Hello folks, this is Rodrigo Werle,. I'm the new Extension Cropping Systems Weed Scientists with UW-Madison and
UW-Extension and my objective here today is to provide you with a brief
summary on the dispersal and the spread of herbicide resistant weeds across the state of Wisconsin.
Earlier this year, in January,
we conducted a survey
during the agronomy update meetings and, as part of my survey, I asked participants what were the most concerning
weeds that they were dealing with in their operations and the number one was Waterhemp
followed by Giant ragweed. So those are the two most concerning weeds we're dealing with in the state of Wisconsin according to survey participants.
In our survey, we also, asked participants whether they were dealing with
glyphosate-resistant weeds in the acres that they farm
or that they manage and I want to acknowledge my postdoc Max Oliveira for
compiling all the data and generating these figures here. So what we've, we have here in this figure
we divided
the answers in different categories so you have the different professionals out there if you
would. So you have responses from agronomist, industry reps, co-ops, and also the farmers, okay?
So according to agronomist co-ops and industry reps, there's a lot of concern
and a lot of those folks are dealing with, glyphosate resistant waterhemp out there and
also, glyphosate- resistant ragweed to some extent. The one thing that
was interesting about these results here if you
Would if you look at the farmers data their majority of the farmers believe they are not dealing with
Glyphosate resistant weeds so just an air is year one they, may not have the presence of glyphosate resistant weeds in their operations or?
They might be they might have it but may not be aware of the problem so i think it's important that
We get the word out there and then, we make sure farmers are, aware that we do have
Playfully resistant weeds in the state of wisconsin, and that might help them you know
Proper identify the herbicide program is they're, going to be using in the 2018 growing season and also moving forward
So as i mentioned waterhemp
Is the most concerning weed in the state as of now i just
Want to provide you an update in the occurrence of glyphosate resistance across the various counties that
We have so in this figure is here that i'm going to be showing to you the red counties or the counties
Where glyphosate resistant waterhemp has been confirmed so as of 2015, we had 12
Miss constant counties with confirmed glyphosate resistant waterhemp
populations
in
2016, we had 22 counties with, glyphosate resistant waterhemp
Populations and we also found two counties with ppo resistant populations and then as of?
2017 25 counties confirmed with
Glyphosate resistant populations and also for counties confirmed with ppo resistant
Populations and those coyotes were iowa monroe pierce and st.
Croix and this is a typical trend that we you know, we see and we've seen in other states?
you get glyphosate resistance
It starts spreading around as
We were seeing here in wisconsin once farmers start getting
Glyphosate resistant weeds the herbicide option for management for post emergence management of this which become your pp os or your group 14?
okay
And as we start relying on?
Group, 14 for control of glyphosate resistant weeds was then start selecting for ppo resistant weeds and this is exactly
What, we are saying what we're seeing here in the state
Another weed that's a concerning one for our farmers is giant ragweed
And this is some work done by, my colleague, dave dr. Dave stoltenberg here
And he's found the population has confirmed the population, that's als resistant in columbia county
And we also have a confirmed case of glyphosate resistance in giant ragweed in rock county and
Munication with farmers agronomists and industry reps you know. They'd be telling us that there are more counties where resistant
giant ragweed
populations are present
Last weed i'm going to talk, about here today is palmer amaranth
palmer amaranth is a, new weed to the state of wisconsin if you, would it was first detected in
2011 and rock county and since then it's been identified in six different counties
across the state and in three counties these populations i've actually been confirmed to be
resistant to herbicides
So you have dane county and you have sauk county
where palmer amaranth populations were confirmed to be resistant to glyphosate and
then
in iowa, county, we have a population, that, was confirmed to be resistant resistant to h ppd in als
Inhibitors so, we have palmer amaranth coming in to the state via
Contaminated seed or you know, moving with equipment those seeds are coming to wisconsin
Some of these populations you know are already resistant to herbicides i just want to put a plug
Here i you know
Challenge our farmers and our agronomist you keep an eye
For this weed it's not widespread in the state and we want to keep it like that
Once established it tends to be a very aggressive weed species very competitive and difficult to control
So i urge you know our ag community in the state as concen to keep our state palmer free as much now as we can
So just you kind of wrap things up here you know, we as i showed them this maps, we have you know
Several instances of glyphosate resistant waterhemp
We have glyphosate resistant giant ragweed confirmed in the state and also a less resistant giant ragweed confirmed
So there are resistant weeds out there
You know it's important the farmers can, identify there you know
Whether they have it or not and you know once they do that you know
They'll, help, them select the herbicide programs as you know
As they try to manage this difficult to control weeds so just some you know. Strategies. You, may, want to think about
for this difficult you could throw weeds
We weed scientists recommend farmers to start clean put a good pre-emergent herbicide out there
Containing a couple effective modes of action
Don't wait too long to come with a post program when you come with a post program weeds are breaking through the residual
Herbicide there you know, add an effective herbicide
Post you know for post control
But if the canopy is not close you know if your crop is not close to closing canopy yet you may
Want to consider bringing additional residual in season particularly in soybeans so you
Have products such as the group 15 herbicides that could be tank mixed with
Your post program to bring, some additional in season residual activity there
We also encourage farmers to think outside the jug as often as possible you know
Take, some of that selection pressure away, from herbicide you know managing herbicide resistant weeds with herbicides
You know it's it's not gonna be a sustainable strategy as, we move down the road with the limited tools that
We have in a toolbox so we gotta start thinking outside the jug there if you, would you know
Take advantage of your no chemical strategy is your tillage practices you know, make your crop
Competitive change the row space and as possible go as narrow as you can into row
Cultivation the adoption of cover crops all the strategies they're, not solution for weed management however
They can certainly help you out, some of the other things you know
You, drive around the state and then you see fields with
Excellent level of weed control but you watch the field edges the edges are full of weeds in there and oftentimes you know
Trouble some weeds that, we don't, want to have in our operations so again
you know challenging farmers to make sure that the field edges you know are kept weed free because that's gonna minimize the influx of weed
seeds back to your field
Optimized weed control in rotational ears for instance there are a lot of herbicide options
They're, very effective on big weeds and the rag weeds in a corn
Ear so take advantage of that okay, you know, do the best that you can to control those weeds where there are options
And that's gonna help you all when you come back to a, soybean heater, where your options are some
You have a lower
Seed bank pressure there minimize still dispersed so if you have fields that have resistant weeds you know
Make, sure you have you harvest those fields last
And when you're moving that equipment around?
Your death you know harvesting equipment or the tillage equipment or planting equipment
Make, sure you're cleaning that equipment so you're, not spreading the problem around
Because at the end of the day it's all about seed bank management because if you have
No, seed you're not gonna have a weed there so we got to do the best that
We can to avoid you know having this turbo
Some weeds producing seeds in our cropping systems so with that i want to thank you for attention i have my contact
Information listed in here if you, would like to discuss
Herbicide or herbicide program or if you have weed science related questions
Feel free to reach out to us here thank you very much
you