat's reducing control with
glyphosate in some instances too?
JD Green (25:09):
That's a good point, yes, where we're trying to use
glufosinate instead ofglyphosate, the glufosinate is
just, which is basically libertyis not as effective on Johnson
grass and other grasses as asglyphosate would be. So, yeah.
So we get those failures with,you know, you burn it back, it
(25:33):
looks like you've got someinitial activity, and then
within weeks, it's gone. So orit comes back, is what I'm meant
to
Sarah Lancaster (25:44):
So going forward, what do you think the
answers might be, if we thinkabout the tools that we have and
maybe some of the tools thatcould be coming, what do you see
as the future for Johnson grass management?
JD Green (26:01):
Well, we we have some good tools that are still
working for the most part. Wejust need to use them in the
right way, in the right timing,and not rely just on the one
tool in the box to to get thejob done. So I think we just
(26:22):
gotta, gotta be conscientious ofof being diversified in our weed
management program. And I thinkthat's the main message that
we're trying to get across asweed scientists, that it's, it's
gotta be a variety of tools. AndI won't mention another scenario
where I've gotten a lot ofJohnson grass questions in the
(26:43):
past 15 plus years, is Johnsongrass in grass hay fields? You
know, we're back to not having aherbicide tool that works in
that situation. And most of ourgrass here in Kentucky is cool
season grasses, things likeorchard grass and tall fescue
and so forth. There are noherbicides that we can apply to
(27:08):
a grass hay field that's goingto be fed to cattle. Now, the
non crop folks have some toolsthat they can use, but they're
not approved for use inpastures, and probably because
of the chance of risk of injuryto the desirable species is one,
one reason for that. Now, coolseason grasses, like Bermuda
grass, they do have a couple ofproducts that that can help them
(27:31):
on Johnson grass down south inthose environments, but I bring
that up in hay fields from thestandpoint it's been one more
frustrating scenarios for me tocome up with answers for,
because I don't have any goodanswers. But the things I talk
about is you've got to dosomething different. Your hay
production system is propagatingJohnson grass. Now, once you get
(27:52):
a get a pocket started, how manytimes do you roll through that
field to cut it, to rake it,tether it, and then front
probably run the baler throughthe field. You're just moving
stuff around, particularly thoselater season cuttings that we
have with Johnson grass is inits full reproductive stages of
(28:13):
growth. So my main message isyou've got to do something
different, and that may meantaking that field out of
production for a few years. Ifit's a field that could grow
grain crops, use that as your asyour your tool. Now we have some
producers. That's not an optionfor them, very logically. And
(28:34):
the other is, I can go ahead andproduce hay for the first
cutting, but let's turn it intopasture field, because where you
continuously graze pastures,Johnson grass is basically, you
know, animals are continuouslygrazing. In fact, I hear a lot
of people tell me, cattle preferto graze Johnson grass over the
(28:55):
other grasses that are outthere. But again, going back to
our earlier conversation, you'vegot to be you gotta manage that.
We get late in the season andand it comes time where we're
going to start transitioning tothe fall of the year and frost
happening. We need to get thoseanimals off of there so, you
know, the exposure standpoint.But, but to me, as an example,
the grass hay scenario was, is,is, it's there are. There's no
(29:20):
good answers for other than thatbasic principle for weed
management overall, we have todo different things so you can't
rely on one tactic time aftertime and expect to be
successful.
Sarah Lancaster (29:33):
Think that is a great summary of weed control,
but it's kind of nice to takethat kind of big art from kind
of the beginning of your careerto today. JD, and just thinking
about how things kind of what'sold is new again, right? Kind of
back where we started and soabsolutely. So. Alyssa, did you
(29:54):
have anything that we maybemissed talking about today? Nope.
Alyssa Essman (29:58):
The only other thing that came. To mine was
brought up right at the end, youknow, the grazing and and, or
mowing, or, you know, those kindof non chemical control options
that he touched on there. Ithink it's another tool,
Sarah Lancaster (30:09):
yeah, I mean, it's, it can be a tough space.
It's interesting for me to hearyou talk about Frost being the
major concern, because we getconcerned about Frost, but we
also worry a lot about droughtstress,
JD Green (30:20):
right? I guess yes, because that
Sarah Lancaster (30:23):
triggers all of those, those stress responses
JD Green (30:26):
that, yeah, they can be at the same concern under
under drought stress as well.Yes.
Sarah Lancaster (30:33):
So, all right, did you have any closing
thoughts, JD, anything that Ishould have asked you, but
didn't you know, not
JD Green (30:39):
necessarily, but I mean, this has been a good
opportunity for me to comeopportunity for me to kind of
reflect back on my my careerworking with, when with one
particular weed. That's not thatI've spent my whole time working
on Johnson grass problems, butit's was one of the key weeds I
worked with, specifically when Ifirst started my career, and
then as I've wrapped up anddealt with this last case of
(31:04):
potentially multiple, multipleresistance and it, and what is,
you know, you ask a key questionthere. So what do we do when we
run into that? And, and I'mgoing to actually just just jog
my memory, is when I was doingthe my initial work with accent
(31:24):
documenting the accent resistantpopulation back in oh, about
2000 or so. We finished up thatproject. The county agent I was
working with this one RoundupReady corn was just being
introduced for use, and he and Iwere just having a nice little
discussion and saying, Well, youknow, the roundup pretty corners
(31:46):
probably gonna solve this, thisindividual's problem. But he was
very insightful. He says, so howlong would that last? Getting at
the fact that, you know,ultimately, we may have
resistance there as well. And aswe've discussed here today, you
know, we don't have itdocumented yet in Kentucky, but
(32:07):
there are states around us inwhich they are already starting
to find some resistance thatthat they can confirm, and as
much as which beginning to showup these populations, I think it
could be a matter of time beforewe want to have a document
again. Documented case for forour state, and perhaps other
states like yourselves in Kansasor Ohio, where, wherever. So I
(32:30):
hope not soon, but keeps us,keeps us in our careers,
Sarah Lancaster (32:36):
job security, and you know, nothing like a
weed to keep a person humble.
JD Green (32:41):
Absolutely, absolutely.
Sarah Lancaster (32:44):
So hey, thank you JD, for taking time to kind
of polish off all the some ofthe points of your career and
for talking with us today. Weappreciate it. We also
appreciate folks listeningtoday, and we hope you'll join
us again next time.
(33:09):
Thanks for listening to the waragainst weeds podcast. We
appreciate support from thenorth central Integrated Pest
Management Center and thecollaboration with the Crop
Protection Network. At cropprotection network.org, you can
find this podcast, otherpodcasts, and a variety of other
(33:30):
pest management resources.
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