Herbicide Resistance
Peter Sikkema, University of Guelph, Canada
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05/14/2025
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Description
Herbicides have been placed in Herbicide Groups (HG) based on their sites of action. A major driving force for this classification system is that growers have been encouraged to rotate or mix herbicides from different HG to delay the evolution of herbicide-resistant weeds; because, in theory, all active ingredients within a herbicide group physiologically affect weeds similarly. Although herbicide resistance in weeds has been studied for decades, recent research has demonstrated patterns of cross-resistance are more complex than merely stating a certain weed biotype is resistant to a HG. The objective of this presentation is to highlight the intricacies associated with cross-resistance patterns within HG.
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- [00:00:00.640]The following presentation is part of the Agronomy and Horticulture Seminar Series
- [00:00:05.760]at the University of Nebraska-Lincoln. Well, good morning everyone. Thank you very much for being
- [00:00:10.720]here for the seminar of Dr. Peter Sikkema as a part of our Thursday seminar series.
- [00:00:16.880]My name is Amit Jhala. I'm a weed scientist in the department and it is my honor and pleasure to
- [00:00:24.880]introduce Dr. Peter Sikkema. I know him for last 20 years and he know me since I was a PhD student
- [00:00:33.920]at University of Alberta in Edmonton and he was a professor of weed science at University of
- [00:00:39.520]Guelph in Ontario. So I used to meet him every year in Canadian weed science society meetings
- [00:00:46.080]and I always get good suggestions from him about my presentation and poster and so he knows me very
- [00:00:53.600]well and I know him very well. After I joined UNL he was also serving on my graduate students
- [00:01:00.320]committee and I have served on his graduate students committee so it is always an honor
- [00:01:06.960]to work with Dr. Sikkema. He just retired last year after 36 years of outstanding service in
- [00:01:15.600]weed science research teaching and extension. In Canadian universities usually extension is
- [00:01:23.440]mostly like responsibility of state government but in case of Dr. Sikkema he was very actively
- [00:01:28.640]working on his extension programming whatever he does applied research in number of crops
- [00:01:35.280]for weed management. He has given number of presentations in extension meetings and
- [00:01:40.880]growers meetings across the country and also in the USA. He was very regularly attending
- [00:01:47.600]our north central weed science society meetings and also weed science society of America meetings
- [00:01:53.280]so I had an honor to visit with him almost every year multiple times actually in north
- [00:01:58.960]central weed science society meeting and then weed science society of America meetings and
- [00:02:03.440]his students have always participated in weed contest organized by north central
- [00:02:09.360]weed science society so our students are also familiar with his program and his students and
- [00:02:14.000]he is an outstanding scientist published like almost 450 papers throughout his career
- [00:02:23.120]uh he's the only individual that I know of he's a fellow of
- [00:02:27.280]Canadian weed science society he's a fellow of Canadian society of agronomy
- [00:02:33.600]he's a fellow of north central weed science society as well as he's a fellow of weed science
- [00:02:39.760]society of America so very distinguished carrier and I'm glad he's here and he's going to talk
- [00:02:46.800]about this important topic about herbicide resistant weeds in Nebraska we have at least
- [00:02:52.960]nine weeds which are resistant to at least one herbicide including six weeds are now resistant
- [00:02:58.640]to glyphosate and same thing in Ontario they have number of weeds are resistant to glyphosate and
- [00:03:04.320]some other commonly used herbicides in corn and soybeans so yeah please join me to welcome Dr.
- [00:03:10.960]Sikhaimai at UNL well thank you very much Amit for that introduction
- [00:03:23.200]so in my presentation today I'm going to address a question that's been on my mind for the last
- [00:03:30.480]number of years and before I begin in my presentation you'll note that I typed a number
- [00:03:37.280]of my slides using a third person pronoun however when I present the information I'm going to use a
- [00:03:45.120]first person pronoun simply because I don't want to make the assumption that everybody
- [00:03:52.640]shares the same message as I do in terms of herbicide resistance so the question that I
- [00:03:59.920]plan to address in my presentation this morning is in my quest to simplify my message with respect
- [00:04:07.840]with respect to herbicide resistance am I misleading agronomists ag retailers and producers
- [00:04:17.600]so in with respect to herbicide resistance
- [00:04:22.480]university professors weed scientists extension agents and personnel from the agricultural
- [00:04:28.800]products companies are conservative and we err on the side of caution so the question is is why
- [00:04:38.480]am I so conservative in my message with respect to herbicide resistance
- [00:04:45.440]and the reason is is university professors weed scientists extension agents and personnel from
- [00:04:52.320]the agricultural products companies reputation is on the line in all their communication
- [00:04:58.880]my respect from producers depends on them getting commercially acceptable weed control
- [00:05:07.200]and therefore I simplify my message to ensure producer success
- [00:05:15.440]so this happens to be the atrazine label in Canada I just went to the pest management
- [00:05:22.160]regulatory agency website just like you have the EPA we have the PMRA in Canada
- [00:05:28.160]and this is the first panel on the atrazine label in Canada and you will notice it says
- [00:05:36.000]right in the top right hand corner that atrazine is a group 5 herbicide and if you go to section
- [00:05:44.560]14 on the atrazine label this is what it says on the label to delay herbicide resistance
- [00:05:52.000]where possible rotate the use of atrex liquid 480 herbicide or other group 5 herbicides within
- [00:06:00.200]a growing season or sequence or among growing seasons with different herbicide groups that
- [00:06:07.240]control the same weeds in the field and you can see I just cut and paste this from page 20
- [00:06:13.980]on the atrazine label I will say though that however laboratory greenhouses
- [00:06:21.840]and field research conclude that herbicide resistance is far more complex or nuanced
- [00:06:29.700]than that and our research has shown that in many cases herbicide resistance is specific
- [00:06:38.060]to the chemical family within a herbicide group it could be specific to one active ingredient
- [00:06:46.080]within a herbicide group it could be dependent on the mechanism of herbicide resistance
- [00:06:51.680]the particular amino acid substitution in a weed biotype the application timing as well as the
- [00:07:00.980]temperature at application timing and herbicide resistance is not herbicide group specific so my
- [00:07:11.840]concern is because I have dramatically oversimplified my message I have removed very useful herbicide
- [00:07:21.520]and reduced grower success so that's a really uncomfortable position to be in as an extension
- [00:07:30.420]weed scientist and when I get home from doing a grower meeting I look myself in the mirror
- [00:07:36.500]and I say to myself I haven't said one lie today right I don't what I presented was based on
- [00:07:44.860]science and the next thing I say to myself and it makes me feel really uncomfortable I
- [00:07:51.360]didn't tell the whole story right and the reason why I didn't is because it's really complex
- [00:07:58.420]so in this presentation I will use 10 examples from Ontario and I'm sure you could use examples
- [00:08:07.300]from Nebraska and make the same message supported by research around the globe
- [00:08:13.660]that in many cases it's an oversimplification to simply say weed biotypes are herbicides
- [00:08:21.200]herbicide group resistant so I'm going to start with the very first herbicide resistant weed
- [00:08:28.940]biotype ever discovered on the globe that was in 1957 it was found in the province of Ontario
- [00:08:37.100]and it was group four resistant wild carrot and so here you can see a corn field with
- [00:08:45.480]wild carrot that I took in a producer's field in Ontario anyway
- [00:08:51.040]please note that this was published in the Canadian Journal of Plant Science it was published
- [00:08:57.120]in 1963 six years after it was discovered and here they're looking at the injury caused by
- [00:09:06.700]various herbicides to wild carrot they looked at three different formulations of 2,4-D in this
- [00:09:15.100]study it was the sodium salt the amine salt and the ester salt this is the injury rating
- [00:09:20.880]so this is how they did the study 75 or 65 years ago and I noticed that with the three 2,4-D
- [00:09:30.020]formulations it started out they had an injury rating of five and by six weeks after application
- [00:09:37.280]the injury was zero these biotypes were resistant to 2,4-D I think that's really interesting
- [00:09:45.040]what fascinates me more though is they used another phenoxycarbide
- [00:09:50.720]carboxylate herbicide 2,4-5-T and it was killed right and so what these authors wrote
- [00:09:59.340]and once again and I just cut and pasted it when treated with 2,4-D plants of the
- [00:10:05.860]susceptible strain died within a few weeks while those of the resistant strain recovered after
- [00:10:11.980]showing severe injury symptoms and the authors went on to write treatment with 2,4-5-T
- [00:10:20.560]killed both the susceptible and resistant strains I sure don't expect everybody in the room to know
- [00:10:27.960]the chemical structure of 2,4-D versus 2,4-5-T the only difference is 2,4-D has a chlorine at
- [00:10:36.060]the two and four position 2,4-5-T has a chlorine at the two four and five position it's only one
- [00:10:42.760]chlorine atom and because of the difference in that chemical structure some weeds were resistant
- [00:10:50.400]to the herbicide and others were still susceptible so please note that I have group four resistant
- [00:10:57.940]wild carrot that's a complete misnomer I should more accurately call it 2,4-D resistant wild
- [00:11:06.000]carrot it's not resistant to all the group four herbicides and really interesting
- [00:11:13.780]I have a group four resistant palmer amaranth a population of palmer amaranth
- [00:11:20.240]from Kansas is resistant to 2,4-D and MCPA the phenoxycarboxylates but it is
- [00:11:27.740]sensitive to dicamba a benzoate another herbicide family within the group four
- [00:11:34.400]herbicides so once again my title on my slide is incorrect it shouldn't say
- [00:11:41.540]group four resistant palmer amaranth it should say a herbicide family and it is
- [00:11:48.380]the phenoxy it is a
- [00:11:50.080]phenoxy carboxylate resistant palmer amaranth and not group four so in
- [00:11:56.400]terms of a group four resistant weeds they can be active ingredient specific
- [00:12:01.320]as I showed you in wild carrot or it could be herbicide family specific as I
- [00:12:07.920]showed in palmer amaranth so while the second example that I'll go through is
- [00:12:14.960]group five resistant lambsquarters the above caption is inaccurate
- [00:12:19.920]it's an over a simplification and the very first herbicide resistant weed in a
- [00:12:27.180]cornfield on the entire globe actually was found in Ontario and you'll see it
- [00:12:34.260]was found in 1973 and once again I just cut and paste a few comments out of this
- [00:12:42.600]manuscript I was amazed by how bright these weed scientists were so many years
- [00:12:49.760]ago and so John Bandine and Doug McLaren wrote the possibility of weeds becoming
- [00:12:56.960]resistant to repeated treatment with herbicides was pointed out by Harper in
- [00:13:02.940]1956 and the need for rotations was suggested by Abel in 1954 and the
- [00:13:12.320]authors received a report in 1974 that atrazine had failed to control lambs
- [00:13:17.540]quarters in field corn on a farm
- [00:13:19.600]located near Ripley in Bruce County on Ontario and the authors went on to write
- [00:13:26.360]that field corn had been grown continuously for approximately 10 years
- [00:13:30.940]in this field and atrazine was the only herbicide used prior to 1973 so for the
- [00:13:40.020]young people in the room I think a lot of you are thinking wow that was really
- [00:13:45.000]bad management right they're growing continuous corn and they're only using
- [00:13:49.440]one herbicide for weed management guess what herbicide resistant weed had never
- [00:13:56.000]been found in a cornfield on the globe right so this guy was doing managing his
- [00:14:02.200]crop I'm sure he was trying to maximize farm profitability and the way that he
- [00:14:07.940]could do that is by growing continuous corn and using atrazine continuously for
- [00:14:13.400]weed control because no weed had evolved resistant to atrazine prior to that
- [00:14:19.280]so in the Ontario crop protection hub that's where our information is for
- [00:14:25.700]farmers anyways within the group 5 herbicides you have the triazines
- [00:14:30.800]atrazine sold under the trade name of atrex and the lambsquarters control
- [00:14:36.020]rating is 95% and then the triazine owns its metribuzin sencor and they're
- [00:14:43.200]equally as good on lambsquarters
- [00:14:49.120]once again I just cut and paste from the manuscript Doug John Bandeen and Doug
- [00:14:56.460]McLaren wrote plants from the Elora selection this is the susceptible
- [00:15:00.620]biotype were completely killed by applications of the symmetrical triazines
- [00:15:06.100]such as atrazine and they said plants from the Ripley selection were not killed
- [00:15:12.800]by atrazine and they found the first herbicide resistant weed in a cornfield
- [00:15:18.960]on the globe so that's really interesting what I find more
- [00:15:24.960]interesting they went on to write the asymmetrical triazinone such as
- [00:15:30.960]metribuzin and zencort killed both selections so once again you'll note
- [00:15:37.080]that I have group 5 resistant lambsquarters at the top of the slide it's
- [00:15:41.760]incorrect it is a triazine resistant lambsquarters and the triazinone metribuzin
- [00:15:48.800]kills it even though they're both within the same herbicide group so absolutely
- [00:15:55.940]fascinating to me in Ontario lambsquarters is resistant to atrazine
- [00:16:01.200]but sensitive to zencort and lorox and it should be more
- [00:16:07.220]accurately be described as a triazine resistant lambsquarters not group 5
- [00:16:13.560]really interesting in Germany a lambsquarters population with the
- [00:16:18.640]leucine to valine amino acid substitution at position 218 it's
- [00:16:24.280]resistant to zencort but sensitive to the triazines and it would be more
- [00:16:30.280]accurately called metribuzin resistant lambsquarters and just recently
- [00:16:37.600]published and from Prince Edward Island in Canada a lambsquarters population
- [00:16:44.320]with a different amino acid substitution a serine to glycine
- [00:16:48.480]at position 264 is resistant to zencort but sensitive to lorox and it too
- [00:16:58.320]should be called a metribuzin resistant lambsquarters. The third example I'll
- [00:17:05.680]give you is a group 4 resistant green pigweed and I'll say the above caption
- [00:17:11.760]is inaccurate it's an oversimplification so in terms of a group 4 resistant green
- [00:17:18.320]pigweed here's the weedy control this happens to be Earl Elgie's farm in
- [00:17:23.460]Ontario and it was just published a year ago that green pigweed had
- [00:17:29.740]evolved resistance to the group 4 herbicide MCPA. It had a really low
- [00:17:36.300]resistance factor of 4.4 and that was published last year. Really interesting
- [00:17:43.680]to me you use another group 4 herbicide dicamba
- [00:17:48.160]and you have near perfect control right and so once again my caption is wrong
- [00:17:55.060]and more accurately this is MCPA resistant green pigweed and not group 4
- [00:18:03.280]resistant pigweed. So in reality group 4 resistant green pigweed is active
- [00:18:09.820]ingredient specific. I only gave you a very small amount out of the manuscript
- [00:18:15.340]that was published. This biotype
- [00:18:18.000]is resistant to MCPA, phenoxycarboxylate, and sensitive to 2,4-D
- [00:18:24.620]within the exact same herbicide family and the only difference is there's a
- [00:18:30.120]methyl at the two position on the phenoxy ring versus a chlorine. So the
- [00:18:35.600]fourth example I'll give you is a group 2 resistant green pigweed. Once again
- [00:18:41.600]that's an oversimplification. Within the group 2 herbicides there's a number of
- [00:18:47.840]pesticide families. The ones that are used the most in agriculture are the
- [00:18:52.760]imidazolinones such as Imazemox or Imazethapyr and they're sold under the
- [00:18:59.720]trade names of Raptor and Pursuit in the United States. You have the triazoloprimidine
- [00:19:05.240]such as Cloransilam and Flumetsilam. They are first-rate in Python and you
- [00:19:11.900]have the sulfonylureas, Clorimuron, Halosulfuron, Prosulfuron and
- [00:19:17.680]Flumetiluron and they're sold under the trade names of Classic, Permit, Peak and
- [00:19:22.700]Harmony. So in terms of group 2 resistance, what we know today is that
- [00:19:29.960]mutations at eight different sites on the ALS enzyme or the DNA that codes
- [00:19:36.680]for the ALS enzyme, there are 29 different distinct amino acid
- [00:19:42.360]substitutions that confer group 2 resistance in weeds that have been
- [00:19:47.520]identified so far. Here you can see the eight locations of those amino acid
- [00:19:54.200]substitutions and a really good question on your part would be is how do you get
- [00:19:59.460]29 out of 8? And there's 11 different amino acid substitutions at proline 197
- [00:20:08.820]that confer resistance to group 2 herbicides in various weed species. So this is the
- [00:20:17.360]very first manuscript that was published on group 2 resistant pigweed in Ontario and you'll notice
- [00:20:24.580]that it was published by Ferguson et al about 20 years ago in 2001 and in their research
- [00:20:33.140]the harrow biotype was considered to be the susceptible biotype and the susceptible
- [00:20:39.840]biotype is arbitrarily given a resistance factor of one and then you compare the resistant biotype
- [00:20:47.200]to the sensitive biotype so harrow is just a town in Ontario Brigden's a different town in Ontario
- [00:20:57.120]and you'll notice that Brigden 29 it had a resistance factor of 1284 to pursuit and 1257
- [00:21:07.420]to harmony keep in mind I just showed you the research by Isabel Aiklin and the resistance
- [00:21:14.760]factor to MCPA was four decimal
- [00:21:17.040]four right so here you're just talking scales higher in terms of how resistant weeds are to
- [00:21:24.560]the group two herbicide so that's interesting what interests me far more though is Brigden 39
- [00:21:33.160]so it's the same town it's got to be really close together geographically it is highly
- [00:21:40.760]resistant to the group two herbicide pursuit and it has negative cross resistance
- [00:21:46.880]to the group two herbicide harmony so that means you can use lower than the labeled field rate to
- [00:21:53.820]kill this biotype so I would ask you the rhetorical question do you think it's responsible
- [00:22:03.220]for me to recommend the group two herbicide harmony on the group two resistant Brigden 39
- [00:22:10.220]biotype it's got negative cross resistance it's going to control it better than it does the
- [00:22:16.720]sensitive control so now 20 years later we did our research I just then it was published in the
- [00:22:25.540]last couple of years we know that through advances in molecular weed science in a green pig weaned
- [00:22:32.480]some biotypes of the serine 653 threonine amino acid substitution that amino acid substitution
- [00:22:41.500]confers resistance to the images or unknown herbicide pursuit
- [00:22:46.560]it confers resistance to the triazoloperimidine first rate
- [00:22:51.160]it confers resistance to the sulfonylurea herbicide classic and amazing harmony is still
- [00:23:00.280]effective and that's exactly what they showed 20 years earlier in that brigden 39 biotype
- [00:23:09.040]so now we know the actual amino acid substitution that confers resistance to all of the
- [00:23:16.400]group twos with the exception of harmony so i would ask you is it okay for me to say to earl lg
- [00:23:26.280]that's the farm where we collected this seed from that he has group two resistant green pigweed in
- [00:23:32.140]his identity preserved you say non-genetically modified soybean when i know that harmony will
- [00:23:39.240]provide near perfect weed control on his farm so now i'll go on to uh
- [00:23:46.240]group two resistant waterhemp once again the above caption is inaccurate it's an over
- [00:23:52.720]simplification there are two amino acid substitutions in waterhemp that confer resistance
- [00:23:59.140]to the group two herbicides in ontario the first amino acid substitution that confers resistance
- [00:24:06.560]is a tryptophan to leucine amino acid substitution at position 574 and that confers resistance
- [00:24:16.080]to all of the group twos right so every single group two that we've evaluated it's resistant
- [00:24:22.780]to the imidazolinones pursuit and raptor the sulfonylureas classic harmony permit and express
- [00:24:29.680]and the triazoloperimidines first rate in python and just to show you what it looked like in our
- [00:24:36.660]greenhouse research so the tryptophan to leucine amino acid substitution at position 574 confers
- [00:24:45.920]resistance to three group two herbicide families it's resistant to the imidazolinone pursuit the
- [00:24:55.320]sulfonylurea classic and the triazoloperimidine first rate however there's a different amino
- [00:25:03.820]acid substitution that also confers group two resistance and it's a serine to asparagine
- [00:25:10.580]amino acid substitution at position 653
- [00:25:15.760]and it confers resistance only to the imidazolinone pursuit and raptor so if you're the unlucky farmer
- [00:25:26.120]in ontario and your water hemp has the tryptophan to leucine 574 amino acid substitution
- [00:25:34.460]it confers resistance to all of the herbicides that i just mentioned
- [00:25:40.040]in contrast to that if you're the lucky farmer in ontario
- [00:25:45.600]and you have the serine to asparagine amino acid substitution at position 653
- [00:25:52.400]it's resistant to the imidazolinones but it's susceptible to the sulfonylureas and the
- [00:25:59.220]triazoloperimidines and i would ask you the same question is it okay for me to say to an identity
- [00:26:07.840]preserved soybean grower who has water hemp with the serine to asparagine amino acid substitution
- [00:26:15.440]that he has group two resistant water hemp when i know that six out of the eight herbicides i
- [00:26:23.120]mentioned there still work right and so uh in reality group two resistant water hemp is amino
- [00:26:30.920]acid substitution and herbicide family specific so now i'll move on to group 14 resistant green
- [00:26:41.400]pigweed once again the above caption is inaccurate
- [00:26:45.280]i once again i went to the crop protection hub i'm looking at two different herbicides they're
- [00:26:51.900]in two different families so you have the n-phenyl triazolinone family the active ingredient is
- [00:26:58.540]sulfentrazine sulfentrazone sorry and its authority and you have the n-phenyl imides
- [00:27:04.800]it's flumioxazine and it's valor and both of them have a green pigweed control rating of 95
- [00:27:11.300]and our provincial uh weed
- [00:27:15.120]guide so really interesting to me when you take it to the field authority the n-phenyl
- [00:27:23.280]triazolinone fails and valor the n-phenyl imide still provided 78 percent control
- [00:27:31.820]this is what it looked like in the field here you can see the uh weed escapes with authority
- [00:27:39.520]and it's really disappointing absolutely amazing to me another
- [00:27:44.960]group 14 herbicide i said it's group 14 resistant green pigweed and you have near perfect control
- [00:27:53.920]so i say there's group 14 resistant green pigweed when i know that valor a group 14 herbicide
- [00:28:02.320]provides very good control in terms of the my seventh example glyphosate resistant
- [00:28:10.380]marestail in canada this is called canada fleabane
- [00:28:14.800]i went through and changed it for my lecture today and just this morning
- [00:28:19.560]amit told me you guys call it marestail so anyways so uh glyphosate resistant marestail
- [00:28:27.200]is influenced by temperature as well as a mechanism of resistance there's two mechanisms
- [00:28:33.720]of resistance in ontario there's an altered target site as well as vacuolar sequestration
- [00:28:40.360]vacuolar sequestration is really interesting
- [00:28:44.640]glyphosate can be sequestered in the vacuole or extracellular space which prevents it by
- [00:28:50.740]from being translocated to the site of action in the meristems and in marestail the amount
- [00:28:57.780]of glyphosate in the vacuole and the sensitive biotype was 15 that means 85 can move to the
- [00:29:07.200]chloroplast that's where the shikimate biosynthetic pathway is and you get control of every weed
- [00:29:14.480]on the globe where glyphosate's been applied really interesting in this research published
- [00:29:22.060]by gay et al in 2011 the amount of glyphosate in the vacuole and the resistant biotype was 85
- [00:29:29.660]and there wasn't enough glyphosate to go to the chloroplast and you have a resistant biotype
- [00:29:37.620]on the farm and the sequestration in the vacuole is through abc transporters
- [00:29:44.320]that move the glyphosate into the vacuole really interesting though temperature has been found to
- [00:29:53.740]affect vacuolar sequestration of glyphosate and marestail and when temperature was applied at
- [00:30:00.600]less than 12 degrees Celsius 54 degrees Fahrenheit vacuolar sequestration of glyphosate was inhibited
- [00:30:07.720]and the resistant biotypes were susceptible to that treatment so I looked at the
- [00:30:14.160]weather forecast forecast for Lincoln Nebraska on Sunday the high temperature is nine degrees
- [00:30:21.520]Celsius it's about 48 degrees Fahrenheit and Mick Jolla could recommend to every farmer that has
- [00:30:28.840]marestail if their mechanism of resistance is vacuose sequestration spray roundup on Sunday
- [00:30:35.400]you'll get perfect control because it's influenced by temperature at the time of application
- [00:30:44.000]so if marestail is resistant to glyphosate due to vacuose sequestration and it's applied at less
- [00:30:51.200]than 54 degrees Fahrenheit then glyphosate is still effective in contrast if resistance is
- [00:30:59.720]due to an altered surrogate site there's no effective temperature in terms of a group 27
- [00:31:06.900]resistant waterhemp it's influenced by time of application so a group 27 resistant
- [00:31:13.840]in waterhemp is due to enhance metabolism which confers our resistance to the group
- [00:31:20.740]27 herbicides applied post emergence but the group 27 herbicides applied prior to
- [00:31:29.500]waterhemp emergence still work so well this is some research that was completed
- [00:31:37.000]by Hannah Symington well she was a graduate student in my program and you
- [00:31:43.680]apply Callisto post emergence make sure you note that it's post emergence at the
- [00:31:48.780]top there and it's highly resistant right Callisto does not kill group 27
- [00:31:55.620]resistant waterhemp when it's applied post emergence this biotype is also
- [00:32:01.620]resistant to atrazine and it's resistant to the tank mix of a Callisto plus
- [00:32:07.320]atrazine and so Hannah Symington published a manuscript in Canada
- [00:32:13.520]and said that we have group 27 resistant waterhemp in the province but
- [00:32:19.760]once again that's an oversimplification I asked Hannah to repeat that research
- [00:32:26.360]and I asked her to put in a hundred seeds in each one of these flats and
- [00:32:31.100]then apply the herbicides pre-emergence before the waterhemp had germinated and
- [00:32:37.580]emerged this is the control that's where atrazine was applied the
- [00:32:43.360]exact herbicide on the same biotype from the same field where Callisto
- [00:32:49.060]totally failed when it was applied post emergence gave a hundred percent the
- [00:32:54.160]same herbicide provided a hundred percent control when it was applied
- [00:32:59.160]pre-emergence and here you can see the tank mix of our Callisto plus atrazine
- [00:33:05.160]and perfect weed control so what does this mean on the farm and so
- [00:33:13.200]the mechanism of resistance is enhanced metabolism if you apply the group 27
- [00:33:19.980]herbicides Armizan, Callisto, Lottis and Shieldex post emergence they
- [00:33:25.080]completely fail and in contrast to that if you applied Acuron balance or Callisto
- [00:33:32.280]soil applied you would get perfect control of a group 27 resistant biotype
- [00:33:38.520]just by changing your time of application
- [00:33:43.040]so I would ask you the rhetorical question is it okay for me to say
- [00:33:48.640]there's group 27 resistant waterhemp when I know that group the group 27
- [00:33:54.680]herbicides Acuron balance and Callisto applied pre-emergence provide excellent
- [00:33:59.960]control actually the best herbicide we have for the control of group 27
- [00:34:06.720]resistant waterhemp in Ontario and corn it's Acuron applied pre-emergence right
- [00:34:12.880]and so best herbicide is a group 27 herbicide I think the intersection
- [00:34:21.520]between chemical structure and mechanism of resistance for a group 5 resistant
- [00:34:26.020]waterhemp is fascinating so this is a commercial soybean field in Ontario that
- [00:34:33.700]is the density of multiple herbicide resistant waterhemp that some farmers
- [00:34:40.060]are dealing with in the province
- [00:34:42.720]so once again this is an oversimplification there are two
- [00:34:46.720]mechanisms of resistance you have non-target site resistance which is due
- [00:34:52.020]to enhanced metabolism and you have a target site resistance which is an
- [00:34:58.880]amino acid substitution at positions 264 so if you have non-target site
- [00:35:07.500]resistance it's enhanced metabolism it's enhanced metabolism by
- [00:35:12.560]by a GST enzyme, glutathione S-transferase enzyme,
- [00:35:17.100]and it confers a high level of resistance to atrazine.
- [00:35:20.920]This is the first graduate student that worked on glyphosate-resistant waterhemp in Ontario,
- [00:35:28.080]and Mike Shriver found that the biotype was not only resistant to glyphosate,
- [00:35:34.080]it was also resistant to atrazine,
- [00:35:37.160]and this just happens to be the 22nd field that he collected seed from,
- [00:35:42.600]and A is his short form for atrazine, and you can see it's highly resistant.
- [00:35:47.860]But metribuzin is still effective,
- [00:35:51.800]and that is supported by manuscripts that have been published in the peer-reviewed literature.
- [00:35:59.820]So this happens to be Doug Nelson's farm.
- [00:36:03.640]If I say his name and if I put his name on my slide, that means I like him.
- [00:36:08.180]Anyways, here you can see atrazine,
- [00:36:11.940]and it's a total failure, right, on his farm.
- [00:36:16.400]And we did trials on his farm.
- [00:36:20.240]This is the first year I was there.
- [00:36:22.120]And we did a soybean experiment 100 meters away, 100 yards away,
- [00:36:28.720]and we had perfect control.
- [00:36:30.780]And I said to myself, this doesn't make sense.
- [00:36:34.640]I'm working with two Group 5 herbicides, atrazine and Sencor,
- [00:36:41.280]one provides near perfect control, almost 100%, I think you'd agree with me,
- [00:36:47.620]and the other one is a complete failure on the farm.
- [00:36:51.900]And so the question is, is why does atrazine fail,
- [00:36:57.120]and why does metribuzin work?
- [00:36:59.600]And remember I said this was enhanced metabolism,
- [00:37:03.140]it was by a specific glutathione S-transferase enzyme.
- [00:37:07.940]And here's the...
- [00:37:10.620]Here's the chemical structure for atrazine.
- [00:37:13.040]I almost never put up the chemical structure of a herbicide
- [00:37:17.540]when I do an extension presentation for farmers in Ontario.
- [00:37:21.480]You will just lose your audience when you put them up,
- [00:37:25.040]and guess what?
- [00:37:25.840]I do it every time I talk about waterhemp and waterhemp control.
- [00:37:30.320]And I put up this slide,
- [00:37:32.720]and notice I put a red box around the chlorine atom
- [00:37:36.840]at the number one position.
- [00:37:38.660]In contrast,
- [00:37:40.340]here is the chemical structure of metribuzin,
- [00:37:44.240]and you can see I put a green box around the oxygen
- [00:37:49.580]at the number one position.
- [00:37:51.220]So the reason why atrazine fails
- [00:37:55.280]when you spray atrazine on a group 5 resistant biotype
- [00:38:00.660]where the mechanism of resistance is enhanced metabolism
- [00:38:03.660]by glutathione S-transferase
- [00:38:06.560]is that enzyme binds to the chlorine
- [00:38:10.260]at the number one position.
- [00:38:12.740]So now you have the herbicide that's conjugated to glutathione,
- [00:38:18.120]which is just a 3-amino acid polypeptide.
- [00:38:21.280]That conjugated molecule is recognized by ABC transporters
- [00:38:26.740]and it dumps it into the vacuo.
- [00:38:29.200]The herbicide doesn't get it to the chloroplast
- [00:38:33.200]at a lethal concentration
- [00:38:34.680]and you have a resistant biotype on the farm.
- [00:38:38.400]In contrast,
- [00:38:39.980]notice that metribuzin has an oxygen at the number one position.
- [00:38:45.980]That does not provide a binding site for glutathione S-transferase.
- [00:38:51.320]Therefore, glutathione or metribuzin is not dumped into the vacuo
- [00:38:56.360]and it remains biologically active in the plant
- [00:38:59.380]and it provides perfect control
- [00:39:02.380]of a group 5 resistant waterhemp plant on the farm.
- [00:39:07.580]In contrast to that,
- [00:39:09.960]if you're the unlucky farmer in Ontario
- [00:39:12.860]and you have waterhemp with the serine to glycine amino acid
- [00:39:18.060]substitution at position 264,
- [00:39:20.940]it confers resistance to the triazines, atrazine,
- [00:39:24.960]as well as the triazinones, metribuzin.
- [00:39:28.460]So this is the control.
- [00:39:31.440]Sorry about that.
- [00:39:33.620]So if you have enhanced metabolism
- [00:39:36.680]as the mechanism of resistance in waterhemp,
- [00:39:40.020]and you apply Sencor, you get perfect control.
- [00:39:43.220]If you're the unlucky farmer,
- [00:39:45.920]and you have the altered target site,
- [00:39:48.740]and so you can see this is Tony Stratman's farm
- [00:39:51.860]compared to Doug Nelson's,
- [00:39:53.680]and it's a complete failure,
- [00:39:55.860]and it's because the mechanism of resistance is different.
- [00:39:59.980]It's an altered target site versus enhanced metabolism.
- [00:40:04.420]And so a mechanism of resistance
- [00:40:08.760]influences field performance of Sencor.
- [00:40:12.560]So what does this mean on the farm?
- [00:40:15.920]If you're the unlucky farmer like Tony Stratman,
- [00:40:18.980]and he has the altered target site,
- [00:40:22.580]it confers resistance to atrazine,
- [00:40:25.080]symmetrical triazine herbicide,
- [00:40:29.120]and it also confers resistance to Sencor metribuzin,
- [00:40:35.440]the asymmetrical triazinone.
- [00:40:38.220]Inclusively,
- [00:40:38.580]in contrast to that,
- [00:40:40.160]Doug Nelson,
- [00:40:41.840]he has enhanced metabolism,
- [00:40:43.940]and it confers resistance to atrazine,
- [00:40:47.340]and Sencor would provide perfect control on his farm.
- [00:40:51.960]So I would ask you the question again,
- [00:40:55.300]is it okay for me to say to Doug Nelson
- [00:40:57.800]that he has group 5 resistant waterhemp
- [00:41:00.300]when I know that the group 5 herbicide Sencor
- [00:41:04.580]provides excellent control on his farm,
- [00:41:08.300]and I showed you how good it was,
- [00:41:10.860]like it's near perfect control in a soybean.
- [00:41:14.280]So in reality, I say there's group 5 resistant waterhemp
- [00:41:19.240]to simplify my message to ensure grower success,
- [00:41:22.660]even though I know that it's affected by chemical structure
- [00:41:27.060]and mechanism of resistance.
- [00:41:29.780]And the last example that I'll go through
- [00:41:33.320]is group 1 resistant large crabgrass.
- [00:41:36.280]Once again, the above captioning
- [00:41:38.280]is inaccurate.
- [00:41:39.220]It's an oversimplification.
- [00:41:41.500]So within the group 1 herbicide,
- [00:41:44.240]there's three herbicide families.
- [00:41:46.180]So you have the phenylpyrazoanone,
- [00:41:49.040]which is pinoxidine,
- [00:41:51.960]sold under the trade name of Axial.
- [00:41:54.500]You have the cyclohexanediones,
- [00:41:57.300]clethodim, sethoxidim, and tralcoxidim,
- [00:41:59.980]sold under the trade names of Select, Post, and Achieve.
- [00:42:03.740]And then you have the ariloxy, phenoxypropionates,
- [00:42:07.940]oxyprop, fluazephrop, and puzalephrop,
- [00:42:10.480]sold under the trade names of Ristar, Fusilade, and Assure.
- [00:42:14.440]And I went to the Ontario Crop Protection Hub,
- [00:42:17.980]but there's no ratings for three of them
- [00:42:20.520]that are used for weed control in wheat, barley, and oats,
- [00:42:24.420]simply because large crabgrass isn't a problem in those crops.
- [00:42:28.040]But they have an equal rating for the other four herbicides
- [00:42:33.220]at 85% control.
- [00:42:35.820]So here, Assure,
- [00:42:37.800]was applied.
- [00:42:38.580]This is Waterloo County,
- [00:42:40.520]perfect control of large crabgrass.
- [00:42:44.040]This is Huron County,
- [00:42:45.620]and it's resistant.
- [00:42:47.400]And that didn't surprise me, right?
- [00:42:49.380]I mean, we just don't randomly go to a farmer's field and collect seed.
- [00:42:53.260]The farmer called me and said they had poor control.
- [00:42:55.800]And our greenhouse research totally supported
- [00:42:59.040]what the farmer had seen in the field.
- [00:43:00.900]So that wasn't surprising.
- [00:43:02.900]Keep in mind,
- [00:43:04.660]Assure is within one family,
- [00:43:06.660]the araloxyphenols,
- [00:43:07.660]phenoxypropionates.
- [00:43:09.060]Then we went to a different family,
- [00:43:11.300]the cyclohexanediones post.
- [00:43:13.580]Here you can see Waterloo County
- [00:43:16.080]and the Huron County ones resistant.
- [00:43:19.060]So it looks like it's resistant
- [00:43:21.800]to at least two herbicide families,
- [00:43:23.920]the araloxyphenoxypropionates
- [00:43:26.280]and the cyclohexanediones.
- [00:43:28.820]And this really surprised me.
- [00:43:32.120]And I remember taking this picture
- [00:43:34.560]in the greenhouse
- [00:43:35.260]and I kept my mouth shut
- [00:43:37.520]I was convinced
- [00:43:40.000]sorry Alex
- [00:43:41.340]I was convinced that my research
- [00:43:44.120]technician screwed up
- [00:43:45.560]I was convinced that he did
- [00:43:47.560]host and select really similar
- [00:43:50.160]chemical structure, they're both
- [00:43:51.800]cyclohexanediones
- [00:43:53.080]and I thought he put something else in the jug
- [00:43:56.460]and he must have made a mistake
- [00:43:58.680]but I am
- [00:44:00.540]67 years old and I've learned
- [00:44:02.740]to keep my mouth shut
- [00:44:04.000]and I just thought this makes no sense
- [00:44:06.920]to me
- [00:44:07.380]anyways we took it to the field
- [00:44:10.240]here's post the cyclohexanedione
- [00:44:13.220]total failure
- [00:44:14.720]in the field select
- [00:44:16.160]exactly what I showed you
- [00:44:18.440]in the greenhouse perfect control
- [00:44:20.040]so obviously Alex my technician
- [00:44:22.380]didn't screw up he did it perfectly
- [00:44:24.780]and our field results
- [00:44:26.680]supported what we
- [00:44:27.900]found in the greenhouse
- [00:44:30.260]so here's the chemical structure
- [00:44:32.600]of both post and select
- [00:44:34.800]and if you look to the left
- [00:44:37.000]of
- [00:44:37.240]where I put that purple bar
- [00:44:39.360]they're identical right
- [00:44:41.000]and it's just subtle differences
- [00:44:43.520]in the substitution at position
- [00:44:45.800]two of the
- [00:44:47.780]two chemical structures
- [00:44:49.900]that results in
- [00:44:51.920]one of the herbicides working
- [00:44:53.740]and the other failing
- [00:44:54.820]notice in selected has a two carbon
- [00:44:57.840]chain here here you have the
- [00:44:59.720]nitrogen oxygen two carbon chain
- [00:45:02.020]double bonded carbon and chlorine
- [00:45:04.100]and you'll notice that
- [00:45:05.920]the post is
- [00:45:07.100]not quite as complex it has a
- [00:45:09.720]two carbon chain and a three
- [00:45:11.500]carbon chain and one works
- [00:45:13.840]in the field and one doesn't
- [00:45:16.120]so well once again I'd
- [00:45:17.860]ask you is it right for me
- [00:45:19.740]to say to Earl Becker that he has group
- [00:45:21.700]one resistant large crabgrass
- [00:45:23.540]in his identity preserved soybean
- [00:45:25.620]when I know that the group
- [00:45:27.680]one herbicide select
- [00:45:29.220]will provide excellent
- [00:45:31.460]control on his farm
- [00:45:33.420]so to
- [00:45:35.440]summarize I
- [00:45:36.960]say there are weeds that are
- [00:45:39.140]resistant to various herbicide groups
- [00:45:41.180]to simplify my message
- [00:45:43.040]to ensure grower success
- [00:45:45.520]even though I
- [00:45:47.360]know that this is not
- [00:45:49.400]always accurate
- [00:45:50.700]right and consequently
- [00:45:53.000]I am eliminating very
- [00:45:55.380]effective weed management tools
- [00:45:57.380]and my questions
- [00:45:59.180]for you are is it
- [00:46:00.800]responsible or right for me
- [00:46:02.900]to simplify my message to the
- [00:46:04.980]extent that effective
- [00:46:06.820]weed management tools are removed
- [00:46:08.900]and grower success is negatively
- [00:46:11.100]impacted
- [00:46:12.000]are you comfortable with my
- [00:46:14.940]communication with respect
- [00:46:16.940]to herbicide resistance
- [00:46:18.640]and due to the complexity
- [00:46:21.320]of herbicide resistance
- [00:46:22.760]that I presented this morning
- [00:46:24.640]can this complexity
- [00:46:26.600]be effectively communicated
- [00:46:28.780]to producers
- [00:46:29.640]and I think we should continue
- [00:46:32.440]to be conservative in our message
- [00:46:34.480]regarding herbicide resistance
- [00:46:36.320]and assume a weed biotype
- [00:46:38.660]is resistant to all herbicides
- [00:46:40.680]within a group
- [00:46:41.580]except where through advances
- [00:46:44.660]in weed science
- [00:46:45.920]molecular weed science
- [00:46:48.440]genomics
- [00:46:49.140]the mechanism of resistance
- [00:46:50.980]and efficacy of active ingredients
- [00:46:53.060]within a herbicide group are known
- [00:46:55.060]I think it's responsible
- [00:46:57.240]weed management to use
- [00:46:58.860]efficacious herbicides
- [00:47:01.060]within that herbicide group
- [00:47:03.180]to improve weed control
- [00:47:04.800]reduce weed
- [00:47:05.820]seed additions to the soil seed bank
- [00:47:08.860]and thereby reduce
- [00:47:11.080]the future evolution
- [00:47:12.500]of our herbicide resistance
- [00:47:14.960]so I'm going to just
- [00:47:16.960]make a few assumptions here
- [00:47:18.580]let's assume that a grower has a three crop
- [00:47:20.980]rotation of identity
- [00:47:22.980]preserved
- [00:47:23.760]a three crop rotation of corn
- [00:47:27.300]identity preserved
- [00:47:28.900]soybean and wheat
- [00:47:30.080]the time horizon is five cycles
- [00:47:33.020]of that three crop rotation
- [00:47:34.720]or
- [00:47:35.240]50
- [00:47:35.800]years
- [00:47:36.500]personally
- [00:47:37.760]I think it's responsible herbicide
- [00:47:40.720]stewardship
- [00:47:41.360]for Earl Becker to use the group one
- [00:47:44.440]herbicide select
- [00:47:45.780]five times in a 15 year period
- [00:47:48.760]for the control of group one resistant
- [00:47:50.720]large crabgrass
- [00:47:52.180]where the mechanism of resistance
- [00:47:54.560]is known to be gene
- [00:47:56.480]over expression
- [00:47:57.540]and I showed you it provides perfect
- [00:48:00.320]control of that
- [00:48:02.000]large crabgrass
- [00:48:03.380]I think it's responsible
- [00:48:05.440]for Doug Nelson to use the group five
- [00:48:07.800]herbicide Sencor
- [00:48:09.220]five times in a 15 year period
- [00:48:12.220]for the control of group five
- [00:48:14.300]resistant waterhemp
- [00:48:15.600]where the mechanism of
- [00:48:18.220]resistance is enhanced metabolism
- [00:48:20.460]and finally
- [00:48:22.220]I think it's responsible
- [00:48:23.720]for Craig King to use the group
- [00:48:26.060]27 herbicide Acuron
- [00:48:28.360]applied pre-emergence
- [00:48:30.760]five times in a 15 year period
- [00:48:33.180]for the control of group
- [00:48:35.080]27 resistant water hemp
- [00:48:37.040]where the mechanism of resistance
- [00:48:39.140]is enhanced metabolism
- [00:48:42.000]so I'd like to
- [00:48:43.960]thank you for your time
- [00:48:45.440]I thoroughly enjoy doing
- [00:48:47.180]presentations for growers
- [00:48:49.060]and students
- [00:48:49.820]if you have any questions at all
- [00:48:52.800]in terms of what I presented
- [00:48:54.500]I am more than happy to try
- [00:48:57.200]to address them
- [00:48:58.080]I think what I presented this morning
- [00:49:00.660]is equally as applicable
- [00:49:02.380]to the entomologists in your department
- [00:49:04.720]as well as the plant pathologist
- [00:49:07.320]and obviously it's
- [00:49:09.000]applicable to weed science
- [00:49:11.760]so if you have any questions
- [00:49:20.880]I mean how do you communicate
- [00:49:23.160]this resistance to farmers
- [00:49:24.800]anyone
- [00:49:27.840]yeah let's use this
- [00:49:30.000]that was excellent
- [00:49:32.760]I
- [00:49:33.940]I'm a soils guy
- [00:49:36.100]and the
- [00:49:37.120]the nitrogen people
- [00:49:38.960]they sometimes use
- [00:49:40.640]what they call a postage stamp
- [00:49:42.460]or small plots
- [00:49:43.400]very close to each other
- [00:49:44.840]with different nitrogen rates
- [00:49:46.120]to evaluate
- [00:49:46.800]performance and efficiency
- [00:49:49.740]and stuff like that
- [00:49:50.760]is there an opportunity
- [00:49:52.340]since
- [00:49:53.300]many of the
- [00:49:54.660]the farmers in Canada
- [00:49:56.280]aren't going to have access
- [00:49:57.820]to your
- [00:49:58.720]on-farm research
- [00:50:00.420]correct
- [00:50:00.960]an opportunity
- [00:50:02.600]for you
- [00:50:03.700]or
- [00:50:03.920]a commercial entity
- [00:50:04.840]to
- [00:50:05.680]to go out
- [00:50:06.760]into their fields
- [00:50:07.700]and
- [00:50:08.540]set up
- [00:50:10.680]half a dozen little plots
- [00:50:11.840]and spray them with
- [00:50:12.520]something different
- [00:50:13.220]to see which one
- [00:50:14.960]and what type of
- [00:50:16.080]resistance they have
- [00:50:17.080]so for sure
- [00:50:18.700]that's a possibility
- [00:50:19.980]the problem is
- [00:50:21.100]is there's
- [00:50:21.560]28,000
- [00:50:22.540]corn soybean growers
- [00:50:23.680]in the province of Ontario
- [00:50:25.100]and it's
- [00:50:25.680]you know
- [00:50:25.940]it's just impossible
- [00:50:27.480]to do it
- [00:50:28.140]I think there's
- [00:50:29.380]huge opportunities
- [00:50:30.440]for the young people
- [00:50:31.420]in the room
- [00:50:32.020]I think
- [00:50:33.240]through advanced
- [00:50:33.900]advances
- [00:50:34.060]in molecular
- [00:50:34.880]weed science
- [00:50:35.860]I showed you
- [00:50:37.060]a number of the
- [00:50:37.860]amino acid
- [00:50:38.600]substitutions
- [00:50:39.580]you can send
- [00:50:40.580]leaf samples
- [00:50:41.660]you can send seed
- [00:50:42.600]to Turnkey Genomics
- [00:50:43.960]in Guelph, Ontario
- [00:50:45.000]and they can tell you
- [00:50:46.860]in two weeks
- [00:50:47.820]what amino acid
- [00:50:49.980]substitution
- [00:50:50.740]is in that plant
- [00:50:52.140]and then
- [00:50:53.300]if you had
- [00:50:54.180]the information
- [00:50:54.840]just like you were
- [00:50:55.700]talking about
- [00:50:56.460]you may or may not
- [00:50:58.020]know which herbicides
- [00:50:59.160]are still effective
- [00:51:00.040]and which ones are not
- [00:51:00.960]so I think
- [00:51:02.280]for all the young
- [00:51:03.400]people in the room
- [00:51:03.880]the horizon is
- [00:51:05.600]super bright
- [00:51:06.500]for you
- [00:51:07.020]and this area
- [00:51:08.420]of molecular
- [00:51:09.100]weed science
- [00:51:09.860]that's not my
- [00:51:10.860]forte at all
- [00:51:11.740]I'm too old
- [00:51:12.480]for that
- [00:51:12.940]but I mean
- [00:51:14.400]I use it
- [00:51:16.000]all the time
- [00:51:16.560]I talk about it
- [00:51:17.520]all the time
- [00:51:18.100]I don't know
- [00:51:18.600]how to do it
- [00:51:19.180]I think the future
- [00:51:20.300]is bright
- [00:51:20.900]for weed
- [00:51:22.520]scientists
- [00:51:22.960]in the future
- [00:51:23.680]I think
- [00:51:24.440]any of you
- [00:51:25.420]that are doing
- [00:51:26.260]your degree
- [00:51:27.680]with a mint
- [00:51:28.300]man I think
- [00:51:29.380]your future
- [00:51:29.880]is bright
- [00:51:30.260]in weed science
- [00:51:31.040]and this is
- [00:51:32.900]going to become
- [00:51:33.320]commonplace
- [00:51:33.860]you talk about
- [00:51:35.160]nitrogen
- [00:51:35.600]you think about
- [00:51:37.020]farmers
- [00:51:37.520]they routinely
- [00:51:38.380]do soil tests
- [00:51:39.800]to know how much
- [00:51:41.280]phosphorus
- [00:51:42.320]potassium
- [00:51:42.940]to put on
- [00:51:43.520]I think farmers
- [00:51:44.620]in the future
- [00:51:45.180]will routinely
- [00:51:45.960]do genomic
- [00:51:48.000]analysis
- [00:51:48.500]on their weed
- [00:51:49.360]escapes
- [00:51:49.820]and they may
- [00:51:51.400]know the exact
- [00:51:52.520]mechanism of
- [00:51:53.960]resistance
- [00:51:54.360]and which
- [00:51:55.200]herbicides
- [00:51:55.960]still work
- [00:51:56.540]so the future
- [00:51:58.400]is bright
- [00:51:58.980]for weed
- [00:52:00.100]science
- [00:52:00.600]students
- [00:52:01.440]yeah
- [00:52:02.980]I think
- [00:52:03.840]we use
- [00:52:05.360]this
- [00:52:05.740]group
- [00:52:08.320]rotation
- [00:52:08.880]to try
- [00:52:09.960]and reduce
- [00:52:10.520]the amount
- [00:52:11.000]of risk
- [00:52:12.580]involved in
- [00:52:13.660]developing
- [00:52:14.140]some herbicide
- [00:52:15.180]resistance
- [00:52:15.880]do you think
- [00:52:17.280]there's any
- [00:52:17.860]difference
- [00:52:18.640]in terms
- [00:52:19.640]of that
- [00:52:21.140]success
- [00:52:21.880]if you do
- [00:52:23.440]the rotation
- [00:52:24.160]within the
- [00:52:25.120]group
- [00:52:25.460]among these
- [00:52:27.000]resistant
- [00:52:28.360]and susceptible
- [00:52:29.260]types
- [00:52:29.840]so a really
- [00:52:31.560]good question
- [00:52:32.300]and let me
- [00:52:33.680]assure you
- [00:52:34.500]when I do
- [00:52:35.660]a presentation
- [00:52:36.280]for farmers
- [00:52:37.260]in Ontario
- [00:52:37.920]I don't show
- [00:52:39.540]them what I
- [00:52:39.980]showed you
- [00:52:40.500]what I do
- [00:52:41.640]is I say
- [00:52:42.180]we have
- [00:52:42.480]group 2, 5, 9, 14
- [00:52:43.740]and 27
- [00:52:44.280]resistant
- [00:52:44.880]waterhemp
- [00:52:45.460]and I leave
- [00:52:46.200]it
- [00:52:46.420]right
- [00:52:46.740]but the
- [00:52:48.300]thing is
- [00:52:48.960]so let's say
- [00:52:49.800]Doug Nelson's
- [00:52:50.620]farm where I
- [00:52:51.140]know
- [00:52:51.340]CENCOR
- [00:52:51.920]gives 100%
- [00:52:53.160]control
- [00:52:53.620]I also know
- [00:52:54.340]Doug Nelson's
- [00:52:55.100]farm has
- [00:52:56.140]you know
- [00:52:56.560]group 2, 9, 14
- [00:52:58.760]and 27
- [00:52:59.380]resistance
- [00:53:00.060]if I want to
- [00:53:01.620]help Doug Nelson
- [00:53:02.560]to not
- [00:53:03.520]have
- [00:53:04.660]greater potential
- [00:53:06.100]for the evolution
- [00:53:06.920]of additional
- [00:53:07.700]herbicide resistant
- [00:53:08.660]waterhemp on his farm
- [00:53:09.720]he should have
- [00:53:10.620]perfect weed control
- [00:53:11.840]on his soybean
- [00:53:12.440]with zero weed seed
- [00:53:13.600]returned to the soil
- [00:53:14.680]and
- [00:53:15.760]that way
- [00:53:16.520]there's not going to be
- [00:53:17.520]the chance
- [00:53:18.400]for evolution
- [00:53:19.240]to occur
- [00:53:19.880]and so
- [00:53:20.880]I think it's
- [00:53:21.980]responsible for me
- [00:53:23.460]where I have
- [00:53:24.900]that detailed
- [00:53:25.640]information
- [00:53:26.240]to answer
- [00:53:27.560]your question
- [00:53:28.060]I think it's
- [00:53:28.900]perfectly responsible
- [00:53:30.040]as a matter of fact
- [00:53:31.380]I think I'm helping
- [00:53:32.340]them out
- [00:53:32.740]long term
- [00:53:33.420]by reducing
- [00:53:34.720]the number of seeds
- [00:53:35.580]in the seed bank
- [00:53:36.420]and
- [00:53:37.340]the
- [00:53:38.040]potential evolution
- [00:53:39.540]for resistance
- [00:53:40.320]to other herbicide groups
- [00:53:41.500]in terms of
- [00:53:44.380]resistance
- [00:53:45.040]it's always
- [00:53:46.380]a numbers game
- [00:53:47.320]the more
- [00:53:48.500]weed
- [00:53:49.280]plants
- [00:53:50.580]that are exposed
- [00:53:51.500]to the herbicide
- [00:53:52.320]the greater the chance
- [00:53:53.700]you're going to find
- [00:53:54.280]that one plant
- [00:53:55.180]that has a mutation
- [00:53:56.940]that confers resistance
- [00:53:58.160]yeah go ahead
- [00:54:03.320]I have one question
- [00:54:05.540]like
- [00:54:05.820]so you
- [00:54:07.080]mentioned a lot of
- [00:54:09.040]examples where like
- [00:54:09.940]one specific herbicide
- [00:54:11.240]is not working
- [00:54:12.060]from a group
- [00:54:12.580]but other herbicide
- [00:54:13.760]is working
- [00:54:14.220]like atrazine
- [00:54:14.840]is not working
- [00:54:15.600]metribuzine is working
- [00:54:16.940]so did you see
- [00:54:18.340]the results
- [00:54:18.860]from just one year
- [00:54:20.060]or you also did
- [00:54:20.940]like repeated
- [00:54:21.720]two or three years
- [00:54:22.540]study using the same
- [00:54:23.480]herbicide and see that
- [00:54:24.520]how that particular
- [00:54:25.760]herbicide behaved
- [00:54:26.740]in like two or three years
- [00:54:28.100]yeah
- [00:54:28.860]really a really
- [00:54:30.420]good question
- [00:54:31.140]and so
- [00:54:31.940]you know where we do
- [00:54:33.140]our
- [00:54:33.220]research
- [00:54:33.740]we always go to the
- [00:54:34.960]farms with the heaviest
- [00:54:36.080]weed pressure
- [00:54:36.760]because that's where
- [00:54:38.000]you get the best data
- [00:54:39.020]and so we did
- [00:54:40.380]research on
- [00:54:41.300]Doug Nelson's farm
- [00:54:42.360]starting in
- [00:54:43.080]2016
- [00:54:44.340]and
- [00:54:45.600]right up to the
- [00:54:46.460]end of my career
- [00:54:47.120]and Sencor always
- [00:54:48.420]worked
- [00:54:48.740]and Atrazine always
- [00:54:49.980]failed
- [00:54:50.280]right
- [00:54:50.740]and so it's
- [00:54:51.600]really consistent
- [00:54:52.700]across his farm
- [00:54:54.360]the mechanism
- [00:54:55.180]is
- [00:54:55.760]enhanced metabolism
- [00:54:57.060]and
- [00:54:58.160]Atrazine always
- [00:54:59.220]fails
- [00:54:59.560]Sencor always works
- [00:55:00.680]and from all the
- [00:55:02.180]examples I've seen
- [00:55:03.120]I've like
- [00:55:03.820]mostly seen that
- [00:55:04.800]what you are saying
- [00:55:06.140]that
- [00:55:06.480]oversimplifying
- [00:55:08.060]is not
- [00:55:08.760]correct
- [00:55:09.560]saying like
- [00:55:10.540]group 4 or group 5
- [00:55:11.920]or be said
- [00:55:12.320]rather than
- [00:55:12.680]we should be specific
- [00:55:13.580]but
- [00:55:13.940]looking at all the
- [00:55:15.220]examples I am seeing
- [00:55:16.220]that
- [00:55:16.560]oversimplifying
- [00:55:18.420]is not
- [00:55:19.100]great
- [00:55:19.640]specifically
- [00:55:20.180]if you talk
- [00:55:20.840]about like
- [00:55:21.560]target side
- [00:55:22.200]resistance
- [00:55:22.720]do you
- [00:55:24.160]do you also
- [00:55:24.580]think the same
- [00:55:25.180]or it's like
- [00:55:26.060]yes you can
- [00:55:27.320]you are correct
- [00:55:28.080]if you are talking
- [00:55:28.680]about like
- [00:55:29.140]non-target side
- [00:55:30.320]resistance
- [00:55:30.820]compared to
- [00:55:31.380]target side
- [00:55:31.900]resistance
- [00:55:32.340]how you
- [00:55:33.020]differentiate
- [00:55:33.740]between them
- [00:55:34.440]yeah and the
- [00:55:35.820]complexity goes
- [00:55:36.860]across
- [00:55:37.480]mechanism or
- [00:55:38.640]resistance
- [00:55:39.120]I showed you
- [00:55:40.320]you know with
- [00:55:40.880]enhanced metabolism
- [00:55:42.020]atrazine
- [00:55:42.840]fails and
- [00:55:44.700]sencor works
- [00:55:45.580]with an altered
- [00:55:46.300]target site
- [00:55:47.080]if you have a
- [00:55:47.680]tryptophan 574
- [00:55:49.160]leucine amino
- [00:55:49.980]acid substitution
- [00:55:51.160]that confers
- [00:55:52.600]resistance to
- [00:55:53.420]all the group
- [00:55:54.160]twos
- [00:55:54.520]if you have the
- [00:55:55.160]serine 653
- [00:55:56.900]asparagine
- [00:55:57.480]it's only the
- [00:55:58.700]imidazolam
- [00:55:59.300]so it
- [00:56:00.380]it is not
- [00:56:01.520]a target
- [00:56:02.880]site specific
- [00:56:03.760]it crosses
- [00:56:04.860]both target
- [00:56:05.760]site and
- [00:56:06.340]and non-target
- [00:56:07.320]site
- [00:56:07.600]thank you
- [00:56:08.540]yeah no
- [00:56:09.200]great question
- [00:56:09.960]i love the
- [00:56:10.660]questions
- [00:56:11.120]i i could
- [00:56:12.160]talk all day
- [00:56:13.000]but i told
- [00:56:14.040]my son who
- [00:56:14.780]lives in
- [00:56:15.200]iowa that i
- [00:56:15.940]visit him
- [00:56:16.460]this afternoon
- [00:56:17.120]and we have
- [00:56:19.580]seen similar
- [00:56:20.360]results
- [00:56:20.880]for example
- [00:56:23.280]palmer emirant
- [00:56:24.180]resistant to
- [00:56:25.080]atrazine and
- [00:56:25.840]we have seen
- [00:56:26.320]good control
- [00:56:27.000]with metribuzine
- [00:56:28.020]excellent yeah
- [00:56:28.940]and that's why
- [00:56:30.480]i think now
- [00:56:30.960]metribuzine is
- [00:56:32.020]coming back
- [00:56:32.740]to the market
- [00:56:33.540]especially in
- [00:56:35.380]soybean weed
- [00:56:36.180]management
- [00:56:36.760]herbicide
- [00:56:37.840]portfolio
- [00:56:38.320]if you see
- [00:56:39.680]in last two
- [00:56:40.300]to three
- [00:56:40.680]years at
- [00:56:41.720]least seven
- [00:56:43.240]eight different
- [00:56:44.460]herbicide products
- [00:56:45.400]came to the
- [00:56:45.980]market where
- [00:56:47.640]metribuzine was
- [00:56:48.520]a part of
- [00:56:49.380]the premix
- [00:56:50.120]which is good
- [00:56:50.820]compared with
- [00:56:51.600]metribuzine
- [00:56:52.260]applying alone
- [00:56:53.160]will not be
- [00:56:53.780]very effective
- [00:56:54.340]but as a
- [00:56:55.580]tank mix
- [00:56:56.560]partner
- [00:56:57.020]metribuzine
- [00:56:57.940]has a really
- [00:56:58.940]good value
- [00:56:59.660]and in last
- [00:57:01.100]two to three
- [00:57:01.560]years we
- [00:57:02.320]have done
- [00:57:02.600]some work
- [00:57:03.420]about
- [00:57:04.640]which will
- [00:57:05.980]be the best
- [00:57:06.620]tank mix
- [00:57:07.140]partner of
- [00:57:07.760]metribuzine
- [00:57:08.220]that can
- [00:57:08.720]provide good
- [00:57:09.440]control of
- [00:57:10.100]palmar
- [00:57:10.380]eminence
- [00:57:10.860]applied
- [00:57:11.400]pre-emergence
- [00:57:12.240]in soybean
- [00:57:12.840]so I
- [00:57:14.480]consider
- [00:57:14.920]metribuzine
- [00:57:15.600]as a
- [00:57:16.340]atrazine
- [00:57:17.060]of soybean
- [00:57:17.520]like if you
- [00:57:18.560]remember before
- [00:57:19.300]30 years
- [00:57:20.160]when corn
- [00:57:21.780]and atrazine
- [00:57:22.640]came to the
- [00:57:23.180]market it
- [00:57:23.800]was like a
- [00:57:24.640]top-notch
- [00:57:25.120]herbicide and
- [00:57:25.940]then it was
- [00:57:26.540]a part of
- [00:57:27.220]the number
- [00:57:27.960]of the
- [00:57:28.360]pre-mix
- [00:57:28.780]herbicide
- [00:57:29.320]came to
- [00:57:30.020]the market
- [00:57:30.420]in corn
- [00:57:31.180]and now
- [00:57:32.140]metribuzine
- [00:57:32.460]is becoming
- [00:57:33.220]another
- [00:57:33.920]etrazine of
- [00:57:34.720]soybean
- [00:57:34.980]which has a
- [00:57:36.480]great value
- [00:57:37.020]as a
- [00:57:37.640]tech mix
- [00:57:37.960]partner
- [00:57:38.320]and you
- [00:57:41.240]know I
- [00:57:41.540]will just
- [00:57:41.940]add to
- [00:57:42.480]what
- [00:57:42.880]Amit just
- [00:57:44.080]said
- [00:57:44.500]that is
- [00:57:45.300]totally
- [00:57:45.880]dependent
- [00:57:46.380]on the
- [00:57:47.240]weed
- [00:57:47.460]biotype
- [00:57:48.140]and the
- [00:57:48.440]mechanism
- [00:57:48.840]of resistance
- [00:57:49.520]right I
- [00:57:50.160]showed that
- [00:57:50.840]if you
- [00:57:51.160]have the
- [00:57:52.280]serine to
- [00:57:53.000]glycine amino
- [00:57:53.800]acid substitution
- [00:57:54.940]at position
- [00:57:56.060]264
- [00:57:57.160]metribuzine
- [00:57:58.400]totally fails
- [00:57:59.300]in the work
- [00:58:00.300]that you know
- [00:58:01.080]and Andrew
- [00:58:02.280]McKenzie
- [00:58:02.720]did in
- [00:58:03.600]Prince Edward
- [00:58:04.000]Island
- [00:58:04.400]they have
- [00:58:05.860]you know
- [00:58:06.280]an amino
- [00:58:06.680]acid substitution
- [00:58:07.800]metribuzine
- [00:58:08.720]totally fails
- [00:58:09.360]so metribuzine
- [00:58:11.020]really good
- [00:58:12.120]if your
- [00:58:12.460]mechanism of
- [00:58:13.200]resistance is
- [00:58:13.920]enhanced metabolism
- [00:58:14.980]if it's an
- [00:58:15.960]altered target
- [00:58:16.620]site it may
- [00:58:17.400]or may not
- [00:58:17.940]work
- [00:58:18.620]go ahead
- [00:58:20.000]John
- [00:58:20.340]hi Peter
- [00:58:21.120]thanks for
- [00:58:22.540]coming to
- [00:58:22.920]Lincoln
- [00:58:23.080]it's good
- [00:58:23.460]to see you
- [00:58:23.900]I have
- [00:58:24.920]a few
- [00:58:26.400]students that
- [00:58:27.180]are in my
- [00:58:27.740]class the
- [00:58:28.260]weed science
- [00:58:28.660]class that I
- [00:58:29.220]taught just
- [00:58:29.620]before the
- [00:58:30.100]seminar today
- [00:58:30.760]and some of
- [00:58:31.320]them are here
- [00:58:32.100]I think this
- [00:58:32.700]is a great
- [00:58:33.120]presentation for
- [00:58:34.420]them to see
- [00:58:34.900]your
- [00:58:36.700]presentation
- [00:58:37.460]the premise
- [00:58:39.040]is that
- [00:58:39.560]we're
- [00:58:40.700]oversimplifying
- [00:58:41.540]our message
- [00:58:42.300]that things
- [00:58:43.000]are complicated
- [00:58:44.040]much more
- [00:58:44.980]complicated than
- [00:58:45.780]the way we
- [00:58:46.880]send that
- [00:58:47.640]message
- [00:58:48.040]but
- [00:58:48.640]then you
- [00:58:50.760]had some
- [00:58:51.100]conclusions at
- [00:58:51.940]the end
- [00:58:52.380]and I think
- [00:58:53.180]it's also a
- [00:58:53.700]little more
- [00:58:53.980]complicated than
- [00:58:54.720]that because
- [00:58:55.560]I would say
- [00:58:56.780]so for example
- [00:58:57.580]you have a
- [00:58:58.180]resistance to
- [00:58:58.840]atrazine but
- [00:58:59.880]not the
- [00:59:00.560]metribuzin
- [00:59:01.380]that may be
- [00:59:04.100]true and it
- [00:59:04.560]may be very
- [00:59:05.180]good idea for
- [00:59:05.880]that grower to
- [00:59:06.700]use the
- [00:59:07.320]metribuzin to
- [00:59:08.080]manage those
- [00:59:08.760]weeds but I
- [00:59:09.240]would always do
- [00:59:10.100]that with caution
- [00:59:10.820]because you have
- [00:59:11.520]atrazine resistance
- [00:59:12.300]for a reason
- [00:59:13.040]and you said
- [00:59:14.200]well you could
- [00:59:14.720]use Sencor for
- [00:59:16.320]five times out
- [00:59:17.680]of 15 years
- [00:59:18.560]I would also
- [00:59:21.440]caution that
- [00:59:22.200]those farmers
- [00:59:22.820]be watching
- [00:59:23.820]those populations
- [00:59:24.980]to make sure
- [00:59:25.760]that they do
- [00:59:26.320]not develop
- [00:59:27.360]some new
- [00:59:27.900]resistance because
- [00:59:28.720]again it becomes
- [00:59:29.400]more complicated
- [00:59:30.100]you only need
- [00:59:30.720]one
- [00:59:31.100]plant right
- [00:59:32.160]that's resistant
- [00:59:32.840]to now have
- [00:59:34.160]a completely
- [00:59:34.580]new population
- [00:59:35.320]that's resistant
- [00:59:35.920]to both
- [00:59:36.260]adresin and
- [00:59:37.200]metribuzin
- [00:59:37.860]you're absolutely
- [00:59:39.340]correct John
- [00:59:39.980]right
- [00:59:40.460]but
- [00:59:41.020]you know
- [00:59:42.160]when you think
- [00:59:43.560]about it
- [00:59:44.020]philosophically
- [00:59:45.020]if you can
- [00:59:46.860]so I've
- [00:59:48.540]changed my
- [00:59:49.100]thinking in
- [00:59:49.660]terms of
- [00:59:50.040]weed management
- [00:59:50.580]over my
- [00:59:51.220]career
- [00:59:51.560]when I
- [00:59:52.620]started doing
- [00:59:53.420]weed management
- [00:59:54.120]research at
- [00:59:55.060]Ridgetown
- [00:59:55.760]campus in
- [00:59:56.480]1993
- [00:59:57.300]the older
- [00:59:59.260]weed scientists
- [01:00:00.160]in the
- [01:00:00.680]province
- [01:00:01.160]the common
- [01:00:02.580]thought was
- [01:00:03.380]if you had
- [01:00:03.840]100% weed
- [01:00:05.040]control
- [01:00:05.500]you spent
- [01:00:06.300]too much
- [01:00:06.680]money on
- [01:00:07.080]herbicides
- [01:00:07.680]and there
- [01:00:08.620]was an
- [01:00:09.000]unnecessarily
- [01:00:10.020]loading of
- [01:00:10.660]the environment
- [01:00:11.240]with these
- [01:00:11.880]pesticides
- [01:00:12.340]right
- [01:00:12.840]and I
- [01:00:14.820]have completely
- [01:00:15.660]changed my
- [01:00:16.460]thinking in
- [01:00:17.380]terms of
- [01:00:17.940]weed management
- [01:00:18.640]for weeds
- [01:00:20.020]that have
- [01:00:20.600]the propensity
- [01:00:21.900]to evolve
- [01:00:22.760]resistance to
- [01:00:23.640]multiple herbicide
- [01:00:24.700]modes of
- [01:00:25.200]action
- [01:00:25.560]my
- [01:00:26.900]recommendations
- [01:00:27.560]to farmer
- [01:00:28.240]it is
- [01:00:28.800]100%
- [01:00:30.040]weed
- [01:00:30.260]control
- [01:00:30.740]every year
- [01:00:31.500]and zero
- [01:00:32.140]weed
- [01:00:32.440]seed
- [01:00:32.680]return
- [01:00:33.040]to the
- [01:00:33.480]soil
- [01:00:33.760]and if
- [01:00:34.680]you do
- [01:00:34.940]that
- [01:00:35.240]John
- [01:00:35.640]you're
- [01:00:36.660]going to
- [01:00:36.880]avoid
- [01:00:37.260]the
- [01:00:37.680]evolution
- [01:00:38.300]of future
- [01:00:38.840]resistance
- [01:00:39.460]and I've
- [01:00:41.740]changed my
- [01:00:42.200]thinking
- [01:00:42.500]we have
- [01:00:43.820]five way
- [01:00:44.280]resistant
- [01:00:44.680]water
- [01:00:45.040]hemp
- [01:00:45.220]that's
- [01:00:45.560]removed
- [01:00:45.920]80%
- [01:00:46.800]of our
- [01:00:47.800]corn and
- [01:00:48.280]soybean
- [01:00:48.620]herbicides
- [01:00:49.260]for
- [01:00:49.560]affected
- [01:00:50.020]farmers
- [01:00:50.560]go ahead
- [01:00:51.420]so
- [01:00:52.460]building
- [01:00:53.140]off of
- [01:00:53.480]that
- [01:00:53.900]so
- [01:00:55.360]Jim
- [01:00:55.620]said
- [01:00:55.840]he's
- [01:00:56.040]a
- [01:00:56.280]soil
- [01:00:56.980]person
- [01:00:57.340]I'm
- [01:00:57.620]an
- [01:00:57.800]ecologist
- [01:00:58.300]I'm
- [01:00:58.760]an
- [01:00:58.860]even
- [01:00:59.000]lower
- [01:00:59.300]life
- [01:00:59.620]form
- [01:00:59.820]maybe
- [01:01:00.100]so
- [01:01:01.140]much
- [01:01:03.560]respect
- [01:01:04.160]for
- [01:01:04.580]all
- [01:01:05.140]those
- [01:01:05.560]disciplines
- [01:01:06.060]thanks
- [01:01:07.140]but
- [01:01:07.440]yeah
- [01:01:07.640]no
- [01:01:07.820]I
- [01:01:07.980]honestly
- [01:01:08.880]part
- [01:01:09.540]of
- [01:01:09.600]the
- [01:01:09.680]reason
- [01:01:09.820]I
- [01:01:10.000]came
- [01:01:10.220]to
- [01:01:10.320]your
- [01:01:10.460]talk
- [01:01:10.820]is
- [01:01:10.980]because
- [01:01:11.160]I
- [01:01:11.380]agree
- [01:01:12.520]this
- [01:01:12.820]is
- [01:01:12.960]really
- [01:01:13.180]complex
- [01:01:13.920]complicated
- [01:01:14.880]I
- [01:01:15.100]love
- [01:01:15.660]thinking
- [01:01:16.040]about
- [01:01:16.320]complexity
- [01:01:16.840]and
- [01:01:17.200]scale
- [01:01:17.580]any
- [01:01:17.780]of
- [01:01:17.900]my
- [01:01:18.080]colleagues
- [01:01:18.560]probably
- [01:01:19.360]know
- [01:01:20.260]that
- [01:01:20.460]about
- [01:01:20.700]me
- [01:01:20.880]but
- [01:01:21.140]building
- [01:01:21.860]off
- [01:01:22.120]of
- [01:01:22.200]that
- [01:01:22.400]my
- [01:01:22.580]question
- [01:01:22.960]for
- [01:01:23.200]you
- [01:01:23.520]do
- [01:01:23.980]you
- [01:01:25.160]actually
- [01:01:25.500]think
- [01:01:25.800]it's
- [01:01:26.020]possible
- [01:01:26.520]to
- [01:01:28.300]achieve
- [01:01:28.760]what
- [01:01:29.020]your
- [01:01:29.160]last
- [01:01:30.040]message
- [01:01:30.580]was
- [01:01:30.880]there
- [01:01:31.100]and
- [01:01:31.320]I
- [01:01:31.480]say
- [01:01:32.100]that
- [01:01:32.500]because
- [01:01:33.260]I
- [01:01:33.520]think
- [01:01:33.800]about
- [01:01:34.040]these
- [01:01:34.280]things
- [01:01:34.520]all
- [01:01:34.680]the
- [01:01:34.800]time
- [01:01:35.060]scale
- [01:01:35.400]and
- [01:01:35.560]complexity
- [01:01:36.020]because
- [01:01:37.080]what
- [01:01:37.260]you're
- [01:01:37.440]arguing
- [01:01:37.780]for
- [01:01:38.180]is
- [01:01:38.380]actually
- [01:01:38.740]complete
- [01:01:39.320]control
- [01:01:39.880]of
- [01:01:40.160]the
- [01:01:40.340]complexity
- [01:01:40.840]through
- [01:01:42.040]the
- [01:01:42.240]use
- [01:01:42.560]of
- [01:01:43.220]herbicides
- [01:01:43.920]to
- [01:01:44.240]control
- [01:01:44.660]the
- [01:01:44.880]seed
- [01:01:45.080]spread
- [01:01:45.500]although
- [01:01:46.480]the
- [01:01:47.180]issue
- [01:01:47.460]there
- [01:01:47.800]is
- [01:01:48.020]that
- [01:01:48.220]the
- [01:01:48.460]scale
- [01:01:48.980]of
- [01:01:49.220]control
- [01:01:49.720]is
- [01:01:50.020]actually
- [01:01:50.340]limited
- [01:01:50.800]to
- [01:01:51.120]the
- [01:01:51.340]scale
- [01:01:51.780]of
- [01:01:52.080]where
- [01:01:52.420]you're
- [01:01:52.700]applying
- [01:01:53.140]the
- [01:01:53.340]herbicide
- [01:01:53.860]but
- [01:01:54.500]the
- [01:01:54.660]mechanisms
- [01:01:55.180]that
- [01:01:55.500]might
- [01:01:55.720]be
- [01:01:55.900]driving
- [01:01:56.440]some
- [01:01:56.780]of
- [01:01:56.880]these
- [01:01:57.020]evolutionary
- [01:01:57.560]pressures
- [01:01:58.100]are
- [01:01:58.380]probably
- [01:01:58.740]occurring
- [01:01:59.200]at
- [01:01:59.400]scales
- [01:01:59.740]that
- [01:01:59.900]are
- [01:02:00.000]much
- [01:02:00.260]larger
- [01:02:00.820]than
- [01:02:01.080]the
- [01:02:01.260]scale
- [01:02:01.540]of
- [01:02:01.720]control
- [01:02:02.200]so
- [01:02:02.940]knowing
- [01:02:03.360]that
- [01:02:03.800]because
- [01:02:04.260]that's
- [01:02:04.520]a
- [01:02:04.640]basic
- [01:02:04.920]ecological
- [01:02:05.460]principle
- [01:02:06.040]knowing
- [01:02:06.460]that
- [01:02:06.900]can
- [01:02:07.880]we
- [01:02:08.020]actually
- [01:02:08.420]say
- [01:02:08.840]that
- [01:02:09.300]in
- [01:02:09.860]good
- [01:02:10.300]conscience
- [01:02:10.960]that
- [01:02:11.900]it's
- [01:02:12.140]even
- [01:02:12.620]achievable
- [01:02:13.340]for
- [01:02:14.280]us
- [01:02:14.540]long
- [01:02:14.940]term
- [01:02:15.220]to
- [01:02:15.460]avoid
- [01:02:16.000]herbicide
- [01:02:16.460]resistance
- [01:02:17.100]period
- [01:02:17.980]the
- [01:02:19.140]answer is
- [01:02:19.600]no
- [01:02:19.820]and
- [01:02:20.420]you're
- [01:02:20.680]absolutely
- [01:02:21.420]right
- [01:02:21.900]I
- [01:02:22.300]think
- [01:02:22.560]it's
- [01:02:22.960]inevitable
- [01:02:23.540]that
- [01:02:24.760]over
- [01:02:25.240]time
- [01:02:25.840]there's
- [01:02:26.700]going
- [01:02:26.840]to
- [01:02:26.860]be
- [01:02:27.060]additional
- [01:02:27.600]weed
- [01:02:27.920]biotypes
- [01:02:28.580]that
- [01:02:28.860]evolve
- [01:02:29.580]resistance
- [01:02:30.120]to
- [01:02:30.420]additional
- [01:02:30.900]herbicide
- [01:02:31.420]modes
- [01:02:31.680]of
- [01:02:31.820]action
- [01:02:32.060]that
- [01:02:32.340]is
- [01:02:32.520]just
- [01:02:32.760]the
- [01:02:32.960]reality
- [01:02:33.380]of
- [01:02:33.620]it
- [01:02:33.820]however
- [01:02:35.020]in
- [01:02:36.540]terms
- [01:02:36.940]of
- [01:02:37.220]advocating
- [01:02:38.560]for
- [01:02:39.200]100%
- [01:02:40.620]resistance
- [01:02:41.240]I
- [01:02:41.900]did
- [01:02:42.280]use
- [01:02:43.020]a
- [01:02:43.440]corn
- [01:02:43.660]soybean
- [01:02:44.040]wheat
- [01:02:44.380]rotation
- [01:02:44.940]so
- [01:02:45.740]you
- [01:02:46.260]have
- [01:02:46.680]two
- [01:02:46.860]summer
- [01:02:47.160]crops
- [01:02:47.480]you
- [01:02:47.620]have
- [01:02:47.720]a
- [01:02:47.840]winter
- [01:02:48.000]annual
- [01:02:48.360]crop
- [01:02:48.780]you
- [01:02:49.440]have
- [01:02:49.960]we
- [01:02:50.640]did
- [01:02:50.980]a
- [01:02:51.220]study
- [01:02:51.560]you
- [01:02:51.760]know
- [01:02:51.920]where
- [01:02:52.140]we
- [01:02:52.360]had
- [01:02:52.600]a
- [01:02:52.740]corn
- [01:02:52.920]soybean
- [01:02:53.280]wheat
- [01:02:53.540]rotation
- [01:02:54.020]we
- [01:02:54.220]had
- [01:02:54.360]12
- [01:02:54.680]different
- [01:02:55.000]treatments
- [01:02:55.480]over
- [01:02:56.300]a
- [01:02:56.640]you
- [01:02:56.840]know
- [01:02:57.000]three
- [01:02:57.280]year
- [01:02:57.520]period
- [01:02:57.980]anyways
- [01:02:58.940]you
- [01:02:59.520]know
- [01:02:59.620]we
- [01:02:59.760]used
- [01:03:00.040]cover
- [01:03:00.320]crops
- [01:03:00.800]in
- [01:03:01.320]our
- [01:03:01.480]rotation
- [01:03:01.940]we
- [01:03:02.300]used
- [01:03:02.720]narrow
- [01:03:03.100]row
- [01:03:03.420]widths
- [01:03:03.780]as
- [01:03:03.900]part
- [01:03:04.220]of
- [01:03:04.340]it
- [01:03:04.500]we
- [01:03:05.160]used
- [01:03:05.520]three
- [01:03:05.760]different
- [01:03:06.100]crops
- [01:03:06.560]and
- [01:03:06.820]then
- [01:03:07.100]effective
- [01:03:07.740]herbicides
- [01:03:08.460]in
- [01:03:08.720]each
- [01:03:08.980]one
- [01:03:09.200]of
- [01:03:09.320]the
- [01:03:09.500]crops
- [01:03:09.840]in
- [01:03:10.040]the
- [01:03:10.140]rotation
- [01:03:10.620]and
- [01:03:11.620]we
- [01:03:11.920]had
- [01:03:12.560]a
- [01:03:13.280]65%
- [01:03:14.240]reduction
- [01:03:15.060]in
- [01:03:15.480]the
- [01:03:15.640]number
- [01:03:15.920]of
- [01:03:16.080]water
- [01:03:16.340]hemp
- [01:03:16.540]seeds
- [01:03:16.900]in
- [01:03:17.300]the
- [01:03:17.520]seed
- [01:03:17.760]bank
- [01:03:18.160]by
- [01:03:18.580]doing
- [01:03:18.940]that
- [01:03:19.220]right
- [01:03:19.500]am
- [01:03:20.180]I
- [01:03:20.420]saying
- [01:03:20.760]it's
- [01:03:20.980]going
- [01:03:21.100]to
- [01:03:21.140]be
- [01:03:21.300]perfect
- [01:03:21.680]um
- [01:03:22.340]boy
- [01:03:23.020]biology
- [01:03:23.700]has
- [01:03:23.880]always
- [01:03:24.120]proven
- [01:03:24.480]me
- [01:03:24.660]wrong
- [01:03:24.940]right
- [01:03:25.620]and so
- [01:03:26.160]what
- [01:03:26.420]am I
- [01:03:27.100]saying
- [01:03:27.360]will
- [01:03:27.660]that
- [01:03:28.000]be
- [01:03:28.180]perfect
- [01:03:28.520]no
- [01:03:29.120]do
- [01:03:29.520]I
- [01:03:29.700]think
- [01:03:29.920]farmers
- [01:03:30.320]should
- [01:03:30.680]implement
- [01:03:32.560]more
- [01:03:33.360]complexity
- [01:03:34.060]into
- [01:03:34.520]their
- [01:03:34.760]crop
- [01:03:35.080]and
- [01:03:35.240]weed
- [01:03:35.400]management
- [01:03:35.780]programs
- [01:03:36.440]absolutely
- [01:03:37.280]and
- [01:03:38.200]they
- [01:03:38.480]have
- [01:03:39.040]to
- [01:03:39.340]rely
- [01:03:39.900]on
- [01:03:40.360]weed
- [01:03:40.620]management
- [01:03:41.060]tactics
- [01:03:41.680]beyond
- [01:03:42.120]herbicides
- [01:03:42.800]well
- [01:03:44.140]following up
- [01:03:44.760]on that
- [01:03:45.000]same
- [01:03:45.220]kind
- [01:03:45.440]of
- [01:03:45.540]thought
- [01:03:45.800]is
- [01:03:46.140]all
- [01:03:46.740]of
- [01:03:46.940]your
- [01:03:47.320]examples
- [01:03:48.760]there
- [01:03:49.180]had
- [01:03:49.860]pure
- [01:03:50.640]stands
- [01:03:51.080]of
- [01:03:51.220]the
- [01:03:51.320]biotypes
- [01:03:51.920]is
- [01:03:52.920]that
- [01:03:53.000]common
- [01:03:54.180]place
- [01:03:54.720]or are
- [01:03:55.120]there
- [01:03:55.260]mixes
- [01:03:55.720]and what
- [01:03:56.740]additional
- [01:03:57.360]risk
- [01:03:57.780]might be
- [01:03:58.260]involved
- [01:03:58.780]when there
- [01:03:59.600]are mixes
- [01:04:00.120]in terms
- [01:04:00.740]of both
- [01:04:01.380]control
- [01:04:02.020]and also
- [01:04:03.160]getting
- [01:04:03.640]genetic
- [01:04:04.040]crosses
- [01:04:04.540]that then
- [01:04:05.120]create
- [01:04:05.980]resistance
- [01:04:08.240]to both
- [01:04:08.760]types
- [01:04:09.220]yeah
- [01:04:10.500]and so
- [01:04:11.540]for sure
- [01:04:12.460]I'd say
- [01:04:13.480]that you
- [01:04:13.860]know
- [01:04:14.040]on an
- [01:04:14.600]average
- [01:04:15.000]farm
- [01:04:15.380]in
- [01:04:15.560]Ontario
- [01:04:16.080]you would
- [01:04:16.580]have
- [01:04:16.880]between
- [01:04:17.220]five and
- [01:04:17.880]ten
- [01:04:18.120]different
- [01:04:18.480]weed
- [01:04:18.720]species
- [01:04:19.200]the
- [01:04:20.120]reason
- [01:04:20.500]why
- [01:04:20.960]mine
- [01:04:21.360]were
- [01:04:21.560]monocultures
- [01:04:22.400]and
- [01:04:22.940]he
- [01:04:22.980]time
- [01:04:23.260]we
- [01:04:23.420]have
- [01:04:23.540]a
- [01:04:23.640]glyphosate
- [01:04:24.180]resistant
- [01:04:24.600]weed
- [01:04:24.920]we
- [01:04:25.440]spray
- [01:04:25.720]round
- [01:04:26.080]up
- [01:04:26.280]over
- [01:04:26.480]the
- [01:04:26.640]entire
- [01:04:27.640]experimental
- [01:04:28.140]area
- [01:04:28.520]so we
- [01:04:28.880]can
- [01:04:29.020]focus
- [01:04:29.340]on
- [01:04:29.560]the
- [01:04:29.680]weed
- [01:04:29.880]species
- [01:04:30.260]of
- [01:04:30.500]interest
- [01:04:30.940]that
- [01:04:31.680]does
- [01:04:32.000]not
- [01:04:32.320]represent
- [01:04:32.960]what
- [01:04:33.480]the
- [01:04:33.660]farmer
- [01:04:34.100]originally
- [01:04:34.860]had
- [01:04:35.280]in
- [01:04:35.420]that
- [01:04:35.620]field
- [01:04:35.920]and
- [01:04:36.580]so
- [01:04:36.820]no
- [01:04:37.100]they're
- [01:04:37.300]not
- [01:04:37.580]monocultures
- [01:04:38.380]of
- [01:04:38.640]weeds
- [01:04:38.940]they
- [01:04:39.300]are
- [01:04:39.600]multiple
- [01:04:41.260]different
- [01:04:41.680]weed
- [01:04:41.900]species
- [01:04:42.420]you're
- [01:04:46.240]saying
- [01:04:46.560]are
- [01:04:46.760]there
- [01:04:47.000]different
- [01:04:47.560]biotypes
- [01:04:48.260]within
- [01:04:48.600]a
- [01:04:48.760]weed
- [01:04:48.960]species
- [01:04:49.440]potentially
- [01:04:50.100]and
- [01:04:51.100]so
- [01:04:51.460]you know
- [01:04:51.880]I
- [01:04:52.040]showed
- [01:04:52.420]you
- [01:04:52.560]the
- [01:04:52.760]difference
- [01:04:53.100]between
- [01:04:53.580]Brigden
- [01:04:54.000]29
- [01:04:54.660]Brigden
- [01:04:55.120]39
- [01:04:55.780]man
- [01:04:56.620]they're
- [01:04:56.920]really
- [01:04:57.260]close
- [01:04:57.620]I
- [01:04:57.920]don't
- [01:04:58.420]know
- [01:04:58.580]where
- [01:04:58.760]they
- [01:04:58.920]were
- [01:04:59.100]but
- [01:04:59.300]they're
- [01:04:59.680]close
- [01:05:00.520]to
- [01:05:00.720]the
- [01:05:00.920]same
- [01:05:01.220]town
- [01:05:01.600]in
- [01:05:01.820]Ontario
- [01:05:02.320]that's
- [01:05:03.200]how
- [01:05:03.460]the
- [01:05:05.620]weed
- [01:05:06.160]scientists
- [01:05:06.680]at
- [01:05:06.980]the
- [01:05:07.140]time
- [01:05:07.420]identified
- [01:05:08.000]them
- [01:05:08.380]do
- [01:05:09.180]I
- [01:05:09.360]think
- [01:05:09.600]it's
- [01:05:09.820]possible
- [01:05:10.340]that
- [01:05:11.060]you
- [01:05:11.320]know
- [01:05:11.420]there
- [01:05:11.580]could
- [01:05:11.820]be
- [01:05:11.980]movement
- [01:05:12.320]of
- [01:05:12.600]green
- [01:05:13.260]pig
- [01:05:13.520]weed
- [01:05:13.740]seed
- [01:05:14.060]from
- [01:05:14.340]one
- [01:05:14.640]field
- [01:05:14.860]to
- [01:05:15.040]the
- [01:05:15.160]other
- [01:05:15.340]and
- [01:05:15.500]you
- [01:05:15.620]could
- [01:05:15.780]have
- [01:05:15.960]two
- [01:05:16.200]different
- [01:05:16.620]amino
- [01:05:17.680]acid
- [01:05:18.080]substitutions
- [01:05:18.900]now
- [01:05:19.180]the
- [01:05:19.560]answer
- [01:05:19.820]absolutely
- [01:05:20.560]yes
- [01:05:20.920]that
- [01:05:21.680]doesn't
- [01:05:22.120]take away
- [01:05:22.680]from
- [01:05:23.280]me
- [01:05:24.300]recommending
- [01:05:25.040]to
- [01:05:25.740]elevate
- [01:05:26.380]your
- [01:05:26.740]game
- [01:05:27.100]and
- [01:05:27.840]try to
- [01:05:28.820]get
- [01:05:29.060]near
- [01:05:29.400]perfect
- [01:05:29.800]control
- [01:05:30.320]on
- [01:05:31.100]your
- [01:05:31.280]farm
- [01:05:31.640]and
- [01:05:32.440]what's
- [01:05:32.720]really
- [01:05:33.120]interesting
- [01:05:33.900]there's
- [01:05:35.140]farmers
- [01:05:35.580]in
- [01:05:35.780]Ontario
- [01:05:36.180]that have
- [01:05:36.640]zero
- [01:05:37.140]herbicide
- [01:05:38.920]resistant
- [01:05:39.360]weed
- [01:05:39.660]biotypes
- [01:05:40.200]on
- [01:05:40.400]their
- [01:05:40.560]farm
- [01:05:40.840]you
- [01:05:41.680]know
- [01:05:41.780]what
- [01:05:41.960]most
- [01:05:42.680]of
- [01:05:42.860]them
- [01:05:43.040]are
- [01:05:43.500]cattle
- [01:05:43.860]farmers
- [01:05:44.300]either
- [01:05:44.560]beef
- [01:05:44.860]or
- [01:05:45.040]dairy
- [01:05:45.320]where
- [01:05:46.360]they
- [01:05:46.660]have
- [01:05:47.140]long
- [01:05:47.640]term
- [01:05:47.860]rotations
- [01:05:48.400]they
- [01:05:48.740]have
- [01:05:48.920]forages
- [01:05:49.400]in
- [01:05:49.580]the
- [01:05:49.700]rotation
- [01:05:50.260]those
- [01:05:51.260]weeds
- [01:05:51.640]don't
- [01:05:52.520]a pig
- [01:05:52.960]weed
- [01:05:53.180]plant
- [01:05:53.540]is not
- [01:05:53.900]a problem
- [01:05:54.380]in an
- [01:05:54.680]alfalfa
- [01:05:55.180]stand
- [01:05:55.500]right
- [01:05:55.860]and
- [01:05:56.700]so
- [01:05:57.200]you
- [01:05:58.480]know
- [01:05:58.700]those
- [01:05:59.280]farmers
- [01:05:59.820]that
- [01:06:00.100]have
- [01:06:00.300]more
- [01:06:00.660]complexity
- [01:06:01.420]in
- [01:06:02.760]their
- [01:06:03.060]crop
- [01:06:03.400]production
- [01:06:03.800]systems
- [01:06:04.340]have
- [01:06:04.640]fewer
- [01:06:05.080]herbicide
- [01:06:06.240]resistant
- [01:06:06.600]biotypes
- [01:06:07.140]I'm not
- [01:06:07.560]saying
- [01:06:07.800]zero
- [01:06:08.140]I'm
- [01:06:08.820]saying
- [01:06:09.060]fewer
- [01:06:09.380]that
- [01:06:09.980]that's
- [01:06:10.380]awesome
- [01:06:10.780]and
- [01:06:11.220]that
- [01:06:11.400]that
- [01:06:11.700]that
- [01:06:12.020]might
- [01:06:12.200]be
- [01:06:12.340]the
- [01:06:12.500]most
- [01:06:12.740]important
- [01:06:13.140]thing
- [01:06:13.520]that
- [01:06:13.800]I've
- [01:06:14.120]heard
- [01:06:14.320]in
- [01:06:14.480]this
- [01:06:14.640]entire
- [01:06:14.980]talk
- [01:06:15.460]as
- [01:06:16.900]an
- [01:06:17.040]ecologist
- [01:06:17.620]is
- [01:06:18.780]that
- [01:06:19.100]because
- [01:06:19.900]I think
- [01:06:20.460]that's
- [01:06:20.820]true
- [01:06:21.100]across
- [01:06:21.520]disciplines
- [01:06:22.100]I think
- [01:06:22.660]we're
- [01:06:22.880]realizing
- [01:06:23.400]that
- [01:06:23.700]is
- [01:06:24.240]that
- [01:06:24.420]actually
- [01:06:24.800]embracing
- [01:06:25.400]rather
- [01:06:25.720]than
- [01:06:25.980]controlling
- [01:06:26.420]complexity
- [01:06:27.000]is the
- [01:06:27.520]key
- [01:06:27.840]when
- [01:06:28.700]we're
- [01:06:28.860]talking
- [01:06:29.140]about
- [01:06:29.420]managing
- [01:06:29.960]complex
- [01:06:30.580]systems
- [01:06:31.080]managing
- [01:06:31.940]complex
- [01:06:32.560]systems
- [01:06:32.960]is not
- [01:06:33.380]about
- [01:06:33.760]oversimplifying
- [01:06:35.320]our
- [01:06:35.920]management
- [01:06:36.340]it's
- [01:06:36.660]about
- [01:06:37.160]embracing
- [01:06:38.760]complexity
- [01:06:40.520]so thank
- [01:06:41.120]you
- [01:06:41.260]that's
- [01:06:41.660]great
- [01:06:42.080]I grew
- [01:06:43.700]up on
- [01:06:44.080]a
- [01:06:44.220]dairy
- [01:06:44.440]and hog
- [01:06:44.880]farm
- [01:06:45.280]my
- [01:06:45.600]brother
- [01:06:46.020]and
- [01:06:46.520]nephew
- [01:06:46.820]still
- [01:06:47.200]have
- [01:06:47.420]the
- [01:06:47.580]farm
- [01:06:47.900]and
- [01:06:49.020]it's
- [01:06:49.740]been in
- [01:06:50.040]the
- [01:06:50.160]family
- [01:06:50.520]since
- [01:06:50.900]1965
- [01:06:51.800]my
- [01:06:52.220]parents
- [01:06:52.620]did
- [01:06:52.860]immigrate
- [01:06:53.260]from
- [01:06:53.460]the
- [01:06:53.620]Netherlands
- [01:06:53.960]after
- [01:06:54.960]World
- [01:06:55.280]War
- [01:06:55.500]II
- [01:06:55.780]they
- [01:06:56.640]have
- [01:06:56.780]zero
- [01:06:57.140]herbicide
- [01:06:58.740]resistant
- [01:06:59.300]weeds
- [01:07:00.100]on
- [01:07:00.360]their
- [01:07:00.540]farm
- [01:07:00.860]after
- [01:07:01.780]farming
- [01:07:02.540]it
- [01:07:02.860]since
- [01:07:03.580]65
- [01:07:04.420]60
- [01:07:04.760]years
- [01:07:05.160]right
- [01:07:05.440]but
- [01:07:06.720]man
- [01:07:07.260]they
- [01:07:07.460]have
- [01:07:07.660]complexity
- [01:07:08.380]and
- [01:07:10.060]you
- [01:07:10.260]know
- [01:07:10.440]you say
- [01:07:12.020]you're
- [01:07:12.320]an
- [01:07:12.680]ecologist
- [01:07:13.200]I
- [01:07:13.460]mean
- [01:07:13.700]they're
- [01:07:14.320]pretty
- [01:07:14.880]committed
- [01:07:16.780]to
- [01:07:17.540]soil
- [01:07:18.140]health
- [01:07:18.660]I
- [01:07:18.820]mean
- [01:07:19.000]they
- [01:07:19.140]take
- [01:07:19.500]off
- [01:07:19.740]their
- [01:07:19.920]winter
- [01:07:20.140]wheat
- [01:07:20.420]the
- [01:07:20.980]same
- [01:07:21.300]day
- [01:07:21.620]they'll
- [01:07:21.960]plant
- [01:07:22.300]a
- [01:07:22.520]blend
- [01:07:23.500]of
- [01:07:23.900]peas
- [01:07:24.680]and
- [01:07:25.080]oats
- [01:07:25.440]on
- [01:07:26.240]September
- [01:07:26.820]15
- [01:07:27.280]they
- [01:07:27.480]put
- [01:07:27.700]in
- [01:07:27.820]the
- [01:07:27.980]silo
- [01:07:28.340]September
- [01:07:28.860]16
- [01:07:29.440]they
- [01:07:29.680]plant
- [01:07:30.000]cereal
- [01:07:31.000]rye
- [01:07:31.420]they
- [01:07:31.680]burn
- [01:07:31.960]it
- [01:07:32.100]off
- [01:07:32.360]on
- [01:07:32.540]May
- [01:07:32.780]10
- [01:07:33.060]put
- [01:07:33.780]it
- [01:07:33.900]in
- [01:07:34.040]the
- [01:07:34.200]silo
- [01:07:34.580]and
- [01:07:34.720]plant
- [01:07:34.980]soybean
- [01:07:35.400]they
- [01:07:35.660]grow
- [01:07:35.940]four
- [01:07:36.340]cash
- [01:07:36.820]generating
- [01:07:37.360]crops
- [01:07:37.780]in
- [01:07:37.940]a
- [01:07:38.060]24
- [01:07:38.400]month
- [01:07:38.720]period
- [01:07:39.040]and
- [01:07:39.880]it
- [01:07:40.040]is
- [01:07:40.260]complex
- [01:07:40.900]and
- [01:07:41.300]you
- [01:07:41.420]know
- [01:07:41.500]what
- [01:07:41.660]there's
- [01:07:41.960]benefits
- [01:07:42.400]and
- [01:07:44.720]this
- [01:07:44.960]is
- [01:07:45.080]the
- [01:07:45.240]message
- [01:07:45.520]we
- [01:07:45.760]are
- [01:07:45.880]giving
- [01:07:46.140]to
- [01:07:46.360]our
- [01:07:46.600]growers
- [01:07:46.980]whenever
- [01:07:48.160]I
- [01:07:48.480]give
- [01:07:48.680]my
- [01:07:48.900]presentation
- [01:07:49.300]my
- [01:07:50.280]last
- [01:07:50.680]slide
- [01:07:50.960]is
- [01:07:51.200]always
- [01:07:51.760]like
- [01:07:53.080]do
- [01:07:53.240]not
- [01:07:53.420]rely
- [01:07:53.680]only
- [01:07:53.960]on
- [01:07:54.140]herbicides
- [01:07:54.680]you
- [01:07:54.960]have
- [01:07:55.100]to
- [01:07:55.260]think
- [01:07:55.520]about
- [01:07:55.960]any
- [01:07:56.380]other
- [01:07:56.780]methods
- [01:07:57.900]number
- [01:07:58.800]one
- [01:07:59.220]don't
- [01:07:59.780]let
- [01:08:00.140]weeds
- [01:08:00.560]to
- [01:08:00.740]emerge
- [01:08:01.220]you
- [01:08:01.880]can
- [01:08:02.040]use
- [01:08:02.300]cover
- [01:08:02.600]crops
- [01:08:04.620]that
- [01:08:04.840]can
- [01:08:05.060]suppress
- [01:08:05.540]the
- [01:08:05.760]emergence
- [01:08:06.200]of
- [01:08:06.440]weed
- [01:08:06.640]species
- [01:08:07.000]and
- [01:08:07.980]if
- [01:08:08.180]some
- [01:08:08.400]reason
- [01:08:08.700]I'm
- [01:08:09.080]sure
- [01:08:09.220]some
- [01:08:09.500]weeds
- [01:08:09.700]are
- [01:08:09.860]going
- [01:08:10.060]to
- [01:08:10.240]emerge
- [01:08:10.560]right
- [01:08:10.820]so
- [01:08:11.300]and
- [01:08:11.500]then
- [01:08:11.800]at
- [01:08:12.300]that
- [01:08:12.500]time
- [01:08:12.740]you
- [01:08:12.900]can
- [01:08:13.080]use
- [01:08:13.480]maybe
- [01:08:13.940]some
- [01:08:14.240]post
- [01:08:14.500]emergence
- [01:08:14.860]herbicides
- [01:08:15.420]and
- [01:08:15.680]we
- [01:08:15.780]have
- [01:08:15.900]been
- [01:08:16.020]working
- [01:08:16.300]with
- [01:08:16.640]John
- [01:08:17.000]Deere
- [01:08:17.380]and
- [01:08:17.620]Green
- [01:08:17.860]Eye
- [01:08:17.980]Technology
- [01:08:18.500]they
- [01:08:18.760]have
- [01:08:18.920]developed
- [01:08:19.260]this
- [01:08:19.560]new
- [01:08:20.040]precision
- [01:08:21.320]sprayers
- [01:08:22.440]that
- [01:08:22.680]can
- [01:08:22.880]detect
- [01:08:23.200]the
- [01:08:23.400]weeds
- [01:08:23.600]in
- [01:08:23.780]real
- [01:08:23.980]time
- [01:08:24.280]and
- [01:08:24.460]spray
- [01:08:24.680]herbicide
- [01:08:25.180]only
- [01:08:25.620]like
- [01:08:25.900]a
- [01:08:26.020]spot
- [01:08:26.260]application
- [01:08:26.740]target
- [01:08:27.160]weed
- [01:08:27.400]management
- [01:08:27.780]so
- [01:08:29.080]that
- [01:08:29.340]was
- [01:08:29.560]second
- [01:08:29.860]message
- [01:08:30.320]and
- [01:08:30.920]some
- [01:08:31.280]reason
- [01:08:31.880]if
- [01:08:32.340]weeds
- [01:08:34.180]are
- [01:08:34.400]emerged
- [01:08:34.820]then
- [01:08:35.200]don't
- [01:08:35.540]let
- [01:08:35.840]them
- [01:08:36.060]to
- [01:08:36.260]produce
- [01:08:36.680]seeds
- [01:08:37.200]because
- [01:08:37.700]that
- [01:08:37.900]is
- [01:08:38.060]what
- [01:08:38.300]going
- [01:08:38.620]back
- [01:08:38.880]to
- [01:08:39.020]the
- [01:08:39.200]soil
- [01:08:39.500]and
- [01:08:39.760]then
- [01:08:39.980]next
- [01:08:40.240]year
- [01:08:40.420]you
- [01:08:40.520]have
- [01:08:40.660]to
- [01:08:40.800]deal
- [01:08:40.980]with
- [01:08:41.180]them
- [01:08:41.480]not
- [01:08:41.840]only
- [01:08:42.040]one
- [01:08:42.240]year
- [01:08:42.420]but
- [01:08:42.660]for
- [01:08:42.960]five
- [01:08:43.200]to
- [01:08:43.340]six
- [01:08:43.580]years
- [01:08:43.820]for
- [01:08:44.020]example
- [01:08:44.340]palmer
- [01:08:44.760]emirate
- [01:08:45.100]can
- [01:08:45.780]persist
- [01:08:46.240]in
- [01:08:46.460]the
- [01:08:46.620]soil
- [01:08:46.880]for
- [01:08:47.140]five
- [01:08:47.380]to
- [01:08:47.520]six
- [01:08:47.760]years
- [01:08:48.040]and
- [01:08:48.360]they
- [01:08:48.820]can
- [01:08:48.960]emerge
- [01:08:49.380]whenever
- [01:08:49.700]there
- [01:08:50.020]is
- [01:08:50.140]an
- [01:08:50.280]opportunity
- [01:08:50.800]especially
- [01:08:51.660]when
- [01:08:51.980]they
- [01:08:52.160]are
- [01:08:52.280]on
- [01:08:52.420]the
- [01:08:52.560]surface
- [01:08:52.820]of
- [01:08:53.040]the
- [01:08:53.180]soil
- [01:08:53.460]or
- [01:08:53.680]they
- [01:08:53.840]are
- [01:08:53.960]deep
- [01:08:54.300]one
- [01:08:54.640]inch
- [01:08:55.000]layer
- [01:08:55.440]below
- [01:08:55.740]the
- [01:08:55.960]soil
- [01:08:56.180]so
- [01:08:57.240]that
- [01:08:57.480]is
- [01:08:57.640]our
- [01:08:57.900]third
- [01:08:58.460]message
- [01:08:58.980]don't
- [01:08:59.360]let
- [01:08:59.580]them
- [01:08:59.800]to
- [01:08:59.980]produce
- [01:09:00.340]seeds
- [01:09:00.740]some
- [01:09:01.780]reason
- [01:09:02.100]if
- [01:09:02.320]they
- [01:09:02.500]produce
- [01:09:02.860]seeds
- [01:09:03.360]then
- [01:09:04.040]make
- [01:09:04.300]sure
- [01:09:04.500]they
- [01:09:04.720]don't
- [01:09:04.980]go
- [01:09:05.200]back
- [01:09:05.460]to
- [01:09:05.620]the
- [01:09:05.780]ground
- [01:09:06.080]so
- [01:09:06.580]now
- [01:09:06.800]we
- [01:09:07.200]are
- [01:09:07.300]working
- [01:09:07.560]with
- [01:09:07.800]some
- [01:09:08.020]companies
- [01:09:08.460]like
- [01:09:08.780]John
- [01:09:09.060]Deere
- [01:09:09.400]and
- [01:09:09.660]there
- [01:09:09.840]are
- [01:09:10.080]Haldington
- [01:09:11.680]seed
- [01:09:12.000]destructor
- [01:09:12.560]that
- [01:09:13.180]was
- [01:09:13.380]invented
- [01:09:13.760]in
- [01:09:14.100]Australia
- [01:09:14.520]so
- [01:09:15.220]what
- [01:09:15.620]they
- [01:09:15.800]do
- [01:09:15.960]is
- [01:09:16.100]when
- [01:09:16.280]they
- [01:09:16.420]go
- [01:09:16.620]for
- [01:09:16.880]combining
- [01:09:17.340]their
- [01:09:17.800]grains
- [01:09:18.520]there
- [01:09:19.360]is
- [01:09:19.500]a
- [01:09:19.740]attachment
- [01:09:20.280]at
- [01:09:20.680]the
- [01:09:20.820]back
- [01:09:21.020]of
- [01:09:21.220]the
- [01:09:21.460]combine
- [01:09:21.740]which
- [01:09:22.560]will
- [01:09:22.860]basically
- [01:09:23.460]grind
- [01:09:23.960]all
- [01:09:24.340]the
- [01:09:24.560]seeds
- [01:09:25.020]which
- [01:09:25.620]are
- [01:09:25.780]dropping
- [01:09:26.500]back
- [01:09:26.880]from
- [01:09:27.180]the
- [01:09:27.360]combine
- [01:09:27.700]so
- [01:09:28.440]you
- [01:09:28.600]are
- [01:09:28.720]basically
- [01:09:29.080]not
- [01:09:29.520]throwing
- [01:09:29.900]the
- [01:09:30.120]seeds
- [01:09:30.440]behind
- [01:09:31.000]the
- [01:09:31.400]combine
- [01:09:31.960]in
- [01:09:32.360]the
- [01:09:32.540]soil
- [01:09:32.880]but
- [01:09:33.400]you
- [01:09:33.520]are
- [01:09:33.640]breaking
- [01:09:34.240]them
- [01:09:34.580]in
- [01:09:34.720]a
- [01:09:34.860]powder
- [01:09:35.080]form
- [01:09:35.440]so
- [01:09:35.660]they
- [01:09:35.860]are
- [01:09:36.000]no
- [01:09:36.180]more
- [01:09:36.380]long
- [01:09:36.640]seeds
- [01:09:37.020]and
- [01:09:37.300]they
- [01:09:37.440]cannot
- [01:09:37.680]emerge
- [01:09:38.200]so
- [01:09:39.300]this
- [01:09:39.560]is
- [01:09:39.720]my
- [01:09:39.900]last
- [01:09:40.180]slide
- [01:09:40.440]in
- [01:09:40.640]each
- [01:09:40.960]and
- [01:09:41.060]every
- [01:09:41.260]presentation
- [01:09:41.820]like
- [01:09:42.720]don't
- [01:09:43.020]let
- [01:09:43.240]the
- [01:09:43.400]weeds
- [01:09:43.580]to
- [01:09:43.740]emerge
- [01:09:44.200]don't
- [01:09:44.900]let
- [01:09:45.100]them
- [01:09:45.320]to
- [01:09:45.520]produce
- [01:09:45.900]seeds
- [01:09:46.440]if
- [01:09:46.780]they
- [01:09:46.920]produce
- [01:09:47.260]seeds
- [01:09:47.540]don't
- [01:09:47.900]let
- [01:09:48.100]the
- [01:09:48.360]seeds
- [01:09:48.800]to
- [01:09:49.000]go
- [01:09:49.140]back
- [01:09:49.320]to
- [01:09:49.480]the
- [01:09:49.640]soil
- [01:09:49.820]seed
- [01:09:50.000]bank
- [01:09:50.280]so
- [01:09:50.860]weed
- [01:09:51.080]management
- [01:09:51.420]now
- [01:09:51.820]is
- [01:09:52.080]complex
- [01:09:52.580]because
- [01:09:53.060]it's
- [01:09:54.360]not
- [01:09:54.540]only
- [01:09:55.020]about
- [01:09:55.320]using
- [01:09:55.720]herbicide
- [01:09:56.380]X and
- [01:09:56.960]Y
- [01:09:57.240]for
- [01:09:57.620]one
- [01:09:57.900]year
- [01:09:58.120]or
- [01:09:58.260]two
- [01:09:58.420]year
- [01:09:58.660]but
- [01:09:58.920]it's
- [01:09:59.200]all
- [01:09:59.420]about
- [01:09:59.760]how
- [01:10:00.100]best
- [01:10:00.420]you
- [01:10:00.660]can
- [01:10:00.840]do
- [01:10:00.980]your
- [01:10:01.200]job
- [01:10:01.580]to
- [01:10:02.160]reduce
- [01:10:02.540]the
- [01:10:02.800]weed
- [01:10:03.000]seed
- [01:10:03.200]production
- [01:10:03.600]in
- [01:10:03.880]your
- [01:10:04.100]soil
- [01:10:04.360]seed
- [01:10:04.540]bank
- [01:10:04.840]any
- [01:10:08.920]question
- [01:10:09.360]for
- [01:10:09.680]Dr.
- [01:10:09.980]Sikama
- [01:10:10.340]my
- [01:10:13.020]last
- [01:10:13.340]question
- [01:10:13.660]is
- [01:10:13.900]when
- [01:10:14.120]you
- [01:10:14.260]say
- [01:10:14.440]green
- [01:10:14.760]pig
- [01:10:15.020]weed
- [01:10:15.240]that
- [01:10:15.480]is
- [01:10:15.660]similar
- [01:10:15.940]to
- [01:10:16.200]red
- [01:10:16.420]root
- [01:10:16.560]pig
- [01:10:16.780]weed
- [01:10:16.980]or
- [01:10:17.220]that
- [01:10:17.460]is
- [01:10:17.600]some
- [01:10:17.820]different
- [01:10:18.200]species
- [01:10:18.620]very
- [01:10:19.160]similar
- [01:10:19.580]I
- [01:10:19.780]think
- [01:10:20.000]you
- [01:10:20.140]call
- [01:10:20.420]it
- [01:10:20.580]Powell
- [01:10:20.940]Amaranth
- [01:10:22.040]okay
- [01:10:22.940]well
- [01:10:25.440]thank you
- [01:10:25.820]very much
- [01:10:26.140]for joining
- [01:10:26.560]us today
- [01:10:26.960]thank you
- [01:10:31.640]you
- [01:10:32.260]Thank you.
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