Management of Herbicide-Resistant Weeds: Challenges and Opportunities

Rodrigo Werle, assistant professor and extension cropping systems weed scientist, Department of Agronomy, University of Wisconsin-Madison Author

04/22/2021 Added

35 Plays

Description

Herbicide-resistant weeds represent a major threat to sustainability and profitability of row crop production systems in the U.S. Midwest and beyond. Werle will discuss ongoing research efforts in Wisconsin to provide growers and decision influencers with research-based information to support effective and sustainable integrated weed management systems.

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[00:00:00.820]The following presentation is part
[00:00:02.720]of the Agronomy and Horticulture seminar series,
[00:00:05.850]at the University of Nebraska, Lincoln.
[00:00:08.940]So it's my pleasure today to introduce
[00:00:10.560]our guest speaker, Dr. Rodrigo Werle.
[00:00:13.690]So I will talk before we start presentation
[00:00:15.620]just tell a couple of words about Rodrigo
[00:00:17.890]and then we'll move on to his presentation.
[00:00:21.020]So Dr. Werle joined the University of Wisconsin-Madison
[00:00:24.720]in January, 2018 as an Assistant Professor
[00:00:27.470]and Extension Cropping System of Weed Scientist
[00:00:32.120]and then here's Research and Extension Program, UW Madison
[00:00:34.990]Wisconsin Weeds focuses on agriculture based approaches
[00:00:39.770]to address sustainable weed management in corn,
[00:00:42.450]soybeans and small grain in Wisconsin and beyond.
[00:00:46.370]So his program also focused on weed management strategies
[00:00:49.880]that can help growers address herbicide resistant,
[00:00:52.968]protect water quality,
[00:00:55.180]enhance agro-ecosystem services
[00:00:57.210]and decrease food security.
[00:00:59.030]So Dr. Werle received his bachelor's degree in agronomy
[00:01:02.570]at Sao Paulo State University in Brazil
[00:01:05.130]and he completed his master's
[00:01:06.730]and PhD in agronomy with specialization in weed science
[00:01:10.680]from University of Nebraska-Lincoln,
[00:01:12.930]under Dr. John Lindquist.
[00:01:15.100]So Dr. Werle served almost two years
[00:01:17.550]as an Assistant Professor in cropping system specialist
[00:01:22.160]at University of Nebraska-Lincoln
[00:01:24.220]at West Central Research and Extension Center
[00:01:26.630]before joining UW-Madison.
[00:01:29.580]I just need to add something here
[00:01:31.750]while he was a graduate student
[00:01:33.180]he received many academic honors and awards,
[00:01:36.770]and he was after his time,
[00:01:38.294]after he completed his PhD
[00:01:40.940]he mentored and co-mentored numerous students.
[00:01:43.730]Today he has a lot of kind of the domestic
[00:01:47.810]and international peer reviewed publications.
[00:01:50.350]And today Dr. Werle will be talking about
[00:01:52.840]The Management of Herbicide-Resistant Weed
[00:01:55.270]with the Focus on Challenges and Opportunities.
[00:01:58.540]So Rodrigo, thank you again for joining us today.
[00:02:01.140]And we look forward to listen about your work right now.
[00:02:06.220]So first of all,
[00:02:07.070]thank you for that introduction Miller.
[00:02:09.120]Thank you for the invitation.
[00:02:11.720]It's such an honor for me to be here today.
[00:02:14.860]It feels like almost I'm going home.
[00:02:16.940]We spent seven years in Nebraska
[00:02:18.370]so this is a very special opportunity for me,
[00:02:20.660]and I'm very humbled and honored to be here.
[00:02:24.400]So today I'm gonna be talking about,
[00:02:25.810]Management of Herbicide Resistant Weeds,
[00:02:28.000]Challenges and Opportunities.
[00:02:30.700]A lot of the challenges that our farmers are facing
[00:02:33.690]have become research opportunities.
[00:02:35.850]And I think through applied research and good extension
[00:02:39.346]theses challenges are also becoming opportunities.
[00:02:42.210]And I'm gonna make a case here today that
[00:02:44.930]because of resistant weeds,
[00:02:46.470]we're rethinking about our systems
[00:02:48.330]and we're potentially enhancing sustainability
[00:02:51.830]of our production systems.
[00:02:54.754]All right.
[00:02:55.587]So before I get started here,
[00:02:57.690]I think I just wanna take a moment to acknowledge
[00:03:01.010]the University of Nebraska-Lincoln.
[00:03:05.750]I had amazing opportunities during my time at UNL.
[00:03:10.050]For those of you who don't know me,
[00:03:11.640]I first came to the United States in 2009
[00:03:16.130]as an undergraduate student at that time.
[00:03:18.680]I worked with Dr. Mark Bernards.
[00:03:20.540]Dr. Bernards trusted in me.
[00:03:22.400]He gave me the opportunity to come spend six months
[00:03:26.380]as an intern, worked with him.
[00:03:28.300]His graduate students worked closely with Lowell Sandell
[00:03:32.220]who also became a tremendous mentor.
[00:03:36.400]And at that time I was trying to define
[00:03:38.390]where to go with my career.
[00:03:39.860]I knew I wanted to go back to Brazil
[00:03:41.610]graduate with a bachelor's degree in agronomy
[00:03:43.702]get a master's degree and become a crop consultant.
[00:03:47.650]I loved research.
[00:03:48.620]I loved working with farmers
[00:03:50.040]and then I came here to the States
[00:03:51.500]and this is what Dr. Bernards and Lowell Sandell
[00:03:55.160]were doing at that time,
[00:03:56.220]working with Keith Glewen and many others through Extension.
[00:03:59.750]And I just fell in love with Extension.
[00:04:02.440]And that time during that internship,
[00:04:05.510]had a position where I could do Extension work with growers
[00:04:08.640]and continue to advance,
[00:04:10.240]the science as the research became my goal.
[00:04:14.240]Went back home to Brazil, graduated.
[00:04:17.350]And at that time it was offered graduate school at UNL.
[00:04:19.920]So I got both my master's and my PhD
[00:04:23.500]at the University of Nebraska-Lincoln,
[00:04:26.150]under Dr. John. Lindquist.
[00:04:29.269]I'm very thankful for all of the opportunities I had.
[00:04:32.630]I had the chance to do a lot of field research
[00:04:35.140]which is something I'm truly passionate about
[00:04:37.800]but I was exposed to molecular research.
[00:04:40.240]I was also exposed to modeling.
[00:04:43.080]I had the chance to be exposed to Extension
[00:04:46.000]work with the amazing weeds team at UNL
[00:04:49.480]and then teach the lab of Dr. Lindquist class,
[00:04:52.890]work with Ahmed many others
[00:04:55.230]and work with Dr. Predicted Tandberg
[00:04:57.640]in the modeling aspect.
[00:04:59.040]So it was just an amazing experience.
[00:05:01.350]And for that, I'm always gonna be very thankful.
[00:05:05.980]And it was a lot,
[00:05:07.100]it was about six, seven years from this point this point.
[00:05:10.700]We came my wife today wife Lee and I came
[00:05:14.640]to get our degrees.
[00:05:15.640]And we left with a family.
[00:05:16.990]We made a lot of really good colleagues
[00:05:19.510]a lot of friends that are still good friends up to this day.
[00:05:23.350]So we're very thankful for everything that Lincoln
[00:05:25.270]and UNL offered us and always with the support
[00:05:28.071]with our family in Brazil.
[00:05:32.190]So I graduated with my PhD exactly five years ago.
[00:05:36.280]It was actually last week,
[00:05:37.580]the five-year anniversary of my PhD graduation,
[00:05:40.980]that picture that I had on the corner
[00:05:42.750]with my PhD advisory committee.
[00:05:45.350]And then the week after a Lee and I were starting
[00:05:47.790]a new program at the West Central Research
[00:05:49.857]and Extension Center in North Platte, okay?
[00:05:54.140]So I had accepted at that point an Extension
[00:05:56.570]Cropping Systems position.
[00:05:59.080]We were there for two years.
[00:06:00.720]We built an amazing team doing cropping systems research
[00:06:05.140]in semi-arid environments.
[00:06:07.170]And at that point between 17 and 18,
[00:06:09.673]I had the opportunity to move
[00:06:11.110]to the University of Wisconsin, Madison
[00:06:13.600]to work more in the weed science role.
[00:06:16.480]So here we are, two years later we transitioned back
[00:06:19.540]starting a new lab at a new place.
[00:06:23.320]19 we had our lab up and going.
[00:06:25.510]2019 for those of you who recall it,
[00:06:27.840]it was a very wet year,
[00:06:29.120]a very challenging year for field research.
[00:06:31.710]2020 comes with COVID.
[00:06:33.720]We have to be socially distant
[00:06:35.500]one person per car,
[00:06:37.090]limited number of people.
[00:06:39.140]So a lot has happened in this five years.
[00:06:42.400]However, despite all the challenges we had,
[00:06:45.350]I've learned so much
[00:06:47.110]in this whole time, this past five years
[00:06:49.190]it's been always about the people
[00:06:51.530]the people that we've had the chance to work with,
[00:06:54.110]the people in my lab,
[00:06:56.170]the people in the lab and North Platte
[00:06:57.640]the people now at the lab,
[00:06:59.010]at our lab in Wisconsin
[00:07:01.010]my colleagues at UNL,
[00:07:02.610]my colleagues at UW Madison.
[00:07:04.280]It's just been an amazing ride
[00:07:05.850]despite all the challenges.
[00:07:08.735]We are getting vaccinated.
[00:07:10.670]Some look much better now in the 21 growing season.
[00:07:13.090]And Soybean Board and the Crop Protection Industry.
[00:07:15.410]As you're gonna see today,
[00:07:17.020]we have a very applied program
[00:07:18.260]where at Research Extension Program
[00:07:19.650]we conduct applied research and our funding sources
[00:07:22.840]kind of dictate some of the work that we do.
[00:07:26.520]All right.
[00:07:27.353]So why are weeds important?
[00:07:28.186]Why is controlling weeds such an important thing?
[00:07:31.280]So I have some pictures here,
[00:07:32.440]this is pictures from around the world
[00:07:33.990]of research specialists,
[00:07:35.770]poor management of weeds,
[00:07:37.790]good management of weeds.
[00:07:38.930]And right there, you can get the message.
[00:07:40.890]When left uncontrolled weeds can reduce crop yield
[00:07:45.080]in quantity and quality.
[00:07:47.250]We have a demanding,
[00:07:50.320]an increasing demand for food out there.
[00:07:54.090]So we need it minimize this loss
[00:07:56.690]or this gap due to weed competition.
[00:07:59.240]Not only that,
[00:08:00.073]having weeds in your field make harvest more difficult
[00:08:03.560]and some of the export markets
[00:08:05.730]they don't wanna see contaminated grain anymore.
[00:08:08.820]So having weed seeds in the grain is becoming a big no.
[00:08:14.380]So this is a 30,000 foot view
[00:08:18.230]of why weeds are such a problem.
[00:08:20.520]And then when we think about weeds,
[00:08:22.450]we directly start thinking about glyphosate resistance.
[00:08:26.170]But one thing that I wanna point out here
[00:08:27.450]is that weeds have been evolving for a very long time, okay?
[00:08:32.660]And plants are constantly adapting.
[00:08:36.180]And one thing that I,
[00:08:37.210]one slide that I like to show is this slide here
[00:08:40.210]with this paper from weedy rice, okay?
[00:08:44.900]This is work,
[00:08:46.220]some samples that were collected in Asia.
[00:08:48.460]So about 1,000 years or more ago
[00:08:50.610]when they were growing rice,
[00:08:52.540]the farmers they were hand weeding, right?
[00:08:54.710]And this is what the weedy version
[00:08:56.650]of a barnyard grass looked like in their fields,
[00:09:00.970]but because they were hand weeding
[00:09:02.270]and separating that from the crop
[00:09:03.880]they selected a biotype that looked just like the crop.
[00:09:08.230]So when they did that,
[00:09:09.080]at that point they could not separate the crop from the weed
[00:09:13.030]through hand weeding.
[00:09:13.960]So this is selection at its finest here.
[00:09:18.910]I also wanna present this example here
[00:09:22.060]from the late Dr. Sbatella
[00:09:24.020]who was a postdoc with Dr. Bob Wilson
[00:09:26.480]out in Panhandle, Nebraska.
[00:09:28.872]Years ago, they published this very interesting work,
[00:09:33.057]what they were doing here,
[00:09:33.890]they had continuous corn
[00:09:35.440]and they were using isoxaflutole as a herbicide
[00:09:37.670]with soil residual activity.
[00:09:39.970]And after using this herbicide years after year
[00:09:41.923]that herbicide wasn't providing the same level of control.
[00:09:45.000]And at first they thought they were dealing
[00:09:46.550]with an isoxaflutole resistant biotype of kochia
[00:09:50.260]but then Gustavo did some work.
[00:09:52.580]And what they actually learned is that
[00:09:54.170]through using that same herbicide over and over
[00:09:56.460]they actually selected the biotype
[00:09:58.413]that had a delayed emergence window.
[00:10:01.320]So instead of coming early in the season
[00:10:02.883]when that herbicide it's high concentration in the soil,
[00:10:06.530]the bio-type was emerging later
[00:10:08.260]escaping the residual control from that herbicide.
[00:10:11.570]So my point here is that weeds are amazing
[00:10:13.670]if we do the same thing over and over and over,
[00:10:15.625]they're going to evolve.
[00:10:18.830]So those who are not familiar with the terminology.
[00:10:22.060]I'm gonna shift now into herbicide resistance.
[00:10:25.910]And this is the definition
[00:10:27.150]by the Weed Science Society of America.
[00:10:29.560]Herbicide resistance is the inherited ability
[00:10:32.470]of a plant to survive and reproduce
[00:10:35.530]following exposure to a dose of herbicide,
[00:10:38.310]normally lethal to the wild type.
[00:10:40.490]In other words,
[00:10:41.323]the herbicide used to work on that weed species
[00:10:43.630]and it's no longer used because we have overused it.
[00:10:47.940]Several efforts have started
[00:10:50.360]to help growers overcome resistance.
[00:10:53.850]These are some work that was done
[00:10:56.010]by my predecessor here at UW-Madison, Vince Davis.
[00:11:01.020]And at that time, 2014, working with the USB
[00:11:03.920]our colleagues estimated the resistant weeds
[00:11:06.650]were causing an additional $2 billion cost
[00:11:10.950]on an annual basis to our farmers out there.
[00:11:14.660]So this is a huge cost.
[00:11:16.650]And once they have resistance,
[00:11:18.100]we have to change practices.
[00:11:20.100]And sometimes those practices are not the best practices
[00:11:23.900]in regards to soil conservation.
[00:11:26.250]So in order to address there,
[00:11:27.920]the United Soybean Board has created a group,
[00:11:30.037]the Take Action Group.
[00:11:31.640]There's a lot of great resources that are made available
[00:11:35.690]from academics to practitioners
[00:11:37.960]to help them overcome.
[00:11:39.760]There are some other groups that have also being created
[00:11:44.090]to help growers overcome this challenge.
[00:11:46.630]And another example here is
[00:11:48.280]the Grow or Getting Rid of Weeds.
[00:11:51.060]They have their own website
[00:11:52.280]with a lot of great research based resources for farmers.
[00:11:55.910]And I know Dr. John Lindquist is part of this group here.
[00:12:02.020]So let's talk about resistance.
[00:12:03.180]When we talk about resistance,
[00:12:04.130]everybody thinks about glyphosate resistance, right?
[00:12:07.830]So I just wanna show you this figure
[00:12:09.750]by Dr. Ian Heap is available on his website,
[00:12:12.980]and I wanna draw your attention to glyphosate.
[00:12:14.370]Glyphosate is right here, okay?
[00:12:17.500]So resistance has been happening for a long time.
[00:12:20.400]Resistance is happening since we started using herbicides
[00:12:23.570]in the 60s and 70s.
[00:12:25.550]So you see the trend here for resistant cases
[00:12:28.330]for the group five herbicides,
[00:12:30.390]as we start having more and more resistance to group five
[00:12:33.480]growers switched to group two herbicides,
[00:12:35.890]and here you see the increase in group two.
[00:12:38.140]So resistance is more than glyphosate.
[00:12:40.910]The challenge now with glyphosate resistance
[00:12:42.730]is that glyphosate was such an effective herbicide,
[00:12:46.280]easy to use broad spectrum.
[00:12:48.910]And when glyphosate stops working,
[00:12:50.770]it becomes challenging to manage weeds post emergence,
[00:12:53.610]as we're gonna discuss in a minute.
[00:12:56.780]On top of that,
[00:12:57.780]this is what the discovery pipeline looked like
[00:13:00.730]from the mid 50s, okay?
[00:13:03.050]All the way through the 80s here.
[00:13:05.260]So during this 30 year period, every three years
[00:13:09.370]we had two new sites of action being introduced
[00:13:13.610]into the marketplace.
[00:13:14.530]I'm not even talking about active ingredients
[00:13:16.190]or herbicide products.
[00:13:17.023]I'm talking about sites of action,
[00:13:19.410]but since the mid 80s,
[00:13:21.800]we have this flat line.
[00:13:23.650]So we have resistance that continues to increase
[00:13:26.550]the number of cases to all herbicides that we're using.
[00:13:29.080]And we have a shortage of new herbicide sites of action.
[00:13:32.590]And this represents one of the biggest challenges
[00:13:34.980]in regards to chemical weed control.
[00:13:39.560]This is a slide
[00:13:41.300]from the Weed Science Society of America survey
[00:13:44.220]that they have conducted.
[00:13:45.290]They do the surveys every two and three years
[00:13:48.060]and they report the most common
[00:13:49.920]and the most troublesome weeds and several cropping systems.
[00:13:53.600]And I'm using soybeans as my example here.
[00:13:56.077]And one thing to notice from the last survey is that
[00:13:59.780]the most common weeds are also considered
[00:14:03.500]the most troublesome.
[00:14:05.530]So we've done a very fine job,
[00:14:07.340]selecting some very troublesome weeds
[00:14:09.440]that are commonly found across the landscape
[00:14:12.650]in our soybean production systems.
[00:14:15.920]And I'm gonna use this slide here to put some faces
[00:14:18.830]to the names.
[00:14:19.970]Those are pictures that we took,
[00:14:21.760]the top two pictures are pictures that we took this week.
[00:14:24.690]So there's this horseweed,
[00:14:26.160]again, one of the most common and most troublesome weeds.
[00:14:28.880]This is what horseweeds looks like
[00:14:30.900]out in the field right now.
[00:14:32.370]Most of the horseweed germinates in the fall,
[00:14:35.060]and it's taken off now early in the spring
[00:14:37.080]in the absence of a crop.
[00:14:38.850]Here's giant ragweed.
[00:14:40.420]Giant ragweed is a major weed species here in Wisconsin.
[00:14:43.431]It's a little different than the way it behaves in Nebraska.
[00:14:45.943]Here in Wisconsin giant rag
[00:14:47.740]has a very extended emergence window.
[00:14:49.990]So it's actually one of the difficult weeds to control
[00:14:53.140]in our cropping systems.
[00:14:54.260]And this is a picture that Nick Arneson,
[00:14:56.210]our Outreach Specialist in our program took
[00:14:58.550]earlier this week.
[00:14:59.383]It's just starting to emerge.
[00:15:01.250]And these are pictures from last year, okay?
[00:15:04.710]So we have the two weeds on the top,
[00:15:06.757]horseweed and giant rag that are trouble early season.
[00:15:10.090]And then the two on the bottom here,
[00:15:11.263]waterhemp and Palmer amaranth,
[00:15:13.430]they become more of a problem mid-season.
[00:15:15.980]Waterhemp and Palmer amaranth
[00:15:17.417]they're not emerging here in the upper Midwest yet.
[00:15:20.440]We tend to see them start to emerge late may, early June
[00:15:24.570]and then they continue to emerge
[00:15:25.960]for as long as light is reaching the soil.
[00:15:29.310]And here, I just wanna put a plug.
[00:15:31.550]'Cause when I was in Nebraska,
[00:15:33.110]when I got to Nebraska waterhemp
[00:15:34.277]was becoming a major problem.
[00:15:35.810]At that time Lowell was organizing the herbicide resistance
[00:15:39.320]a few days.
[00:15:40.153]So I learned a lot, okay?
[00:15:41.247]In the 2011, 2012, 2013.
[00:15:45.270]And then I get here to Wisconsin in 2018,
[00:15:47.680]Waterhemp is exploding around the State.
[00:15:50.060]So that exposure that I had in Nebraska really helped me
[00:15:52.972]help us set our program here to teach growers
[00:15:56.680]or help growers the best management practices
[00:15:59.560]for management of waterhemp.
[00:16:01.920]One thing that I wanna point out is that Palmer,
[00:16:03.940]we don't have Palmer like folks in Nebraska have,
[00:16:08.640]when I first got to Nebraska in 2009
[00:16:10.840]I remember folks talking about Palmer from,
[00:16:13.460]in Arkansas or Western part of the State of Nebraska
[00:16:16.490]parts of Kansas.
[00:16:17.690]I left Nebraska in 2007,
[00:16:19.610]and I know it's all over the State
[00:16:21.260]and looking at Ahmet's recent survey,
[00:16:24.060]Palmer went from not being a major problem
[00:16:26.470]to the number one weed in the State of Nebraska.
[00:16:30.290]So I know what's coming.
[00:16:31.990]We're trying to warn our producers up here in Wisconsin.
[00:16:34.870]We have a strong dairy industry as most of you know
[00:16:38.300]so cotton seed is a common feed in our dairy industry.
[00:16:42.610]We have equipment coming in.
[00:16:43.800]We have wildlife coming in.
[00:16:45.330]So we're paying close attention to Palmer amaranth.
[00:16:47.910]'Cause from what we've learned in Nebraska
[00:16:49.970]from what we've learned in other States,
[00:16:51.470]if you let it go it will take over
[00:16:53.940]in a matter of a few years.
[00:16:55.160]So this has been a major effort of our Extension.
[00:17:00.210]This is some work that's been conducted
[00:17:02.690]by our graduate student, Felipe Faleco.
[00:17:05.490]We started this in 2018,
[00:17:07.250]working with the Wisconsin Soybean Marketing Board
[00:17:09.770]and what we did, we created what we call
[00:17:11.820]this whisk weeds research coalition.
[00:17:14.220]Where we work with our agronomists and producers.
[00:17:17.640]We request them to send us samples,
[00:17:19.810]seed samples in this case.
[00:17:21.510]And with those seed samples,
[00:17:22.930]they send the information of their fields.
[00:17:25.683]What we do,
[00:17:26.516]Felipe bring these plants in the greenhouse
[00:17:28.180]and we screened them for resistance
[00:17:30.720]to the various herbicides.
[00:17:32.057]And we send those results back to our growers.
[00:17:34.730]That way we have good knowledge of where resistance is at
[00:17:38.060]where it's moving in the State
[00:17:39.410]and what kind of programs we should be looking at.
[00:17:42.710]So one thing that I wanna point out,
[00:17:43.870]this is a map that Felipe just finalize.
[00:17:45.780]He's gonna be defending his master's soon.
[00:17:48.870]And as you can see here,
[00:17:50.300]the golden dots are populations of waterhemp
[00:17:53.680]that are resistant to glyphosate
[00:17:56.050]and group two herbicides.
[00:17:57.990]So that's widespread.
[00:17:59.700]More than 90% of our populations
[00:18:01.470]have this two types of resistance.
[00:18:05.540]One thing that I'm gonna draw your attention to
[00:18:07.750]is that we don't see resistance to atrazine
[00:18:10.630]as we see in other parts of the country.
[00:18:13.170]And one of the reasons for that is because
[00:18:16.220]here in Wisconsin,
[00:18:17.110]we have atrazine restrictions, okay?
[00:18:21.160]So in certain areas,
[00:18:22.229]the red spots here in this map
[00:18:24.100]are areas we cannot use atrazine
[00:18:26.290]because of the groundwater contamination concerns
[00:18:28.930]and in the rest of the State the rate of atrazine
[00:18:31.260]that can be used is limited depending on the soil type
[00:18:34.110]and how often it's used.
[00:18:35.870]So one thing that I attribute here,
[00:18:37.950]this lower frequency of resistance in our populations
[00:18:40.840]is because of regulations.
[00:18:42.070]We typically don't like regulations
[00:18:44.200]but this is the scenario here where the use of the herbicide
[00:18:46.720]is somewhat regulated.
[00:18:48.530]And we don't seem to see as much resistance
[00:18:51.600]as other States are seeing.
[00:18:55.490]Now that we were talking about resistance,
[00:18:56.880]I wanna talk about the two major types of resistance.
[00:19:00.070]And I'm not gonna go in depth,
[00:19:02.030]but for years here the weed scientist,
[00:19:04.280]the molecular weed scientist
[00:19:05.780]we were focused,
[00:19:07.350]our colleagues were focused
[00:19:08.500]on target-site resistance, right?
[00:19:10.400]So looking for mutations in a specific target-sites
[00:19:14.680]that confer resistance.
[00:19:16.733]There's the recent trend now that we are observing
[00:19:19.710]is this a widespread occurrence now
[00:19:21.880]of non-target-site resistance.
[00:19:24.890]And it's very important that we understand
[00:19:26.500]the difference between the two.
[00:19:28.150]So target-site resistance here on the right
[00:19:30.520]when you have this type of resistance
[00:19:31.793]that resistance is specific to the herbicide
[00:19:34.680]that you're using.
[00:19:35.790]For instance, if you have ALS resistance
[00:19:37.630]you have a mutation on the ALS enzyme there
[00:19:41.070]the herbicide will stop working.
[00:19:42.710]So in other words, you can switch the herbicide
[00:19:44.970]use something else to control the weeds.
[00:19:47.170]For non-target-site or metabolic resistance.
[00:19:49.800]This is really puzzling and intriguing.
[00:19:51.960]I think this is the new frontier in weed science
[00:19:54.610]because by selecting for this type of resistance, okay?
[00:19:58.110]The herbicide never gets to the site of action.
[00:20:00.890]And when you have this type of resistance,
[00:20:02.540]it might be that you're pre-selecting for resistance
[00:20:05.050]to herbicides we're not even using yet.
[00:20:08.110]So this is really scary.
[00:20:10.570]And as I just said,
[00:20:11.700]represents a major frontier on how we manage resistance.
[00:20:15.910]When we started working with this types of resistance
[00:20:17.840]our recommendation out on the field was
[00:20:19.550]let's tank mix, okay?
[00:20:20.970]Let's tank mix.
[00:20:22.150]'Cause that will take care of target-site.
[00:20:24.170]Well, as we start tank mixing,
[00:20:25.600]we're seeing more non-target-site resistance.
[00:20:27.690]So not only we need to tank mix,
[00:20:29.100]but we also need to rotate when using herbicides,
[00:20:32.300]our tank mixtures
[00:20:33.500]to postpone this type of resistance.
[00:20:37.140]And just an example here,
[00:20:38.290]some work that just came out at the University of Arkansas,
[00:20:42.451]excuse me here.
[00:20:43.911]Kansas State University, I'm sorry.
[00:20:46.714]Dr. Jugulam's lab,
[00:20:49.400]where they found this population
[00:20:51.100]in a long-term conservation study case, okay?
[00:20:53.350]So they found in a study
[00:20:54.690]that was being conducted by our colleagues at Kansas State,
[00:20:57.880]a Palmer Amaranth,
[00:20:58.713]that they could not control with multiple herbicides.
[00:21:01.640]Dr. Jugulam's Lab looked into the mechanism of resistance
[00:21:05.040]and they confirmed the population to be resistant
[00:21:07.890]to six sites of action, okay?
[00:21:11.270]And the causes for five of those resistance
[00:21:14.150]to be associated to metabolism based.
[00:21:17.140]Only glyphosate here in this case
[00:21:19.250]was due to a target-site mutation.
[00:21:21.440]Resistance to the other five sites of action
[00:21:24.210]were due to metabolism based resistance.
[00:21:26.590]So very concerning scenario.
[00:21:30.840]So back to Nebraska,
[00:21:32.210]here's some work that we did with waterhemp
[00:21:34.750]Dr. Greg Kruger at that time,
[00:21:36.501]Bruno Vieira and his program was doing a PhD
[00:21:39.810]looking at glyphosate in ALS resistance around Nebraska,
[00:21:43.320]just like Felipe is doing here in Wisconsin.
[00:21:47.190]And then the time we got to Nebraska,
[00:21:49.030]we asked Greg if we could use his populations
[00:21:51.690]and evaluate the frequency of atrazine resistance.
[00:21:55.400]And what we found is that
[00:21:56.680]we screened more than 100 populations,
[00:21:59.050]73 of those populations, 73%, Okay?
[00:22:02.550]A very high number was confirmed
[00:22:04.930]to be resistant to atrazine.
[00:22:09.080]Our first hypothesis there
[00:22:10.490]is that resistance was due to a target-site.
[00:22:12.730]So we worked with Dr. Mithila Jugulam
[00:22:14.940]down at Kansas State University in her lab.
[00:22:18.050]They screened for the potential mutations
[00:22:21.450]that are confirmed to cause target site resistance
[00:22:26.390]to atrazine.
[00:22:27.400]And we did not find a mutation
[00:22:29.100]in any one of our populations.
[00:22:31.560]They conducted some further work.
[00:22:33.350]And then they learned that the populations from Nebraska,
[00:22:36.010]they presented this metabolism type of resistance.
[00:22:40.780]So what happens here,
[00:22:41.613]you spray the herbicide,
[00:22:42.446]this is a control population
[00:22:44.440]those resistant populations,
[00:22:45.780]they can quickly integrate the herbicide.
[00:22:48.497]Again, back to my point,
[00:22:50.010]by having this types of resistance here
[00:22:52.200]growers might be pre-selecting for resistance to herbicides
[00:22:55.570]that we're not even using yet.
[00:22:57.480]And this is very concerning long-term.
[00:23:00.340]A little bit of good news.
[00:23:01.890]When we tested for this populations for atrazine
[00:23:04.080]we also looked at their response to metribuzin
[00:23:07.930]which is in the same herbicide family as atrazine
[00:23:11.170]but it's used in soybeans instead of corn.
[00:23:13.970]And we looked at sulfentrazone,
[00:23:15.220]which is also a pre-emergent herbicide
[00:23:17.370]using soybean and group 14.
[00:23:19.260]And both herbicides were effective in all this population.
[00:23:22.780]So again, understanding the mechanism of resistance
[00:23:24.840]the types of resistance,
[00:23:26.170]screening for other herbicides,
[00:23:27.480]help in providing good information
[00:23:29.730]for our growers to manage these weeds.
[00:23:33.970]Now I wanna switch gears here
[00:23:35.500]and as you're realizing I'm going through a lot really quick
[00:23:39.190]just providing a high level information here.
[00:23:42.210]So folks, if you have questions or concerns,
[00:23:44.380]feel free to reach out,
[00:23:45.620]and I can always share these slides later as well.
[00:23:48.720]So I borrowed this slide from Dr. Pat Tranel
[00:23:50.990]at the University of Illinois.
[00:23:52.470]And I really liked this slide here
[00:23:54.000]'cause it helps us a lot.
[00:23:55.100]And I did a lot of work
[00:23:55.970]with Dr. Lindquist at UNL in modeling.
[00:23:58.810]So I really like to use some modeling hypothetical
[00:24:00.977]scenarios to explain things, okay?
[00:24:03.850]So this is year a grower starts using the herbicide,
[00:24:07.100]year one, okay?
[00:24:08.550]And this is what usually happens if we're not rotating,
[00:24:11.090]if we're doing the same thing over and over.
[00:24:13.180]About year eight, nine or 10,
[00:24:15.410]we start seeing resistance to build, okay?
[00:24:18.690]And this is how we perceive it.
[00:24:19.960]This is how growers perceive it.
[00:24:21.210]And this is usually when we try to take action.
[00:24:23.950]And my point here is that at this point
[00:24:25.283]it's already too late, okay?
[00:24:28.040]This is what it's actually happening.
[00:24:29.620]So this is the same figure.
[00:24:31.330]The only thing that's happening here,
[00:24:33.037]Dr. Tranel changed the y-scale here to a log base, okay?
[00:24:37.340]So it still goes from one or zero to 100.
[00:24:41.600]But what it says here is that
[00:24:42.780]the moment you start using the herbicide
[00:24:44.600]we're already putting selection pressure, okay?
[00:24:47.170]In our system.
[00:24:48.003]So if we're only taking action to preserve that herbicide,
[00:24:52.240]those weeds from evolving resistance,
[00:24:53.667]the herbicide is already too late.
[00:24:56.160]The only way to keep this curve flat
[00:24:59.022]or never reach one,
[00:25:01.710]is to not let those weeds that were exposed go to seed.
[00:25:05.930]That's the only way, okay?
[00:25:07.650]So the zeros tolerance approach,
[00:25:09.220]don't let your weeds go to seed.
[00:25:11.580]Otherwise this is a scenario that we see.
[00:25:14.150]It is important here to bring good
[00:25:17.200]and sound integrated weed management practices.
[00:25:19.567]And this is what our lab is heavily focusing on.
[00:25:25.100]Back to our weed control trend.
[00:25:27.140]We've seen this figure here in the bottom.
[00:25:29.250]I indicated that since the 80s
[00:25:31.310]we haven't had new chemistry
[00:25:33.370]and then we have a flat line
[00:25:35.620]in terms of new sites of action.
[00:25:37.300]So this is the new trend that we see in industry
[00:25:39.830]in the mid 90s Roundup Ready trait became available,
[00:25:43.470]glyphosate tolerance,
[00:25:44.590]it really changed the way we manage weeds
[00:25:47.780]in corn, soybeans, and cotton.
[00:25:51.290]Roundup, a very effective herbicide.
[00:25:54.700]It used to be a very effective herbicide,
[00:25:57.140]very flexible when you can spray
[00:25:58.840]weed size spray condition.
[00:26:00.880]So it became somewhat easy to control weeds in that system.
[00:26:05.470]And that because we overused it
[00:26:07.480]now we are where we are
[00:26:10.110]and we are somewhat forced to change how we do things.
[00:26:13.940]So this recent trend here these are biotech crops
[00:26:16.940]or genetically engineered herbicide resistant crops in 17
[00:26:20.400]The Xtend Crop hits the market
[00:26:22.760]and that confers tolerance to Dicamba and glyphosate.
[00:26:26.380]I'm gonna come back and talk about Dicamba.
[00:26:29.413]Dicamba this past four years
[00:26:30.950]has been a very controversial herbicide
[00:26:33.130]and we've done a lot of work with that.
[00:26:35.420]The next technology that became available in 18,
[00:26:38.410]it used to be a Bayer Technology.
[00:26:40.500]Now is the BSF is the LGT 27.
[00:26:43.660]So glyphosate and glufosinate.
[00:26:46.300]We have the Enlist trait coming into the marketplace
[00:26:49.240]conferring tolerance to glyphosate,
[00:26:52.230]2,4-D Choline and glufosinate.
[00:26:55.310]And this past fall Xtendflex was approved.
[00:26:58.990]So now the Xtend platform here also has
[00:27:02.470]the glufosinate tolerance trait, okay?
[00:27:04.980]So one thing that I wanna point out to you all here
[00:27:07.000]is that yeah, we have new options.
[00:27:08.360]We're bringing some corn herbicides or grass herbicides.
[00:27:10.840]They came in 2,4-D into our soybean systems
[00:27:13.610]but the one common theme here across platforms
[00:27:16.560]doesn't matter if you're talking, Bear pateva
[00:27:19.100]or if we're talking BSF here is glufosinate.
[00:27:22.560]And I think glufosinate is gonna play a major role
[00:27:24.820]for broadleaf post emergence control moving forward.
[00:27:28.790]And just a note here that I found earlier today
[00:27:31.540]that they estimate that the global glufosinate market
[00:27:34.930]is probably gonna double
[00:27:36.480]in the next five years.
[00:27:38.500]Year from 2021 to 2026.
[00:27:41.240]Just indicating how important this herbicide
[00:27:44.110]will likely become for corn and soybean production systems.
[00:27:49.010]So back to Dicamba,
[00:27:51.100]this is actually a picture from Dr. Amit Jhala,
[00:27:54.860]that I'm a chaired with a bunch of colleagues
[00:27:57.639]around the United States.
[00:28:00.020]This picture has been used a lot
[00:28:01.137]and this pretty much reflects
[00:28:03.290]of what happened in 2017, right?
[00:28:05.960]Where you have a grower in the field,
[00:28:07.013]then you have attack.
[00:28:09.750]The worst sort of company,
[00:28:11.640]you have the applicator
[00:28:12.780]you have the farmer,
[00:28:13.613]you have the extension educator
[00:28:14.870]and then you have the State weed specialist,
[00:28:17.990]all staring at each other,
[00:28:19.140]trying to figure out what happened.
[00:28:20.730]Is this particle drift, vapor drift,
[00:28:23.030]or is it tank contamination?
[00:28:24.830]And this is why this technology
[00:28:26.470]has been really controversial.
[00:28:28.810]One thing that I wanna point out is that
[00:28:30.670]what's different with Dicamba
[00:28:32.566]than other herbicides is a synthetic oxen.
[00:28:35.220]And the soybeans just happens to be the best bio indicator
[00:28:38.930]for the Dicamba drift.
[00:28:40.670]And it just so happens that soybeans
[00:28:42.080]is the second largest crop grown in this country.
[00:28:44.580]So when things go wrong and you have a perfect bio indicator
[00:28:47.600]across the landscape,
[00:28:48.720]it will show, okay?
[00:28:50.390]So what has happened with Dicamba this past four years
[00:28:53.690]has really helped us reflect and maybe refine
[00:28:56.970]the way we spray our crops.
[00:28:59.330]Which that itself was a challenge to drift
[00:29:02.590]but how we're perceiving this and how we move forward here.
[00:29:05.410]I think we have a good opportunity to improve
[00:29:07.341]the way we spray our pesticides.
[00:29:11.180]So we've been part of this group
[00:29:12.700]that worked closely with Bayer Crop Science
[00:29:14.840]and multiple academics around the United States
[00:29:17.890]trying to understand vapor drift and particle drift.
[00:29:22.310]We've done a series of work,
[00:29:23.770]we published a paper in weed technology.
[00:29:26.920]If you're interested, we can share that with you.
[00:29:29.220]We conducted a study here in Wisconsin
[00:29:30.900]and the same study was conducted at Otter
[00:29:32.930]for Otter sites in the US and also in Canada
[00:29:36.270]including a site in Nebraska.
[00:29:38.640]We've done a lot of research looking at what we call
[00:29:41.640]this little tunnel volatility trials,
[00:29:43.330]the impact of weather conditions
[00:29:45.330]and the impact of tank mixes on volatility.
[00:29:49.480]And now this work that we've done for this past three years
[00:29:52.000]has been a lot of work.
[00:29:53.340]It was all shared with the US EPA, okay?
[00:29:56.630]All the raw data, all the publications, abstracts,
[00:29:59.370]everything has been made available to the EPA,
[00:30:02.200]not only from the program here in Wisconsin,
[00:30:04.020]but all the weed science programs
[00:30:06.240]that we're working with Dicamba around the country.
[00:30:09.160]And that like what's really neat to see
[00:30:11.420]is that this regulations
[00:30:13.040]are this next five-year registration that just came out.
[00:30:16.720]They really took into consideration some of the learnings
[00:30:19.041]from our large scale drift trials
[00:30:21.140]in our low tunnel volatility trials.
[00:30:23.830]So some of the major changes that we're seeing
[00:30:26.290]in the growing in 2021 moving forward,
[00:30:29.430]the addition of what they call volatility reduction agent.
[00:30:33.540]That is a somewhat of a pH buffer
[00:30:35.800]that reduces the likelihood of the Dicamba salt
[00:30:38.890]or the Dicamba acid dissociating from the soil.
[00:30:41.750]So that minimize volatility.
[00:30:43.300]We've looked at in our trials,
[00:30:44.930]several colleagues have looked at it
[00:30:46.940]and it really reduces the chances for volatility.
[00:30:50.120]We have seen an increase in the buffer areas
[00:30:52.520]and that is to protect endangered species.
[00:30:56.670]We now have a cutoff, June 30th,
[00:30:58.860]that's the federal cutoff.
[00:31:00.010]Some States had some cutoff in the past years,
[00:31:02.490]Wisconsin, for instance, we didn't.
[00:31:04.390]But flowering was our cutoff there
[00:31:06.180]but now we do have a cutoff
[00:31:08.050]and I'm gonna go back to some work
[00:31:09.560]that we did in Nebraska in 17
[00:31:11.610]after the first year that growers use this technology.
[00:31:14.210]And we asked them,
[00:31:15.220]when were they seeing the cases of drift
[00:31:17.570]when it was sprayed.
[00:31:18.920]And usually when they,
[00:31:20.600]folks that sprayed after the June 1st
[00:31:23.250]was when they saw higher risks
[00:31:25.430]of causing injury to neighboring crops,
[00:31:28.010]soybean crops, okay?
[00:31:29.410]So it's neat to see that what we learned
[00:31:30.860]from our survey Nebraska
[00:31:32.020]is actually what is being here disclosed in the EPA label.
[00:31:37.670]And then the one thing that I wanna say here is that,
[00:31:40.220]again, challenges potentially now
[00:31:41.950]but opportunities in the future is this last statement.
[00:31:45.000]The 2020 registration provides new flexibility
[00:31:47.780]for growers and States for opportunities.
[00:31:50.520]For example, there are opportunities for growers to reduce
[00:31:53.560]the downwind spray buffer for soybeans
[00:31:56.480]using hooded sprayers, okay?
[00:31:58.860]So what we did last fall,
[00:31:59.920]we started a series of work looking at hooded sprayers.
[00:32:03.230]After this regulations came out.
[00:32:05.110]This is a protocol that was developed by Dr. Greg Kruger,
[00:32:08.810]who at the time was at that the West Central Research
[00:32:12.290]and Extension Center in North Platte.
[00:32:15.757]His team actually came to Wisconsin.
[00:32:17.440]They did this work at Nebraska and they went to Missouri.
[00:32:20.040]They moved this equipment around.
[00:32:21.950]And what we did,
[00:32:22.783]we looked at a combination of hooded sprayer
[00:32:25.700]versus an open sprayer.
[00:32:27.520]What most farmers are using out there.
[00:32:30.290]We looked at a combination of nozzles
[00:32:32.320]and the drift reduction agents.
[00:32:35.930]And those are some preliminary results
[00:32:38.090]that Dr. Max Olivera just finalized analyzing.
[00:32:42.050]And then for the graduate students in the call here
[00:32:44.450]and folks that are interested in data analysis
[00:32:48.420]in weed science,
[00:32:49.253]I just wanna put a plug for the work that Max is doing.
[00:32:51.960]Max is a research analyst in our program
[00:32:54.480]and he's got his own website,
[00:32:56.220]Open Weed Science,
[00:32:57.053]and a lot of great codes and how to analyze data
[00:32:59.510]and generate neat figures, just like this one.
[00:33:02.350]So make sure you check the work that Max is doing.
[00:33:05.730]But back to this study what we learned is that
[00:33:08.800]a nozzle with a medium droplet size
[00:33:11.430]in an open-hooded sprayer
[00:33:13.940]compared to a horse nozzle
[00:33:16.580]using this hooded sprayer here
[00:33:18.890]there was 100 fold difference in drift exposure.
[00:33:23.940]So it is amazing what using this technology here can do.
[00:33:28.490]Sometimes the applicator won't like it
[00:33:30.040]because it adds a lot of weight to their booms.
[00:33:33.740]It's not as practical,
[00:33:35.200]but we're talking about a significant reduction
[00:33:37.750]in particle drift.
[00:33:38.730]So I foresee this becoming something we see a lot more
[00:33:42.530]in the landscape.
[00:33:43.930]And because of these trials that we have done
[00:33:45.730]this is where our program is going next.
[00:33:48.150]Ryan DeWerf in our program just came back from Minnesota
[00:33:50.910]this past week.
[00:33:51.743]And he picked up our enroll hooded sprayer.
[00:33:55.400]And our intention here is to look at drift
[00:33:57.620]but also start looking at alternative options
[00:34:00.170]that could be used in season
[00:34:01.960]where you would not potentially expose the crop
[00:34:04.270]and focus on the weed control.
[00:34:07.160]This is nothing new.
[00:34:08.390]It has been used,
[00:34:09.450]is commonly used down in Arkansas for instance,
[00:34:12.470]where they do or down South where they have cotton
[00:34:14.870]in lay by applications.
[00:34:16.090]But it's something that we're not using a whole lot
[00:34:18.220]in soybeans.
[00:34:19.080]So how about we use some smart spray systems
[00:34:22.440]where we do this targeted applications
[00:34:24.300]of effective chemistry
[00:34:26.000]and instead of spraying the entire crop.
[00:34:28.640]So this is something we're gonna start working this year.
[00:34:33.410]Another thing that I wanna mention back to glufosinate
[00:34:36.500]I said, I think glufosinate is gonna play a major role
[00:34:38.750]in Felipe's screenings in the greenhouse,
[00:34:41.240]glufosinate is by far the most effective herbicide
[00:34:45.240]for waterhemp control.
[00:34:47.300]However, when we bring it out in the field,
[00:34:49.550]this is a scenario we oftentimes sees
[00:34:52.720]where the grower sprays it,
[00:34:54.180]and then you go there 14, 15 days later,
[00:34:56.340]you see the regrow.
[00:34:57.180]With the case was a contact herbicide.
[00:34:59.010]It's really sensitive to spray conditions.
[00:35:01.950]If you don't hit the weeds more good coverage,
[00:35:04.110]good sunlight, you'll see regrowth.
[00:35:07.960]And by the time we started
[00:35:09.180]some of this research with glufosinate,
[00:35:11.010]I know Dr. Hudson Takano was here probably last fall
[00:35:15.040]and he gave a talk where he talked about
[00:35:17.240]this tank mixes with PPO.
[00:35:19.100]So here is when you spray under ideal condition glufosinate
[00:35:22.960]And I think mix of glufosinate and the PPO,
[00:35:25.780]great controlled in both scenarios
[00:35:27.740]but when you don't have ideal conditions
[00:35:29.980]for glufosinate performance there,
[00:35:32.070]what Hudson observed in his study is that glufosinate alone
[00:35:35.350]was not effective.
[00:35:36.183]Just like I was talking in the field,
[00:35:38.320]but when he mixed with the PPO herbicide,
[00:35:41.050]the control was truly enhanced, okay?
[00:35:43.890]And that really got our attention
[00:35:45.130]'cause we were observing that in the field
[00:35:46.620]in some of the trials we were conducting,
[00:35:48.410]we watched this talk here
[00:35:49.980]and really helped us design some studies
[00:35:51.990]to evaluate this concept.
[00:35:53.860]We've done this workout with Dr. Mark Bernards
[00:35:56.270]at Western Illinois University
[00:35:58.090]where we looked at glufosinate by itself.
[00:36:01.660]We compared glufosinate with PPO herbicides
[00:36:04.850]which are the green arrows here.
[00:36:06.270]And we looked at mixing these two herbicides.
[00:36:08.930]And what we're learning here is that
[00:36:10.350]when we mix a PPO herbicide with glufosinate
[00:36:13.230]we're truly enhancing the control of that glufosinate.
[00:36:16.840]So one, we wanna make sure growers get good weed control
[00:36:20.020]but two, resistance management is a concern.
[00:36:24.040]And when we started this work
[00:36:26.150]this news wasn't out there yet.
[00:36:29.210]And it just came out a couple months ago, okay?
[00:36:32.180]Which again, reinforces the need
[00:36:34.980]for looking at this potential mixtures to enhance control.
[00:36:37.970]So colleagues at the University of Arkansas,
[00:36:40.170]Dr. Tom Barber, Tommy Butts,
[00:36:42.470]a former grad of the department
[00:36:44.610]and Jason Norsworthy,
[00:36:45.560]they just confirmed the first case
[00:36:47.660]of glufosinate resistance and Palmer amaranth, okay?
[00:36:51.222]And that is very concerning because,
[00:36:53.670]as I was just saying,
[00:36:54.503]I mean, this is kind of our silver bullet
[00:36:56.020]if you will, right now moving forward
[00:36:58.000]in terms of post emergence weed control.
[00:36:59.376]And we're starting to see resistance already.
[00:37:03.880]So what does that tell you?
[00:37:04.990]That we gotta change how we operate
[00:37:09.580]back to the drawing board?
[00:37:11.100]One of the recommendations that we have for growers
[00:37:13.690]is to start with an effective pre-emergence program.
[00:37:17.380]Relying on post emergence weed control
[00:37:19.640]is not a sustainable strategy.
[00:37:21.770]And I have some plots here on the left with no pre,
[00:37:24.920]yes pre,
[00:37:25.753]and then you can stare at a plot like this
[00:37:27.950]and talk with your growers for multiple hours,
[00:37:30.180]define resistance,
[00:37:31.250]define weed competition here
[00:37:34.380]and many benefits that this chemistries bring.
[00:37:38.090]When we started in Wisconsin,
[00:37:39.280]we created this series of what we call
[00:37:40.930]the WISC weeds management challenge.
[00:37:42.840]We take chemistry from all portfolios.
[00:37:45.760]We put plots out there,
[00:37:47.400]we invite our growers to come collect their data.
[00:37:50.830]Then in the following fall, we make the data available.
[00:37:53.910]Hopefully helping them refine their adoption,
[00:37:57.960]their practices and also the agronomist
[00:38:00.030]with their recommendations.
[00:38:02.310]One thing that I wanna point out about this particular study
[00:38:04.350]is a competitor besides,
[00:38:06.620]and then we have herbicides with a single mode of action
[00:38:08.780]which has the herbicides in blue.
[00:38:10.410]We have in green, the commercial pre-mixes
[00:38:12.960]they have two sites of action.
[00:38:14.680]And then we have what's becoming standard
[00:38:16.190]now in the industry is to release this pre-mixes
[00:38:18.280]with three different sites of action.
[00:38:20.480]And as you can see here
[00:38:21.313]just by quickly looking at this figures here,
[00:38:23.660]the green and the red bars are often above the 90%
[00:38:27.120]when we're collecting the data,
[00:38:28.450]three, four weeks afterwards.
[00:38:29.860]And this is where we wanna be.
[00:38:32.520]What we did with this data,
[00:38:33.470]we went beyond case.
[00:38:34.610]So we provided the recommendations for growers
[00:38:36.790]but then Alex Rosa, a former post-doc with us.
[00:38:40.020]He was also a PhD student with me during my time
[00:38:42.880]in Nebraska there,
[00:38:43.713]he took all this data set and he took a step back.
[00:38:45.690]And then let's look,
[00:38:46.523]I mean, we're recommending that farmers use
[00:38:48.960]a pre-emerge herbicide with multiple modes of action,
[00:38:51.780]but do we need two modes of action
[00:38:54.030]or do we need three modes of action?
[00:38:55.820]And at first we were following the strand here
[00:38:57.920]and looking at this data and say,
[00:38:58.860]well, the more the merrier, right?
[00:39:00.620]So let's just go with three sites of action.
[00:39:03.460]But then we took a step back
[00:39:05.500]and we started looking at some of the three-way mixes
[00:39:07.960]and what they do because of crop injury, costs,
[00:39:11.140]and because sometimes they're effective at lower rates.
[00:39:13.510]What happens if you look at the constitution of the product
[00:39:16.330]those herbicides are being sprayed at a lower rate
[00:39:18.830]which brings back the resistance concern
[00:39:20.960]when we're using lower rates.
[00:39:22.740]And then Alex ran this analysis
[00:39:24.450]with four site years of data
[00:39:26.330]and all we learn is that,
[00:39:27.803]a herbicide that contains two sites of action,
[00:39:30.710]a pre herbicide,
[00:39:31.700]is performing quite similarly as the herbicides
[00:39:34.320]that contained three sites of action.
[00:39:35.577]And that's visual control and density.
[00:39:38.850]So the current recommendation for growers
[00:39:41.440]that they select a herbicide
[00:39:43.150]that has two sites of action, full rates
[00:39:45.750]and perhaps save that third one
[00:39:48.190]for an in season layered residual approach.
[00:39:52.980]So here's a trend.
[00:39:54.710]It's nice to see this strand because again
[00:39:56.440]a recommendations that farmers use diversified pre programs.
[00:40:00.240]This is what it was.
[00:40:01.670]You see this dip here with the Roundup era,
[00:40:04.250]and now we're going back up.
[00:40:05.810]A lot of diversity in herbicide programs are being used.
[00:40:08.887]And this is really nice to see out in the landscape.
[00:40:14.220]So in my presentation here so far,
[00:40:15.900]I've focused heavily on chemistry.
[00:40:18.290]It talked a lot about herbicides,
[00:40:19.937]fighting resistance,
[00:40:21.970]using effective programs,
[00:40:23.240]post emergence, pre-emergence,
[00:40:26.070]but fighting resistance with herbicides only
[00:40:28.890]won't last, Okay?
[00:40:30.700]And big part of what we do here in our program
[00:40:33.450]is to look at integrated weed control strategies.
[00:40:35.760]So thinking outside of the jug,
[00:40:37.330]bringing other strategies into our weed control portfolio.
[00:40:40.900]When I was an undergrad at San Pablo State
[00:40:43.250]my weed science professor told me
[00:40:44.670]that the most effective weed control strategy
[00:40:46.710]is cultural weed control, okay?
[00:40:48.730]He first ask what we students thought
[00:40:50.810]was the best weed control option
[00:40:52.770]and everybody was throwing herbicide names.
[00:40:54.730]Hey, and he says,
[00:40:55.563]"You guys are all around the best.
[00:40:56.396]"The most sustainable way to go
[00:40:57.987]"is through cultural weed control."
[00:40:59.860]At the time I was a little too young
[00:41:01.070]and I didn't quite get him.
[00:41:02.100]I was always thinking,
[00:41:02.933]Oh, we have great herbicides,
[00:41:04.286]why are we talking about cultural weed control?
[00:41:06.520]And I think this pictures here
[00:41:07.660]they helped me convey that message a little bit.
[00:41:10.040]So these are some of Dr. Roberto Blanco's plots,
[00:41:13.730]actually out in North Platte,
[00:41:14.870]they were doing some on-farm work.
[00:41:16.230]So this is on farm scenario not in our research plots.
[00:41:19.480]On the left here,
[00:41:21.410]it was a winter fallow
[00:41:23.320]and on the right is where we have
[00:41:25.610]a good stand of cereal rye.
[00:41:26.840]And you walk at that cereal rye April
[00:41:28.500]you do not see a single winter annual weed, okay?
[00:41:31.260]Back to the weed control.
[00:41:32.700]If you have a crop that's growing in,
[00:41:35.127]actively growing you're suppressing the weeds.
[00:41:38.520]Here's weed plots out around the grant area,
[00:41:43.300]Western Nebraska,
[00:41:44.270]the farmer ran out of seed on the drill.
[00:41:47.220]And you can see the aerial footage here
[00:41:49.181]Arsenijevic he shared his images with me.
[00:41:52.570]You see the weeds where there is no crop, okay?
[00:41:54.950]Where there's light reaching the ground.
[00:41:56.300]The weeds are very, very opportunistic.
[00:41:57.870]They are in the soil seed bank.
[00:41:59.770]So dark or crop canopy
[00:42:02.290]is one of the most sustainable and best ways
[00:42:04.605]to prevent weeds.
[00:42:06.850]You look at our current systems.
[00:42:08.230]Most of our farmers are either in continuous corn
[00:42:11.170]or corn, soybeans.
[00:42:12.680]And then you look at this crop development.
[00:42:14.990]We have this very, what I call vulnerable period, right?
[00:42:18.210]The soil is somewhat vulnerable
[00:42:20.020]because there's no active crop growing.
[00:42:23.940]And we are giving those weeds a lot of opportunities.
[00:42:26.080]We're planting the crop,
[00:42:26.990]a crop that's planted at about the same time
[00:42:29.040]and harvested at about the same time,
[00:42:30.690]year after year.
[00:42:32.210]So we're doing the same thing over and over
[00:42:33.690]even though we're switching between corn and soybeans
[00:42:36.250]the periods are quite similar.
[00:42:37.670]So we give this weeds an opportunity
[00:42:39.373]to establish and thrive.
[00:42:41.930]So here's when we bring good agronomics,
[00:42:44.500]a good IWM.
[00:42:46.080]And first part that I wanna focus on,
[00:42:48.240]is how do we make our crop
[00:42:49.960]a little more competitive early on?
[00:42:52.950]And this is what Nikola Arsenijevic in our program
[00:42:55.470]is looking at as part of his program,
[00:42:57.719]his Ms. Program at UWA Madison with our group,
[00:43:00.647]are also working with Dr. Sean Collony,
[00:43:02.810]the soybean agronomist.
[00:43:04.500]So what Nikolas is doing,
[00:43:05.490]he is looking at management practices.
[00:43:07.550]How can we change some of those management practices
[00:43:09.930]to enhance a canopy closure?
[00:43:12.390]And this pictures here they were actually taken
[00:43:14.186]on the same day, July 2nd, okay?
[00:43:18.190]This is 30 inch soybeans,
[00:43:19.500]what most of our producers are doing.
[00:43:21.000]The beans were planted late may.
[00:43:23.910]So we harvested corn the previous year in October.
[00:43:26.610]And we're talking July here, July 2nd,
[00:43:29.250]and look how much vulnerability we have in our system.
[00:43:33.760]Here's a simple adjustment,
[00:43:35.080]the same seeding rate,
[00:43:36.230]same planting time.
[00:43:37.370]The difference is the row spacing.
[00:43:39.420]So 30 inch row spacing,
[00:43:41.180]50 inch row spacing.
[00:43:42.300]Bust by going narrow there,
[00:43:43.538]you can enhance how fast you close canopy closure.
[00:43:46.960]And then you can,
[00:43:47.793]if you were a weed here,
[00:43:48.626]I like to ask my growers when I'm giving extension talks
[00:43:51.470]where would you rather be?
[00:43:52.490]Here or here, right?
[00:43:54.220]So let's think about that.
[00:43:56.000]And this is exactly what Nikola tried to do
[00:43:58.480]for his master's degree.
[00:43:59.670]So every week he went out there
[00:44:01.100]and he transplanted literal waterhemp seedlings
[00:44:03.720]and he watched them grow.
[00:44:05.020]And when they flowered, he chopped them, okay?
[00:44:07.490]So the first case here is no crop competition.
[00:44:09.970]You have this Christmas trees by the time they're flowering.
[00:44:13.810]Here's what happened in 30 inch soybeans.
[00:44:16.350]This is what happens,
[00:44:18.780]here's 15 inch soybeans,
[00:44:20.410]30 inch soybeans
[00:44:21.570]and 30 inch corn.
[00:44:22.740]As you can see here the 15 inch soybeans
[00:44:24.620]are really competitive with waterhemp.
[00:44:25.837]And that's what we wanna do.
[00:44:26.900]We wanna slow this waterhemp growth
[00:44:29.180]down as much as possible.
[00:44:31.560]Here's some of the data that he just finished analyzing,
[00:44:34.600]for his thesis chapter.
[00:44:35.760]So I'm gonna go through this quick.
[00:44:37.610]Fallow, you see reduction in height
[00:44:41.080]the later the weeds emerge.
[00:44:42.557]And that makes sense.
[00:44:43.540]'Cause they respond to day length
[00:44:45.200]when they start flowering, okay?
[00:44:47.710]What's really neat here is that early on 15 inch soybeans
[00:44:50.800]are as competitive as corn,
[00:44:53.020]but then later on 15 inch soybeans and 30 inch soybeans
[00:44:56.310]when they're fully closed canopy,
[00:44:58.340]in our case here that's happening mid to late July.
[00:45:01.408]Any waterhemp seedling that's emerging at that point
[00:45:03.970]won't make it,
[00:45:05.070]but in corn they can still make it.
[00:45:08.050]Even though there's a drastic reduction,
[00:45:09.700]this is what Nikola found.
[00:45:10.790]Even though those seedlings are transplanted late.
[00:45:14.700]What does that tell you?
[00:45:15.540]So well after the corn is tasseling,
[00:45:17.560]our growers are typically not scouting for waterhemp
[00:45:20.190]but I can guarantee you if they're not looking for it,
[00:45:22.610]these plants are putting seeds
[00:45:24.120]and they're putting enough seeds to be a problem
[00:45:26.240]for the next growing season.
[00:45:28.320]And this is something we gotta be mindful of
[00:45:30.440]in our rotations.
[00:45:32.350]Nikola also did some work
[00:45:34.040]looking at how agronomic practices can influence the time
[00:45:37.680]to 90% canopy closure.
[00:45:39.490]So we use a canopy app that estimates ground coverage.
[00:45:43.950]And what he's doing here is trying to look at, okay,
[00:45:46.040]when will 90% canopy closure occur?
[00:45:49.050]We looked at different planting times, row spacings.
[00:45:52.310]We looked at the impact that pre herbicides may have
[00:45:54.680]on holding,
[00:45:55.513]some of these pre herbicides can cause early season injury.
[00:45:58.040]So we wanna just see whether they had an impact.
[00:46:00.140]Tillage, and what Nikola learned on the left side first,
[00:46:03.327]the time to 90% closure,
[00:46:05.040]which is what's depicted in this figure here
[00:46:07.300]the most important factors were,
[00:46:09.060]planting time and row spacing.
[00:46:10.820]So if you can plant early and if you can go narrow
[00:46:13.550]you can close canopy as fast as possible.
[00:46:15.920]And sometimes the differences were 11, 12 days, Okay?
[00:46:18.797]11, 12 days may not sound a whole lot
[00:46:21.410]before pigweed control,
[00:46:22.767]11, 12 days can make a huge difference.
[00:46:26.290]The catch here though is on the right side,
[00:46:28.570]is that as the agronomist will say,
[00:46:32.228]and Sean Collony would agree,
[00:46:33.061]and that's actually his recommendation.
[00:46:34.630]The earlier you can plant the higher the yield.
[00:46:36.910]And we saw that on Nikola study.
[00:46:39.270]But there's row spacing going narrow there
[00:46:42.930]did not lead to an increased yield in this study.
[00:46:46.550]So there's mixed results out there.
[00:46:48.330]Sometimes when you go narrow space
[00:46:50.220]and you see enhanced weed control.
[00:46:52.340]But my point is,
[00:46:53.420]if you have the ability to plant narrow
[00:46:55.230]you might not see enhanced yield
[00:46:58.050]but you will certainly see enhanced weed control
[00:47:01.690]in those systems.
[00:47:04.360]So back now to some of the work we were doing
[00:47:06.920]in North Platte
[00:47:07.753]back to the concept of integrated weed management strategy.
[00:47:11.430]So this is a farm are around the macook area.
[00:47:13.340]We did a lot of work with him.
[00:47:15.240]This is a severe Palmer amaranth infestation.
[00:47:17.360]He had a pre down,
[00:47:18.360]he had two post pastors.
[00:47:19.790]This farmer was really struggling with Palmer amaranth.
[00:47:23.660]And what he decided to do that fall
[00:47:25.160]after he harvested soybean was to plant a small grain crop.
[00:47:28.730]And this is what that crop looks like the year after, right?
[00:47:32.350]So we visited the field in May.
[00:47:34.170]There is complete canopy closure
[00:47:36.630]at the time the Palmer is starting to emerge.
[00:47:38.760]Palmer amaranth was not a problem in that subsequent season
[00:47:42.000]even though we had this level of infestation the year prior.
[00:47:46.040]So by changing your rotation,
[00:47:47.810]bringing in a crop that has different develop,
[00:47:51.080]that will develop differently throughout the year
[00:47:53.170]can really trick the weeds.
[00:47:55.650]And I understand that bringing a small grain into the system
[00:47:59.050]may not be an option to all farmers.
[00:48:00.640]Some farmers are potentially locked
[00:48:02.075]into this corn, soybean rotation.
[00:48:04.280]And one thing that we can do is cover crops, right?
[00:48:06.340]Simulate somewhat the scenario of this winter wheat
[00:48:08.660]that I just described.
[00:48:09.930]But then you terminate that cover crop at the time
[00:48:12.990]when you think you have harvested the benefits.
[00:48:15.740]And this is something we're working heavily on.
[00:48:19.370]These are pictures that I took earlier this week,
[00:48:21.936]fields year and they're in Allegheny County,
[00:48:23.780]Southern part of Wisconsin.
[00:48:25.440]These fields are about five miles apart,
[00:48:27.410]same type of style of operation.
[00:48:29.200]The one on the left here we have, I'm sorry.
[00:48:32.120]We have a cover crop that was seeded after corn harvest.
[00:48:35.440]And on the right here, we just have fallow.
[00:48:37.330]And look at all the weeds that are growing.
[00:48:39.810]Look at how the soil there's exposed.
[00:48:42.540]So I think at this point here
[00:48:44.230]we can agree as soil scientists,
[00:48:46.100]agronomists, and I like to refer and weed scientists.
[00:48:49.490]I like to refer to this paper that was published
[00:48:52.300]by colleagues at UNL that was led by,
[00:48:54.580]Dr.Humberto Blanco here,
[00:48:57.370]when we talk about sustainability of our systems,
[00:48:59.720]soil organic carbon, being able to enhance our soil
[00:49:03.520]by bringing cover crops and no till into the system.
[00:49:07.170]And I think as weed scientists, we would agree
[00:49:09.150]'cause by doing so we could also gain weed suppression.
[00:49:12.200]So I think there's a lot of traction here now
[00:49:13.979]with scientists from different areas within agronomy
[00:49:17.120]supporting such a strategy.
[00:49:20.350]And as a result of that,
[00:49:21.700]we've seen a 50% increase in the cover crop area
[00:49:25.190]across the United States from 2012 to 2017.
[00:49:29.130]So growers are really interested.
[00:49:31.100]There are some concerns.
[00:49:32.030]Moisture is always a concern in dryer parts
[00:49:35.250]but I think there's a lot of interest in this
[00:49:37.227]and we have a good movement going.
[00:49:41.045]One of the challenges for us here in Wisconsin
[00:49:43.900]when it comes down to cover crops
[00:49:45.270]is that we're seeding in October,
[00:49:46.880]in November it's getting really cold.
[00:49:49.030]And then we have shorter Springs
[00:49:51.120]if you compare to States South of us.
[00:49:54.550]So this is some of the work that Kolby Grint
[00:49:56.157]a grad student is doing.
[00:49:58.610]We're tracking the amount of biomass produced
[00:50:01.596]at the time we would be planting.
[00:50:03.117]And this is a kind of a standard plant,
[00:50:05.197]the time for us,
[00:50:06.230]the second, third week of May.
[00:50:08.330]And at that time, usually we're at about 300 to 500 pounds
[00:50:13.512]of dry biomass of the cereal rye.
[00:50:16.500]That's not a lot if you're thinking about weed suppression.
[00:50:19.945]What we wanna see is more than 2,000, 3,000 pounds.
[00:50:22.570]And to get to that point,
[00:50:23.580]we need to wait to terminate the cover crop after late May
[00:50:26.910]or early June, okay?
[00:50:29.393]There's two options here,
[00:50:30.860]to growers delay planting,
[00:50:32.090]which they don't like
[00:50:32.923]'cause often they're giving up on yield.
[00:50:34.820]Or what they can do is just go ahead and plant green
[00:50:37.610]and then terminate that cover crop afterwards.
[00:50:39.730]And that's what we're doing a lot of work on.
[00:50:43.000]Why is that beneficial?
[00:50:44.500]I'm starting to run short on time here as usual.
[00:50:47.640]So I'm gonna kind of start wrapping things up
[00:50:49.580]but what we're learning from Kolby trial
[00:50:51.950]where he compares conventional tillage,
[00:50:54.310]no till, early cover crop termination,
[00:50:57.300]cover crop termination,
[00:50:58.390]that planting a forage harvest situation
[00:51:01.090]where we're in the dairy state.
[00:51:02.440]Sometimes we forage harvest that or we grace
[00:51:05.130]or terminating 15 days after,
[00:51:07.350]what we see is that the more biomass we have in our systems
[00:51:10.270]the better weed suppression we obtain.
[00:51:13.640]When we bring a pre-emergent herbicide into the system
[00:51:16.470]we don't see that trend
[00:51:17.420]because the pre's are very effective.
[00:51:19.400]But if we can combine biomass with the pre herbicide
[00:51:23.300]this is when we think we can get
[00:51:24.630]some truly integrated weed control.
[00:51:27.790]And the same trend is through for his soybean studies.
[00:51:31.570]The catch with corn though,
[00:51:32.730]is that corn is more sensitive to this late termination,
[00:51:35.710]if you would.
[00:51:36.543]So two years of studies at Arlington,
[00:51:38.410]we observed reduced yield of corn
[00:51:41.180]when we terminated the cover crop late.
[00:51:44.610]Whereas the other study that was done in Lancaster
[00:51:47.390]we did not see an impact of the late termination
[00:51:50.320]as compared to a no till only.
[00:51:52.280]At that trial of the tillage scenario actually yielded more.
[00:51:55.920]So we're still fine tuning,
[00:51:57.170]trying to understand a little more
[00:51:58.470]how to properly manage these cover crops.
[00:52:01.070]So we minimize the impact on corn.
[00:52:03.520]But the soybeans is where I see promising results,
[00:52:06.300]really interesting results here,
[00:52:08.390]no differences across this management strategies.
[00:52:12.130]Two years of results in each location.
[00:52:14.640]So foresight years here,
[00:52:15.972]no impact of that late termination
[00:52:18.590]as compared to no-till or tillage systems,
[00:52:21.240]so really promising.
[00:52:24.000]Now that we know that
[00:52:24.833]we're starting to fine tune our recommendations
[00:52:26.940]starting to do some additional work
[00:52:28.610]looking at roller crimper,
[00:52:29.750]we get a lot of questions from growers
[00:52:31.279]about roller crimpers.
[00:52:33.230]We did it last year for the first time.
[00:52:35.540]The challenge that we had with a roller crimper is that
[00:52:37.260]a lot of the rye pop back up, okay?
[00:52:39.700]And when he did that
[00:52:40.560]they were still able to set seeds.
[00:52:42.030]And Nick visited one of our fields earlier this week
[00:52:45.010]and this is the situation there
[00:52:46.690]because we didn't get a good cue of this rye,
[00:52:48.900]the rye went to seed.
[00:52:50.300]And this is something we don't want with our cover crops
[00:52:52.330]because in this case here
[00:52:53.220]we're introducing a potential weed into our system.
[00:52:57.130]But while we roll cramped,
[00:52:58.660]and where we put a glyphosate on top of it, okay?
[00:53:01.250]So double effort there to control the rye.
[00:53:04.680]This is what Nick found earlier this week
[00:53:07.040]in some of the plots that we establish.
[00:53:09.040]So there's really nice residue of cover crop
[00:53:12.190]from the previous growing season protecting the soil.
[00:53:15.200]In our trials, we do a system like this.
[00:53:17.160]You combined with the two,
[00:53:18.870]with an effective herbicide of two sites of action.
[00:53:20.640]You see the best levels of control,
[00:53:23.710]attending the WSSC,
[00:53:25.030]Weed Science Society of America meetings a month or so ago.
[00:53:28.580]Those results are also being reported
[00:53:30.590]at several other universities around the country.
[00:53:33.010]So very promising strategy.
[00:53:35.680]We're bringing technology into our systems around the world.
[00:53:38.210]Our program has installed
[00:53:40.790]a pulse-width modulated spray systems behind our planter.
[00:53:44.160]So in this case here we're planting green
[00:53:46.010]and we're spraying as we plant.
[00:53:47.600]Saving a trip.
[00:53:49.260]Looking at ways to minimize herbicide drift.
[00:53:51.690]So a lot of cool things that we're playing with.
[00:53:55.320]So to wrap things up,
[00:53:57.080]assuming you've done everything that you could have.
[00:53:58.946]And if growers still have pigweed plants going to seed,
[00:54:03.500]our recommendation is don't let them go to seed.
[00:54:06.140]Remember that if you let them go to seed,
[00:54:07.970]resistance continues to increase.
[00:54:10.440]Through our coalition we work with stakeholders.
[00:54:12.670]We ask them to grab samples from their cornbine
[00:54:15.510]and more than 90% of those samples,
[00:54:17.900]this is some work that was done by Nick
[00:54:19.690]and Dan in the MPM program.
[00:54:21.340]More than 90% of those samples had weed seed.
[00:54:24.350]So we need to pull those weeds
[00:54:25.720]and we need to clean our cornbine as often as possible.
[00:54:29.090]So we don't spread those weeds from fields to fields.
[00:54:33.080]So with that, some take home messages here,
[00:54:36.230]a lot of challenges that our growers have
[00:54:39.220]and will have in the years to come.
[00:54:40.880]A lot of opportunities in the research
[00:54:42.410]but also great opportunities for our growers
[00:54:44.210]to fine tune their systems
[00:54:46.410]through effective herbicide selection,
[00:54:48.200]rotating those mixtures,
[00:54:50.050]not using the same thing time after time,
[00:54:52.970]using some of the technology that we have available now
[00:54:55.360]to keep our herbicides on target.
[00:54:57.510]Our industry's under scrutiny from the general public.
[00:54:59.870]We don't wanna be on the cover page
[00:55:03.989]were folks are talking about the impact
[00:55:06.480]that agriculture is having the drift and all those issues.
[00:55:08.756]We don't want that to happen to our industry.
[00:55:12.780]And we need to use integrated weed management programs.
[00:55:16.460]This is no longer just something nice
[00:55:19.050]to think about, to reflect.
[00:55:20.060]This is a true necessity here,
[00:55:22.040]given the shortage and the oversimplification,
[00:55:25.540]the shortage of chemistry and the oversimplification
[00:55:28.200]of our cropping systems.
[00:55:30.320]So with that, I know I said a lot.
[00:55:32.050]I went through a lot.
[00:55:34.460]Thank you for sticking with me.
[00:55:36.290]I hope that the information presented was helpful.
[00:55:38.820]Miller, back to you.
[00:55:40.070]Thank you all very much.
[00:55:41.710]Thanks a lot for your presentation, Rodrigo.
[00:55:44.260]So it looks like vapor reduce engagements be used
[00:55:48.320]instead of AMS for corn
[00:55:49.760]they can buy products with the same efficacy.
[00:55:53.430]Yeah.
[00:55:54.263]We've been getting that question a lot.
[00:55:56.180]I don't know if is the efficacy question
[00:55:59.110]in regards to weed control,
[00:56:02.190]is that what you're referring to?
[00:56:05.030]'Cause I got the same question from agronomists
[00:56:07.090]whether they should consider using a VRA
[00:56:09.610]to reduce volatility in farm products.
[00:56:12.050]If they add the VRA will certainly help reduce volatility.
[00:56:15.250]The efficacy aspect is yet to be evaluated.
[00:56:18.370]But talking with colleagues,
[00:56:19.660]apparently the weed control efficacy is not influenced
[00:56:22.410]by replacing EMS with a VRA from a Dicamba perspective.
[00:56:27.130]So the next question,
[00:56:29.160]do you think there is a better small grains than rye.
[00:56:32.570]Rye is usually very cheap seed
[00:56:34.580]and not the very good variety.
[00:56:37.350]Yeah, that basically.
[00:56:38.385]That's a great question.
[00:56:39.890]And I think you would probably have way better answers
[00:56:43.437]than I do.
[00:56:44.478]The reason why cereal rye has become really popular
[00:56:48.210]is that you can plant it really late.
[00:56:49.940]Sometimes they're planted in November.
[00:56:52.133]It won't grow in the fall at all or in the winter
[00:56:55.410]but it takes off really quick, early spring.
[00:56:58.020]So it produces a lot of good biomass
[00:56:59.950]and is relatively easy to kill with glyphosate
[00:57:03.270]as compared to some alternative options,
[00:57:05.450]bin run wheat, trilly kaylee.
[00:57:07.970]So I know there are alternative options.
[00:57:11.720]I'll be really curious to hear your thoughts.
[00:57:14.110]Cereal rye is one cover crop species that really took off
[00:57:17.300]and it's shown really promising results.
[00:57:19.230]We've also compared bin run wheat in our trials,
[00:57:22.470]we see somewhat equivalent results.
[00:57:24.560]It's just that additional faster growth
[00:57:27.470]that we see with the rye
[00:57:29.150]that makes it a highly desirable species as a cover crop.
[00:57:33.280]We have Dr. Jhala who wants to ask a question, so.
[00:57:38.510]Hey Rodrigo, very good presentation.
[00:57:41.670]Yeah, I like the way you are using
[00:57:43.180]all the wonderful photographs
[00:57:45.040]and graphs and giving credit to all your graduate students,
[00:57:49.230]which is very nice really.
[00:57:51.270]So my question is,
[00:57:54.140]like waterhemp and Palmer amaranth
[00:57:56.910]and even common lambsquarters,
[00:57:58.790]now we are seeing they have started emerging late
[00:58:03.610]in the season.
[00:58:04.443]Like maybe before 10 years,
[00:58:06.040]you will not find waterhemp or Palmer
[00:58:08.830]that would emerge in August and September.
[00:58:11.850]But now we are seeing that late emergence
[00:58:14.040]of those small seeded broadleaf weed species
[00:58:19.450]and our best recommendation for now
[00:58:22.700]to control herbicide resistant weed
[00:58:25.480]is by using pre-emergence herbicides
[00:58:28.850]applied at planting in corn and soybean both, right?
[00:58:32.420]So, I had struggled to understand that is the best approach.
[00:58:38.420]So I was thinking whether
[00:58:41.431]we are controlling early emerging weed species
[00:58:45.730]during that plus 20 to 35 days
[00:58:49.320]or we are just pushing those weed species to emerge late?
[00:58:54.740]So does pre-emergence herbicide has any role
[00:58:57.300]to evolve them late emergence
[00:58:59.781]or we are controlling them
[00:59:01.950]and we are getting happy
[00:59:02.930]or it is just weeds they're evolving
[00:59:07.310]the way they are growing late in the season?
[00:59:10.560]Yeah.
[00:59:11.393]And thank you for the great questions there Amit.
[00:59:12.880]And thanks for the comment you made
[00:59:14.360]in regards to acknowledging the students and staff.
[00:59:17.460]I mean, they are the ones that deserve all the credit
[00:59:19.760]for the slides that I presented here today,
[00:59:22.900]very thankful for all the great work that they do.
[00:59:26.010]Without them I wouldn't be here giving this talk today.
[00:59:28.210]So that's the first common.
[00:59:30.120]And then second, your question is fantastic.
[00:59:32.740]After reading late Gustavo's paper there,
[00:59:36.430]it really got me thinking,
[00:59:38.130]it's something we're noticing too.
[00:59:40.110]It seems like you're,
[00:59:42.130]maybe we're still getting a lot of great control
[00:59:44.837]out of pre-emerge herbicides
[00:59:46.410]but we are also observing weeds coming in later
[00:59:49.870]in the growing season.
[00:59:50.720]So that mechanism that Gustavo discussed in their paper
[00:59:54.160]whereby using pre herbicides for multiple years,
[00:59:56.370]you're selecting for later emerging weeds
[00:59:58.860]or weeds that have higher levels of dermis early on.
[01:00:01.770]That is something we're really interested
[01:00:03.190]in investigating actually.
[01:00:04.990]So if you have interest in some of that,
[01:00:07.340]let's touch base.
[01:00:08.320]I don't have a straightforward answer to you
[01:00:09.990]but it's something that I've been thinking a lot
[01:00:11.930]about as well.
[01:00:14.220]Okay, thank you.
[01:00:15.450]Absolutely.
[01:00:16.930]And we observed similar trend I mean.
[01:00:19.720]So looking at the all benefits that you mentioned
[01:00:21.810]about related with the cover crops
[01:00:23.527]and the employment of the diversity
[01:00:25.250]kind of what they're offering.
[01:00:27.610]So considering that this kind of
[01:00:29.380]doesn't directly give the economic input back to farm
[01:00:33.160]how is this kind of how growers
[01:00:34.521]are accepting those kinds of things?
[01:00:36.560]Like down the road,
[01:00:37.393]you're kind of having a lot of the benefits
[01:00:39.037]are directly from kind of the planting cover crops.
[01:00:42.800]Like sometimes they won't kind of be,
[01:00:45.240]I think at least some of them they're hesitant
[01:00:47.610]about the employment on farm.
[01:00:49.910]Yeah.
[01:00:50.770]That's a great question, Miller.
[01:00:52.318]There are parts of the country
[01:00:54.100]that are concerned about moisture,
[01:00:56.750]it's more labor, right?
[01:00:57.890]'Cause you're harvesting,
[01:00:58.723]it's a busy time of the year.
[01:00:59.640]We're talking about drilling something in
[01:01:02.340]and we have a lot of technology right available.
[01:01:05.710]And I think one thing that I talk to the growers is,
[01:01:07.920]if were thinking about is start small,
[01:01:10.250]don't go full throttle.
[01:01:11.230]'Cause when they go full throttle
[01:01:12.290]and this is when you're rushing
[01:01:13.420]and then they don't get a good seed soil contact.
[01:01:15.760]I mean they run across problems.
[01:01:17.750]So target some areas,
[01:01:19.600]be site-specific.
[01:01:20.870]We have so much technology out there.
[01:01:23.320]And then maybe let's use some of the simpler technologies
[01:01:26.240]if you would,
[01:01:27.073]such as drilling a cereal rye with an older drill
[01:01:29.350]in the areas that really needed the field margins.
[01:01:32.230]Nick and I talk a lot about this
[01:01:33.570]during our Extension meetings.
[01:01:34.630]When we drive around the State,
[01:01:35.970]we always see a lot of weeds
[01:01:37.320]coming from the field margins, right?
[01:01:39.370]Those are the areas that are really difficult
[01:01:40.790]to control weeds.
[01:01:41.623]So why not be target specific,
[01:01:42.880]only plant around those areas.
[01:01:46.050]and then start small and see how that works for you, okay?
[01:01:48.490]So it doesn't have to be done in every single acre.
[01:01:50.410]You got to start simple,
[01:01:51.530]you got to start small
[01:01:52.580]you got to learn what works for you,
[01:01:53.730]if that works for your system or not,
[01:01:54.929]and then go from there.
[01:01:57.310]And I think it's great.
[01:01:58.580]We do this in small plots.
[01:02:00.510]We're now starting to take this on farm,
[01:02:02.800]just similar to what Nebraska does there with Extension.
[01:02:05.930]We have the nutrient pest management program.
[01:02:07.910]We've done two, three years, a small plot work.
[01:02:09.810]We're going large strips now,
[01:02:11.380]working with key growers around the State
[01:02:13.820]and seeing whether some of those recommendations will work
[01:02:16.930]and we let them implement
[01:02:18.190]and we come and help collect data
[01:02:20.240]and then make the assessment.
[01:02:21.330]So I'm really excited about that aspect.
[01:02:23.370]And I think here is a tremendous opportunity
[01:02:25.330]for Extension work.
[01:02:27.240]Great quality Extension work
[01:02:29.250]Question, Dr. Baenzinger here is asking,
[01:02:31.087]"In plant pathology
[01:02:32.347]"even pyramiding existing genes are expected to fail
[01:02:35.287]"because the single genes will break.
[01:02:37.557]"With no new herbicide the mode of action
[01:02:40.317]"will herbicide nature extend their use but fail also?"
[01:02:43.944]That is a fantastic question, Dr. Baenzinger.
[01:02:47.780]That's kind of the trend that we observe,
[01:02:51.243]even using this tank mixtures now
[01:02:54.160]because metabolism Bayers resistance we're starting to see
[01:02:58.050]some of that happening.
[01:02:59.310]It takes longer,
[01:03:00.800]but it is starting to happen already.
[01:03:04.450]And that's why the recommendation
[01:03:05.760]to mix and also rotate those mixtures
[01:03:07.820]and integrate them with something else.
[01:03:10.980]It is a true necessity.
[01:03:13.050]And if you stop and think about this,
[01:03:15.650]I was supposed to,
[01:03:17.370]our group here at EW Madison was supposed to be looking at
[01:03:20.200]a site of action that's coming down the pipeline,
[01:03:23.120]that's probably seven, eight years away
[01:03:25.970]from growers to see it.
[01:03:26.970]We couldn't do it this year because the industry
[01:03:29.710]and lawyers couldn't come up to an agreement.
[01:03:31.580]But my point is we don't have anything coming
[01:03:33.450]down to the pipeline that's immediate.
[01:03:35.360]And this new AI or new site of action
[01:03:37.990]it's another under pre-emerge herbicide,
[01:03:39.520]which is great,
[01:03:40.550]but it's not that silver bullet solution
[01:03:41.936]for post-emergence weed control.
[01:03:43.620]So post emergence weed control
[01:03:45.083]and its annual cropping systems, especially soybean.
[01:03:47.960]I think it will be very challenging.
[01:03:49.380]So a lot of good opportunities for good integrated work.
[01:03:55.720]Well, I think that's everything for today.
[01:03:59.250]Thanks again, Rodrigo for your presentation.
[01:04:01.850]I really enjoy listening kind of the different aspects
[01:04:04.170]and different kinds of the things.
[01:04:06.210]Thank you everyone for joining us today
[01:04:07.920]to listen the presentation
[01:04:09.220]and we'll look forward to see you next week.
[01:04:12.490]Thank you, Miller.
[01:04:13.323]Thank you everybody.

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Management of Herbicide-Resistant Weeds: Challenges and Opportunities

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