Announcer: The following presentation is part
of the Agronomy and Horticulture seminar series,
at the University of Nebraska, Lincoln.
Dr. Miller: So it's my pleasure today to introduce
our guest speaker, Dr. Rodrigo Werle.
So I will talk before we start presentation
just tell a couple of words about Rodrigo
and then we'll move on to his presentation.
So Dr. Werle joined the University of Wisconsin-Madison
in January, 2018 as an Assistant Professor
and Extension Cropping System of Weed Scientist
and then here's Research and Extension Program, UW Madison
Wisconsin Weeds focuses on agriculture based approaches
to address sustainable weed management in corn,
soybeans and small grain in Wisconsin and beyond.
So his program also focused on weed management strategies
that can help growers address herbicide resistant,
protect water quality,
enhance agro-ecosystem services
and decrease food security.
So Dr. Werle received his bachelor's degree in agronomy
at Sao Paulo State University in Brazil
and he completed his master's
and PhD in agronomy with specialization in weed science
from University of Nebraska-Lincoln,
under Dr. John Lindquist.
So Dr. Werle served almost two years
as an Assistant Professor in cropping system specialist
at University of Nebraska-Lincoln
at West Central Research and Extension Center
before joining UW-Madison.
I just need to add something here
while he was a graduate student
he received many academic honors and awards,
and he was after his time,
after he completed his PhD
he mentored and co-mentored numerous students.
Today he has a lot of kind of the domestic
and international peer reviewed publications.
And today Dr. Werle will be talking about
The Management of Herbicide-Resistant Weed
with the Focus on Challenges and Opportunities.
So Rodrigo, thank you again for joining us today.
And we look forward to listen about your work right now.
Dr. Werle: So first of all,
thank you for that introduction Miller.
Thank you for the invitation.
It's such an honor for me to be here today.
It feels like almost I'm going home.
We spent seven years in Nebraska
so this is a very special opportunity for me,
and I'm very humbled and honored to be here.
So today I'm gonna be talking about,
Management of Herbicide Resistant Weeds,
Challenges and Opportunities.
A lot of the challenges that our farmers are facing
have become research opportunities.
And I think through applied research and good extension
theses challenges are also becoming opportunities.
And I'm gonna make a case here today that
because of resistant weeds,
we're rethinking about our systems
and we're potentially enhancing sustainability
of our production systems.
All right.
So before I get started here,
I think I just wanna take a moment to acknowledge
the University of Nebraska-Lincoln.
I had amazing opportunities during my time at UNL.
For those of you who don't know me,
I first came to the United States in 2009
as an undergraduate student at that time.
I worked with Dr. Mark Bernards.
Dr. Bernards trusted in me.
He gave me the opportunity to come spend six months
as an intern, worked with him.
His graduate students worked closely with Lowell Sandell
who also became a tremendous mentor.
And at that time I was trying to define
where to go with my career.
I knew I wanted to go back to Brazil
graduate with a bachelor's degree in agronomy
get a master's degree and become a crop consultant.
I loved research.
I loved working with farmers
and then I came here to the States
and this is what Dr. Bernards and Lowell Sandell
were doing at that time,
working with Keith Glewen and many others through Extension.
And I just fell in love with Extension.
And that time during that internship,
had a position where I could do Extension work with growers
and continue to advance,
the science as the research became my goal.
Went back home to Brazil, graduated.
And at that time it was offered graduate school at UNL.
So I got both my master's and my PhD
at the University of Nebraska-Lincoln,
under Dr. John. Lindquist.
I'm very thankful for all of the opportunities I had.
I had the chance to do a lot of field research
which is something I'm truly passionate about
but I was exposed to molecular research.
I was also exposed to modeling.
I had the chance to be exposed to Extension
work with the amazing weeds team at UNL
and then teach the lab of Dr. Lindquist class,
work with Ahmed many others
and work with Dr. Predicted Tandberg
in the modeling aspect.
So it was just an amazing experience.
And for that, I'm always gonna be very thankful.
And it was a lot,
it was about six, seven years from this point this point.
We came my wife today wife Lee and I came
to get our degrees.
And we left with a family.
We made a lot of really good colleagues
a lot of friends that are still good friends up to this day.
So we're very thankful for everything that Lincoln
and UNL offered us and always with the support
with our family in Brazil.
So I graduated with my PhD exactly five years ago.
It was actually last week,
the five-year anniversary of my PhD graduation,
that picture that I had on the corner
with my PhD advisory committee.
And then the week after a Lee and I were starting
a new program at the West Central Research
and Extension Center in North Platte, okay?
So I had accepted at that point an Extension
Cropping Systems position.
We were there for two years.
We built an amazing team doing cropping systems research
in semi-arid environments.
And at that point between 17 and 18,
I had the opportunity to move
to the University of Wisconsin, Madison
to work more in the weed science role.
So here we are, two years later we transitioned back
starting a new lab at a new place.
19 we had our lab up and going.
2019 for those of you who recall it,
it was a very wet year,
a very challenging year for field research.
2020 comes with COVID.
We have to be socially distant
one person per car,
limited number of people.
So a lot has happened in this five years.
However, despite all the challenges we had,
I've learned so much
in this whole time, this past five years
it's been always about the people
the people that we've had the chance to work with,
the people in my lab,
the people in the lab and North Platte
the people now at the lab,
at our lab in Wisconsin
my colleagues at UNL,
my colleagues at UW Madison.
It's just been an amazing ride
despite all the challenges.
We are getting vaccinated.
Some look much better now in the 21 growing season.
And Soybean Board and the Crop Protection Industry.
As you're gonna see today,
we have a very applied program
where at Research Extension Program
we conduct applied research and our funding sources
kind of dictate some of the work that we do.
All right.
So why are weeds important?
Why is controlling weeds such an important thing?
So I have some pictures here,
this is pictures from around the world
of research specialists,
poor management of weeds,
good management of weeds.
And right there, you can get the message.
When left uncontrolled weeds can reduce crop yield
in quantity and quality.
We have a demanding,
an increasing demand for food out there.
So we need it minimize this loss
or this gap due to weed competition.
Not only that,
having weeds in your field make harvest more difficult
and some of the export markets
they don't wanna see contaminated grain anymore.
So having weed seeds in the grain is becoming a big no.
So this is a 30,000 foot view
of why weeds are such a problem.
And then when we think about weeds,
we directly start thinking about glyphosate resistance.
But one thing that I wanna point out here
is that weeds have been evolving for a very long time, okay?
And plants are constantly adapting.
And one thing that I,
one slide that I like to show is this slide here
with this paper from weedy rice, okay?
This is work,
some samples that were collected in Asia.
So about 1,000 years or more ago
when they were growing rice,
the farmers they were hand weeding, right?
And this is what the weedy version
of a barnyard grass looked like in their fields,
but because they were hand weeding
and separating that from the crop
they selected a biotype that looked just like the crop.
So when they did that,
at that point they could not separate the crop from the weed
through hand weeding.
So this is selection at its finest here.
I also wanna present this example here
from the late Dr. Sbatella
who was a postdoc with Dr. Bob Wilson
out in Panhandle, Nebraska.
Years ago, they published this very interesting work,
what they were doing here,
they had continuous corn
and they were using isoxaflutole as a herbicide
with soil residual activity.
And after using this herbicide years after year
that herbicide wasn't providing the same level of control.
And at first they thought they were dealing
with an isoxaflutole resistant biotype of kochia
but then Gustavo did some work.
And what they actually learned is that
through using that same herbicide over and over
they actually selected the biotype
that had a delayed emergence window.
So instead of coming early in the season
when that herbicide it's high concentration in the soil,
the bio-type was emerging later
escaping the residual control from that herbicide.
So my point here is that weeds are amazing
if we do the same thing over and over and over,
they're going to evolve.
So those who are not familiar with the terminology.
I'm gonna shift now into herbicide resistance.
And this is the definition
by the Weed Science Society of America.
Herbicide resistance is the inherited ability
of a plant to survive and reproduce
following exposure to a dose of herbicide,
normally lethal to the wild type.
In other words,
the herbicide used to work on that weed species
and it's no longer used because we have overused it.
Several efforts have started
to help growers overcome resistance.
These are some work that was done
by my predecessor here at UW-Madison, Vince Davis.
And at that time, 2014, working with the USB
our colleagues estimated the resistant weeds
were causing an additional $2 billion cost
on an annual basis to our farmers out there.
So this is a huge cost.
And once they have resistance,
we have to change practices.
And sometimes those practices are not the best practices
in regards to soil conservation.
So in order to address there,
the United Soybean Board has created a group,
the Take Action Group.
There's a lot of great resources that are made available
from academics to practitioners
to help them overcome.
There are some other groups that have also being created
to help growers overcome this challenge.
And another example here is
the Grow or Getting Rid of Weeds.
They have their own website
with a lot of great research based resources for farmers.
And I know Dr. John Lindquist is part of this group here.
So let's talk about resistance.
When we talk about resistance,
everybody thinks about glyphosate resistance, right?
So I just wanna show you this figure
by Dr. Ian Heap is available on his website,
and I wanna draw your attention to glyphosate.
Glyphosate is right here, okay?
So resistance has been happening for a long time.
Resistance is happening since we started using herbicides
in the 60s and 70s.
So you see the trend here for resistant cases
for the group five herbicides,
as we start having more and more resistance to group five
growers switched to group two herbicides,
and here you see the increase in group two.
So resistance is more than glyphosate.
The challenge now with glyphosate resistance
is that glyphosate was such an effective herbicide,
easy to use broad spectrum.
And when glyphosate stops working,
it becomes challenging to manage weeds post emergence,
as we're gonna discuss in a minute.
On top of that,
this is what the discovery pipeline looked like
from the mid 50s, okay?
All the way through the 80s here.
So during this 30 year period, every three years
we had two new sites of action being introduced
into the marketplace.
I'm not even talking about active ingredients
or herbicide products.
I'm talking about sites of action,
but since the mid 80s,
we have this flat line.
So we have resistance that continues to increase
the number of cases to all herbicides that we're using.
And we have a shortage of new herbicide sites of action.
And this represents one of the biggest challenges
in regards to chemical weed control.
This is a slide
from the Weed Science Society of America survey
that they have conducted.
They do the surveys every two and three years
and they report the most common
and the most troublesome weeds and several cropping systems.
And I'm using soybeans as my example here.
And one thing to notice from the last survey is that
the most common weeds are also considered
the most troublesome.
So we've done a very fine job,
selecting some very troublesome weeds
that are commonly found across the landscape
in our soybean production systems.
And I'm gonna use this slide here to put some faces
to the names.
Those are pictures that we took,
the top two pictures are pictures that we took this week.
So there's this horseweed,
again, one of the most common and most troublesome weeds.
This is what horseweeds looks like
out in the field right now.
Most of the horseweed germinates in the fall,
and it's taken off now early in the spring
in the absence of a crop.
Here's giant ragweed.
Giant ragweed is a major weed species here in Wisconsin.
It's a little different than the way it behaves in Nebraska.
Here in Wisconsin giant rag
has a very extended emergence window.
So it's actually one of the difficult weeds to control
in our cropping systems.
And this is a picture that Nick Arneson,
our Outreach Specialist in our program took
earlier this week.
It's just starting to emerge.
And these are pictures from last year, okay?
So we have the two weeds on the top,
horseweed and giant rag that are trouble early season.
And then the two on the bottom here,
waterhemp and Palmer amaranth,
they become more of a problem mid-season.
Waterhemp and Palmer amaranth
they're not emerging here in the upper Midwest yet.
We tend to see them start to emerge late may, early June
and then they continue to emerge
for as long as light is reaching the soil.
And here, I just wanna put a plug.
'Cause when I was in Nebraska,
when I got to Nebraska waterhemp
was becoming a major problem.
At that time Lowell was organizing the herbicide resistance
a few days.
So I learned a lot, okay?
In the 2011, 2012, 2013.
And then I get here to Wisconsin in 2018,
Waterhemp is exploding around the State.
So that exposure that I had in Nebraska really helped me
help us set our program here to teach growers
or help growers the best management practices
for management of waterhemp.
One thing that I wanna point out is that Palmer,
we don't have Palmer like folks in Nebraska have,
when I first got to Nebraska in 2009
I remember folks talking about Palmer from,
in Arkansas or Western part of the State of Nebraska
parts of Kansas.
I left Nebraska in 2007,
and I know it's all over the State
and looking at Ahmet's recent survey,
Palmer went from not being a major problem
to the number one weed in the State of Nebraska.
So I know what's coming.
We're trying to warn our producers up here in Wisconsin.
We have a strong dairy industry as most of you know
so cotton seed is a common feed in our dairy industry.
We have equipment coming in.
We have wildlife coming in.
So we're paying close attention to Palmer amaranth.
'Cause from what we've learned in Nebraska
from what we've learned in other States,
if you let it go it will take over
in a matter of a few years.
So this has been a major effort of our Extension.
This is some work that's been conducted
by our graduate student, Felipe Faleco.
We started this in 2018,
working with the Wisconsin Soybean Marketing Board
and what we did, we created what we call
this whisk weeds research coalition.
Where we work with our agronomists and producers.
We request them to send us samples,
seed samples in this case.
And with those seed samples,
they send the information of their fields.
What we do,
Felipe bring these plants in the greenhouse
and we screened them for resistance
to the various herbicides.
And we send those results back to our growers.
That way we have good knowledge of where resistance is at
where it's moving in the State
and what kind of programs we should be looking at.
So one thing that I wanna point out,
this is a map that Felipe just finalize.
He's gonna be defending his master's soon.
And as you can see here,
the golden dots are populations of waterhemp
that are resistant to glyphosate
and group two herbicides.
So that's widespread.
More than 90% of our populations
have this two types of resistance.
One thing that I'm gonna draw your attention to
is that we don't see resistance to atrazine
as we see in other parts of the country.
And one of the reasons for that is because
here in Wisconsin,
we have atrazine restrictions, okay?
So in certain areas,
the red spots here in this map
are areas we cannot use atrazine
because of the groundwater contamination concerns
and in the rest of the State the rate of atrazine
that can be used is limited depending on the soil type
and how often it's used.
So one thing that I attribute here,
this lower frequency of resistance in our populations
is because of regulations.
We typically don't like regulations
but this is the scenario here where the use of the herbicide
is somewhat regulated.
And we don't seem to see as much resistance
as other States are seeing.
Now that we were talking about resistance,
I wanna talk about the two major types of resistance.
And I'm not gonna go in depth,
but for years here the weed scientist,
the molecular weed scientist
we were focused,
our colleagues were focused
on target-site resistance, right?
So looking for mutations in a specific target-sites
that confer resistance.
There's the recent trend now that we are observing
is this a widespread occurrence now
of non-target-site resistance.
And it's very important that we understand
the difference between the two.
So target-site resistance here on the right
when you have this type of resistance
that resistance is specific to the herbicide
that you're using.
For instance, if you have ALS resistance
you have a mutation on the ALS enzyme there
the herbicide will stop working.
So in other words, you can switch the herbicide
use something else to control the weeds.
For non-target-site or metabolic resistance.
This is really puzzling and intriguing.
I think this is the new frontier in weed science
because by selecting for this type of resistance, okay?
The herbicide never gets to the site of action.
And when you have this type of resistance,
it might be that you're pre-selecting for resistance
to herbicides we're not even using yet.
So this is really scary.
And as I just said,
represents a major frontier on how we manage resistance.
When we started working with this types of resistance
our recommendation out on the field was
let's tank mix, okay?
Let's tank mix.
'Cause that will take care of target-site.
Well, as we start tank mixing,
we're seeing more non-target-site resistance.
So not only we need to tank mix,
but we also need to rotate when using herbicides,
our tank mixtures
to postpone this type of resistance.
And just an example here,
some work that just came out at the University of Arkansas,
excuse me here.
Kansas State University, I'm sorry.
Dr. Jugulam's lab,
where they found this population
in a long-term conservation study case, okay?
So they found in a study
that was being conducted by our colleagues at Kansas State,
a Palmer Amaranth,
that they could not control with multiple herbicides.
Dr. Jugulam's Lab looked into the mechanism of resistance
and they confirmed the population to be resistant
to six sites of action, okay?
And the causes for five of those resistance
to be associated to metabolism based.
Only glyphosate here in this case
was due to a target-site mutation.
Resistance to the other five sites of action
were due to metabolism based resistance.
So very concerning scenario.
So back to Nebraska,
here's some work that we did with waterhemp
Dr. Greg Kruger at that time,
Bruno Vieira and his program was doing a PhD
looking at glyphosate in ALS resistance around Nebraska,
just like Felipe is doing here in Wisconsin.
And then the time we got to Nebraska,
we asked Greg if we could use his populations
and evaluate the frequency of atrazine resistance.
And what we found is that
we screened more than 100 populations,
73 of those populations, 73%, Okay?
A very high number was confirmed
to be resistant to atrazine.
Our first hypothesis there
is that resistance was due to a target-site.
So we worked with Dr. Mithila Jugulam
down at Kansas State University in her lab.
They screened for the potential mutations
that are confirmed to cause target site resistance
to atrazine.
And we did not find a mutation
in any one of our populations.
They conducted some further work.
And then they learned that the populations from Nebraska,
they presented this metabolism type of resistance.
So what happens here,
you spray the herbicide,
this is a control population
those resistant populations,
they can quickly integrate the herbicide.
Again, back to my point,
by having this types of resistance here
growers might be pre-selecting for resistance to herbicides
that we're not even using yet.
And this is very concerning long-term.
A little bit of good news.
When we tested for this populations for atrazine
we also looked at their response to metribuzin
which is in the same herbicide family as atrazine
but it's used in soybeans instead of corn.
And we looked at sulfentrazone,
which is also a pre-emergent herbicide
using soybean and group 14.
And both herbicides were effective in all this population.
So again, understanding the mechanism of resistance
the types of resistance,
screening for other herbicides,
help in providing good information
for our growers to manage these weeds.
Now I wanna switch gears here
and as you're realizing I'm going through a lot really quick
just providing a high level information here.
So folks, if you have questions or concerns,
feel free to reach out,
and I can always share these slides later as well.
So I borrowed this slide from Dr. Pat Tranel
at the University of Illinois.
And I really liked this slide here
'cause it helps us a lot.
And I did a lot of work
with Dr. Lindquist at UNL in modeling.
So I really like to use some modeling hypothetical
scenarios to explain things, okay?
So this is year a grower starts using the herbicide,
year one, okay?
And this is what usually happens if we're not rotating,
if we're doing the same thing over and over.
About year eight, nine or 10,
we start seeing resistance to build, okay?
And this is how we perceive it.
This is how growers perceive it.
And this is usually when we try to take action.
And my point here is that at this point
it's already too late, okay?
This is what it's actually happening.
So this is the same figure.
The only thing that's happening here,
Dr. Tranel changed the y-scale here to a log base, okay?
So it still goes from one or zero to 100.
But what it says here is that
the moment you start using the herbicide
we're already putting selection pressure, okay?
In our system.
So if we're only taking action to preserve that herbicide,
those weeds from evolving resistance,
the herbicide is already too late.
The only way to keep this curve flat
or never reach one,
is to not let those weeds that were exposed go to seed.
That's the only way, okay?
So the zeros tolerance approach,
don't let your weeds go to seed.
Otherwise this is a scenario that we see.
It is important here to bring good
and sound integrated weed management practices.
And this is what our lab is heavily focusing on.
Back to our weed control trend.
We've seen this figure here in the bottom.
I indicated that since the 80s
we haven't had new chemistry
and then we have a flat line
in terms of new sites of action.
So this is the new trend that we see in industry
in the mid 90s Roundup Ready trait became available,
glyphosate tolerance,
it really changed the way we manage weeds
in corn, soybeans, and cotton.
Roundup, a very effective herbicide.
It used to be a very effective herbicide,
very flexible when you can spray
weed size spray condition.
So it became somewhat easy to control weeds in that system.
And that because we overused it
now we are where we are
and we are somewhat forced to change how we do things.
So this recent trend here these are biotech crops
or genetically engineered herbicide resistant crops in 17
The Xtend Crop hits the market
and that confers tolerance to Dicamba and glyphosate.
I'm gonna come back and talk about Dicamba.
Dicamba this past four years
has been a very controversial herbicide
and we've done a lot of work with that.
The next technology that became available in 18,
it used to be a Bayer Technology.
Now is the BSF is the LGT 27.
So glyphosate and glufosinate.
We have the Enlist trait coming into the marketplace
conferring tolerance to glyphosate,
2,4-D Choline and glufosinate.
And this past fall Xtendflex was approved.
So now the Xtend platform here also has
the glufosinate tolerance trait, okay?
So one thing that I wanna point out to you all here
is that yeah, we have new options.
We're bringing some corn herbicides or grass herbicides.
They came in 2,4-D into our soybean systems
but the one common theme here across platforms
doesn't matter if you're talking, Bear pateva
or if we're talking BSF here is glufosinate.
And I think glufosinate is gonna play a major role
for broadleaf post emergence control moving forward.
And just a note here that I found earlier today
that they estimate that the global glufosinate market
is probably gonna double
in the next five years.
Year from 2021 to 2026.
Just indicating how important this herbicide
will likely become for corn and soybean production systems.
So back to Dicamba,
this is actually a picture from Dr. Amit Jhala,
that I'm a chaired with a bunch of colleagues
around the United States.
This picture has been used a lot
and this pretty much reflects
of what happened in 2017, right?
Where you have a grower in the field,
then you have attack.
The worst sort of company,
you have the applicator
you have the farmer,
you have the extension educator
and then you have the State weed specialist,
all staring at each other,
trying to figure out what happened.
Is this particle drift, vapor drift,
or is it tank contamination?
And this is why this technology
has been really controversial.
One thing that I wanna point out is that
what's different with Dicamba
than other herbicides is a synthetic oxen.
And the soybeans just happens to be the best bio indicator
for the Dicamba drift.
And it just so happens that soybeans
is the second largest crop grown in this country.
So when things go wrong and you have a perfect bio indicator
across the landscape,
it will show, okay?
So what has happened with Dicamba this past four years
has really helped us reflect and maybe refine
the way we spray our crops.
Which that itself was a challenge to drift
but how we're perceiving this and how we move forward here.
I think we have a good opportunity to improve
the way we spray our pesticides.
So we've been part of this group
that worked closely with Bayer Crop Science
and multiple academics around the United States
trying to understand vapor drift and particle drift.
We've done a series of work,
we published a paper in weed technology.
If you're interested, we can share that with you.
We conducted a study here in Wisconsin
and the same study was conducted at Otter
for Otter sites in the US and also in Canada
including a site in Nebraska.
We've done a lot of research looking at what we call
this little tunnel volatility trials,
the impact of weather conditions
and the impact of tank mixes on volatility.
And now this work that we've done for this past three years
has been a lot of work.
It was all shared with the US EPA, okay?
All the raw data, all the publications, abstracts,
everything has been made available to the EPA,
not only from the program here in Wisconsin,
but all the weed science programs
that we're working with Dicamba around the country.
And that like what's really neat to see
is that this regulations
are this next five-year registration that just came out.
They really took into consideration some of the learnings
from our large scale drift trials
in our low tunnel volatility trials.
So some of the major changes that we're seeing
in the growing in 2021 moving forward,
the addition of what they call volatility reduction agent.
That is a somewhat of a pH buffer
that reduces the likelihood of the Dicamba salt
or the Dicamba acid dissociating from the soil.
So that minimize volatility.
We've looked at in our trials,
several colleagues have looked at it
and it really reduces the chances for volatility.
We have seen an increase in the buffer areas
and that is to protect endangered species.
We now have a cutoff, June 30th,
that's the federal cutoff.
Some States had some cutoff in the past years,
Wisconsin, for instance, we didn't.
But flowering was our cutoff there
but now we do have a cutoff
and I'm gonna go back to some work
that we did in Nebraska in 17
after the first year that growers use this technology.
And we asked them,
when were they seeing the cases of drift
when it was sprayed.
And usually when they,
folks that sprayed after the June 1st
was when they saw higher risks
of causing injury to neighboring crops,
soybean crops, okay?
So it's neat to see that what we learned
from our survey Nebraska
is actually what is being here disclosed in the EPA label.
And then the one thing that I wanna say here is that,
again, challenges potentially now
but opportunities in the future is this last statement.
The 2020 registration provides new flexibility
for growers and States for opportunities.
For example, there are opportunities for growers to reduce
the downwind spray buffer for soybeans
using hooded sprayers, okay?
So what we did last fall,
we started a series of work looking at hooded sprayers.
After this regulations came out.
This is a protocol that was developed by Dr. Greg Kruger,
who at the time was at that the West Central Research
and Extension Center in North Platte.
His team actually came to Wisconsin.
They did this work at Nebraska and they went to Missouri.
They moved this equipment around.
And what we did,
we looked at a combination of hooded sprayer
versus an open sprayer.
What most farmers are using out there.
We looked at a combination of nozzles
and the drift reduction agents.
And those are some preliminary results
that Dr. Max Olivera just finalized analyzing.
And then for the graduate students in the call here
and folks that are interested in data analysis
in weed science,
I just wanna put a plug for the work that Max is doing.
Max is a research analyst in our program
and he's got his own website,
Open Weed Science,
and a lot of great codes and how to analyze data
and generate neat figures, just like this one.
So make sure you check the work that Max is doing.
But back to this study what we learned is that
a nozzle with a medium droplet size
in an open-hooded sprayer
compared to a horse nozzle
using this hooded sprayer here
there was 100 fold difference in drift exposure.
So it is amazing what using this technology here can do.
Sometimes the applicator won't like it
because it adds a lot of weight to their booms.
It's not as practical,
but we're talking about a significant reduction
in particle drift.
So I foresee this becoming something we see a lot more
in the landscape.
And because of these trials that we have done
this is where our program is going next.
Ryan DeWerf in our program just came back from Minnesota
this past week.
And he picked up our enroll hooded sprayer.
And our intention here is to look at drift
but also start looking at alternative options
that could be used in season
where you would not potentially expose the crop
and focus on the weed control.
This is nothing new.
It has been used,
is commonly used down in Arkansas for instance,
where they do or down South where they have cotton
in lay by applications.
But it's something that we're not using a whole lot
in soybeans.
So how about we use some smart spray systems
where we do this targeted applications
of effective chemistry
and instead of spraying the entire crop.
So this is something we're gonna start working this year.
Another thing that I wanna mention back to glufosinate
I said, I think glufosinate is gonna play a major role
in Felipe's screenings in the greenhouse,
glufosinate is by far the most effective herbicide
for waterhemp control.
However, when we bring it out in the field,
this is a scenario we oftentimes sees
where the grower sprays it,
and then you go there 14, 15 days later,
you see the regrow.
With the case was a contact herbicide.
It's really sensitive to spray conditions.
If you don't hit the weeds more good coverage,
good sunlight, you'll see regrowth.
And by the time we started
some of this research with glufosinate,
I know Dr. Hudson Takano was here probably last fall
and he gave a talk where he talked about
this tank mixes with PPO.
So here is when you spray under ideal condition glufosinate
And I think mix of glufosinate and the PPO,
great controlled in both scenarios
but when you don't have ideal conditions
for glufosinate performance there,
what Hudson observed in his study is that glufosinate alone
was not effective.
Just like I was talking in the field,
but when he mixed with the PPO herbicide,
the control was truly enhanced, okay?
And that really got our attention
'cause we were observing that in the field
in some of the trials we were conducting,
we watched this talk here
and really helped us design some studies
to evaluate this concept.
We've done this workout with Dr. Mark Bernards
at Western Illinois University
where we looked at glufosinate by itself.
We compared glufosinate with PPO herbicides
which are the green arrows here.
And we looked at mixing these two herbicides.
And what we're learning here is that
when we mix a PPO herbicide with glufosinate
we're truly enhancing the control of that glufosinate.
So one, we wanna make sure growers get good weed control
but two, resistance management is a concern.
And when we started this work
this news wasn't out there yet.
And it just came out a couple months ago, okay?
Which again, reinforces the need
for looking at this potential mixtures to enhance control.
So colleagues at the University of Arkansas,
Dr. Tom Barber, Tommy Butts,
a former grad of the department
and Jason Norsworthy,
they just confirmed the first case
of glufosinate resistance and Palmer amaranth, okay?
And that is very concerning because,
as I was just saying,
I mean, this is kind of our silver bullet
if you will, right now moving forward
in terms of post emergence weed control.
And we're starting to see resistance already.
So what does that tell you?
That we gotta change how we operate
back to the drawing board?
One of the recommendations that we have for growers
is to start with an effective pre-emergence program.
Relying on post emergence weed control
is not a sustainable strategy.
And I have some plots here on the left with no pre,
yes pre,
and then you can stare at a plot like this
and talk with your growers for multiple hours,
define resistance,
define weed competition here
and many benefits that this chemistries bring.
When we started in Wisconsin,
we created this series of what we call
the WISC weeds management challenge.
We take chemistry from all portfolios.
We put plots out there,
we invite our growers to come collect their data.
Then in the following fall, we make the data available.
Hopefully helping them refine their adoption,
their practices and also the agronomist
with their recommendations.
One thing that I wanna point out about this particular study
is a competitor besides,
and then we have herbicides with a single mode of action
which has the herbicides in blue.
We have in green, the commercial pre-mixes
they have two sites of action.
And then we have what's becoming standard
now in the industry is to release this pre-mixes
with three different sites of action.
And as you can see here
just by quickly looking at this figures here,
the green and the red bars are often above the 90%
when we're collecting the data,
three, four weeks afterwards.
And this is where we wanna be.
What we did with this data,
we went beyond case.
So we provided the recommendations for growers
but then Alex Rosa, a former post-doc with us.
He was also a PhD student with me during my time
in Nebraska there,
he took all this data set and he took a step back.
And then let's look,
I mean, we're recommending that farmers use
a pre-emerge herbicide with multiple modes of action,
but do we need two modes of action
or do we need three modes of action?
And at first we were following the strand here
and looking at this data and say,
well, the more the merrier, right?
So let's just go with three sites of action.
But then we took a step back
and we started looking at some of the three-way mixes
and what they do because of crop injury, costs,
and because sometimes they're effective at lower rates.
What happens if you look at the constitution of the product
those herbicides are being sprayed at a lower rate
which brings back the resistance concern
when we're using lower rates.
And then Alex ran this analysis
with four site years of data
and all we learn is that,
a herbicide that contains two sites of action,
a pre herbicide,
is performing quite similarly as the herbicides
that contained three sites of action.
And that's visual control and density.
So the current recommendation for growers
that they select a herbicide
that has two sites of action, full rates
and perhaps save that third one
for an in season layered residual approach.
So here's a trend.
It's nice to see this strand because again
a recommendations that farmers use diversified pre programs.
This is what it was.
You see this dip here with the Roundup era,
and now we're going back up.
A lot of diversity in herbicide programs are being used.
And this is really nice to see out in the landscape.
So in my presentation here so far,
I've focused heavily on chemistry.
It talked a lot about herbicides,
fighting resistance,
using effective programs,
post emergence, pre-emergence,
but fighting resistance with herbicides only
won't last, Okay?
And big part of what we do here in our program
is to look at integrated weed control strategies.
So thinking outside of the jug,
bringing other strategies into our weed control portfolio.
When I was an undergrad at San Pablo State
my weed science professor told me
that the most effective weed control strategy
is cultural weed control, okay?
He first ask what we students thought
was the best weed control option
and everybody was throwing herbicide names.
Hey, and he says,
"You guys are all around the best.
"The most sustainable way to go
"is through cultural weed control."
At the time I was a little too young
and I didn't quite get him.
I was always thinking,
Oh, we have great herbicides,
why are we talking about cultural weed control?
And I think this pictures here
they helped me convey that message a little bit.
So these are some of Dr. Roberto Blanco's plots,
actually out in North Platte,
they were doing some on-farm work.
So this is on farm scenario not in our research plots.
On the left here,
it was a winter fallow
and on the right is where we have
a good stand of cereal rye.
And you walk at that cereal rye April
you do not see a single winter annual weed, okay?
Back to the weed control.
If you have a crop that's growing in,
actively growing you're suppressing the weeds.
Here's weed plots out around the grant area,
Western Nebraska,
the farmer ran out of seed on the drill.
And you can see the aerial footage here
Arsenijevic he shared his images with me.
You see the weeds where there is no crop, okay?
Where there's light reaching the ground.
The weeds are very, very opportunistic.
They are in the soil seed bank.
So dark or crop canopy
is one of the most sustainable and best ways
to prevent weeds.
You look at our current systems.
Most of our farmers are either in continuous corn
or corn, soybeans.
And then you look at this crop development.
We have this very, what I call vulnerable period, right?
The soil is somewhat vulnerable
because there's no active crop growing.
And we are giving those weeds a lot of opportunities.
We're planting the crop,
a crop that's planted at about the same time
and harvested at about the same time,
year after year.
So we're doing the same thing over and over
even though we're switching between corn and soybeans
the periods are quite similar.
So we give this weeds an opportunity
to establish and thrive.
So here's when we bring good agronomics,
a good IWM.
And first part that I wanna focus on,
is how do we make our crop
a little more competitive early on?
And this is what Nikola Arsenijevic in our program
is looking at as part of his program,
his Ms. Program at UWA Madison with our group,
are also working with Dr. Sean Collony,
the soybean agronomist.
So what Nikolas is doing,
he is looking at management practices.
How can we change some of those management practices
to enhance a canopy closure?
And this pictures here they were actually taken
on the same day, July 2nd, okay?
This is 30 inch soybeans,
what most of our producers are doing.
The beans were planted late may.
So we harvested corn the previous year in October.
And we're talking July here, July 2nd,
and look how much vulnerability we have in our system.
Here's a simple adjustment,
the same seeding rate,
same planting time.
The difference is the row spacing.
So 30 inch row spacing,
50 inch row spacing.
Bust by going narrow there,
you can enhance how fast you close canopy closure.
And then you can,
if you were a weed here,
I like to ask my growers when I'm giving extension talks
where would you rather be?
Here or here, right?
So let's think about that.
And this is exactly what Nikola tried to do
for his master's degree.
So every week he went out there
and he transplanted literal waterhemp seedlings
and he watched them grow.
And when they flowered, he chopped them, okay?
So the first case here is no crop competition.
You have this Christmas trees by the time they're flowering.
Here's what happened in 30 inch soybeans.
This is what happens,
here's 15 inch soybeans,
30 inch soybeans
and 30 inch corn.
As you can see here the 15 inch soybeans
are really competitive with waterhemp.
And that's what we wanna do.
We wanna slow this waterhemp growth
down as much as possible.
Here's some of the data that he just finished analyzing,
for his thesis chapter.
So I'm gonna go through this quick.
Fallow, you see reduction in height
the later the weeds emerge.
And that makes sense.
'Cause they respond to day length
when they start flowering, okay?
What's really neat here is that early on 15 inch soybeans
are as competitive as corn,
but then later on 15 inch soybeans and 30 inch soybeans
when they're fully closed canopy,
in our case here that's happening mid to late July.
Any waterhemp seedling that's emerging at that point
won't make it,
but in corn they can still make it.
Even though there's a drastic reduction,
this is what Nikola found.
Even though those seedlings are transplanted late.
What does that tell you?
So well after the corn is tasseling,
our growers are typically not scouting for waterhemp
but I can guarantee you if they're not looking for it,
these plants are putting seeds
and they're putting enough seeds to be a problem
for the next growing season.
And this is something we gotta be mindful of
in our rotations.
Nikola also did some work
looking at how agronomic practices can influence the time
to 90% canopy closure.
So we use a canopy app that estimates ground coverage.
And what he's doing here is trying to look at, okay,
when will 90% canopy closure occur?
We looked at different planting times, row spacings.
We looked at the impact that pre herbicides may have
on holding,
some of these pre herbicides can cause early season injury.
So we wanna just see whether they had an impact.
Tillage, and what Nikola learned on the left side first,
the time to 90% closure,
which is what's depicted in this figure here
the most important factors were,
planting time and row spacing.
So if you can plant early and if you can go narrow
you can close canopy as fast as possible.
And sometimes the differences were 11, 12 days, Okay?
11, 12 days may not sound a whole lot
before pigweed control,
11, 12 days can make a huge difference.
The catch here though is on the right side,
is that as the agronomist will say,
and Sean Collony would agree,
and that's actually his recommendation.
The earlier you can plant the higher the yield.
And we saw that on Nikola study.
But there's row spacing going narrow there
did not lead to an increased yield in this study.
So there's mixed results out there.
Sometimes when you go narrow space
and you see enhanced weed control.
But my point is,
if you have the ability to plant narrow
you might not see enhanced yield
but you will certainly see enhanced weed control
in those systems.
So back now to some of the work we were doing
in North Platte
back to the concept of integrated weed management strategy.
So this is a farm are around the macook area.
We did a lot of work with him.
This is a severe Palmer amaranth infestation.
He had a pre down,
he had two post pastors.
This farmer was really struggling with Palmer amaranth.
And what he decided to do that fall
after he harvested soybean was to plant a small grain crop.
And this is what that crop looks like the year after, right?
So we visited the field in May.
There is complete canopy closure
at the time the Palmer is starting to emerge.
Palmer amaranth was not a problem in that subsequent season
even though we had this level of infestation the year prior.
So by changing your rotation,
bringing in a crop that has different develop,
that will develop differently throughout the year
can really trick the weeds.
And I understand that bringing a small grain into the system
may not be an option to all farmers.
Some farmers are potentially locked
into this corn, soybean rotation.
And one thing that we can do is cover crops, right?
Simulate somewhat the scenario of this winter wheat
that I just described.
But then you terminate that cover crop at the time
when you think you have harvested the benefits.
And this is something we're working heavily on.
These are pictures that I took earlier this week,
fields year and they're in Allegheny County,
Southern part of Wisconsin.
These fields are about five miles apart,
same type of style of operation.
The one on the left here we have, I'm sorry.
We have a cover crop that was seeded after corn harvest.
And on the right here, we just have fallow.
And look at all the weeds that are growing.
Look at how the soil there's exposed.
So I think at this point here
we can agree as soil scientists,
agronomists, and I like to refer and weed scientists.
I like to refer to this paper that was published
by colleagues at UNL that was led by,
Dr.Humberto Blanco here,
when we talk about sustainability of our systems,
soil organic carbon, being able to enhance our soil
by bringing cover crops and no till into the system.
And I think as weed scientists, we would agree
'cause by doing so we could also gain weed suppression.
So I think there's a lot of traction here now
with scientists from different areas within agronomy
supporting such a strategy.
And as a result of that,
we've seen a 50% increase in the cover crop area
across the United States from 2012 to 2017.
So growers are really interested.
There are some concerns.
Moisture is always a concern in dryer parts
but I think there's a lot of interest in this
and we have a good movement going.
One of the challenges for us here in Wisconsin
when it comes down to cover crops
is that we're seeding in October,
in November it's getting really cold.
And then we have shorter Springs
if you compare to States South of us.
So this is some of the work that Kolby Grint
a grad student is doing.
We're tracking the amount of biomass produced
at the time we would be planting.
And this is a kind of a standard plant,
the time for us,
the second, third week of May.
And at that time, usually we're at about 300 to 500 pounds
of dry biomass of the cereal rye.
That's not a lot if you're thinking about weed suppression.
What we wanna see is more than 2,000, 3,000 pounds.
And to get to that point,
we need to wait to terminate the cover crop after late May
or early June, okay?
There's two options here,
to growers delay planting,
which they don't like
'cause often they're giving up on yield.
Or what they can do is just go ahead and plant green
and then terminate that cover crop afterwards.
And that's what we're doing a lot of work on.
Why is that beneficial?
I'm starting to run short on time here as usual.
So I'm gonna kind of start wrapping things up
but what we're learning from Kolby trial
where he compares conventional tillage,
no till, early cover crop termination,
cover crop termination,
that planting a forage harvest situation
where we're in the dairy state.
Sometimes we forage harvest that or we grace
or terminating 15 days after,
what we see is that the more biomass we have in our systems
the better weed suppression we obtain.
When we bring a pre-emergent herbicide into the system
we don't see that trend
because the pre's are very effective.
But if we can combine biomass with the pre herbicide
this is when we think we can get
some truly integrated weed control.
And the same trend is through for his soybean studies.
The catch with corn though,
is that corn is more sensitive to this late termination,
if you would.
So two years of studies at Arlington,
we observed reduced yield of corn
when we terminated the cover crop late.
Whereas the other study that was done in Lancaster
we did not see an impact of the late termination
as compared to a no till only.
At that trial of the tillage scenario actually yielded more.
So we're still fine tuning,
trying to understand a little more
how to properly manage these cover crops.
So we minimize the impact on corn.
But the soybeans is where I see promising results,
really interesting results here,
no differences across this management strategies.
Two years of results in each location.
So foresight years here,
no impact of that late termination
as compared to no-till or tillage systems,
so really promising.
Now that we know that
we're starting to fine tune our recommendations
starting to do some additional work
looking at roller crimper,
we get a lot of questions from growers
about roller crimpers.
We did it last year for the first time.
The challenge that we had with a roller crimper is that
a lot of the rye pop back up, okay?
And when he did that
they were still able to set seeds.
And Nick visited one of our fields earlier this week
and this is the situation there
because we didn't get a good cue of this rye,
the rye went to seed.
And this is something we don't want with our cover crops
because in this case here
we're introducing a potential weed into our system.
But while we roll cramped,
and where we put a glyphosate on top of it, okay?
So double effort there to control the rye.
This is what Nick found earlier this week
in some of the plots that we establish.
So there's really nice residue of cover crop
from the previous growing season protecting the soil.
In our trials, we do a system like this.
You combined with the two,
with an effective herbicide of two sites of action.
You see the best levels of control,
attending the WSSC,
Weed Science Society of America meetings a month or so ago.
Those results are also being reported
at several other universities around the country.
So very promising strategy.
We're bringing technology into our systems around the world.
Our program has installed
a pulse-width modulated spray systems behind our planter.
So in this case here we're planting green
and we're spraying as we plant.
Saving a trip.
Looking at ways to minimize herbicide drift.
So a lot of cool things that we're playing with.
So to wrap things up,
assuming you've done everything that you could have.
And if growers still have pigweed plants going to seed,
our recommendation is don't let them go to seed.
Remember that if you let them go to seed,
resistance continues to increase.
Through our coalition we work with stakeholders.
We ask them to grab samples from their cornbine
and more than 90% of those samples,
this is some work that was done by Nick
and Dan in the MPM program.
More than 90% of those samples had weed seed.
So we need to pull those weeds
and we need to clean our cornbine as often as possible.
So we don't spread those weeds from fields to fields.
So with that, some take home messages here,
a lot of challenges that our growers have
and will have in the years to come.
A lot of opportunities in the research
but also great opportunities for our growers
to fine tune their systems
through effective herbicide selection,
rotating those mixtures,
not using the same thing time after time,
using some of the technology that we have available now
to keep our herbicides on target.
Our industry's under scrutiny from the general public.
We don't wanna be on the cover page
were folks are talking about the impact
that agriculture is having the drift and all those issues.
We don't want that to happen to our industry.
And we need to use integrated weed management programs.
This is no longer just something nice
to think about, to reflect.
This is a true necessity here,
given the shortage and the oversimplification,
the shortage of chemistry and the oversimplification
of our cropping systems.
So with that, I know I said a lot.
I went through a lot.
Thank you for sticking with me.
I hope that the information presented was helpful.
Miller, back to you.
Thank you all very much.
Miller: Thanks a lot for your presentation, Rodrigo.
So it looks like vapor reduce engagements be used
instead of AMS for corn
they can buy products with the same efficacy.
-: Yeah.
We've been getting that question a lot.
I don't know if is the efficacy question
in regards to weed control,
is that what you're referring to?
'Cause I got the same question from agronomists
whether they should consider using a VRA
to reduce volatility in farm products.
If they add the VRA will certainly help reduce volatility.
The efficacy aspect is yet to be evaluated.
But talking with colleagues,
apparently the weed control efficacy is not influenced
by replacing EMS with a VRA from a Dicamba perspective.
Miller: So the next question,
do you think there is a better small grains than rye.
Rye is usually very cheap seed
and not the very good variety.
-: Yeah, that basically.
That's a great question.
And I think you would probably have way better answers
than I do.
The reason why cereal rye has become really popular
is that you can plant it really late.
Sometimes they're planted in November.
It won't grow in the fall at all or in the winter
but it takes off really quick, early spring.
So it produces a lot of good biomass
and is relatively easy to kill with glyphosate
as compared to some alternative options,
bin run wheat, trilly kaylee.
So I know there are alternative options.
I'll be really curious to hear your thoughts.
Cereal rye is one cover crop species that really took off
and it's shown really promising results.
We've also compared bin run wheat in our trials,
we see somewhat equivalent results.
It's just that additional faster growth
that we see with the rye
that makes it a highly desirable species as a cover crop.
-: We have Dr. Jhala who wants to ask a question, so.
Dr. Jhala: Hey Rodrigo, very good presentation.
Yeah, I like the way you are using
all the wonderful photographs
and graphs and giving credit to all your graduate students,
which is very nice really.
So my question is,
like waterhemp and Palmer amaranth
and even common lambsquarters,
now we are seeing they have started emerging late
in the season.
Like maybe before 10 years,
you will not find waterhemp or Palmer
that would emerge in August and September.
But now we are seeing that late emergence
of those small seeded broadleaf weed species
and our best recommendation for now
to control herbicide resistant weed
is by using pre-emergence herbicides
applied at planting in corn and soybean both, right?
So, I had struggled to understand that is the best approach.
So I was thinking whether
we are controlling early emerging weed species
during that plus 20 to 35 days
or we are just pushing those weed species to emerge late?
So does pre-emergence herbicide has any role
to evolve them late emergence
or we are controlling them
and we are getting happy
or it is just weeds they're evolving
the way they are growing late in the season?
-: Yeah.
And thank you for the great questions there Amit.
And thanks for the comment you made
in regards to acknowledging the students and staff.
I mean, they are the ones that deserve all the credit
for the slides that I presented here today,
very thankful for all the great work that they do.
Without them I wouldn't be here giving this talk today.
So that's the first common.
And then second, your question is fantastic.
After reading late Gustavo's paper there,
it really got me thinking,
it's something we're noticing too.
It seems like you're,
maybe we're still getting a lot of great control
out of pre-emerge herbicides
but we are also observing weeds coming in later
in the growing season.
So that mechanism that Gustavo discussed in their paper
whereby using pre herbicides for multiple years,
you're selecting for later emerging weeds
or weeds that have higher levels of dermis early on.
That is something we're really interested
in investigating actually.
So if you have interest in some of that,
let's touch base.
I don't have a straightforward answer to you
but it's something that I've been thinking a lot
about as well.
Dr. Jhala: Okay, thank you.
-: Absolutely.
And we observed similar trend I mean.
-: So looking at the all benefits that you mentioned
about related with the cover crops
and the employment of the diversity
kind of what they're offering.
So considering that this kind of
doesn't directly give the economic input back to farm
how is this kind of how growers
are accepting those kinds of things?
Like down the road,
you're kind of having a lot of the benefits
are directly from kind of the planting cover crops.
Like sometimes they won't kind of be,
I think at least some of them they're hesitant
about the employment on farm.
-: Yeah.
That's a great question, Miller.
There are parts of the country
that are concerned about moisture,
it's more labor, right?
'Cause you're harvesting,
it's a busy time of the year.
We're talking about drilling something in
and we have a lot of technology right available.
And I think one thing that I talk to the growers is,
if were thinking about is start small,
don't go full throttle.
'Cause when they go full throttle
and this is when you're rushing
and then they don't get a good seed soil contact.
I mean they run across problems.
So target some areas,
be site-specific.
We have so much technology out there.
And then maybe let's use some of the simpler technologies
if you would,
such as drilling a cereal rye with an older drill
in the areas that really needed the field margins.
Nick and I talk a lot about this
during our Extension meetings.
When we drive around the State,
we always see a lot of weeds
coming from the field margins, right?
Those are the areas that are really difficult
to control weeds.
So why not be target specific,
only plant around those areas.
and then start small and see how that works for you, okay?
So it doesn't have to be done in every single acre.
You got to start simple,
you got to start small
you got to learn what works for you,
if that works for your system or not,
and then go from there.
And I think it's great.
We do this in small plots.
We're now starting to take this on farm,
just similar to what Nebraska does there with Extension.
We have the nutrient pest management program.
We've done two, three years, a small plot work.
We're going large strips now,
working with key growers around the State
and seeing whether some of those recommendations will work
and we let them implement
and we come and help collect data
and then make the assessment.
So I'm really excited about that aspect.
And I think here is a tremendous opportunity
for Extension work.
Great quality Extension work
-: Question, Dr. Baenzinger here is asking,
"In plant pathology
"even pyramiding existing genes are expected to fail
"because the single genes will break.
"With no new herbicide the mode of action
"will herbicide nature extend their use but fail also?"
-: That is a fantastic question, Dr. Baenzinger.
That's kind of the trend that we observe,
even using this tank mixtures now
because metabolism Bayers resistance we're starting to see
some of that happening.
It takes longer,
but it is starting to happen already.
And that's why the recommendation
to mix and also rotate those mixtures
and integrate them with something else.
It is a true necessity.
And if you stop and think about this,
I was supposed to,
our group here at EW Madison was supposed to be looking at
a site of action that's coming down the pipeline,
that's probably seven, eight years away
from growers to see it.
We couldn't do it this year because the industry
and lawyers couldn't come up to an agreement.
But my point is we don't have anything coming
down to the pipeline that's immediate.
And this new AI or new site of action
it's another under pre-emerge herbicide,
which is great,
but it's not that silver bullet solution
for post-emergence weed control.
So post emergence weed control
and its annual cropping systems, especially soybean.
I think it will be very challenging.
So a lot of good opportunities for good integrated work.
-: Well, I think that's everything for today.
Thanks again, Rodrigo for your presentation.
I really enjoy listening kind of the different aspects
and different kinds of the things.
Thank you everyone for joining us today
to listen the presentation
and we'll look forward to see you next week.
Dr. Werle: Thank you, Miller.
Thank you everybody.