Tough Pests Call for Team Solutions: Building a Coalition for Wheat Stem Sawfly

Katherine Frels, Assistant Professor, Small Grain Breeding and Genetics, Agronomy & Horticulture; Jeff Bradshaw, Director, Doctor of Plant Health Program; Amanda Easterly, Research Assistant; Professor, Crop Performance Testing Program, Agronomy & Horticu Author

12/18/2023 Added

23 Plays

Description

Wheat stem sawfly is an emerging crisis in the Northern High Plains. With the potential to affect wheat production, but also to disrupt standard crop rotation and management practices, wheat stem sawfly is a challenge that cannot be solved by one research discipline. This pest is an opportunity to engage in unique, interdisciplinary, multi-state research while simultaneously working towards solutions with our stakeholders.

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[00:00:00.750]The following presentation is part of
[00:00:02.760]the Agronomy and Horticulture seminar series
[00:00:05.790]at the University of Nebraska Lincoln.
[00:00:09.090]Good afternoon, everyone.
[00:00:10.770]Thank you for joining today
[00:00:12.510]for those in-person and online
[00:00:14.700]for the Agronomy and Multicultural seminars.
[00:00:17.790]We're close to the end of the series this year,
[00:00:20.100]and we have the pleasure today
[00:00:21.720]to introduce a team presentation.
[00:00:23.640]It was a great idea from Catherine when we invited her
[00:00:27.000]and we thought it was great to explore other options.
[00:00:30.360]So, I will just pass to her.
[00:00:34.140]But we have Katherine Frels, Assistant Professor,
[00:00:38.400]Small Grains Breeding and Genetics.
[00:00:41.310]And then we'll have also Jeff Bradshaw,
[00:00:43.680]the Director, Doctor of the Plant Health Program.
[00:00:47.340]And then we'll have two participations online.
[00:00:50.160]Amanda Easterly with the Crop Performance Testing Program,
[00:00:53.910]she's a Research Assistant Professor within our department.
[00:00:56.820]and then Cody Creech,
[00:00:57.840]Associate Professor of Dryland Systems.
[00:01:00.233]He will be joining on that.
[00:01:01.620]With that, I will give the floor to Katherine.
[00:01:04.857]And yeah, we'll see how that goes.
[00:01:07.410]All right, well I'll leave this first slide up
[00:01:12.690]for just a little bit longer here,
[00:01:15.090]at least while I'm doing the introductions.
[00:01:17.700]And I'm not gonna say a lot
[00:01:19.890]because most of you know us, or a few of us.
[00:01:23.460]And so the reason we're doing this presentation this way
[00:01:28.800]is that I was asked to do a department seminar
[00:01:32.430]and well, you know,
[00:01:36.240]didn't know if I really wanted to do one,
[00:01:38.490]but then, you know, Sawfly is probably the number one topic
[00:01:42.390]for us in wheat in Nebraska right now.
[00:01:44.640]It is the problem that our stakeholders
[00:01:49.200]asked me to deal with when I came on as the UNL breeder.
[00:01:53.850]It's what the wheat board was most concerned about.
[00:01:58.620]But it's not a problem that I deal with alone.
[00:02:02.610]And we've put together this really awesome team
[00:02:07.140]and we have a lot of fun doing research together.
[00:02:09.900]And so I said, well, rather than me
[00:02:12.390]taking all of your slides and presenting your data,
[00:02:15.900]let's just do this together
[00:02:17.310]and just show an example of integrated research
[00:02:21.480]within the Agronomy and Horticulture Department
[00:02:24.750]as well as outside of the department.
[00:02:27.210]And we'll also talk a little bit about our stakeholders
[00:02:31.050]and research colleagues beyond Nebraska.
[00:02:35.130]So as we get started, I'll just say
[00:02:39.420]that if you have not met Dr. Bradshaw,
[00:02:42.870]it's because up until this year he was out in the Panhandle
[00:02:47.670]as the wheat entomologist there.
[00:02:49.950]Cody and Amanda are still out in the Panhandle.
[00:02:52.590]And as we start answering some of those questions,
[00:02:57.480]the common denominator for three of us
[00:03:00.540]is that three of us have degrees from this department
[00:03:04.050]and in total there are four degrees from UNL.
[00:03:09.810]But one of us, the outlier in this group,
[00:03:12.240]actually happens to have dual PhDs from Iowa State.
[00:03:16.170]So, that's pretty fancy.
[00:03:17.520]So you may not have known this fact about Dr. Bradshaw.
[00:03:22.530]All right, so as we go through the story today,
[00:03:27.360]we're going to be passing off back and forth,
[00:03:31.020]sharing the different parts of the story
[00:03:33.870]that we each focus on and the research.
[00:03:37.080]We're gonna talk a lot about what is sawfly,
[00:03:40.050]why is it such a problem for us?
[00:03:41.850]Why do we really need this interdisciplinary team
[00:03:45.570]to solve the problem?
[00:03:47.127]And so with that, I'm gonna pass it over to Amanda
[00:03:51.900]to talk about why wheat and wheat stem sawfly
[00:03:57.420]are important in Nebraska.
[00:03:59.910]Thank you, Katherine. Hello everybody.
[00:04:03.489]And, wish I could be there in person,
[00:04:05.220]but we'll make do with modern technology.
[00:04:09.090]Few quick stats, a lot of you already know this,
[00:04:11.850]it's pretty common knowledge.
[00:04:14.010]Wheat in Nebraska is the third most significant crop
[00:04:16.530]after corn and soybeans.
[00:04:18.270]Now when we're based in Lincoln,
[00:04:20.040]we don't see it a whole lot, but it is widely grown.
[00:04:24.090]Approximately a million acres a year of winter wheat
[00:04:27.630]are sown in Nebraska.
[00:04:30.000]Yields in the Panhandle range pretty widely
[00:04:34.050]from one to five megagrams per hectare.
[00:04:38.490]And that yield range reflects the variability
[00:04:43.770]of cropping systems in western Nebraska.
[00:04:48.600]I'll have you kick ahead, yep.
[00:04:51.210]The majority again of that wheat production
[00:04:54.312]is in the Panhandle, over half.
[00:04:56.550]But we are starting to see a rise in production
[00:04:59.700]in the Eastern region and the South Central region
[00:05:02.460]because there are a lot of advantages
[00:05:05.250]to including winter wheat in your rotation.
[00:05:09.270]If I can have the next slide please, Dr. Frels.
[00:05:13.710]So again, wheat is cornerstone
[00:05:16.530]for a lot of production in Nebraska and the majority of it
[00:05:20.250]is of the hard red winter wheat class.
[00:05:22.500]And again, preaching to the choir.
[00:05:24.450]But I'll break that down real quickly
[00:05:25.980]for those who may not be familiar.
[00:05:28.740]The designation of hard indicates
[00:05:31.200]the density of the endosperm.
[00:05:33.300]That's in contrast to soft winter wheat,
[00:05:35.700]where the endosperm is mostly starches,
[00:05:39.210]hard winter wheat is higher in protein and in gluten
[00:05:42.900]that makes it better for breads
[00:05:45.840]as opposed to soft wheats that are used more
[00:05:48.000]for cakes and cookies.
[00:05:50.700]The red refers to an aspect of the seed itself,
[00:05:56.640]which reflects again that it has some higher protein
[00:06:00.960]and makes it really good for artisan type or crusty breads.
[00:06:05.100]Winter refers to the lifecycle,
[00:06:07.530]and so winter wheat we plant in September or early October,
[00:06:11.700]we allow it to have some growth in the fall,
[00:06:14.070]it goes into dormancy,
[00:06:15.780]resumes growth and flowers in May or June,
[00:06:18.930]and then is ready to harvest in July.
[00:06:20.670]And so it's a radically different lifecycle
[00:06:25.590]than a lot of our summer annual crops.
[00:06:28.500]The historical rotation in dry line crop production
[00:06:31.740]in the Panhandle and in the High Plains
[00:06:34.350]was wheat and fallow.
[00:06:36.330]So you would grow wheat in one cropping system rotation,
[00:06:39.600]and then after that harvest in July,
[00:06:42.780]the ground would be kept bare
[00:06:45.480]to allow for the accumulation of soil moisture
[00:06:51.245]so that you could have adequate moisture
[00:06:53.460]to plant again in the fall.
[00:06:56.190]Advances in things like no-till production,
[00:06:59.684]chemicals that allow us to maintain chemical fallow,
[00:07:04.380]and keep weeds under better control,
[00:07:06.780]breeding efforts in what we would call
[00:07:10.050]the alternative crops of dry land corn,
[00:07:13.277]have allowed for diversification
[00:07:16.710]and intensification of our cropping systems.
[00:07:19.650]So for those who haven't been out in Western Nebraska,
[00:07:23.280]we still see some wheat-fallow rotations.
[00:07:27.180]We see a lot of wheat-corn-fallow,
[00:07:29.280]a lot of wheat-proso millet-fallow.
[00:07:32.670]Sometimes folks will even advance
[00:07:34.680]and throw in some field peas or sunflowers
[00:07:38.550]or green sorghum as conditions in market allow.
[00:07:42.870]But the common denominator is always wheat.
[00:07:48.390]Wheat itself has some pretty good agroecosystem benefits,
[00:07:51.330]particularly as you move out west.
[00:07:55.080]Because of that long growing season through the fall
[00:07:57.780]of one year and the spring of the next,
[00:07:59.910]we have good ground cover and protection from erosion.
[00:08:03.570]The residue after harvest is key
[00:08:08.460]to trapping some soil moisture for the next year,
[00:08:12.960]and that's usually in the form of snow
[00:08:15.330]so that the residue traps snow similar
[00:08:17.910]to how a lot of no-till production functions,
[00:08:21.630]you know, widely in the US.
[00:08:25.170]The residue can also be used for grazing or bailing
[00:08:28.590]and it's friendly for no-till planting
[00:08:31.980]of the following crops.
[00:08:34.080]The other aspect of wheat that is beneficial
[00:08:36.480]is that the production of wheat has fairly good stability
[00:08:41.280]under variable rainfall patterns
[00:08:43.590]and it has a good response to input.
[00:08:45.690]So it's kind of the best of both worlds in that regard
[00:08:49.290]because you're generally going to get something to harvest.
[00:08:52.800]There is that wide range of potential yields,
[00:08:56.070]but generally you get something
[00:08:57.990]and then if conditions are favorable,
[00:09:00.300]you can manage the crop to best capture
[00:09:04.140]that yield potential.
[00:09:06.030]But there are challenges, just as there are in any crop.
[00:09:11.866]We have fungal diseases like smuts
[00:09:13.860]that are occasionally present.
[00:09:15.150]We have viral diseases that can be quite devastating.
[00:09:19.740]There's a high frequency of hail
[00:09:21.990]and crop failure in Western Nebraska.
[00:09:24.180]We call it the white combine that comes down from the sky.
[00:09:28.980]And then along comes the sawfly.
[00:09:32.220]And with that, I'll kick it to Jeff.
[00:09:37.440]Thanks Amanda. Is this working okay?
[00:09:40.620]No, it's not working at all? You can't hear me?
[00:09:44.490]Can you hear me online?
[00:09:47.880]Okay, well, I'll just speak loudly.
[00:09:50.640]So, that's right.
[00:09:52.650]I'm Director of the Doctor of Plant Health Program,
[00:09:54.270]also an entomologist.
[00:09:55.680]And so I get really excited
[00:09:57.150]when I get to talk about insects.
[00:09:59.340]One insect that's been really challenging in wheat
[00:10:02.340]has been the wheat stem sawfly.
[00:10:04.800]It was originally described from Colorado,
[00:10:07.080]it's a native insect, was described in Colorado in 1876.
[00:10:11.690]It was the first specimen described,
[00:10:14.130]not too long after that became a major pest of,
[00:10:16.950]I feel like I'm getting an echo, maybe it's just me.
[00:10:20.190]Nope, I'm good. All right, maybe it is me.
[00:10:23.760]I'll do this. Take my hearing aid out. How's that?
[00:10:27.810]So, it was found to be a pest of wheat,
[00:10:31.080]primarily in the prairie provinces of Canada
[00:10:34.260]in around 1910, 1915.
[00:10:38.040]Quickly moved into other spring wheats,
[00:10:40.410]primarily that were grown in North Central Montana.
[00:10:43.980]Eventually developed and adapted to winter wheat
[00:10:46.560]as that population adapted over time.
[00:10:49.590]Here's a picture of the adult insect
[00:10:51.480]with the bright yellow legs.
[00:10:53.490]It's called a sawfly, but it's actually a wasp.
[00:10:56.760]And the challenge with this insect is
[00:11:02.130]as the wheat stem sawfly female you can see pictured there
[00:11:06.330]lays an egg within the stem of a wheat tiller
[00:11:09.660]that larva hatches out
[00:11:10.980]and then feeds on the pith
[00:11:13.110]within the center of that wheat plant.
[00:11:15.840]And as it develops, it moves down in the tiller.
[00:11:18.750]Usually as the wheat starts to senesce,
[00:11:22.020]light starts penetrating that stem
[00:11:24.690]and then that larva will pupate the base of the stem
[00:11:28.380]after it girdles it.
[00:11:29.970]And as Amanda indicated,
[00:11:32.490]there are storms that happen in the west,
[00:11:34.320]some then are pretty fierce,
[00:11:36.360]and that wind will cause lodging of the wheat
[00:11:38.427]and that lodging can be problematic
[00:11:40.860]both for yield recovery...
[00:11:45.690]Oh hey, a little animation. That's cute.
[00:11:50.280]Wow, that's awesome. Good job.
[00:11:55.740]So they lodge the wheat,
[00:11:57.210]and obviously that can be a challenge for yield recovery.
[00:12:00.750]There is some yield loss
[00:12:01.890]due to the feeding of the wheat stem sawfly.
[00:12:03.540]We'll talk about that a little bit later
[00:12:04.950]in terms of the grain weight.
[00:12:07.440]But the main challenge is this lodging that results.
[00:12:12.840]So Amanda mentioned kind of the cropping system cycle
[00:12:17.580]in dry land in the west.
[00:12:20.070]Kind of the life cycle in short
[00:12:23.850]is the adult emerges typically in April or May,
[00:12:28.740]she lays her eggs in the wheat,
[00:12:31.020]typically mid to late May into early June,
[00:12:33.630]they have four to five week emergence period,
[00:12:37.035]over time they'll feed within the wheat.
[00:12:39.930]So they're coming out of the wheat-fallow
[00:12:41.790]and then moving into this year's wheat crop
[00:12:46.290]as indicated by that fancy animation.
[00:12:49.080]And then that next wheat section of fallow
[00:12:51.540]is gonna be the next wheat.
[00:12:53.130]So generally we talk about the highest risk wheat
[00:12:56.820]are those systems that are wheat on wheat-fallow,
[00:13:00.150]particularly the no-till systems
[00:13:01.740]where they're conserving wheat residue for all great reasons
[00:13:04.890]for soil holding and soil moisture capture.
[00:13:07.920]That's also a really good environment
[00:13:09.600]for wheat stem sawfly survival.
[00:13:12.810]So the hunch goes.
[00:13:16.230]Here's some video that Amanda took
[00:13:17.730]down at the High Plains ag lab, I believe,
[00:13:19.680]of the wheat stem sawfly adults flying around in some wheat.
[00:13:25.290]So you can see they can be quite abundant,
[00:13:26.880]they're very easy to see as you look out
[00:13:29.760]across the wheat canopy.
[00:13:31.890]Over the years they've become more and more abundant.
[00:13:34.620]Since around 2012 we started seeing populations
[00:13:38.010]really increase across Western Nebraska.
[00:13:41.250]Pictured on the right is some lodged wheat
[00:13:44.010]resulting from that wheat stem sawfly larval activity
[00:13:46.740]that you might find in early to mid-July.
[00:13:50.400]Usually around the time the combines show up
[00:13:52.920]is when we discover that the wheat's lodged.
[00:13:55.590]It happens fairly rapidly after that wind event.
[00:13:59.640]And then pictured here inset is the crown of the wheat
[00:14:03.270]that's left behind after that sawfly has lodged it.
[00:14:06.660]So as the winter goes on,
[00:14:08.670]sometimes the soil line will cover over that wheat crown
[00:14:11.970]and so fields might be smooth and flat
[00:14:14.820]and not have much residue left behind at all.
[00:14:19.500]So over time this insect has expanded in range.
[00:14:24.300]While its geographic range is quite broad,
[00:14:26.730]in terms of the pest range in wheat,
[00:14:28.920]that's expanded over time.
[00:14:30.960]This graph is from an older,
[00:14:32.700]somewhat older publication from 2018.
[00:14:35.550]The dark shaded gray area's where kind of
[00:14:37.620]the original economic pest problem arose
[00:14:40.590]primarily in spring wheat a few years back.
[00:14:43.770]And then this dotted line, that gray shared area,
[00:14:46.830]back in 2018 we were kind of projecting
[00:14:49.320]that kind of severe area primarily around the High Plains
[00:14:54.116]to Central High Plains area.
[00:14:56.460]And that represents pretty much the full range that we see
[00:14:59.820]fields that can have documented economic populations
[00:15:03.000]of wheat stem sawfly,
[00:15:04.770]so including Wyoming and Nebraska, et cetera.
[00:15:09.180]The economic impact has been measured
[00:15:11.850]both in Montana and Colorado.
[00:15:13.590]And as you can read there, it's quite significant,
[00:15:16.770]greater or equal to $350 million per year
[00:15:19.860]just in yield loss in Colorado,
[00:15:22.500]somewhere around 3$0-33 million per year in loss
[00:15:26.280]estimated recently.
[00:15:28.620]And again, that yield loss is just considering
[00:15:31.020]the direct loss of yield,
[00:15:33.480]mostly through the result of lodging,
[00:15:35.820]not including potential impacts from residue loss.
[00:15:39.720]Oops, sorry, just wanted to see that again.
[00:15:42.777]And so that population range,
[00:15:45.360]the frequency of fields being affected by wheat stem sawfly
[00:15:48.210]over that range has expanded.
[00:15:50.010]Economic impact has also expanded
[00:15:52.290]as has the increase in density over that geographic range.
[00:15:57.390]So this graph is just showing a number of different surveys
[00:16:00.600]that have been conducted both by myself
[00:16:03.030]here in Nebraska in the blue
[00:16:06.342]with just some trend lines snapped
[00:16:09.300]over those sampling years,
[00:16:11.880]along with Colorado and North Dakota.
[00:16:14.640]And so there's just a general trend
[00:16:16.290]and increase in population densities over time.
[00:16:19.140]And then recently the green dot there on the map
[00:16:21.450]is Northwest Kansas.
[00:16:23.970]So we're all excited that they get to join us
[00:16:27.030]in this adventure as well.
[00:16:30.750]And so I think it's onto Katherine.
[00:16:32.910]Yeah, so, and I am realizing
[00:16:35.880]as I'm watching this now that we forgot one slide,
[00:16:40.770]that we all know this by heart,
[00:16:43.470]but it's why do we need such a big research team
[00:16:48.450]to deal with this pest?
[00:16:50.010]Why hasn't Bayer or BASF or Dow,
[00:16:54.900]any of the chemical companies,
[00:16:56.610]why haven't they fixed this problem for us, Jeff?
[00:16:59.055]And it's been a problem for 80 years.
[00:17:02.130]We've been trying to tackle this.
[00:17:04.200]Well, we've not taken a team approach
[00:17:05.970]on this before, Katherine.
[00:17:06.960]It's true, it's true.
[00:17:08.310]But it's also, Jeff mentioned,
[00:17:09.990]that that three to four week flight for sawfly's
[00:17:14.550]we cannot spray.
[00:17:15.750]You'd have to be out there spraying every day
[00:17:17.820]to try to actually see economic impact
[00:17:21.150]by pesticide application.
[00:17:23.430]And so we're really left with solving this
[00:17:26.820]the old fashioned way
[00:17:28.530]and that's why we are building this research team.
[00:17:32.310]So today,
[00:17:36.044]UC really represented our Team Sawfly at UNL.
[00:17:42.060]We work very closely with our wheat stakeholders for this.
[00:17:46.950]This is something that they really care about.
[00:17:49.680]Also, all of the industry breeding companies,
[00:17:54.960]they're working hard on this,
[00:17:56.250]but they're also really looking to the universities
[00:17:59.010]for leadership on this problem
[00:18:00.510]because it is such a challenging pest to work with.
[00:18:04.590]So this is just a little schematic
[00:18:07.560]of how our research teams work together,
[00:18:12.887]help each other out.
[00:18:14.760]I could not do this alone
[00:18:16.350]and you'll really see these different aspects
[00:18:20.220]represented throughout the presentation,
[00:18:24.450]how we work together to get this research cycle going.
[00:18:31.320]You wanna, why don't you talk about this?
[00:18:33.750]You're a leader in this.
[00:18:34.950]Oh, something like that.
[00:18:37.590]So one of the things,
[00:18:39.000]one of the challenges with wheat stem sawfly
[00:18:42.300]has been several groups working independently
[00:18:45.630]in trying to solve a problem.
[00:18:47.100]So one new opportunity we had was with kind of
[00:18:50.520]a reformation process that the USDA facility in Akron
[00:18:55.350]went through recently with their- (mic cutting out)
[00:18:58.188]To kind of reform what they were doing out there
[00:19:01.860]and refocus their strategy.
[00:19:04.140]Again, like when Katherine came on,
[00:19:06.240]their stakeholders were pretty vocal about wheat stem sawfly
[00:19:08.910]needs to be a problem that we need to solve
[00:19:11.040]or manage in some way.
[00:19:12.510]Same thing was expressed to the USDARS in Akron
[00:19:16.080]and now they're home base in Fort Collins.
[00:19:18.360]So I've been working very closely with them
[00:19:20.040]to try to grow our team,
[00:19:21.210]grow our network across the multi-state,
[00:19:23.580]multi-agency, multi-university effort
[00:19:27.000]to try to see if we can tackle this together
[00:19:29.970]and to bring our forces together to see
[00:19:32.640]if we can garner some greater support for this.
[00:19:36.120]So a subset of that group, primarily entomologists,
[00:19:40.890]have been involved in trying to do a bit of work this year.
[00:19:44.940]We put in a proposal that was awarded
[00:19:47.220]through the North Central IPM program
[00:19:49.830]with the thought of, you know,
[00:19:51.150]as we work together as a broader team
[00:19:53.923]of cropping system specialists,
[00:19:54.990]wheat breeders, and entomologists,
[00:19:57.690]we can come up with some some solutions,
[00:19:59.820]but what if they can't adapt to the different regions?
[00:20:03.450]So I've gone out to five states
[00:20:07.110]that are participating in this effort,
[00:20:08.760]conducted focus group meetings with growers,
[00:20:11.340]been in the pickups with them, they drove me around,
[00:20:13.410]and was really impressed with just how
[00:20:15.540]these dry land cropping systems are.
[00:20:17.790]For example, in Western North Dakota
[00:20:19.260]it's completely different to North Central Montana,
[00:20:21.720]completely different to Eastern Colorado.
[00:20:24.780]Really impressed me that we-
[00:20:25.950]And they all still have have sawfly, so.
[00:20:27.957]And they all have sawfly in common.
[00:20:30.360]But different cropping systems, different fallow regimes,
[00:20:33.960]different no-fallow regimes.
[00:20:36.060]So what we did is we launched,
[00:20:37.890]in addition to those focus group surveys,
[00:20:40.320]focus group efforts,
[00:20:41.940]use that as an opportunity to AB test some questions
[00:20:44.430]for a survey tool that we then launched online.
[00:20:48.030]The shaded counties that you see here,
[00:20:50.280]this is representing the response rates
[00:20:52.980]and the response map of that survey that we launched.
[00:20:56.850]The dots that you see are a companion survey.
[00:20:59.670]It was a biological survey component of this work
[00:21:02.790]looking at what we call a cut stub survey
[00:21:05.316]where we went out and sampled wheat fields
[00:21:07.470]looking for cut sawfly-infested wheat tillers,
[00:21:12.570]principally cut tillers to look at
[00:21:14.157]the most severe conditions across that landscape.
[00:21:17.670]And maybe it's not too much of a surprise
[00:21:19.980]that we see most of our hits
[00:21:21.090]on the survey responses overlapping
[00:21:22.890]were some of the highest densities
[00:21:24.810]in some of those locations.
[00:21:26.370]So some of this we kind of knew as researchers
[00:21:28.980]working with a lot of these stakeholders already.
[00:21:31.230]But it's nice to have this data here to back up
[00:21:33.510]as we move into this next year
[00:21:35.430]with a really strong foundation of needs
[00:21:38.670]and opportunities assessed.
[00:21:41.880]All right, so that's really
[00:21:43.230]the scope of the problem.
[00:21:45.210]Let's start talking about some of the research
[00:21:47.520]that we have initiated to develop solutions.
[00:21:53.700]So the number one thing we can do right now
[00:21:57.930]for helping our stakeholders
[00:22:00.450]is develop host plant resistance.
[00:22:03.310]There are several ways that we can do this.
[00:22:06.960]The primary trait right now is solid stem wheat.
[00:22:12.360]And so what I mean by solid stem
[00:22:15.600]is that we actually have the pith nearly completely
[00:22:20.220]or completely fill in that stem.
[00:22:23.130]This is a royal pain of a trait to work with,
[00:22:31.320]I think is the nice way to put it.
[00:22:33.510]Even though we have a really actually pretty good marker
[00:22:38.460]for a gene that controls up to 75%
[00:22:42.570]of the variation for this trait.
[00:22:44.790]However, the expression is very variable.
[00:22:47.160]It's also very dependent on the growth stage,
[00:22:51.240]the environment, and minor gene contributions.
[00:22:56.130]It also has a lot of yield drag associated with it.
[00:22:59.310]So the first generation of varieties
[00:23:02.970]from any breeding program with this trait are not great.
[00:23:07.890]They show significant yield loss
[00:23:13.710]because they're just not adapted.
[00:23:15.660]They, you know, this trait causes some drag itself.
[00:23:19.260]And you only see a benefit of having them
[00:23:21.450]in those severe infestations.
[00:23:24.090]But yet it's really the best we have right now.
[00:23:26.220]And so that's the primary thing we're working on.
[00:23:30.000]And this is one of the reasons
[00:23:31.740]why we kind of hate this trait.
[00:23:33.090]And so this is Sydney and Cole out in Lincoln this year.
[00:23:38.190]Yeah, that's our sad 2023 wheat.
[00:23:40.710]It was about seven inches tall, and fun fact,
[00:23:44.550]Cole and Sydney discovered that when you have drought,
[00:23:47.640]everything is solid.
[00:23:50.070]So not only did they do the phenotyping in Lincoln,
[00:23:53.490]they actually had to go do it out in Sydney
[00:23:55.410]where there was water.
[00:23:56.910]How weird is that, that there was water out west,
[00:23:59.460]and no water in Lincoln.
[00:24:01.200]And do it again so that we could get a better score
[00:24:04.830]to actually select on.
[00:24:07.390]The other challenge is there's actually multiple ways
[00:24:09.690]you can score this solidness.
[00:24:12.480]You could just do a quick and dirty,
[00:24:16.860]like what we're doing here,
[00:24:18.900]take one node and we usually do the bottom node here,
[00:24:23.250]and rate it on a one through five scale.
[00:24:26.880]What we really should be doing
[00:24:29.250]is looking at every single node because,
[00:24:32.847]and rating each node,
[00:24:34.620]because the sawfly lay their eggs up here
[00:24:37.350]and the larva crawl all the way down.
[00:24:40.320]That's too time consuming to do
[00:24:43.590]for every single breeding plot.
[00:24:45.300]So, we do the quick and dirty way.
[00:24:49.200]It's the best we've got.
[00:24:50.850]And we do, you know,
[00:24:51.870]you could see these are varieties of,
[00:24:54.750]in the breeding program,
[00:24:56.370]we actually do have some that look pretty good
[00:24:59.640]for solidness.
[00:25:00.750]The trick is getting them that yield, so.
[00:25:05.190]All right, so this is the typical breeding program pipeline.
[00:25:08.280]You start out with tons of genetic variation,
[00:25:10.830]you work your way through the breeding program
[00:25:14.550]and you get, you derive lines,
[00:25:17.550]you get out to yield trials,
[00:25:19.590]advanced yield trials, multi-loc, multi-replication,
[00:25:23.790]you add on variety testing,
[00:25:25.800]and then you finally get to one cultivar release.
[00:25:30.120]So, let's look at our solid stem breeding pipeline.
[00:25:33.060]It looks pretty similar.
[00:25:35.700]The difference is that we've been running this program
[00:25:40.320]since the early 1900's in some form or another.
[00:25:45.090]The current iteration of the program
[00:25:46.890]has really been more or less the same since the 50s.
[00:25:51.330]But for solid stem, I went back in the database,
[00:25:54.570]and what I could find was that the first crosses
[00:25:57.930]with solid stem donor materials,
[00:25:59.850]or the first cross,
[00:26:00.750]there was only one in 2010 that I could find.
[00:26:03.390]First cross was made in 2010.
[00:26:05.550]They really started in about 2013 making a lot more crosses
[00:26:10.290]with solid stem materials.
[00:26:12.780]So really about the first time we got to deriving rows
[00:26:17.250]was 2017.
[00:26:20.040]First preliminary observation,
[00:26:21.840]so that's a one loc, one plot,
[00:26:23.850]no replication trial here in Lincoln.
[00:26:26.310]So not where we're targeting these lines.
[00:26:29.040]So, that was 2019.
[00:26:31.170]2020 is really about the first preliminary yield trial
[00:26:34.500]from what I can tell.
[00:26:35.580]I arrived in 2021, and we moved them in 2022.
[00:26:40.530]We actually started our first
[00:26:43.110]multi-replication, multi-location yield trial,
[00:26:47.760]specifically for solid stem lines.
[00:26:51.360]This year is the first time we divided it up into two trials
[00:26:54.780]so that we had really good materials
[00:26:57.060]that were targeting towards variety release.
[00:26:59.910]And we have that first gen kind of yields,
[00:27:03.480]multi-location yield trial.
[00:27:06.300]We put lines into variety testing with Amanda
[00:27:09.690]for the first time this year.
[00:27:11.610]And guess what, we have not released variety,
[00:27:13.890]but we're trying to push really hard.
[00:27:16.620]So really we started breeding for this trait
[00:27:20.190]sometime between 2010 to 2013.
[00:27:24.480]And we're hoping that by 2025, 2026,
[00:27:27.930]we can get a variety out.
[00:27:30.750]It's a pretty long time to wait,
[00:27:32.940]especially for a trait that we don't really like that much.
[00:27:37.860]It helps for sure, but it's not everything.
[00:27:42.330]And this is really the first year,
[00:27:44.910]and when I say this year,
[00:27:46.560]remember we're working in winter wheat.
[00:27:48.450]So I've already, I'm done with 2023,
[00:27:52.110]I've been thinking about 2024 for three months now.
[00:27:56.400]So this year is the first year
[00:27:58.260]where I would actually consider us
[00:27:59.850]having a full solid stem breeding pipeline.
[00:28:06.600]So, this is one of those examples of research
[00:28:11.430]that's really key to keep that integrated aspect.
[00:28:14.790]This is from Jeff's research
[00:28:19.590]and one of the things he had mentioned
[00:28:22.950]is that there is seed size reduction on infested stems.
[00:28:29.490]So the question is, if solid stems prevent lodging,
[00:28:33.480]do they also prevent that seed size loss?
[00:28:36.870]And the answer is, maybe.
[00:28:40.170]Not always.
[00:28:41.430]So for example, and Amanda, correct me if I'm wrong,
[00:28:44.730]4483 is full solid, right?
[00:28:48.630]Yes. Okay.
[00:28:49.860]So, that's a west bred line. Full solid.
[00:28:52.380]Fortify SF is Colorado State's first gen semi-solid line.
[00:28:57.990]So, it's not a full solid.
[00:29:00.030]We see in Fortify SF,
[00:29:02.040]so this is basically a contrast here,
[00:29:05.100]we're looking at the difference in seed size
[00:29:08.430]from an un-infested tiller with an infested tiller.
[00:29:13.020]You see that in several of these lines
[00:29:16.800]we have a pretty big difference in seed size.
[00:29:23.970]And in some of them we don't.
[00:29:28.200]But what we're seeing here
[00:29:30.371]is that solid stem trait doesn't necessarily guarantee
[00:29:35.100]that we won't see that reduction in yield
[00:29:38.070]due to smaller seeds.
[00:29:40.200]So, that's the thing about solid stem,
[00:29:43.320]the sawflys can still infest the wheat,
[00:29:47.438]they just don't tend to do quite as well.
[00:29:52.710]Good example of teamwork.
[00:29:55.072]You give your colleague your data slide
[00:29:56.970]and have them explain it.
[00:29:59.070]I had to practice that one.
[00:30:00.690]So if solid stem isn't everything, what else do we have?
[00:30:05.370]Well, we can try for non preference,
[00:30:07.770]which is, where sawflys love this variety,
[00:30:11.520]they hate this variety.
[00:30:13.740]We can look for antibiosis, or mortality,
[00:30:17.370]which is where the larvae get in the wheat,
[00:30:19.950]but then the wheat produces
[00:30:21.630]some sort of chemical and they croak.
[00:30:23.910]That'd be great.
[00:30:25.440]We could also have tolerance,
[00:30:27.150]which is where the sawfly still infest the wheat,
[00:30:33.180]but we don't see yield loss.
[00:30:35.070]So that would be a good example where
[00:30:36.570]we maybe don't see lodging
[00:30:39.540]and we don't see that loss in seed size.
[00:30:46.260]Problem with these is these are also
[00:30:48.180]really hard to phenotype.
[00:30:50.250]But we'll start with,
[00:30:52.080]and I'm gonna hand this to Amanda for this slide,
[00:30:54.690]because this is something that she noticed,
[00:30:56.790]and is really kind of the foundation
[00:30:58.710]of our start at looking for non solid stem resistance
[00:31:03.267]in our breeding program,
[00:31:04.710]and actually led to the project
[00:31:06.510]that Sydney Graham is working on.
[00:31:08.610]So, Amanda, how did notice this in the state variety trials?
[00:31:16.560]So, full disclosure, I walk a lot of wheat plots.
[00:31:20.490]I know Dr. Frels walks quite a few too
[00:31:22.800]with her breeding program.
[00:31:24.330]But I run 18 locations of a state variety trial
[00:31:29.156]and a good number of those testing locations
[00:31:31.920]are in the western side of the state.
[00:31:33.240]So, counties that are impacted by wheat stem sawfly.
[00:31:36.420]And as I walked these trials
[00:31:38.040]and walked other trials that we have over and over again,
[00:31:41.610]I saw that there was a hollow stem
[00:31:44.160]that just stood up better
[00:31:46.020]and there was no rational reason for it.
[00:31:48.990]And that variety was Wesley.
[00:31:50.970]Now Wesley is an interesting wheat.
[00:31:53.280]It's not bred as a dry land variety.
[00:31:55.830]It's bred for irrigated production,
[00:31:58.127]has a little bit different look to it.
[00:32:00.750]It's what we call a bronze chaffed wheat.
[00:32:02.820]So, it's pretty obvious out in the field.
[00:32:05.790]But other than that it's a hollow stem.
[00:32:08.040]There was no reason that there should be reduced lodging.
[00:32:13.230]And so, you know, at first I thought maybe it's a one-off.
[00:32:17.550]But then we started consistently rating the lodging
[00:32:20.490]ahead of the combine for our variety trials
[00:32:22.710]at a few locations.
[00:32:24.990]And in this sawfly score that's on this slide,
[00:32:28.380]a lower sawfly score means less lodging,
[00:32:31.740]a higher sawfly score is more lodging.
[00:32:34.680]And consistently, Wesley was a couple points
[00:32:38.400]below the average.
[00:32:41.040]And so that drew us to say, okay, so what is at play here?
[00:32:44.640]Because it's obviously not that solid stem trait.
[00:32:47.400]Could it be one of those alternative methods of resistance
[00:32:50.190]that Katherine just talked about?
[00:32:53.550]And so this is why it's really important,
[00:32:55.470]especially as new faculty,
[00:32:57.000]to really make friends with your colleagues.
[00:33:00.060]Because this observation from Amanda
[00:33:03.900]got written into a grant, our Wheat Cap Grant,
[00:33:07.320]before I was even employed here at Nebraska.
[00:33:10.890]I wouldn't have had that without Amanda's observations
[00:33:14.280]and I wouldn't have had the germ plasm
[00:33:18.180]that I'm gonna talk about here
[00:33:20.070]without another former graduate of our department,
[00:33:24.450]Mary Guttieri,
[00:33:25.283]who is also a member of our broader Sawfly Coalition.
[00:33:29.820]Mary had actually generated a recombinant inbred line
[00:33:33.420]population from Panhandle by Wesley.
[00:33:38.310]For those of you who have been here for a long time,
[00:33:40.440]this is from our old cadmium work.
[00:33:42.480]So, really cool that it worked.
[00:33:45.690]The other great news is
[00:33:47.010]that we don't have Panhandle in the variety trials anymore,
[00:33:50.190]which is why we didn't have it on the previous slide.
[00:33:52.020]But Amanda could say, with good confidence,
[00:33:55.590]Panhandle pretty much sucks for sawfly, so.
[00:33:58.740]It lays flat.
[00:33:59.910]It lays flat.
[00:34:01.380]So, we had an observation and we had a population.
[00:34:07.080]Great.
[00:34:07.913]So, we've got a recombinant inbred line population,
[00:34:11.550]we've planted it now in multiple locations.
[00:34:14.280]And so I'm gonna show some of Sydney's
[00:34:15.990]preliminary data here.
[00:34:18.300]The challenge is that it is really hard to phenotype this.
[00:34:23.280]So, this is maybe one of my favorite slides.
[00:34:29.550]Sydney put this together. This was her harvest sampling.
[00:34:33.780]So all of these, this is like 800, some from Sydney,
[00:34:38.670]and then over here there's 800 bundles
[00:34:41.040]in this University of Nebraska van from Alliance.
[00:34:45.150]And then guess what?
[00:34:46.530]We made everyone split stems
[00:34:49.170]because we can't phenotype them by just slicing them over
[00:34:52.470]and looking for stem solidness
[00:34:54.240]because these are both hollow stem varieties.
[00:34:58.380]Instead if we wanna see if they're infested or not,
[00:35:01.500]and this is where we asked our entomology team,
[00:35:04.080]hey, is there any other way to do this?
[00:35:05.520]And they said no. Join the stem splitting club.
[00:35:09.660]To see if there is resistance, or one of those,
[00:35:13.710]tolerance, the non preference, the mortality,
[00:35:16.950]you actually have to vertically split those stems open
[00:35:19.860]and it sucks.
[00:35:21.720]I'm using that word a lot more than I normally do,
[00:35:24.210]but that's because we're talking about sawfly
[00:35:27.390]and it's just a really hard pest.
[00:35:29.340]So this is Sydney's,
[00:35:33.000]she actually calculated this out for us.
[00:35:36.060]And so this is what she came up with.
[00:35:40.560]If one person was doing all this phenotyping,
[00:35:43.320]it's seven weeks of post-harvest processing,
[00:35:46.147]$3000+ in labor, it's actually quite a bit more
[00:35:48.630]because she calculated at a lower pay rate
[00:35:51.120]than what I pay the interns now.
[00:35:52.620]So, it's quite a bit more.
[00:35:55.470]The other thing is,
[00:35:56.310]is we turn our breeding program around in six weeks.
[00:36:00.000]We harvest and we get things back in the ground
[00:36:02.580]in six weeks.
[00:36:03.600]So, that's not gonna work.
[00:36:04.710]So we really are looking for other things.
[00:36:07.680]Sydney's research is using UAVs.
[00:36:12.120]So she has gone
[00:36:13.860]and with that stem splitting data,
[00:36:17.340]she's looked at tunnel length,
[00:36:18.750]which is a trait we're not gonna talk about too much,
[00:36:21.210]but we've counted the proportion infested for stems.
[00:36:25.470]And then we also,
[00:36:27.420]prior to the combine going through the plots,
[00:36:29.340]we rated how many stems were cut.
[00:36:32.130]The good news here is that in this bi-parental population,
[00:36:36.120]we saw genotypic effects.
[00:36:38.070]So we haven't done any of the bi-parental mapping yet.
[00:36:40.680]We don't have the genotyping data back yet.
[00:36:44.310]But we know that there is genotypic effects.
[00:36:47.790]We're hopeful that we're gonna be able
[00:36:49.740]to find something here.
[00:36:50.820]And so Sydney's also been trying to use UAV data.
[00:36:55.200]So that's our sawfly traits,
[00:36:58.140]they're positively correlated.
[00:36:59.700]That makes sense.
[00:37:01.650]But what we're really looking at is,
[00:37:03.630]can we look at that stem infested
[00:37:07.140]and could we maybe pick this up with a UAV?
[00:37:10.890]Those correlations aren't great yet,
[00:37:12.510]but this is the first year of the study
[00:37:14.220]and we learned a lot this year.
[00:37:15.480]So hopefully we'll be able to go
[00:37:18.240]a little bit further with that.
[00:37:21.120]And so we did see
[00:37:23.160]that we've got some significant factors.
[00:37:26.820]She's actually got a lot more data
[00:37:28.380]in other flights to analyze.
[00:37:29.940]So, we may end up with better data.
[00:37:32.040]So this is all to say that maybe we've got
[00:37:34.710]some other ways to address wheat stem sawfly
[00:37:39.930]in the breeding program.
[00:37:41.310]But we're gonna try and do it faster than that 15 year gap.
[00:37:46.620]All right, let's switch to the cropping systems.
[00:37:48.930]And Cody's gonna take this over.
[00:37:51.540]Okay, well it's good to be with you guys today.
[00:37:54.960]And so I spend a lot of time with growers.
[00:37:56.760]I take a lot of calls from growers,
[00:37:58.557]and they of course are growing increasingly frustrated
[00:38:02.040]with sawfly, that's no surprise.
[00:38:04.800]But the thing that the growers notice a lot is the lodging.
[00:38:09.150]That's what they get angry with, is the lodging.
[00:38:11.040]They don't really think about the yield loss
[00:38:13.500]that comes from the reduced grain fill and the smaller grain
[00:38:16.964]because it's not easy to see from a combine.
[00:38:21.990]But we started to think about, well,
[00:38:23.160]what is the impact on maybe other crops,
[00:38:27.720]you know, the crop that follows?
[00:38:28.800]Is there any other link that we need to start looking at?
[00:38:32.430]So in the next slide we have a picture here
[00:38:36.240]of two wheat varieties.
[00:38:38.640]One on the left is Warhorse.
[00:38:40.530]It's a wheat variety out of Montana. It's a solid stem.
[00:38:44.220]And you can see this was taken in February
[00:38:46.560]and that wheat's standing up pretty well.
[00:38:49.020]We have a wheat variety on the right, Goodstreak.
[00:38:51.480]That's a UNL hollow stem line
[00:38:53.190]that's laying down pretty flat.
[00:38:55.050]And so Katherine already talked about
[00:38:58.410]the yield drag that comes from using a solid stem.
[00:39:01.800]And so a lot of our growers have been hesitant
[00:39:05.190]to use that wheat variety because of that yield drag.
[00:39:08.700]And so our thought was, well,
[00:39:10.620]perhaps there is a yield drag with the wheat crop,
[00:39:13.440]but maybe having a solid stem
[00:39:15.390]could benefit the subsequent corn crop.
[00:39:18.267]And so that's where this project took off.
[00:39:21.570]We would plant plots like this and we would come back
[00:39:23.700]and we would plant corn in there.
[00:39:26.340]The idea being that
[00:39:27.450]the longer the wheat stem stays vertical,
[00:39:29.580]it's going to perhaps capture more snow,
[00:39:33.210]the longer it stays off the soil surface.
[00:39:35.620]Perhaps that would slow the rate of degradation
[00:39:38.520]of that wheat residue down
[00:39:40.350]and help to protect the soil moisture in the soil
[00:39:45.600]longer in the next growing season when the corn's growing.
[00:39:49.140]So we thought that there could some other potential benefits
[00:39:52.800]that could be worth looking at.
[00:39:55.980]So we've done this a few years now.
[00:39:58.020]This is continuing,
[00:39:58.950]but here's just kind of a snapshot
[00:40:00.540]where we looked at the amount of standing residue
[00:40:02.884]of different varieties over time there in June.
[00:40:08.220]It's no surprise again that Warhorse had the most,
[00:40:11.340]compared to Pronghorn, which we've talked about.
[00:40:14.460]Just doesn't stand very well.
[00:40:17.340]Go ahead to the next slide.
[00:40:20.550]This brings us to a study we have ongoing right now
[00:40:23.130]that we have a graduate student, Benny,
[00:40:25.530]who is taking this on,
[00:40:27.420]where we thought we would take this to the next level
[00:40:29.880]and start to think about kind of the same principle,
[00:40:34.470]hollow stem wheat, semi-solid and solid stem wheat.
[00:40:38.460]But we wanted to add the level
[00:40:40.440]of whether it's infested or un-infested.
[00:40:44.700]So we put exclusion cages up
[00:40:46.860]where we could exclude the sawfly from an area
[00:40:49.230]and then once the sawfly flight was over,
[00:40:51.450]we would remove those cages and allow the wheat to mature.
[00:40:54.870]We would harvest this wheat off
[00:40:56.610]and then the whole purpose was to focus
[00:40:58.710]on the soil water content of these plots
[00:41:01.500]and the corn yield in the subsequent year.
[00:41:04.260]We weren't so concerned about
[00:41:06.270]what the wheat did in these plots.
[00:41:08.430]Moreso what the corn did
[00:41:10.929]in infested and un-infested wheat residue.
[00:41:18.120]In the first year we had, as was mentioned,
[00:41:20.970]we had a lot of rain,
[00:41:22.020]and we didn't really get much for differences
[00:41:24.600]in the corn yield in this first year.
[00:41:27.120]We would expect to see greater differences
[00:41:29.430]when we have drier conditions.
[00:41:31.410]But this year we had just an abundance of moisture
[00:41:33.627]and the whole purpose of this research
[00:41:35.220]was to look at corn under stress
[00:41:38.219]when it's not raining like it did this year.
[00:41:41.220]So this work will continue on
[00:41:44.160]and we hope that we'll see results
[00:41:46.740]that would kind of confirm our thoughts
[00:41:48.450]of that un-infested wheat might provide those added benefits
[00:41:54.750]or the solid stem or those semi-solid wheat
[00:41:59.190]might provide added benefit for the corn.
[00:42:02.220]Hopefully in the coming years we'll look at that.
[00:42:05.850]And then in the next slide, Jeff did this work,
[00:42:08.910]but our growers again were growing increasingly frustrated
[00:42:12.600]with this pest and so they started to ask more questions.
[00:42:15.570]Well, what about tillage?
[00:42:17.670]Which is crazy to think about
[00:42:19.140]because we've worked so hard to get to this stage
[00:42:21.000]where we're using no-till.
[00:42:22.800]But in reality this might be one of the downsides of no-till
[00:42:26.400]is that the no-till has created
[00:42:27.900]the perfect environment for sawfly.
[00:42:29.790]And it might've actually helped encourage this pest
[00:42:32.520]to really gain a foothold in our region out here.
[00:42:36.780]But through Jeff's work here
[00:42:38.700]where he looked at one pass versus two passes of tillage,
[00:42:41.790]that really reduced the amount of emergence of sawfly
[00:42:44.880]because we're turning those crowns upside down.
[00:42:46.650]And when those crowns are turned upside down,
[00:42:48.270]it really limits the ability of sawfly to emerge.
[00:42:51.930]So, this is very effective.
[00:42:54.780]However, sawfly are very mobile,
[00:42:57.600]and so if you till your field
[00:42:59.970]and a neighbor doesn't till their field,
[00:43:02.190]those sawfly are going to move into your wheat field
[00:43:04.770]regardless of whether you use tillage or not.
[00:43:07.950]So yes, it's effective.
[00:43:09.750]I think it would have to be more widely used.
[00:43:12.300]And then we're going to lose a lot of those benefits
[00:43:14.160]we've been working so hard to get
[00:43:15.480]as far as residue on the soil surface
[00:43:17.940]that provides those benefits for our following crop.
[00:43:24.450]All right, so now we move on
[00:43:26.070]to our entomology type solutions.
[00:43:28.650]So far we have not yet gotten to a surefire great solution
[00:43:34.710]for the sawfly problem.
[00:43:35.760]Are you going to deliver one Jeff?
[00:43:37.380]That's why we call it management and not control.
[00:43:41.970]Yeah, actually that last slide,
[00:43:43.350]that last data set that Cody shared,
[00:43:45.510]I actually presented that at a no-till conference once.
[00:43:47.850]I don't know why they haven't invited me back.
[00:43:53.610]So one of my colleagues at Colorado State University
[00:43:57.690]Erika Peirce conducted a review study recently.
[00:44:01.440]That's what this somewhat complicated chart on the left
[00:44:04.350]is showing is the wheat stem sawfly kind of over the course
[00:44:09.360]of the life of a wheat crop.
[00:44:11.430]And these Bracon adults labeled there,
[00:44:14.190]which are the principal parasitoids of the wheat stem sawfly
[00:44:17.580]in fact work that was done at Montana State University
[00:44:21.773]doing some life table entomology
[00:44:24.900]are kind of strange in case you didn't know that.
[00:44:27.060]We do actuary work and sometimes life table work,
[00:44:31.110]but they did a live table study
[00:44:33.150]showed that the wheat stem sawfly parasitoids,
[00:44:35.973]these Bracon species are actually an irreplaceable
[00:44:41.333]mortality factor on wheat stem sawfly populations.
[00:44:44.880]So, what's that?
[00:44:46.060]Oh, I just forgot that you can advance
[00:44:47.940]your own slides.
[00:44:50.520]And so what this chart is showing
[00:44:51.900]is just some pieces of information we know
[00:44:54.690]about the wheat stem sawfly over the course
[00:44:57.240]of the wheat growth over the season
[00:45:01.140]from host plant preference
[00:45:02.610]to factors involving egg and early larval development,
[00:45:09.180]these parasitoid host relationships,
[00:45:12.360]factors that affect delayed cutting.
[00:45:15.210]All of these are gonna have to be taken into consideration
[00:45:17.730]when we explore interactions
[00:45:19.890]to understand host plant resistance better.
[00:45:23.160]So that's what this chart is talking about,
[00:45:24.900]is just how can we overlay these different factors.
[00:45:28.260]Maybe there's factors within the plant
[00:45:29.760]that we could introduce that would attract the parasitoids,
[00:45:32.918]which we already understand
[00:45:33.930]are an irreplaceable mortality factor to that crop.
[00:45:37.440]Maybe there's cropping systems approaches
[00:45:39.180]that we could think about that as well.
[00:45:42.930]We had conducted the survey when I was,
[00:45:45.360]when I worked in Scotts Bluff,
[00:45:46.710]we had about seven years of survey data we collected.
[00:45:50.040]And this chart is just showing a phenomenon
[00:45:52.080]that was kind of impressive to me.
[00:45:54.420]So this isn't the same field that we sampled every year
[00:45:57.330]because you can't sample exactly the same field
[00:46:00.960]that's wheat every year.
[00:46:02.160]But basically adjacent fields as part of this survey.
[00:46:05.400]Blue bars are showing infested wheat tillers
[00:46:07.410]out of a hundred that we sampled out of the field.
[00:46:09.840]The orange bars are the number of live sawfly larvae.
[00:46:13.560]We really like splitting wheat tillers.
[00:46:15.810]We did thousands of wheat tillers.
[00:46:18.770]But this is the kind of information you can learn.
[00:46:20.820]So you split the tiller, you can understand it.
[00:46:22.980]Is there alive or present? Is it alive or dead?
[00:46:26.310]We're really obsessed with death. We wanna know why it died.
[00:46:29.880]And then suddenly in 2015 at this location,
[00:46:32.670]we started seeing these Breconid pupae present.
[00:46:36.450]Not only are they present,
[00:46:37.770]you can see they're a pretty major source of mortality
[00:46:40.050]for those populations that we're sampling.
[00:46:44.940]And to kind of try to keep this as short as I can
[00:46:49.260]because I'm running out on time
[00:46:51.450]we had some observations through surveys
[00:46:55.080]that we were conducting.
[00:46:56.280]We weren't just sampling wheat fields,
[00:46:58.170]we were sampling grass landscapes
[00:47:00.420]around those wheat fields as well
[00:47:02.561]because a lot of cool seasoned grasses
[00:47:03.660]are good hosts for wheat stem sawfly.
[00:47:06.270]Things like intermediate wheat grass, western wheat grass.
[00:47:09.120]And we were trying to find sources
[00:47:12.420]that could serve as really good parasitoid hosts
[00:47:14.580]as well within that.
[00:47:17.141]And around that time that we started seeing
[00:47:19.717]those affected fields up and around Hemingford
[00:47:22.890]by the parasitoid,
[00:47:24.720]we noticed that there was kind of this relationship
[00:47:26.880]where the sawflies and the Braconids
[00:47:30.060]in the southern Panhandle,
[00:47:31.170]where we don't see effective populations in the parasitoids,
[00:47:33.630]there's about a 30 day gap in peak between sawfly emergence
[00:47:37.380]and that parasitoid emergence from those grassy landscapes
[00:47:40.200]around those wheat fields
[00:47:42.150]where it was effective in the northern Panhandle,
[00:47:44.430]there's about a seven day gap in peak
[00:47:46.080]between the sawfly population and the parasitoids.
[00:47:50.270]So that got us thinking, well,
[00:47:51.420]maybe there's just a lag in time and a bit of a numbers game
[00:47:55.620]that plays in there as well.
[00:47:57.780]So, as you go further south into Colorado,
[00:48:01.560]they can find the parasitoids in grasslands,
[00:48:03.420]but they've never shown to be effective in the re-crop.
[00:48:07.140]So as part of this teamwork with the ARS,
[00:48:09.780]one of the things that we've done is looked at
[00:48:12.150]what we call this bug baler project.
[00:48:13.920]This collaboration between the Akron ARS Research Lab
[00:48:17.340]and High Plains Ag Lab to see if we could bail up
[00:48:22.274]parasitoid invested wheat straw and ship it to Colorado
[00:48:27.150]and see if we can establish it
[00:48:28.800]on some of these CRP lands that are adjacent to wheat.
[00:48:32.460]But just an example of a a pretty active collaboration
[00:48:35.760]that's just in the process of forming.
[00:48:39.420]All right,
[00:48:40.253]I think Amanda's gonna bring us home here.
[00:48:42.630]All right, so in case you haven't grasped it yet,
[00:48:46.710]is that we work really closely,
[00:48:48.150]we're in almost constant communication.
[00:48:51.390]If we go to the next slide real quick,
[00:48:54.300]all of our team has has a wide range of experience
[00:48:58.410]and training and backgrounds.
[00:49:00.960]Some of us grew up in ag systems,
[00:49:04.110]some of us, you know, come from more urban environments.
[00:49:08.370]But those experiences and trainings that are so different
[00:49:11.610]and yet overlap enough
[00:49:13.290]really, really improve our ability to move forward.
[00:49:16.920]And that makes us a really robust team.
[00:49:20.070]We're able to take on more projects
[00:49:21.960]because we're working collaboratively.
[00:49:23.370]So, we're able to tackle more of these different aspects
[00:49:25.980]of this one single pest problem,
[00:49:28.320]coming at it from all different angles.
[00:49:31.020]And those multiple perspectives really help increase
[00:49:36.242]how the quality of the research, you know,
[00:49:40.230]thinking about those giant sawfly cages,
[00:49:42.750]that's nothing that I would've thought of
[00:49:45.690]were it not for Jeff and his experiences in that.
[00:49:49.560]Dr. Creech brings forward thinking
[00:49:51.420]about this is a systems approach.
[00:49:53.700]So yeah, we have a yield loss,
[00:49:56.250]but how does that play into, you know, the system as a whole
[00:49:59.730]because farming doesn't exist in a vacuum.
[00:50:03.210]And then Dr. Frels bringing a wealth of expertise
[00:50:06.630]in that breeding and genetic side,
[00:50:08.190]so we can really hone in genetically
[00:50:10.770]on how we can breed for sawfly resistance.
[00:50:15.120]And then moving forward-
[00:50:17.670]Ooh, there we go.
[00:50:19.440]Little trigger happy.
[00:50:21.750]We get to train the next generation
[00:50:23.970]and I use, we call it training,
[00:50:27.300]but to be honest, we're learning just as much
[00:50:29.400]from a lot of these students as we hope to teach them.
[00:50:33.120]They bring in their own experiences
[00:50:35.610]and their own knowledge base
[00:50:37.380]and their own innovation
[00:50:38.550]that really help drive this forward.
[00:50:40.020]And so on the left of this panel,
[00:50:41.460]you see a handful of students that we call
[00:50:44.190]our first generation sawfly grad students.
[00:50:47.040]Luana Simão is now pursuing a PhD at Kansas State.
[00:50:51.960]In that top center is Bethany Thomas.
[00:50:54.660]She was spearheading a lot of that tillage research
[00:50:57.810]under Dr. Bradshaw.
[00:50:59.790]And then Maria Sciencia was alongside me
[00:51:02.220]for a lot of those variety trials
[00:51:04.620]and looking at that splitting over and over and over again
[00:51:08.760]and that stem cutting.
[00:51:10.470]And then today we have two PhD students,
[00:51:13.920]Sydney Graham and Vinny,
[00:51:16.380]that are currently working on the next phases
[00:51:20.460]of the project in addition to other MS students,
[00:51:23.910]other interns.
[00:51:25.410]And so it's really an opportunity
[00:51:27.270]to not only train these students
[00:51:30.030]but also to showcase for them
[00:51:31.740]how effective collaboration can be.
[00:51:36.030]And then for our last official,
[00:51:38.880]my usually favorite slide,
[00:51:41.100]is our acknowledgements.
[00:51:43.260]Again, team effort.
[00:51:44.400]And it's not just UNL teams.
[00:51:46.710]We have the support of our Nebraska Wheat Board
[00:51:50.490]and we have frequent conversations
[00:51:52.680]with our Wheat Board members
[00:51:53.850]because they are the growers
[00:51:55.800]that face this problem day in and day out.
[00:51:58.740]Some of the research in that Warhorse solid stem wheat
[00:52:04.050]that Cody had showcased was sponsored
[00:52:06.570]by the Water for Food Institute.
[00:52:08.820]We are of course collaborating closely with the ARS,
[00:52:11.790]and with NIFA,
[00:52:13.170]we have funding from IPM,
[00:52:15.900]and Sarah that helped move this forward.
[00:52:18.690]And then in addition, not pictured adequately enough here
[00:52:23.100]are all the talented staff, students,
[00:52:26.040]visiting scholars that put the work in.
[00:52:29.550]We're really lucky to get to work with so many good folks.
[00:52:34.170]And I would encourage any of you that are interested
[00:52:38.130]to head west next summer.
[00:52:39.840]We have our wheat tour field days starting in June.
[00:52:43.710]So, June 10th through 14th, mark your calendars.
[00:52:47.040]And you can come out and see this team in action.
[00:52:51.630]Thank you. Wonderful presentation, great coordination.
[00:52:54.150]The media was with us today, so.
[00:52:56.550]Let's open the floor for some questions.
[00:52:58.230]We have some time, so just raise your hands,
[00:53:00.720]and we can bring you the microphone.
[00:53:12.049]Hi, I am from the remote sensing world.
[00:53:13.560]I'm wondering why you picked those indices that you selected
[00:53:17.430]and also what was the resolution of the drone and if you,
[00:53:23.040]it seems like you have a wide potential
[00:53:26.220]in terms of your study in terms of a geographic area.
[00:53:29.700]So would you look for possibly a higher resolution
[00:53:33.630]commercial satellite along the 16 centimeter range
[00:53:36.870]and switch towards something
[00:53:38.250]of a more informetrical SAR base?
[00:53:41.160]So you could actually see the degradation
[00:53:44.867]of the soft light at a higher range
[00:53:47.217]and resolution and capture wider area as well?
[00:53:52.140]Okay, hi, I am the PhD student
[00:53:54.060]who works on the drone research.
[00:53:56.220]I'm Sydney, for those of you who don't know me.
[00:53:58.740]I'm not sure I can answer all of those questions
[00:54:01.020]very eloquently.
[00:54:02.760]Those vegetation indices were chosen mostly for simplicity.
[00:54:07.170]It's a range of indexes.
[00:54:08.760]And this is all very preliminary analysis
[00:54:11.460]that we have so far.
[00:54:14.250]The resolution, the ground sampling distance
[00:54:16.020]that we're getting on that is about 1.5 centimeter.
[00:54:20.100]I don't think that we would move towards
[00:54:22.110]using satellite based imaging,
[00:54:24.360]at least for the breeding work,
[00:54:26.130]because we're working with such small plot data.
[00:54:29.130]That might be something that would show more utility
[00:54:32.040]in more of the variety testing level
[00:54:34.650]or something even bigger than that.
[00:54:36.779]And I'm happy to chat more.
[00:54:41.220]So the solid stem reduces
[00:54:44.970]the mobility of the larvae, correct?
[00:54:48.090]So what about the relative stem strength
[00:54:51.990]between hollow and solid stem?
[00:54:56.610]So, that's a really good question.
[00:54:59.550]I would say that stem strength-wise,
[00:55:04.320]if we're talking about wind lodging or root lodging,
[00:55:08.070]we don't necessarily see a difference.
[00:55:12.630]There is definitely,
[00:55:14.340]so one of the reasons we think Wesley
[00:55:16.080]may be better as a hollow stem
[00:55:18.600]is it is a really strong irrigated wheat.
[00:55:22.380]And so maybe it's just the stronger cell wall content
[00:55:26.190]of that line.
[00:55:27.030]And that's why we're seeing some maybe non preference
[00:55:29.970]or some kind of...
[00:55:32.790]The entomologist is looking at me
[00:55:34.320]and I'm going, don't say the wrong thing.
[00:55:36.000]This is gonna be on Sydney's comprehensive exam 100%.
[00:55:39.270]So, you know, when we're talking
[00:55:41.467]about other stem related traits, you know,
[00:55:45.210]if we're not,
[00:55:46.260]or if we're talking about things
[00:55:47.880]that aren't sawfly related lodging,
[00:55:50.220]we don't tend to see a lot of difference so far,
[00:55:55.050]unless you've maybe seen something
[00:55:56.790]out in the Panhandle, Jeff?
[00:55:58.650]Or Amanda, you can chime in too.
[00:56:03.600]I guess I would say the other thing with wheat
[00:56:06.570]is that a lot of times like,
[00:56:08.940]straw strength is measured more qualitatively
[00:56:12.450]and I don't know if that plays in as well.
[00:56:14.640]And then Dr. Guttieri chimed in mentioning
[00:56:17.490]that Wesley is unique in the Nebraska germ plasm
[00:56:20.880]because it has the RHT8 wheat allele.
[00:56:26.220]And so that may be playing into some of that as well
[00:56:30.067]as far as the reduced lodging.
[00:56:32.910]The other aspect I was gonna mention,
[00:56:34.620]it's fairly preliminary from Phineas' data,
[00:56:38.970]that it looks like maybe lignin levels are a little higher
[00:56:42.690]in Wesley as well.
[00:56:43.770]And that's a fairly commonly known antifeedant
[00:56:46.530]for chewing insects.
[00:56:49.080]And so there could be something going on there
[00:56:51.390]that wouldn't necessarily be, well,
[00:56:53.820]I guess that would be structurally related,
[00:56:55.470]but maybe in a different way.
[00:56:59.100]What are the chances of inserting BT gene
[00:57:03.543]in this plant?
[00:57:05.727]Oh, wouldn't that be nice?
[00:57:08.580]Very, very low there.
[00:57:11.010]GMO acceptance in the wheat community is very low.
[00:57:15.990]Not necessarily because of the breeders
[00:57:18.360]or even some of our wheat growers,
[00:57:22.560]they wouldn't have a problem with that.
[00:57:24.390]It's more on the consumer side
[00:57:26.250]and given that most,
[00:57:28.110]a lot of the wheat in the US is exported,
[00:57:30.420]there's a lot of concern in export markets about GMO.
[00:57:33.600]So, we are seeing some changes in GMO wheat
[00:57:39.060]with the HB4 gene coming out of Argentina.
[00:57:43.320]So maybe in, you know,
[00:57:47.400]I don't know, 10, 20 years maybe?
[00:57:49.890]Yeah, before I retire, we may see more GMOs,
[00:57:53.190]but as of right now, that's not something that's an option.
[00:57:57.480]Another question.
[00:57:58.920]You talked about a yield drag,
[00:58:01.560]that loss of carbon sequestration,
[00:58:05.250]I'll call it that, in the grain,
[00:58:07.080]is that made up by an increase
[00:58:09.390]in the amount of carbon in the stem?
[00:58:13.530]So, it could be.
[00:58:14.640]I mean, that's one of the things
[00:58:15.900]that we haven't taken apart piece by piece and looked at,
[00:58:21.420]but that definitely could be.
[00:58:26.030]There's varying opinions on the amount of yield loss.
[00:58:29.220]So there's some papers out of Montana that say no,
[00:58:31.590]there's not a yield drag.
[00:58:34.681](Jeff mumbling)
[00:58:36.450]Yeah, it depends on whether it's germ wheat or bread wheat.
[00:58:42.360]You know, we just don't have the data
[00:58:43.800]but I think all, you know,
[00:58:45.300]you talk to a Colorado state breeder
[00:58:47.010]and he'd agree with me that there's 100% a yield drag.
[00:58:53.280]Any other questions?
[00:58:54.870]Think we have a question online.
[00:58:57.090]Two questions. Let me see.
[00:59:05.160]So it says that Wesley is somewhat unique
[00:59:07.920]in Nebraska germ plasm.
[00:59:09.930]Is that RHT8 wheat a second reduced high allele?
[00:59:17.400]Any thoughts on whether this additional reduction height
[00:59:21.210]might be affecting non preferences?
[00:59:25.740]Is that coming from Mary?
[00:59:30.480]And I think that goes back to Jeff's comment
[00:59:32.760]on possibly the lignin as well.
[00:59:34.980]I don't know if they're interrelated,
[00:59:37.290]but we do think that there could be some of that at play.
[00:59:43.290]And there's a lot to look at at Wesley just in general.
[00:59:46.140]Yeah, I think that's where
[00:59:47.730]the Panhandle by Wesley population
[00:59:49.560]is gonna be really interesting
[00:59:51.030]and hopefully we can start to tease some of those out more.
[00:59:55.500]So, thank you Mary for joining us.
[00:59:58.350]She is a key member of our team
[01:00:00.957]and is going to be helping us really look
[01:00:03.180]at some of those differences in Wesley
[01:00:05.458]through that population.
[01:00:08.970]In that...
[01:00:11.400]Splitting these stems is a real pain in the butt type thing,
[01:00:15.210]you might take a lesson from the electricians.
[01:00:18.360]They have a wire stripper that they can easily use
[01:00:23.370]to strip any size of wire
[01:00:25.848]and just pull it through and it's done.
[01:00:29.040]Yeah, we've been talking to,
[01:00:32.790]ARS has sort of a engineering division
[01:00:35.400]and we've been having some discussions with them.
[01:00:38.550]They have some interest in kind of developing a device for,
[01:00:41.910]I guess, semi-high throughput stem splitting
[01:00:44.940]but it's not been developed yet.
[01:00:48.120]But once you have, one of the things that you take away,
[01:00:51.750]if you split a lot of stems,
[01:00:53.010]you start to understand across different varieties,
[01:00:55.050]they kind of behave differently.
[01:00:58.043]Like Pronghorn splits very differently than Goodstreak
[01:01:02.010]in terms of how you can run the blade down it
[01:01:03.930]and whether or not it jumps off to the side
[01:01:06.150]of the tiller frequently or not.
[01:01:08.310]You get some really weird subtle observations
[01:01:10.590]if you're splitting a bunch of wheat varieties
[01:01:12.390]longitudinally.
[01:01:13.680]But yeah, we're trying to explore-
[01:01:16.620]He's got a junior scientist working on some methodologies
[01:01:20.610]for improving our splitting abilities.
[01:01:23.940]Yeah, so my son, 3D printed a stem splitter
[01:01:27.600]that actually did well at the Nebraska State Fair.
[01:01:30.120]He won $100 with it,
[01:01:31.816]for a science project at the state fair.
[01:01:34.320]But yeah, the challenge with the wheat that we face,
[01:01:37.920]even with my son's stem splitter,
[01:01:39.450]is that the wheat stem diameter changes from top to bottom.
[01:01:44.580]And so you need something that will help keep that stem
[01:01:47.220]centered to split it down the center.
[01:01:51.240]We'd probably have some volunteers
[01:01:53.640]in the small grains lab for beta testing, Cody.
[01:01:57.330]We can test it, for sure.
[01:02:00.390]Okay, I think we have time
[01:02:01.560]for one more question and then...
[01:02:04.740]I guess just a comment
[01:02:06.180]and then an observation.
[01:02:08.280]I commend you.
[01:02:10.680]Wheat stem sawfly, for getting this group together,
[01:02:13.020]wheat stem sawfly was first found in Nebraska in 1993.
[01:02:17.250]And no one would believe me that it was gonna be a problem
[01:02:20.340]for 15 years until I left.
[01:02:23.310]And in 2009 it was first found in Sydney at the AG Lab.
[01:02:27.960]But going back to the reflectance relationships,
[01:02:32.040]when I found it in 1993-
[01:02:34.024](mumbling)
[01:02:35.861]It was because there were heads, I mean,
[01:02:38.670]it wasn't a very heavy infestation,
[01:02:40.920]but there were individual heads that were turning color
[01:02:43.860]slightly earlier in front of the other heads.
[01:02:47.670]And that's really why I started looking in those heads.
[01:02:53.436]They were just a slight off color
[01:02:56.370]from the other heads that were in the field
[01:02:58.590]and we could de tell it pretty easily
[01:03:00.060]because it was-
[01:03:02.084](mic cutting off)
[01:03:06.660]Good to know.
[01:03:09.701]Do you remember what variety that was?
[01:03:17.009]Okay, let's give them a round of applause.
[01:03:19.002](audience applauding)

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Tough Pests Call for Team Solutions: Building a Coalition for Wheat Stem Sawfly

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