April 9, 2025 • 37 mins
This week we have Dan Beran and Bob Bruss on to talk about dichlorprop-p. They cover the history and potential future of this active ingredient. Listen now!
To find more information about Nufarm go here: https://nufarm.com/uscrop/
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Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Sarah Lancaster (00:00):
Sarah, welcome back to the war against weeds
(00:08):
podcast. This is SarahLancaster. I'm an Extension weed
management specialist at KansasState University. Our co host
this week is Joe Ikley, howdy,Joe!
Joe Ikley (00:19):
hello!
Sarah Lancaster (00:20):
We have a couple of guests on with us
today, and I will let themintroduce themselves before we
jump into the subject matter. SoDan, do you want to lead off?
Kind of tell us a little bitabout yourself and what you do
for Nufarm and kind of how yougot into that role.
Dan Beran (00:37):
Sarah, thanks for the invite. Joe. Appreciate the
opportunity. So my name is DanBeran, tech service director for
Nufarm. Yeah, I've been in thisrole going on six years. It's
gone quickly, and a lot of thattime I've shared working closely
with our other guests heretoday. And yeah, looking forward
to the conversation.
Sarah Lancaster (00:56):
And then our second guest is Bob Bruss, Bob,
do you want to introduceyourself?
Bob Bruss (01:01):
Yeah, I was, I worked with Nufarm for 13 years that
retired about a year ago. Butyou know, guess the topic today
is dichlorprop, and one of thesub topic is the history of
dichlorprops. So Dan thoughtwe'd bring in an old guy to talk
about an old product. So I'lllet Dan handle a lot of more
(01:23):
recent, up to date stuff, andwhen we get to the history part,
then I'll jump in.
Sarah Lancaster (01:28):
Okay I think that sounds like a great plan.
So as Bob said, our our keysubject today is dichlorprop,
which is a group 4herbicide. SoDan, I think with that
introduction, I think maybe weshould let you kind of take it
away. How does dichlorpropcompare to other group four
herbicides?
Dan Beran (01:49):
Yeah, this is a really interesting one, and
since joining Nufarm in in 2019it's been a major area of of
development and R&D workaround this molecule that's been
around for a long time, andspecifically dichlorprop, or
2,4-D P is phenoxy herbicide.It's been used, maybe a bit of a
(02:12):
minor use herbicide in specialtysituations to maintain maybe
broader uses overseas and inCanada. But yeah 2,4-D P, or
dichlorprop is a product we'vebeen working on, or an active
ingredient we've been working onspecifically for kochia
management. And there's a reallyinteresting story on how an old
(02:33):
chemistry was given new life.And so Bob, maybe you can talk a
little bit about, maybe how itregenerated and what, what
brought it back to life, andmaybe a little bit of the story
of the isomer piece as well,too, because that's an
interesting component to all ofthis.
Bob Bruss (02:49):
Okay, so it's very closely related to 2,4-D so
dichlorprop has just got a extramethyl group where the ring
structure in the side chainstructure meet and just has one
more methyl group than 2,4-D sovery closely related and 2,4-D
was first reported in 1941 butfirst airing fine on the census
(03:13):
of dichlorprop was 1950 so itactually outdates me by Two
years. So you know I was born in'52 so dichlorprop came around
in 1950 and it really didn't getits first registration until
around 1960 and the deal wasthat 2,4-D was a lot cheaper to
(03:34):
make and actually had a broaderspectrum on a lot of annual crop
weeds, and there wasn't muchknown resistance at the time to
2,4-D and so there wasn't, youknow, much reason to spend the
extra money that you have to doto get something registered on
food crops in the us, you know,like your rotational crop
studies and plant metabolismstudies. And so they just
(03:58):
registered it, you know, for useon special crops, not food
crops, to start with, back inthe 60s. And now something that
was a property of dichlorpropseemed to penetrate woody
tissues better than 2,4-D so itwas a good brush herbicide. But
back then, there was a bettercompetit or, and 2,4,-5T, you
(04:21):
know, which so dichlorprop justkind of muddled along there, you
know, in the 60s, being kind ofa specialty herbicide used at
times for turf mixtures and alsofor brush control. Now, one
milestone that kind of helpedout dichlorprop a little bit is
2,4,-5T was a component of ofAgent Orange, and when they use
(04:48):
that in Vietnam, the 2,4,-5T youknow, the herbicide itself was
okay, but when they were makingthe active ingredient got
contaminated with dioxin. And sodioxin as a contaminant. The
2,4,-5T caused a lot ofproblems. And 2,4,-5T went away.
You know, can never recover fromthe political baggage, even
(05:10):
though they learned how to makeit without dioxin and so without
2,4,-5T, dichlorprop picked upits use for brush control
because of its ability topenetrate woody issues.
Something else that happened isthat Dan was saying dichlorprop.
When it first came out, was amixture of two isomers, and R,
which is the active isomer, andS isomer. And so these optical
(05:32):
isomers, you know, you had topay a little bit extra when you
had the mixed isomer to get thedirty one as well as the active
one. So, but if the 60s wentalong, they learned how to make
just the R isomer or the activeone. And so you get into the
late 60s and 70s, and be reallycareful, were you saying
(05:54):
dichlorprop or dichlorprop-pbecause, you know, dichlorprop,
back then was still available insome product that had both
isomers as well as you have thepure isomer available as
dichlorprop-p. So now you moveforward, and you know 2007 and
dichlorprop is having to gothrough registration review at
(06:16):
that time, the upgradedregistration work was just done
for the active isomerdichlorprop-P, and so all
products now register that havedichlorprop-P contained just the
active isomer so you don't haveany mixed isomer products out
there. Now, another milestonethat happened along the way was,
(06:37):
I believe it was around 1971well, actually already on that
in 1966 they found a patent forsynergism between if you had a
dichlorprop and 2,4-D anddicamba, you know, the you got a
synergistic effect from thethree of them being together.
(06:58):
And PBI Gordon was able tolicense that patent, and they
had an exclusive for the use ofthe Trimac herbicide, you know,
the three way herbicides thatyou see common, you know, for
controlling your broadleaf weedsand your lawn. They had an
exclusive on that for a longtime. You know, that blocked
other people from usingdichlorprop, 2,4-D and dicamba.
(07:18):
And that patent is off now. Soyou go into your thick box
stores now you'll see a lot ofyour bond herbicides still
contain these three wayherbicides. So that gave
dichlorprop a boost. Now, theother thing is, when they went
through re registration on wasthe work done on the active
isomer, but they realized theywere going to have to repeat a
(07:39):
lot of toxicity. You know,toxicological studies to
maintain the high rates thatwere originally registered. And
so at that time, they had to cutback on the rates of
dichlorprop, which made it alittle bit weak for a lot of the
uses for brush control on itsown. So after that, it was only
(08:01):
used in combination products,and you didn't have any type of
product by itself for a longtime. So through the 70s, 80s
and 90s, this kind of went alongthere. It's mixture products,
you know, for turf and brushcontrol. And the thing that
brought it to Nufarm's attentionwas we are also being contacted
by folks at Texas A and M,working closely with Corteva,
(08:25):
and they had launched enlistcotton in South Texas, and this
allowed cotton to be sprayedwith 2,4-D and without killing
it. The problem was, in SouthTexas, they still have a
believable eradication programin place, and it's mandatory
that you control your cottonafter it's been picked so it
won't re sprout. And they wereusing 2,4-D to control this
(08:47):
cotton. And now within LIScotton, they didn't have the
options to control the cottonafter it was picked, but cortiva
realized that even though thegene they inserted allowed the
cotton to tolerate 2,4-D it didnot tolerate dichlorprop-P. And
(09:07):
so they actually contacted us,you know, Corti though through
Texas A and M, and we worked toget a pure dichlorprop product
register to terminate cotton inSouth Texas after the cotton had
been picked those of us inNufarm, though, now that we were
kind of alert to this, we'rethinking, Well, if you got some
crops and things that aretolerant to 2,4-D but sensitive
(09:31):
dichlorprop, maybe now we gotthese resistant weeds out there
and and maybe you'll see somethings there too, where now
dichlorprop can work on someweeds that are resistant to 4d
so the first thing we did is wewent to North Platte station for
University of Nebraska, youknow, worked with the, you know,
some studies there. And thefirst time we looked at the
(09:54):
water hemp that was, had theydiscovered they had high
resistance to 2,4-D and. Now,one thing about picking pigweed
species, dichlorprop itself,even on susceptible species,
isn't that great on pigweedspecies. So if you had a
susceptible water hemp, it tooka lot less 2,4-D to control it,
then you would dichlorprop. Butif you had the resistant
(10:18):
population of the water hemp,you know, it took a whole lot of
2,4-D but it took the sameamount of dichlorprop, so it
wasn't affected by theresistance. That just took a
higher amount of Doctor pop tocontrol water in. So next thing
we said, what about kochia?That's where we got in, and we
(10:39):
found out the same thing oncoaches that coaches that was
resistant to 2,4-D and also somepopulations that are resistant
to Dicamba. And for octave here,eventually, was still
susceptible, that would nolonger was susceptible to 4d
that dichlorprop-P would workon. And so that's kind of where,
(11:00):
you know, Dan and I, we startedworking with folks like Joe and
other influencers, Sarah, youknow, a lot of researchers
throughout the Midwest, youknow, picked up on looking this.
So turn it back to Dan then, andhe can pick up with, you know,
how we got going with thisthing.
Dan Beran (11:20):
Yeah, it's, it's, it's quite a story how an AI
bounces around, you know,through companies and, you know,
initial discoveries and kind ofthe interaction between the
regulatory world and and, andwhere we ended up at so it's an
interesting one, because itwasn't a straight line from a
molecule was developed a marketin mind and things like that.
(11:44):
So, yeah, it's been interesting.
Sarah Lancaster (11:47):
I was just thinking as Bob was kind of
telling that story, though, Danthat a lot of times we hear
folks talk about, you know,we're just bringing things off
the shelf and dusting off old,old molecules, but sometimes it
has sort of, like a little bitof a negative feel to it. But I
think this is a case where it's,it's not just reusing a molecule
(12:09):
that we could put away. It'sbringing an old molecule into a
totally different use pattern.So it's, it's a really, I think,
interesting story, like yousaid, Yeah.
Dan Beran (12:20):
And one of the the fun things about this is, as
you're really reevaluatingsomething that hasn't been
considered in various usepatterns, and kind of opening
the door for other crop uses.And like Bob said, the way the
the tolerances were at the time,when we first started working
with dichlorprop, there wererate and cropping limitations,
(12:43):
so we kind of had to discoverwhat the potential would be to
then start to build the case toalmost treat this as a new AI,
and therefore bring all thenecessary regulatory pieces. And
Bob, I know you were a part ofthat, and some of those key aha
moments war when you startedworking with, you know, so much
(13:03):
University collaboration withthis one too, like, well, I'll
maybe let you, I'll hand off toyou and kind of talk about the
resistant kochia strains,because CSU had, kind of had
some key populations that theyhad been working with. And I
know you connected with PhilWestra early on in this project
Bob.
Bob Bruss (13:20):
yeah, especially Phil Westra and Vipin Kumar, who was
there at K State, and KirkHowatt up at NDSU. Worked a lot
with Joe. But yeah, you know,there are populations that, you
know, Phil has a lot of them,you know, but you know, Dicamba
resistant populations we'restill really sensitive to
(13:42):
dichlorprop. It doesn't meanthat you might have some
populations out there that as weuse it more, we'll select for
resistance with dichlorprop onits own, because kind of the
interesting thing in the storyis where herbicide tolerant
crops made us learn more aboutsome of these compounds and we
then apply to weed control. Soturns out, with the herbicide
(14:03):
tolerant crops, ones that aretolerant to 2,4-D you have some
that are still sensitive todichlorprop, like most of the
fact, all the ones I'm aware of,the events that are in soybeans
and cotton that make it tolerantto 2,4-D are still sensitive to
(14:23):
dichlorprop-P and works on both.A lot of the they're slightly
different events that are in the2,4-D tolerant corn and lot of
those events also conveytolerance to dichlorprop. And
Joe did a lot of work with thatas well. Some of the stuff were
kind of flushed out that, oh,wow, you can use real high rates
(14:46):
of dichlorprop on some of these2,4-D tolerant corn varieties.
And so it learns, you learn thatthink about it's just one methyl
group hanging down there wherethe side chain attaches to the
ring structure. And that's asite. Where these detox enzymes
can get in and just a little bitof twisting can with some
enzymes that can't get aroundthat extra methyl group, some
(15:08):
can. So it really opened up oureyes and but it made us also
aware why it was very importantto work with all the weed
scientists in the Midwest. Isthat you dichlorprop with, you
know, without proper stewardshipand management and rotation, is
going to be susceptible toselecting for resistance as
(15:28):
well. So that's why we've workedto try and get combination
products that have at least twoherbicides in there, that work
on kochia for resistancemanagement, you know, trying to
work on programs where it'salternated with other things.
It's one thing where we'vetrying to be pushing to get at
the market quick, and we're withgetting some benefit from some
(15:52):
states, getting some speciallocal need labels, because you
don't want the registration todrag out until you just have
Dicamba and perox repair andsome things that don't work
anymore. And then you have torely on dichlorprop. So you want
to bring all your tools intogether so that you can rotate
it.
Dan Beran (16:09):
That waiting piece has been part of the dichlorprop
story. Sarah, as you you hear,I've heard that too. Oh, this
is, this is just old chemistry.Just dust it off and bring it
back in. But really it requireda whole new set of tolerance,
residue, rotational studies thatthat have been just like a new
AI almost takes a lot of time tobring those to market, and so
(16:31):
it's kind of like we're watchingthis Kochia resistance story.
It's like watching the house ison fire for smoke, and it's
like, well, we're waiting toturn the hose, on to at least
add another tool and anotherchemistry to the to the
management of Kochia being inand there's kind of two markets
that we focused on with this.Ai, one would be fallow, and the
(16:53):
second would be in small grains.One of the unique things about
dichlorprop-P is is a gooddegree of tolerance in wheat. So
it kind of fits that MCPAtolerance range is kind of how I
describe it. And then when youmix it with bramos, with this
proposed Maestro ext product forsmall grains, you end up having
(17:14):
two effective AIS in fallow.That's really where you better
sharpen your sharpen your tools,because it's, it's a really
challenging area, becauseobviously you don't have crop
tolerance. You tend to be indrier environments, or, I should
say, crop competition. And,yeah, there's a lot of failures
(17:35):
that are happening out there,and rescue applications with
paraquat. So that's a bit of themess that we're jumping into
with scorch EXT that followproducts. So there's certainly
to Bob's comment, a lot ofstewardship that goes into
maintaining a product'sviability long term because of
the investment that we'retalking about.
Bob Bruss (17:56):
There's a little benefit thing from the
combination products. And theydid this out K State Research
Station Hayes, is that they kindof rediscovered that synergism
that they'd seen, you know, inthe 60s and 70s, on the turf
products. So product like ScorchEXT has dichlorprop 2,4-D and
(18:16):
dicamba. So that's that samethree way of a propionic acetic
acid and dicamba and Dr. KumarVipan saw that same type of
synergism in controlling some ofthe resistant kochia that they
have out there in westernKansas.
Joe Ikley (18:33):
So the other thing I think might be a good time to
talk about this now is talkedabout some synergism, but then
maybe talk a little bit aboutantagonism or the lack thereof.
And we're, we're audio onlymedium, so you can't see Sarah
and I just grinning, because itis just so fascinating the one
extra methyl group. But we alsokind of figured out some of
these things with dichloropropand the group one herbicides for
(18:56):
this wheat concept. And spaceworth going into kind of that
research and story as well.
Bob Bruss (19:03):
Yeah, that was kind of work that was done there. And
Fargo with Kirk Howatt and NDSUand so we wanted to check
because 2,4-D is, you know, canbe antagonistic to the action of
some of the grass herbicides. Sowe thought, well, we'll check it
out and see how a grassherbicides will perform a
(19:24):
dichlorprop. And so I remembergoing visit his boss the first
time, you know, and Kirk willstill tell the story that he
kind of did, like a big reveal,you know, one of these HGTV, you
know, shows you know that hewouldn't get me go through the
2,4-D stuff and the grass thingby itself. And sure enough,
you're seeing the antagonism andthe 2,4-D grass herbicide plots.
(19:47):
And then a big reveal, it showsdichlorprop, and saw much less
antagonism. You know, there'sstill some there. And you know,
can say it's been on the rates,the combination products you
use, but yeah, you see. A lotless antagonism with
dichlorprop-P mixed with some ofthe herbicides they're used for
grass control out there. Soyeah, as you said, that one
(20:11):
extra methyl group can make abig difference. Another thing I
remember is visiting a plot PhilWester had there near Fort
Collins, because dichlorprop-pdoesn't work on sunflowers. And
as Joe knows, we even thoughtmaybe we might be able to use a
for as a, you know, for domesticsunflowers in there. So
dichlorprop-p really work onsome flowers. But yeah, work on
(20:34):
Kochia. And Phil had a plotthere. There's just a thick
mixture of kochia andsunflowers, and side by side,
you had 2,4-D versusdichlorprop, where 2,4-D was
braided, taking out all thesunflowers, but all the kochia
was there, and they just rightnext to it. You know, the
dichlorprop taken out of Kochia,and it was pretty filled with
(20:54):
sunflowers, just side by side.That one knuckle group made
their stand, pure stand ofsunflowers and pure stand of
Kochia.
Dan Beran (21:02):
Yeah, it's, it's an interesting piece, like, when
you're talking about maybe thedifferent events on too far de
tolerances, as well as crop andor as far as weed tolerance, you
know, whether you're looking atKochia or sunflower side by
side, it it kind of points tosomething that I hadn't given
much thought to, is how uniquethese group four herbicides are
(21:23):
from a binding site, from theauxin receptors as well as the
metabolic enzymes that are, youknow, able to detoxify the group
four herbicides, whether it bein a weed or a crop. And so it's
really uncovered a lot ofthoughts around this combination
approach. And so, yeah, this onecontinues to be a mystery, done
(21:46):
on furl, and part of it getsinto this whole idea of how we
continue to steward and protectand maintain the value of the of
the group for herbicides,because in this world of kochia,
we need to continue to be ableto control kochia with Dicamba
flux appear, you know,dichlorprop, all of those, and
(22:11):
maybe even get additive effectsof others that are maybe less
active, but things like, there'sjust other ais that potentially
could be group fours, that thatcan help overwhelm weed
resistance, or at least preventor not have such a severe
selection pressure that appearsto happen when you lean on one
AI in a geography too heavily.
Sarah Lancaster (22:33):
So that was that question that had had come
to my mind as we were talkinghere. Dan, so we're talking
about stewardship, but I'm goingto ask, kind of the inverse,
almost in a way. Do you guyshave visions, and some of this,
you maybe can't say, but do youguys have visions for additional
combinations going afterdifferent cropping systems,
(22:54):
aside from this kind of wheatintensive systems that we see in
the western plains,
Dan Beran (23:00):
yeah, I can, I can speak to that a little bit, and
maybe I jump past it a littlebit. So we kind of have the
Scorch EXT dicamba, 2,4-DDuplosan or dichlorprop mixture
for pre plant and fallow. Andthat's, that's probably where
that product concept will stay.Just because of those three AIS,
(23:21):
you're going to be pretty muchlimited to pre plant uses. And
then in in the small grains,barley included in there as
well. It's the bromoxenoldichlorprop remix there. Now,
when you start to think aboutcompounds in wheat that would
have additional activity from abroad leaf Kochia perspective,
(23:42):
there's some targets out therethat we're looking at. Some are
ais that are currently beingused, as well as some that
potentially could come into themarket, and, you know, the next
three to four years, and that'sbecause of the regulatory time
frame. It's like glacial ice,way to describe it. So, yeah,
we've got to be thinking aboutmixtures, you know, five years
(24:05):
down the road. And so thatincludes ais that are available
now, and ais that may becomeavailable down the road. And you
know, there's new AIS popping upout of some non traditional
sources. Certainly AI discoveryis happening beyond the, you
know, the typical five or sixcompanies that traditionally had
been generating the the theresearch efforts for for new
(24:28):
herbicides. So that's kind ofwhere we're at as far as other
cropping systems. It's, it'sunique because of the mixture
approach that we'll need to takewith, with dichlorprop, it it
starts to limit the number ofcrops that will potentially go
on. There's, you know, the thingthat's that we have to keep an
eye on too with, although we'renot developing the new herbicide
traits, clearly, there's goingto be more group four resistance
(24:54):
traits beyond the one that weall know of between them list
and things like that. So there'ssome additional. Traits. And,
you know, there's a potentialthat some of those may have, may
confer tolerance to dichlorprop.It just kind of depends, you
know, whether it's an event likethe endless corn wander or not.
So that would also be part ofit. The stewardship piece is the
(25:14):
biggest, the biggest thing thatwe probably wrestle with as
well. It's like, okay, these arethe first generation products,
but how do you maintain thevalue and, you know, obviously
the the viability of this longterm, you know, mixtures is a
big part of it, but that's,that's only step one of maybe
two or three that that we needto digest here.
Bob Bruss (25:36):
I was just gonna say and correct me, I'm wrong, but I
think Nufarm is moving forwardto add range and pasture. Am I
correct on that? Dan and eventhough kochia like the problem
and range and pasture as it is,and crops willing to come to
roadside spraying, a lot ofthose applicators don't like
(25:59):
using tension that doesn't havea range and pasture label in
case it drifts on the other sideof the fence right and so, and
of course, for a long roadsidecoaching, control is important,
and so I think in that range andpasture label will open up some
use of sign range and pasturebut also it's more roadside
spraying.
Dan Beran (26:18):
Yep, big no spot on that is that'll be in the next
round of regulatory submissions.So yeah, we have that Scorch EXT
has a roadside label, but thethe dichlorprop piece does not
have grazing tolerances. So lasttime I checked, I think they
like to mow those roadsides andhay 'em up in North and South
Dakota. Joe, so yeah, that'spart of the deal.
Joe Ikley (26:40):
Well, yeah, big ditches and we like to bail.
Dan Beran (26:45):
Can you grow can you grow corn in the right of ways?
Sarah Lancaster (26:51):
I see folks that try. they farm to the
gravel
Joe Ikley (26:56):
There's at least plenty volunteer sunflowers
lined those areas.
Sarah Lancaster (27:00):
So I guess the last question that we need to
maybe tackle kind of head onhere is this idea you've talked
about stewardship, but how doeshow do you see dichlorprop
fitting in efforts for herbicideor resistance management Dan?
Dan Beran (27:16):
yeah, so I think because we know there's group
four, the group 14 resistancethat obviously, Joe's been
highly tied to. We know we'regetting into more populations
that that are probably trendingtowards some metabolic
resistance. And that's, that's,that's a big challenge. You
know, it's, if it's sitespecific, the dip probably is
(27:40):
targeting a different, you know,auxin receptor, than than the
flux appear, di Canvas. So justjust having an additional AI
brings a bit more diversity,particularly in small grains,
you're adding a different AIthat's impacting a different
auxin receptor, so to speak,than than probably, flux appear.
So that helps. So it's adding abit more diversity in both of
(28:03):
those cropping systems. Sothat's, that's kind of step one.
What we're doing, from maybe abasic research standpoint, is
working with some of the folksat CSU Todd Gaines. I know you
guys know him well. So some ofthose folks were, were
interested in just getting tomore of the basic understanding
(28:24):
around group four herbicideresistance, and trying to
understand how dichlorpropcompared to some of the others.
And so once we get some of thatmore basic research, it kind of
gives us ideas, okay, what wouldbe the types of mixtures and
other approaches that that couldmaybe be used to manage
(28:45):
resistance, you know, Nufarms,you know, a relative, from a
from a people in the fieldstandpoint, we're quite a bit
smaller than many of our peersin this, in this marketplace,
and whether it comes to this,this development of this, AI,
we've leaned heavily on, on theuniversity weed specialists, and
so I would, I would say, we'reprobably better off working with
(29:09):
you folks on developingstewardship practices, because
the ability to communicate croprotation app, you know, we can
talk about application timingand, you know, herbicide
rotations and all that kind ofstuff, but we're just one voice.
So that's, that's part of it.So, you know, continue to work
with with the wheat scientistsacross the Kochia geography is
(29:29):
probably a big part of how, youknow, we, we work and, you know,
that's kind of how we we try tofigure out how our product best
fits. And you know, if we'redoing something idiotic, I'm
pretty sure that you guys wouldprobably call us out on it, so
hopefully we're not doinganything like that.
Sarah Lancaster (29:44):
So one not very applied question that I had
around resistance and resistancemanagement, and I think again,
this is another thing I thinkwe've kind of tiptoed around,
but it might be good just to askthe question. So dichloroprop
with the initial. Socialmetabolic steps in most plants
(30:04):
be a different enzyme than2,4-D, Dicamba. Some of the
other group forests that were,you're, we're used to thinking
about, because my, my contexthere is thinking about, you
know, I know it's, it's Palmer,not kochia, but we know that,
you know, 2,4-D can plants candevelop metabolic resistance to
2,4-D and so, you know, it'seasy to think about target side
(30:26):
stuff, but I was just wonderinghow much we, you guys, have
figured out that that you cantell us about the degradation
and how this might fit in withmetabolic resistant populations.
Dan Beran (30:36):
Yeah that would, that would certainly go to a lot of
that basic research that wasjust touching on at CSU, and so
they actually are looking atsome of the metabolic versus
target size, target siteresistance. What we do think is
that additional methyl group is,and this would be both on weeds
as well as some of the traits,is that that is less impacted by
(31:00):
some of the metabolic enzymesthat quickly chew apart 2,4-D,
and clearly, there's probablymore robust enzymes that would
be able to chew up dichlorpropas well. Because, again, we know
there's a, you know, a trade outthere that has Metabolic Enzymes
that do that and and I believethat's in a metabolic resistance
and endless corn and Bob call meout if I'm if I'm out of bounds
(31:23):
there, but I think that was kindof our hypothesis.
Bob Bruss (31:27):
Yeah, it's fine, because a lot of those just been
kind of what we've learned fromthe herbicide tolerant crops.
And, you know, we mentioned thatthe cotton soybeans that are
tolerance to 2,4-D are stillsusceptible to dichlorprop-P,
those enzymes that are producedwill break down the inactive
isomer of dichlorprop. So justthat little methyl group is not
(31:52):
just the methyl group, but theway it's configured and allows
the enzymes to get in there. Soyou have enzymes that can get in
and break that in both 2,4-D anddichlorprop and some enzymes
that can get in there and breakdown 2,4-D but are blocked by
the methyl group, and so allthose enzymes are out there.
What we don't know, it goes tothe mode of action piece. We
(32:13):
really can't explain why 2,4-Dwould work on some things, and
dichlorprop doesn't, becausethat probably goes to the target
site. Because, when you thinkabout it, you know, an enzyme
that can get in and break down,2,4-D right? You know,
dichlorprop, you know, has thatmethyl group. So, you know, why
are there? You know, likesunflowers, and we're talking
(32:36):
about marestail, it's not veryactive on that. Why, you know,
is dichlorprop not able to workon things that 2,4-D can work
on, because you would think thatit would be, you know, not to
incline the metabolism becauseof that extra methyl group is
2,4-D you know, outside thatether methyl group, everything's
the same. So there's somethingabout structure there that we
(32:59):
just don't know about that besome good talks for some
graduate students.
Sarah Lancaster (33:06):
Enzyme kinetics sounds like biochemistry. So
Joe, did you have any otherquestions that you wanted to put
in front of these guys?
Joe Ikley (33:17):
I think we've covered most of the story and the
questions I had along the way.
Sarah Lancaster (33:22):
So I guess then our last question before we turn
these two loose. Do you guys, Iguess, Dan, this is mostly a you
question. Do you have anywebsites or social media types
of resources that you would liketo point our listeners to to
learn more about the product orto ask other questions.
Dan Beran (33:42):
Yeah, yeah. I guess for for folks who are listening
Nufarm.com/uscrop is a good spotto keep up on labels, you know.
And as we've been talking aboutthis, we kind of haven't really
laid out the fact thatdichloprop is pending
registration for use on smallgrains and in fallow, with the
(34:04):
exception of a couple of 24 C'sKansas, here state being one of
those. But yeah, that's wherewe'll, you know, communicate
registration, which is pending.And obviously, knock on wood,
2025 looks to be a promisingyear to cross that finish line.
So yeah, just obviously we'reout there on social media, but
certainly plenty places to catchup with all things. Nufarm on
(34:26):
the interweb, as I like to callit.
Sarah Lancaster (34:31):
Alright, any last comments, Dan or Bob,
before we we wrap this up?
Dan Beran (34:37):
Bob, I think you should catch the listeners up on
maybe what you've been doing thepast few months and and how you
keep connected with those of usat Nufarm.
Bob Bruss (34:48):
transitioning from crop weed control to weed
control in St Augustine lawns sodown here in Florida, trying to
get my yard in shape. So that'skind of been my main focus, and
so it's great to dust off somelittle notes on dichlorprop. Get
on here with y'all today. So Ireally enjoyed it. Thanks for
(35:09):
including me in on the talk.
Joe Ikley (35:11):
Are you using dichlorprop on that St Augustine
grass lawn?
Bob Bruss (35:15):
No, not really. MCPA, MCPP, which are closely related,
you know, used, but thedichlorprop in 2,4-D, on St
Augustine aren't quite thatgreat.
Sarah Lancaster (35:32):
St Augustine, grass is a unique one. So, yeah,
having lived, having lived inFlorida, Bob, I feel like
everything is predatory inFlorida. So, so enjoy the
sunshine, but, but beware,beware the critters.
Bob Bruss (35:44):
Yeah, i got excited because, well even the plants. I
got excited because we had thisCarolina Jasmine blooming just
in the back. And even though wehad, I got excited because I was
gonna get beehives, and then Iread and find out that it's
toxic to bees, you know. Areeven the plants down here, as
(36:04):
well as the Gators, the snakesand all the other things you
gotta look out for.
Joe Ikley (36:10):
Florida Man.
Sarah Lancaster (36:15):
Well, Bob, thank you for taking time to
share with us what you know. Ithink it's awesome that we get a
chance to capture some of theexperience that kind of walks
out the door sometimes whenfolks move on to different
seasons of life. So thank youfor for taking the time to talk
with us today, and thanks Danfor for being willing to spend
some time with us as well.Thanks also to the listeners,
(36:37):
and we'll see you guys againnext time. (music)
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
(37:02):
find this podcast, otherpodcasts and a variety of other
pest management resources.
Sarah, welcome back to the war against weeds
(00:08):
podcast. This is SarahLancaster. I'm an Extension weed
management specialist at KansasState University. Our co host
this week is Joe Ikley, howdy,Joe!
Joe Ikley (00:19):
hello!
Sarah Lancaster (00:20):
We have a couple of guests on with us
today, and I will let themintroduce themselves before we
jump into the subject matter. SoDan, do you want to lead off?
Kind of tell us a little bitabout yourself and what you do
for Nufarm and kind of how yougot into that role.
Dan Beran (00:37):
Sarah, thanks for the invite. Joe. Appreciate the
opportunity. So my name is DanBeran, tech service director for
Nufarm. Yeah, I've been in thisrole going on six years. It's
gone quickly, and a lot of thattime I've shared working closely
with our other guests heretoday. And yeah, looking forward
to the conversation.
Sarah Lancaster (00:56):
And then our second guest is Bob Bruss, Bob,
do you want to introduceyourself?
Bob Bruss (01:01):
Yeah, I was, I worked with Nufarm for 13 years that
retired about a year ago. Butyou know, guess the topic today
is dichlorprop, and one of thesub topic is the history of
dichlorprops. So Dan thoughtwe'd bring in an old guy to talk
about an old product. So I'lllet Dan handle a lot of more
(01:23):
recent, up to date stuff, andwhen we get to the history part,
then I'll jump in.
Sarah Lancaster (01:28):
Okay I think that sounds like a great plan.
So as Bob said, our our keysubject today is dichlorprop,
which is a group 4herbicide. SoDan, I think with that
introduction, I think maybe weshould let you kind of take it
away. How does dichlorpropcompare to other group four
herbicides?
Dan Beran (01:49):
Yeah, this is a really interesting one, and
since joining Nufarm in in 2019it's been a major area of of
development and R&D workaround this molecule that's been
around for a long time, andspecifically dichlorprop, or
2,4-D P is phenoxy herbicide.It's been used, maybe a bit of a
(02:12):
minor use herbicide in specialtysituations to maintain maybe
broader uses overseas and inCanada. But yeah 2,4-D P, or
dichlorprop is a product we'vebeen working on, or an active
ingredient we've been working onspecifically for kochia
management. And there's a reallyinteresting story on how an old
(02:33):
chemistry was given new life.And so Bob, maybe you can talk a
little bit about, maybe how itregenerated and what, what
brought it back to life, andmaybe a little bit of the story
of the isomer piece as well,too, because that's an
interesting component to all ofthis.
Bob Bruss (02:49):
Okay, so it's very closely related to 2,4-D so
dichlorprop has just got a extramethyl group where the ring
structure in the side chainstructure meet and just has one
more methyl group than 2,4-D sovery closely related and 2,4-D
was first reported in 1941 butfirst airing fine on the census
(03:13):
of dichlorprop was 1950 so itactually outdates me by Two
years. So you know I was born in'52 so dichlorprop came around
in 1950 and it really didn't getits first registration until
around 1960 and the deal wasthat 2,4-D was a lot cheaper to
(03:34):
make and actually had a broaderspectrum on a lot of annual crop
weeds, and there wasn't muchknown resistance at the time to
2,4-D and so there wasn't, youknow, much reason to spend the
extra money that you have to doto get something registered on
food crops in the us, you know,like your rotational crop
studies and plant metabolismstudies. And so they just
(03:58):
registered it, you know, for useon special crops, not food
crops, to start with, back inthe 60s. And now something that
was a property of dichlorpropseemed to penetrate woody
tissues better than 2,4-D so itwas a good brush herbicide. But
back then, there was a bettercompetit or, and 2,4,-5T, you
(04:21):
know, which so dichlorprop justkind of muddled along there, you
know, in the 60s, being kind ofa specialty herbicide used at
times for turf mixtures and alsofor brush control. Now, one
milestone that kind of helpedout dichlorprop a little bit is
2,4,-5T was a component of ofAgent Orange, and when they use
(04:48):
that in Vietnam, the 2,4,-5T youknow, the herbicide itself was
okay, but when they were makingthe active ingredient got
contaminated with dioxin. And sodioxin as a contaminant. The
2,4,-5T caused a lot ofproblems. And 2,4,-5T went away.
You know, can never recover fromthe political baggage, even
(05:10):
though they learned how to makeit without dioxin and so without
2,4,-5T, dichlorprop picked upits use for brush control
because of its ability topenetrate woody issues.
Something else that happened isthat Dan was saying dichlorprop.
When it first came out, was amixture of two isomers, and R,
which is the active isomer, andS isomer. And so these optical
(05:32):
isomers, you know, you had topay a little bit extra when you
had the mixed isomer to get thedirty one as well as the active
one. So, but if the 60s wentalong, they learned how to make
just the R isomer or the activeone. And so you get into the
late 60s and 70s, and be reallycareful, were you saying
(05:54):
dichlorprop or dichlorprop-pbecause, you know, dichlorprop,
back then was still available insome product that had both
isomers as well as you have thepure isomer available as
dichlorprop-p. So now you moveforward, and you know 2007 and
dichlorprop is having to gothrough registration review at
(06:16):
that time, the upgradedregistration work was just done
for the active isomerdichlorprop-P, and so all
products now register that havedichlorprop-P contained just the
active isomer so you don't haveany mixed isomer products out
there. Now, another milestonethat happened along the way was,
(06:37):
I believe it was around 1971well, actually already on that
in 1966 they found a patent forsynergism between if you had a
dichlorprop and 2,4-D anddicamba, you know, the you got a
synergistic effect from thethree of them being together.
(06:58):
And PBI Gordon was able tolicense that patent, and they
had an exclusive for the use ofthe Trimac herbicide, you know,
the three way herbicides thatyou see common, you know, for
controlling your broadleaf weedsand your lawn. They had an
exclusive on that for a longtime. You know, that blocked
other people from usingdichlorprop, 2,4-D and dicamba.
(07:18):
And that patent is off now. Soyou go into your thick box
stores now you'll see a lot ofyour bond herbicides still
contain these three wayherbicides. So that gave
dichlorprop a boost. Now, theother thing is, when they went
through re registration on wasthe work done on the active
isomer, but they realized theywere going to have to repeat a
(07:39):
lot of toxicity. You know,toxicological studies to
maintain the high rates thatwere originally registered. And
so at that time, they had to cutback on the rates of
dichlorprop, which made it alittle bit weak for a lot of the
uses for brush control on itsown. So after that, it was only
(08:01):
used in combination products,and you didn't have any type of
product by itself for a longtime. So through the 70s, 80s
and 90s, this kind of went alongthere. It's mixture products,
you know, for turf and brushcontrol. And the thing that
brought it to Nufarm's attentionwas we are also being contacted
by folks at Texas A and M,working closely with Corteva,
(08:25):
and they had launched enlistcotton in South Texas, and this
allowed cotton to be sprayedwith 2,4-D and without killing
it. The problem was, in SouthTexas, they still have a
believable eradication programin place, and it's mandatory
that you control your cottonafter it's been picked so it
won't re sprout. And they wereusing 2,4-D to control this
(08:47):
cotton. And now within LIScotton, they didn't have the
options to control the cottonafter it was picked, but cortiva
realized that even though thegene they inserted allowed the
cotton to tolerate 2,4-D it didnot tolerate dichlorprop-P. And
(09:07):
so they actually contacted us,you know, Corti though through
Texas A and M, and we worked toget a pure dichlorprop product
register to terminate cotton inSouth Texas after the cotton had
been picked those of us inNufarm, though, now that we were
kind of alert to this, we'rethinking, Well, if you got some
crops and things that aretolerant to 2,4-D but sensitive
(09:31):
dichlorprop, maybe now we gotthese resistant weeds out there
and and maybe you'll see somethings there too, where now
dichlorprop can work on someweeds that are resistant to 4d
so the first thing we did is wewent to North Platte station for
University of Nebraska, youknow, worked with the, you know,
some studies there. And thefirst time we looked at the
(09:54):
water hemp that was, had theydiscovered they had high
resistance to 2,4-D and. Now,one thing about picking pigweed
species, dichlorprop itself,even on susceptible species,
isn't that great on pigweedspecies. So if you had a
susceptible water hemp, it tooka lot less 2,4-D to control it,
then you would dichlorprop. Butif you had the resistant
(10:18):
population of the water hemp,you know, it took a whole lot of
2,4-D but it took the sameamount of dichlorprop, so it
wasn't affected by theresistance. That just took a
higher amount of Doctor pop tocontrol water in. So next thing
we said, what about kochia?That's where we got in, and we
(10:39):
found out the same thing oncoaches that coaches that was
resistant to 2,4-D and also somepopulations that are resistant
to Dicamba. And for octave here,eventually, was still
susceptible, that would nolonger was susceptible to 4d
that dichlorprop-P would workon. And so that's kind of where,
(11:00):
you know, Dan and I, we startedworking with folks like Joe and
other influencers, Sarah, youknow, a lot of researchers
throughout the Midwest, youknow, picked up on looking this.
So turn it back to Dan then, andhe can pick up with, you know,
how we got going with thisthing.
Dan Beran (11:20):
Yeah, it's, it's, it's quite a story how an AI
bounces around, you know,through companies and, you know,
initial discoveries and kind ofthe interaction between the
regulatory world and and, andwhere we ended up at so it's an
interesting one, because itwasn't a straight line from a
molecule was developed a marketin mind and things like that.
(11:44):
So, yeah, it's been interesting.
Sarah Lancaster (11:47):
I was just thinking as Bob was kind of
telling that story, though, Danthat a lot of times we hear
folks talk about, you know,we're just bringing things off
the shelf and dusting off old,old molecules, but sometimes it
has sort of, like a little bitof a negative feel to it. But I
think this is a case where it's,it's not just reusing a molecule
(12:09):
that we could put away. It'sbringing an old molecule into a
totally different use pattern.So it's, it's a really, I think,
interesting story, like yousaid, Yeah.
Dan Beran (12:20):
And one of the the fun things about this is, as
you're really reevaluatingsomething that hasn't been
considered in various usepatterns, and kind of opening
the door for other crop uses.And like Bob said, the way the
the tolerances were at the time,when we first started working
with dichlorprop, there wererate and cropping limitations,
(12:43):
so we kind of had to discoverwhat the potential would be to
then start to build the case toalmost treat this as a new AI,
and therefore bring all thenecessary regulatory pieces. And
Bob, I know you were a part ofthat, and some of those key aha
moments war when you startedworking with, you know, so much
(13:03):
University collaboration withthis one too, like, well, I'll
maybe let you, I'll hand off toyou and kind of talk about the
resistant kochia strains,because CSU had, kind of had
some key populations that theyhad been working with. And I
know you connected with PhilWestra early on in this project
Bob.
Bob Bruss (13:20):
yeah, especially Phil Westra and Vipin Kumar, who was
there at K State, and KirkHowatt up at NDSU. Worked a lot
with Joe. But yeah, you know,there are populations that, you
know, Phil has a lot of them,you know, but you know, Dicamba
resistant populations we'restill really sensitive to
(13:42):
dichlorprop. It doesn't meanthat you might have some
populations out there that as weuse it more, we'll select for
resistance with dichlorprop onits own, because kind of the
interesting thing in the storyis where herbicide tolerant
crops made us learn more aboutsome of these compounds and we
then apply to weed control. Soturns out, with the herbicide
(14:03):
tolerant crops, ones that aretolerant to 2,4-D you have some
that are still sensitive todichlorprop, like most of the
fact, all the ones I'm aware of,the events that are in soybeans
and cotton that make it tolerantto 2,4-D are still sensitive to
(14:23):
dichlorprop-P and works on both.A lot of the they're slightly
different events that are in the2,4-D tolerant corn and lot of
those events also conveytolerance to dichlorprop. And
Joe did a lot of work with thatas well. Some of the stuff were
kind of flushed out that, oh,wow, you can use real high rates
(14:46):
of dichlorprop on some of these2,4-D tolerant corn varieties.
And so it learns, you learn thatthink about it's just one methyl
group hanging down there wherethe side chain attaches to the
ring structure. And that's asite. Where these detox enzymes
can get in and just a little bitof twisting can with some
enzymes that can't get aroundthat extra methyl group, some
(15:08):
can. So it really opened up oureyes and but it made us also
aware why it was very importantto work with all the weed
scientists in the Midwest. Isthat you dichlorprop with, you
know, without proper stewardshipand management and rotation, is
going to be susceptible toselecting for resistance as
(15:28):
well. So that's why we've workedto try and get combination
products that have at least twoherbicides in there, that work
on kochia for resistancemanagement, you know, trying to
work on programs where it'salternated with other things.
It's one thing where we'vetrying to be pushing to get at
the market quick, and we're withgetting some benefit from some
(15:52):
states, getting some speciallocal need labels, because you
don't want the registration todrag out until you just have
Dicamba and perox repair andsome things that don't work
anymore. And then you have torely on dichlorprop. So you want
to bring all your tools intogether so that you can rotate
it.
Dan Beran (16:09):
That waiting piece has been part of the dichlorprop
story. Sarah, as you you hear,I've heard that too. Oh, this
is, this is just old chemistry.Just dust it off and bring it
back in. But really it requireda whole new set of tolerance,
residue, rotational studies thatthat have been just like a new
AI almost takes a lot of time tobring those to market, and so
(16:31):
it's kind of like we're watchingthis Kochia resistance story.
It's like watching the house ison fire for smoke, and it's
like, well, we're waiting toturn the hose, on to at least
add another tool and anotherchemistry to the to the
management of Kochia being inand there's kind of two markets
that we focused on with this.Ai, one would be fallow, and the
(16:53):
second would be in small grains.One of the unique things about
dichlorprop-P is is a gooddegree of tolerance in wheat. So
it kind of fits that MCPAtolerance range is kind of how I
describe it. And then when youmix it with bramos, with this
proposed Maestro ext product forsmall grains, you end up having
(17:14):
two effective AIS in fallow.That's really where you better
sharpen your sharpen your tools,because it's, it's a really
challenging area, becauseobviously you don't have crop
tolerance. You tend to be indrier environments, or, I should
say, crop competition. And,yeah, there's a lot of failures
(17:35):
that are happening out there,and rescue applications with
paraquat. So that's a bit of themess that we're jumping into
with scorch EXT that followproducts. So there's certainly
to Bob's comment, a lot ofstewardship that goes into
maintaining a product'sviability long term because of
the investment that we'retalking about.
Bob Bruss (17:56):
There's a little benefit thing from the
combination products. And theydid this out K State Research
Station Hayes, is that they kindof rediscovered that synergism
that they'd seen, you know, inthe 60s and 70s, on the turf
products. So product like ScorchEXT has dichlorprop 2,4-D and
(18:16):
dicamba. So that's that samethree way of a propionic acetic
acid and dicamba and Dr. KumarVipan saw that same type of
synergism in controlling some ofthe resistant kochia that they
have out there in westernKansas.
Joe Ikley (18:33):
So the other thing I think might be a good time to
talk about this now is talkedabout some synergism, but then
maybe talk a little bit aboutantagonism or the lack thereof.
And we're, we're audio onlymedium, so you can't see Sarah
and I just grinning, because itis just so fascinating the one
extra methyl group. But we alsokind of figured out some of
these things with dichloropropand the group one herbicides for
(18:56):
this wheat concept. And spaceworth going into kind of that
research and story as well.
Bob Bruss (19:03):
Yeah, that was kind of work that was done there. And
Fargo with Kirk Howatt and NDSUand so we wanted to check
because 2,4-D is, you know, canbe antagonistic to the action of
some of the grass herbicides. Sowe thought, well, we'll check it
out and see how a grassherbicides will perform a
(19:24):
dichlorprop. And so I remembergoing visit his boss the first
time, you know, and Kirk willstill tell the story that he
kind of did, like a big reveal,you know, one of these HGTV, you
know, shows you know that hewouldn't get me go through the
2,4-D stuff and the grass thingby itself. And sure enough,
you're seeing the antagonism andthe 2,4-D grass herbicide plots.
(19:47):
And then a big reveal, it showsdichlorprop, and saw much less
antagonism. You know, there'sstill some there. And you know,
can say it's been on the rates,the combination products you
use, but yeah, you see. A lotless antagonism with
dichlorprop-P mixed with some ofthe herbicides they're used for
grass control out there. Soyeah, as you said, that one
(20:11):
extra methyl group can make abig difference. Another thing I
remember is visiting a plot PhilWester had there near Fort
Collins, because dichlorprop-pdoesn't work on sunflowers. And
as Joe knows, we even thoughtmaybe we might be able to use a
for as a, you know, for domesticsunflowers in there. So
dichlorprop-p really work onsome flowers. But yeah, work on
(20:34):
Kochia. And Phil had a plotthere. There's just a thick
mixture of kochia andsunflowers, and side by side,
you had 2,4-D versusdichlorprop, where 2,4-D was
braided, taking out all thesunflowers, but all the kochia
was there, and they just rightnext to it. You know, the
dichlorprop taken out of Kochia,and it was pretty filled with
(20:54):
sunflowers, just side by side.That one knuckle group made
their stand, pure stand ofsunflowers and pure stand of
Kochia.
Dan Beran (21:02):
Yeah, it's, it's an interesting piece, like, when
you're talking about maybe thedifferent events on too far de
tolerances, as well as crop andor as far as weed tolerance, you
know, whether you're looking atKochia or sunflower side by
side, it it kind of points tosomething that I hadn't given
much thought to, is how uniquethese group four herbicides are
(21:23):
from a binding site, from theauxin receptors as well as the
metabolic enzymes that are, youknow, able to detoxify the group
four herbicides, whether it bein a weed or a crop. And so it's
really uncovered a lot ofthoughts around this combination
approach. And so, yeah, this onecontinues to be a mystery, done
(21:46):
on furl, and part of it getsinto this whole idea of how we
continue to steward and protectand maintain the value of the of
the group for herbicides,because in this world of kochia,
we need to continue to be ableto control kochia with Dicamba
flux appear, you know,dichlorprop, all of those, and
(22:11):
maybe even get additive effectsof others that are maybe less
active, but things like, there'sjust other ais that potentially
could be group fours, that thatcan help overwhelm weed
resistance, or at least preventor not have such a severe
selection pressure that appearsto happen when you lean on one
AI in a geography too heavily.
Sarah Lancaster (22:33):
So that was that question that had had come
to my mind as we were talkinghere. Dan, so we're talking
about stewardship, but I'm goingto ask, kind of the inverse,
almost in a way. Do you guyshave visions, and some of this,
you maybe can't say, but do youguys have visions for additional
combinations going afterdifferent cropping systems,
(22:54):
aside from this kind of wheatintensive systems that we see in
the western plains,
Dan Beran (23:00):
yeah, I can, I can speak to that a little bit, and
maybe I jump past it a littlebit. So we kind of have the
Scorch EXT dicamba, 2,4-DDuplosan or dichlorprop mixture
for pre plant and fallow. Andthat's, that's probably where
that product concept will stay.Just because of those three AIS,
(23:21):
you're going to be pretty muchlimited to pre plant uses. And
then in in the small grains,barley included in there as
well. It's the bromoxenoldichlorprop remix there. Now,
when you start to think aboutcompounds in wheat that would
have additional activity from abroad leaf Kochia perspective,
(23:42):
there's some targets out therethat we're looking at. Some are
ais that are currently beingused, as well as some that
potentially could come into themarket, and, you know, the next
three to four years, and that'sbecause of the regulatory time
frame. It's like glacial ice,way to describe it. So, yeah,
we've got to be thinking aboutmixtures, you know, five years
(24:05):
down the road. And so thatincludes ais that are available
now, and ais that may becomeavailable down the road. And you
know, there's new AIS popping upout of some non traditional
sources. Certainly AI discoveryis happening beyond the, you
know, the typical five or sixcompanies that traditionally had
been generating the the theresearch efforts for for new
(24:28):
herbicides. So that's kind ofwhere we're at as far as other
cropping systems. It's, it'sunique because of the mixture
approach that we'll need to takewith, with dichlorprop, it it
starts to limit the number ofcrops that will potentially go
on. There's, you know, the thingthat's that we have to keep an
eye on too with, although we'renot developing the new herbicide
traits, clearly, there's goingto be more group four resistance
(24:54):
traits beyond the one that weall know of between them list
and things like that. So there'ssome additional. Traits. And,
you know, there's a potentialthat some of those may have, may
confer tolerance to dichlorprop.It just kind of depends, you
know, whether it's an event likethe endless corn wander or not.
So that would also be part ofit. The stewardship piece is the
(25:14):
biggest, the biggest thing thatwe probably wrestle with as
well. It's like, okay, these arethe first generation products,
but how do you maintain thevalue and, you know, obviously
the the viability of this longterm, you know, mixtures is a
big part of it, but that's,that's only step one of maybe
two or three that that we needto digest here.
Bob Bruss (25:36):
I was just gonna say and correct me, I'm wrong, but I
think Nufarm is moving forwardto add range and pasture. Am I
correct on that? Dan and eventhough kochia like the problem
and range and pasture as it is,and crops willing to come to
roadside spraying, a lot ofthose applicators don't like
(25:59):
using tension that doesn't havea range and pasture label in
case it drifts on the other sideof the fence right and so, and
of course, for a long roadsidecoaching, control is important,
and so I think in that range andpasture label will open up some
use of sign range and pasturebut also it's more roadside
spraying.
Dan Beran (26:18):
Yep, big no spot on that is that'll be in the next
round of regulatory submissions.So yeah, we have that Scorch EXT
has a roadside label, but thethe dichlorprop piece does not
have grazing tolerances. So lasttime I checked, I think they
like to mow those roadsides andhay 'em up in North and South
Dakota. Joe, so yeah, that'spart of the deal.
Joe Ikley (26:40):
Well, yeah, big ditches and we like to bail.
Dan Beran (26:45):
Can you grow can you grow corn in the right of ways?
Sarah Lancaster (26:51):
I see folks that try. they farm to the
gravel
Joe Ikley (26:56):
There's at least plenty volunteer sunflowers
lined those areas.
Sarah Lancaster (27:00):
So I guess the last question that we need to
maybe tackle kind of head onhere is this idea you've talked
about stewardship, but how doeshow do you see dichlorprop
fitting in efforts for herbicideor resistance management Dan?
Dan Beran (27:16):
yeah, so I think because we know there's group
four, the group 14 resistancethat obviously, Joe's been
highly tied to. We know we'regetting into more populations
that that are probably trendingtowards some metabolic
resistance. And that's, that's,that's a big challenge. You
know, it's, if it's sitespecific, the dip probably is
(27:40):
targeting a different, you know,auxin receptor, than than the
flux appear, di Canvas. So justjust having an additional AI
brings a bit more diversity,particularly in small grains,
you're adding a different AIthat's impacting a different
auxin receptor, so to speak,than than probably, flux appear.
So that helps. So it's adding abit more diversity in both of
(28:03):
those cropping systems. Sothat's, that's kind of step one.
What we're doing, from maybe abasic research standpoint, is
working with some of the folksat CSU Todd Gaines. I know you
guys know him well. So some ofthose folks were, were
interested in just getting tomore of the basic understanding
(28:24):
around group four herbicideresistance, and trying to
understand how dichlorpropcompared to some of the others.
And so once we get some of thatmore basic research, it kind of
gives us ideas, okay, what wouldbe the types of mixtures and
other approaches that that couldmaybe be used to manage
(28:45):
resistance, you know, Nufarms,you know, a relative, from a
from a people in the fieldstandpoint, we're quite a bit
smaller than many of our peersin this, in this marketplace,
and whether it comes to this,this development of this, AI,
we've leaned heavily on, on theuniversity weed specialists, and
so I would, I would say, we'reprobably better off working with
(29:09):
you folks on developingstewardship practices, because
the ability to communicate croprotation app, you know, we can
talk about application timingand, you know, herbicide
rotations and all that kind ofstuff, but we're just one voice.
So that's, that's part of it.So, you know, continue to work
with with the wheat scientistsacross the Kochia geography is
(29:29):
probably a big part of how, youknow, we, we work and, you know,
that's kind of how we we try tofigure out how our product best
fits. And you know, if we'redoing something idiotic, I'm
pretty sure that you guys wouldprobably call us out on it, so
hopefully we're not doinganything like that.
Sarah Lancaster (29:44):
So one not very applied question that I had
around resistance and resistancemanagement, and I think again,
this is another thing I thinkwe've kind of tiptoed around,
but it might be good just to askthe question. So dichloroprop
with the initial. Socialmetabolic steps in most plants
(30:04):
be a different enzyme than2,4-D, Dicamba. Some of the
other group forests that were,you're, we're used to thinking
about, because my, my contexthere is thinking about, you
know, I know it's, it's Palmer,not kochia, but we know that,
you know, 2,4-D can plants candevelop metabolic resistance to
2,4-D and so, you know, it'seasy to think about target side
(30:26):
stuff, but I was just wonderinghow much we, you guys, have
figured out that that you cantell us about the degradation
and how this might fit in withmetabolic resistant populations.
Dan Beran (30:36):
Yeah that would, that would certainly go to a lot of
that basic research that wasjust touching on at CSU, and so
they actually are looking atsome of the metabolic versus
target size, target siteresistance. What we do think is
that additional methyl group is,and this would be both on weeds
as well as some of the traits,is that that is less impacted by
(31:00):
some of the metabolic enzymesthat quickly chew apart 2,4-D,
and clearly, there's probablymore robust enzymes that would
be able to chew up dichlorpropas well. Because, again, we know
there's a, you know, a trade outthere that has Metabolic Enzymes
that do that and and I believethat's in a metabolic resistance
and endless corn and Bob call meout if I'm if I'm out of bounds
(31:23):
there, but I think that was kindof our hypothesis.
Bob Bruss (31:27):
Yeah, it's fine, because a lot of those just been
kind of what we've learned fromthe herbicide tolerant crops.
And, you know, we mentioned thatthe cotton soybeans that are
tolerance to 2,4-D are stillsusceptible to dichlorprop-P,
those enzymes that are producedwill break down the inactive
isomer of dichlorprop. So justthat little methyl group is not
(31:52):
just the methyl group, but theway it's configured and allows
the enzymes to get in there. Soyou have enzymes that can get in
and break that in both 2,4-D anddichlorprop and some enzymes
that can get in there and breakdown 2,4-D but are blocked by
the methyl group, and so allthose enzymes are out there.
What we don't know, it goes tothe mode of action piece. We
(32:13):
really can't explain why 2,4-Dwould work on some things, and
dichlorprop doesn't, becausethat probably goes to the target
site. Because, when you thinkabout it, you know, an enzyme
that can get in and break down,2,4-D right? You know,
dichlorprop, you know, has thatmethyl group. So, you know, why
are there? You know, likesunflowers, and we're talking
(32:36):
about marestail, it's not veryactive on that. Why, you know,
is dichlorprop not able to workon things that 2,4-D can work
on, because you would think thatit would be, you know, not to
incline the metabolism becauseof that extra methyl group is
2,4-D you know, outside thatether methyl group, everything's
the same. So there's somethingabout structure there that we
(32:59):
just don't know about that besome good talks for some
graduate students.
Sarah Lancaster (33:06):
Enzyme kinetics sounds like biochemistry. So
Joe, did you have any otherquestions that you wanted to put
in front of these guys?
Joe Ikley (33:17):
I think we've covered most of the story and the
questions I had along the way.
Sarah Lancaster (33:22):
So I guess then our last question before we turn
these two loose. Do you guys, Iguess, Dan, this is mostly a you
question. Do you have anywebsites or social media types
of resources that you would liketo point our listeners to to
learn more about the product orto ask other questions.
Dan Beran (33:42):
Yeah, yeah. I guess for for folks who are listening
Nufarm.com/uscrop is a good spotto keep up on labels, you know.
And as we've been talking aboutthis, we kind of haven't really
laid out the fact thatdichloprop is pending
registration for use on smallgrains and in fallow, with the
(34:04):
exception of a couple of 24 C'sKansas, here state being one of
those. But yeah, that's wherewe'll, you know, communicate
registration, which is pending.And obviously, knock on wood,
2025 looks to be a promisingyear to cross that finish line.
So yeah, just obviously we'reout there on social media, but
certainly plenty places to catchup with all things. Nufarm on
(34:26):
the interweb, as I like to callit.
Sarah Lancaster (34:31):
Alright, any last comments, Dan or Bob,
before we we wrap this up?
Dan Beran (34:37):
Bob, I think you should catch the listeners up on
maybe what you've been doing thepast few months and and how you
keep connected with those of usat Nufarm.
Bob Bruss (34:48):
transitioning from crop weed control to weed
control in St Augustine lawns sodown here in Florida, trying to
get my yard in shape. So that'skind of been my main focus, and
so it's great to dust off somelittle notes on dichlorprop. Get
on here with y'all today. So Ireally enjoyed it. Thanks for
(35:09):
including me in on the talk.
Joe Ikley (35:11):
Are you using dichlorprop on that St Augustine
grass lawn?
Bob Bruss (35:15):
No, not really. MCPA, MCPP, which are closely related,
you know, used, but thedichlorprop in 2,4-D, on St
Augustine aren't quite thatgreat.
Sarah Lancaster (35:32):
St Augustine, grass is a unique one. So, yeah,
having lived, having lived inFlorida, Bob, I feel like
everything is predatory inFlorida. So, so enjoy the
sunshine, but, but beware,beware the critters.
Bob Bruss (35:44):
Yeah, i got excited because, well even the plants. I
got excited because we had thisCarolina Jasmine blooming just
in the back. And even though wehad, I got excited because I was
gonna get beehives, and then Iread and find out that it's
toxic to bees, you know. Areeven the plants down here, as
(36:04):
well as the Gators, the snakesand all the other things you
gotta look out for.
Joe Ikley (36:10):
Florida Man.
Sarah Lancaster (36:15):
Well, Bob, thank you for taking time to
share with us what you know. Ithink it's awesome that we get a
chance to capture some of theexperience that kind of walks
out the door sometimes whenfolks move on to different
seasons of life. So thank youfor for taking the time to talk
with us today, and thanks Danfor for being willing to spend
some time with us as well.Thanks also to the listeners,
(36:37):
and we'll see you guys againnext time. (music)
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
(37:02):
find this podcast, otherpodcasts and a variety of other
pest management resources.
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