Agricultural Pest Control - Plant Recertification

Pesticide Safety Education Program (PSEP) Author

07/18/2018 Added

85 Plays

Description

Two-hour video presentations by Chris Proctor on weeds, Bob Klein on spraying, Justin McMechan on insects, and Tamra Jackson-Ziems on diseases.

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[00:00:00.188](bright music)
[00:00:15.830]Hello, and welcome
[00:00:16.890]to the Pesticide Applicator Recertification Training
[00:00:20.170]for the Agricultural Plant Pest Control category,
[00:00:23.520]number 01 on your license.
[00:00:26.240]This category covers pesticide applications made
[00:00:29.080]to protect agricultural crops, vegetables,
[00:00:32.760]small fruits, tree fruits and nuts,
[00:00:35.650]pastures, grasslands, and non-crop agricultural land.
[00:00:40.740]Today, we'll hear from Extension experts
[00:00:43.070]discussing the strategic management of weeds,
[00:00:46.000]pest insects, and plant diseases in these settings.
[00:00:49.980]This training will provide a valuable review
[00:00:52.190]of practices you may already be using,
[00:00:54.890]as well as more recent information and findings
[00:00:57.410]from Nebraska Extension.
[00:00:59.200]Enjoy.
[00:01:08.220]I'm Chris Proctor, a Weed Management Extension Educator.
[00:01:11.700]I was gonna chat a little bit
[00:01:13.120]about some different principles of weed management
[00:01:16.010]or keys to successful weed management.
[00:01:19.410]So one of the reasons it's even worth talking
[00:01:21.150]about is there's a number of resistant weeds
[00:01:25.170]in the world today, and Nebraska is no exception.
[00:01:28.280]So we have six or eight weed species
[00:01:31.930]that are known to be resistant in Nebraska as of now.
[00:01:35.160]We have some of the pigweeds, kochia,
[00:01:38.810]marestail are some of the big ones, the ragweeds.
[00:01:42.380]So all of these real problem weeds
[00:01:45.900]are certainly resistant to glyphosate,
[00:01:48.200]but we also have a number of other herbicides
[00:01:50.310]that we've found populations to be resistant to,
[00:01:55.110]2,4-D or some of the ALS products as well.
[00:01:59.230]This is just showing that idea just another way.
[00:02:02.320]So this is showing the occurrence
[00:02:04.090]of glyphosate-resistant weeds across Nebraska.
[00:02:07.790]So this is showing the percentage of acres infected,
[00:02:12.480]infested rather in the different regions across the state.
[00:02:16.180]So you can see that marestail in all the regions is one
[00:02:19.940]of the really problematic weeds
[00:02:22.410]in terms of glyphosate resistance, followed by waterhemp.
[00:02:26.323]But we certainly have a number of weed species
[00:02:28.640]that are resistant,
[00:02:29.730]and it's really prevalent across most of the state.
[00:02:34.050]This is a study that was done a year or two ago,
[00:02:37.217]and this was looking at glyphosate-resistant waterhemp.
[00:02:42.170]The darker the red, the more populations
[00:02:44.890]that resist it in that area.
[00:02:48.030]Really the takeaway from this in my thinking is
[00:02:51.530]if you're anywhere in the eastern part of Nebraska
[00:02:53.760]and you have waterhemp,
[00:02:54.860]you're safer to assume that you have some kind
[00:02:57.570]of glyphosate resistance,
[00:02:58.840]because the chances you're gonna be
[00:02:59.897]in one of these small pockets
[00:03:01.780]where there's low incidence of resistance as well,
[00:03:04.485]it's really small, so you're better to manage
[00:03:06.970]these populations as if you have resistance.
[00:03:10.080]Some of what goes into these principles
[00:03:11.780]of weed management is it's using good, sound weed management
[00:03:16.500]or integrated principles to manage for resistance
[00:03:19.590]and try to prevent the additional occurrence of resistance.
[00:03:25.260]This here is showing counties across Nebraska
[00:03:29.060]that have Palmer amaranth present.
[00:03:31.310]So we did a survey asking folks to send in
[00:03:36.190]whether or not they had Palmer somewhere in their county.
[00:03:39.760]So there was a self-identifying survey.
[00:03:42.090]The counties that are red are
[00:03:44.150]where we got positive responses,
[00:03:45.830]so folks sent back responses saying,
[00:03:48.887]"Yeah, somewhere in our county,
[00:03:50.817]"we have a field that has Palmer amaranth."
[00:03:52.970]So it doesn't say too much
[00:03:53.960]about whether there's resistance
[00:03:55.230]or how much is in that county,
[00:03:56.370]but we can see that there's certainly a lot more Palmer
[00:03:59.620]across the southern part of our state,
[00:04:01.420]but it's moved north
[00:04:04.120]and it's becoming a lot more prevalent across the state.
[00:04:10.060]This is a study that relates to that.
[00:04:12.323]This is some work out of west central Nebraska
[00:04:15.100]that the folks out there did,
[00:04:16.680]looking at glyphosate-resistant Palmer amaranth.
[00:04:20.830]The counties that are highlighted,
[00:04:22.170]those are the counties
[00:04:23.003]that they sampled Palmer amaranth populations,
[00:04:25.980]and they tested 'em for glyphosate resistance.
[00:04:28.820]The counties that are red
[00:04:29.880]are the only three populations they found
[00:04:31.630]that are resistant to glyphosate.
[00:04:33.810]When you compare this to the waterhemp story,
[00:04:36.010]as of right now there's a lot less resistant Palmer amaranth
[00:04:39.860]in our state, but it's starting to show up.
[00:04:43.200]Being a pigweed, I think the ability for it
[00:04:47.500]to develop resistance to glyphosate is relatively easy,
[00:04:51.000]so it's something that we need to pay attention to.
[00:04:55.130]So I kinda set that up to say
[00:04:57.410]we have a number of herbicide-resistant weed populations
[00:05:00.860]in our state, and so we really need to think more carefully
[00:05:04.230]and more critically about how we plan
[00:05:05.760]to manage weeds in our different systems.
[00:05:11.510]This is setting up to talk about five different keys
[00:05:14.860]for managing weeds,
[00:05:16.980]some things that are important to think about
[00:05:19.050]if you're gonna be successful,
[00:05:20.080]especially with these resistant populations.
[00:05:21.980]So I'll walk through each of these here
[00:05:24.680]in the next couple of slides.
[00:05:26.550]First one, timing's everything.
[00:05:28.080]So we know when it comes to weed control,
[00:05:31.170]once upon a time
[00:05:34.050]we had glyphosate that was really effective.
[00:05:36.940]You could wait until those weeds got up really tall.
[00:05:39.280]You could spray 'em.
[00:05:40.230]You could kill everything.
[00:05:41.680]But that's not really the case anymore,
[00:05:42.890]especially with these resistant populations,
[00:05:44.630]and so I think we really need
[00:05:46.160]to identify the most important time to control these weeds.
[00:05:49.770]When are we gonna be most effective with our application?
[00:05:53.260]So the recommendation is that we target weeds
[00:05:55.950]when they're four inches or smaller.
[00:05:58.590]That's about the size of a soda can.
[00:06:00.810]So you wanna catch your weeds
[00:06:02.690]before they get anything bigger than that four inch size,
[00:06:04.970]because they become a lot more difficult to control.
[00:06:08.120]You may or may not get good efficacy
[00:06:10.560]when you spray weeds that are a lot taller.
[00:06:13.170]Even in that instance, you might not have resistance,
[00:06:15.170]but you might have poor control
[00:06:16.540]if you're trying to manage weeds
[00:06:17.860]as they get into that six to eight inch size.
[00:06:22.460]This is just another way to demonstrate that same idea.
[00:06:24.580]So this is showing waterhemp at different sizes.
[00:06:28.730]So it ranges from three-inch size up to 11-inch size.
[00:06:32.170]These were sprayed in the greenhouse with Cobra,
[00:06:36.060]and then 28 days after spraying, they were reevaluated.
[00:06:38.680]So you can see
[00:06:40.390]in the flat that had the three-inch waterhemp
[00:06:43.540]got really good control.
[00:06:44.610]So when that waterhemp was small,
[00:06:46.180]Cobra was really effective.
[00:06:47.760]Even at the six-inch size,
[00:06:48.930]we've still got really good control.
[00:06:51.210]By the time we hit eight inches,
[00:06:52.460]you started to see a few weeds that escaped control.
[00:06:56.530]And by the time you hit that 11-inch stage,
[00:06:59.050]you can see there's a number of waterhemp plants
[00:07:01.090]that weren't controlled.
[00:07:02.610]But what's important to note is if you would have showed up
[00:07:04.670]about seven to 10 days after this application,
[00:07:07.690]you would've thought that you had really good control
[00:07:09.760]even in that 11-inch waterhemp.
[00:07:11.740]But you can see from that weed there on the side picture
[00:07:15.270]that actually the waterhemp sprouted new growth
[00:07:18.960]from one of the nodes, and it's regrowing.
[00:07:22.380]So you burn the top back, but it was big enough
[00:07:24.910]so that plant was actually able to recover.
[00:07:26.760]That, again, is why it's important for a lot
[00:07:29.850]of these weed species to control 'em when they're small.
[00:07:32.560]Otherwise, they tend to burn back, but they'll also regrow.
[00:07:36.950]So if you're gonna target weeds when they're small,
[00:07:39.410]it's critical to know when does that occur,
[00:07:41.550]because not all weed species are gonna be the same.
[00:07:44.879]This figure here just shows different weed species
[00:07:47.830]and the typical timing of when they emerge.
[00:07:51.380]You can see something like kochia or giant ragweed tends
[00:07:54.479]to emerge early in the season,
[00:07:57.530]so those are early summer annuals,
[00:08:00.050]so they come up late April to early May.
[00:08:03.890]But then if you kinda work your way down,
[00:08:05.380]you can see a lot of these species
[00:08:06.970]end up emerging a lot later.
[00:08:09.380]So the pigweeds, for example, they're emerging mid-May,
[00:08:12.250]but they'll continue to emerge well into June, July,
[00:08:16.460]and sometimes even into August.
[00:08:18.060]If you're gonna target management
[00:08:20.840]that would control, say, giant ragweed,
[00:08:23.980]but you're not paying attention
[00:08:24.980]that you also have a number of these pigweeds,
[00:08:27.510]say waterhemp in your field,
[00:08:29.520]you'll be effective to control the ragweed,
[00:08:31.300]but you might miss some of the pigweeds.
[00:08:34.120]Timing your applications
[00:08:35.450]or targeting your applications relative to the weeds
[00:08:38.550]to make sure you catch them when they're small is important,
[00:08:40.860]so understanding the biology of the weeds is critical.
[00:08:45.390]This is just showing some Palmer amaranth emergence data
[00:08:49.650]for western Nebraska.
[00:08:51.020]You can see Palmer is a challenge
[00:08:53.290]in that it has a really long emergence window.
[00:08:55.430]So it started to emerge that first week or two in May.
[00:08:59.430]They were still seeing some emergence all the way
[00:09:01.590]into that early part of August,
[00:09:03.450]so that's a really long window
[00:09:05.830]that you have to have some mechanism of weed control present
[00:09:10.210]to be able to manage Palmer.
[00:09:11.380]So something you put down in early May
[00:09:14.820]most likely is still not gonna be effective
[00:09:16.660]all the way into August,
[00:09:17.493]and so you're gonna have to pay attention
[00:09:18.770]that you're using multiple mechanisms
[00:09:21.330]or multiple applications
[00:09:22.760]to try to manage a week like Palmer.
[00:09:25.750]Again, this is for waterhemp,
[00:09:26.970]so it certainly is true for Palmer,
[00:09:28.610]but it's also true for waterhemp.
[00:09:31.070]If you look at that top left figure,
[00:09:34.350]that's showing waterhemp emerging June 7th.
[00:09:38.000]You can see by July 15th it's really exploded.
[00:09:40.520]All the way into August, though, there's a large plant
[00:09:43.640]that looks like it probably emerged close
[00:09:45.740]to that June 7th time,
[00:09:47.030]but right next to it are a number of plants
[00:09:49.120]that are recently emergent.
[00:09:50.260]So even all the way into the end of August,
[00:09:53.210]you can have continued emergence of waterhemp.
[00:09:56.740]That's, again, what makes some
[00:09:58.030]of these pigweeds really challenging,
[00:10:00.190]is what you need to control that escaped waterhemp
[00:10:04.590]is gonna look different than what you need
[00:10:05.990]to control those newly emerging waterhemps in August.
[00:10:11.480]It's something that needs to be paid attention to.
[00:10:14.320]Again, to highlight kinda the challenge with these pigweeds
[00:10:16.880]and why knowing their biology is really important,
[00:10:20.640]this is gonna show the different growth patterns
[00:10:25.180]of waterhemp and Palmer amaranth.
[00:10:27.150]You can imagine a situation where you show up to a field
[00:10:30.580]and you notice you have newly emerged waterhemp
[00:10:33.480]or newly emerged Palmer amaranth.
[00:10:37.070]It's maybe 1/2 an inch to an inch tall.
[00:10:40.460]Thursday afternoon you think, man, I need to call the co-op
[00:10:43.940]to get 'em to come out and spray,
[00:10:46.670]because I wanna catch these weeds while they're small.
[00:10:48.600]So this about four days after these plants have emerged.
[00:10:51.590]You find 'em, they're about that 1/2 inch to inch size.
[00:10:55.110]Six days later, so now this is Sunday afternoon,
[00:10:57.270]maybe Monday morning, a couple days after that.
[00:11:03.050]The co-op still hasn't shown up.
[00:11:03.883]They had a long backlog,
[00:11:05.660]so they weren't able to get to your field just yet.
[00:11:07.770]We're still okay, though.
[00:11:08.630]That Palmer is still three inches,
[00:11:11.196]so we're still under that four inch
[00:11:12.240]recommended height to control.
[00:11:14.750]But you compare that to the waterhemp,
[00:11:15.793]that waterhemp's still under two inches.
[00:11:17.630]That Palmer, you can see, is starting to separate itself.
[00:11:21.380]Here we go eight days after emergence,
[00:11:22.960]so this is four days after you first notice the Palmer
[00:11:26.450]in your field.
[00:11:28.315]It might only be Monday, Tuesday the next week,
[00:11:30.010]so certainly you're looking about a week after it emerges,
[00:11:35.300]maybe four or five days after you see it.
[00:11:38.390]Chances are you may not have had a opportunity
[00:11:40.340]to go out and spray it yet,
[00:11:41.220]but now you're already at that five-inch range
[00:11:44.020]with that Palmer.
[00:11:44.970]You're starting to sneak past that window
[00:11:47.570]of optimal weed control with the Palmer,
[00:11:50.270]whereas the waterhemp's still in that two,
[00:11:52.360]maybe three-inch size.
[00:11:55.070]The chances you're gonna manage the waterhemp
[00:11:56.697]are still pretty good,
[00:11:57.620]but the Palmer is starting to sneak into that range
[00:11:59.530]where you might burn it back, potential for regrowth.
[00:12:03.180]You can see how you go from the ability to control it,
[00:12:07.380]or to the inability to control it
[00:12:08.620]in a relatively short window.
[00:12:10.030]We're only talking eight days.
[00:12:11.210]It's only a week after it emerged that you're in a range
[00:12:14.490]where you might not control it.
[00:12:16.930]And here you go 12 days after and even 16 days after,
[00:12:20.200]so you're looking at about two weeks after,
[00:12:22.400]you have Palmer amaranth that's in the 12-inch range.
[00:12:26.090]The chances you're gonna control this
[00:12:28.150]with something like a Cobra
[00:12:30.040]or a contact herbicide go way, way down.
[00:12:32.530]Whereas that waterhemp,
[00:12:34.700]it's at a stage where it's gonna be challenging to control,
[00:12:37.490]but you're still under eight inches,
[00:12:39.240]and so you might have a shot
[00:12:41.780]if you get a really good application.
[00:12:43.920]Again, paying attention to that Palmer is really important.
[00:12:46.330]I think recognizing
[00:12:48.360]that you're gonna need multiple mechanisms
[00:12:50.530]to manage these weeds and paying attention to some
[00:12:52.920]of these different principles is really important,
[00:12:55.240]'cause these weeds move along so quickly.
[00:12:58.030]They go from small and easy to control
[00:13:01.190]to really large and difficult to control
[00:13:02.760]in a pretty short amount of time.
[00:13:06.200]So tackle problems early, I think, is really important.
[00:13:10.220]This just highlights the idea
[00:13:11.140]that there's very few cost-effective options
[00:13:14.010]once herbicide resistance is established.
[00:13:18.040]If you catch these populations before they're resistant,
[00:13:20.370]you have a lot of options on the table.
[00:13:21.620]Your toolbox is big.
[00:13:23.140]As soon as you start developing resistance,
[00:13:25.450]you start limiting the number of options
[00:13:27.460]that you have to control these different weeds.
[00:13:29.660]So managing early, managing it before you have a problem,
[00:13:34.010]I think, is important.
[00:13:36.040]And then intensively manage.
[00:13:37.260]So if you find that you have a patch
[00:13:38.550]of difficult to control weeds,
[00:13:40.250]it's a lot easier to control that small patch
[00:13:42.560]than it is to try to control an entire field.
[00:13:45.410]Your costs are a lot lower.
[00:13:46.870]The options you have available are a lot greater
[00:13:50.520]if your population's still relatively small.
[00:13:54.040]One of the keys to catching your problems early
[00:13:56.830]or managing your problems early is you really need
[00:13:58.410]to know that you have a problem,
[00:13:59.820]so I think scout, scout, scout is kinda the message.
[00:14:03.440]You need to be out in your fields often.
[00:14:04.972]You need to know what's going on.
[00:14:06.705]So you need to know what's happening at planting.
[00:14:08.660]What's it look like at your first herbicide application?
[00:14:11.690]How did that application do?
[00:14:12.940]Did you get good weed control?
[00:14:14.330]Did you have some escapes?
[00:14:15.480]Are there things you need to do
[00:14:16.390]to come back and clean that up?
[00:14:17.970]What do your fields look like at harvest?
[00:14:19.590]What do they look like after harvest?
[00:14:21.380]What options do you have at that point
[00:14:22.770]to manage weeds as they're coming up?
[00:14:24.300]So these winter annuals come up in the fall.
[00:14:26.180]Maybe that's the time that you wanna manage something
[00:14:28.950]like marestail in the fall to try to capture it
[00:14:31.670]when it's more small and more easy to manage.
[00:14:35.800]So if you wanna early detect these problems,
[00:14:40.060]it means you gotta find the problems early on.
[00:14:44.520]Paying attention.
[00:14:45.470]One way to capture these problems early
[00:14:47.480]is you just have to pay attention
[00:14:48.920]to potential problem areas.
[00:14:52.045]Where are the weeds coming from?
[00:14:53.440]Where is that seed source?
[00:14:54.630]So these dispersal pathways where you have these canals,
[00:14:57.480]these irrigation canals.
[00:14:58.980]They can be moving seed onto your fields.
[00:15:01.090]And you can see the weeds are getting established there
[00:15:04.350]along that irrigation canal,
[00:15:06.670]and so that would be a great opportunity
[00:15:09.030]to try to capture those weeds
[00:15:10.330]before they move across the field
[00:15:12.000]and become a lot more difficult to control.
[00:15:14.790]Or prioritizing where you're gonna control these weeds.
[00:15:16.760]So you have kochia that tumbleweeded across the field.
[00:15:19.760]You can see exactly where the kochia moved across the field.
[00:15:23.820]Instead of going out
[00:15:24.653]and spraying the entire field for kochia,
[00:15:27.430]you could just target this pathway
[00:15:28.770]and catch it before it goes to seed
[00:15:30.360]and before it increases and starts spreading
[00:15:31.930]across the whole field.
[00:15:35.198]This is a figure, I think this is great.
[00:15:37.350]To me, this demonstrates really well this idea
[00:15:40.330]that if you catch the problems early
[00:15:42.630]while the problem's small, you can have a big impact,
[00:15:44.430]but if you wait, these things blow up in a hurry.
[00:15:46.920]This is coming from some work down in Arkansas.
[00:15:52.320]And if you look at that field map on the left,
[00:15:55.500]you can see down at the bottom of that field,
[00:15:57.170]there's a couple of colored dots,
[00:15:58.690]and those are showing Palmer amaranth plants
[00:16:00.910]in that field year one.
[00:16:04.840]Nothing was done to manage that Palmer amaranth year one.
[00:16:08.460]We move to the field map on the right.
[00:16:11.230]It's the same field a year later
[00:16:13.160]without managing that Palmer amaranth,
[00:16:14.500]and now you can see we got Palmer amaranth plants spread
[00:16:17.500]all across that field.
[00:16:19.910]If we were to manage that Palmer patch on the left
[00:16:23.230]in year one, I think we could've done it.
[00:16:25.540]We could've probably gone out
[00:16:26.500]and even hand-pulled 'em at that point.
[00:16:28.320]But now if we move to the field on the left a year later
[00:16:30.780]without managing it,
[00:16:31.613]you can see that combine probably moved a lot
[00:16:33.220]of that seed across the field
[00:16:35.040]and it spread all over the place.
[00:16:36.690]The chances that we're gonna manage that easily,
[00:16:39.630]it's just become a lot more difficult
[00:16:41.130]to try to manage that weed population.
[00:16:44.440]This is another field showing the exact same idea,
[00:16:46.570]that you start with a really small patch that first year,
[00:16:50.590]but if you don't manage it well,
[00:16:51.640]if you don't prevent these plants from going to seed,
[00:16:54.820]your problem can explode
[00:16:56.040]in a relatively short amount of time,
[00:16:57.500]especially with some of these pigweed species.
[00:17:00.920]So, again, this rapid response.
[00:17:02.340]Preventing seed production's really important.
[00:17:04.290]I mean, if you need hand removal, tillage,
[00:17:07.220]spot-spraying, preferably not with Roundup,
[00:17:09.940]'cause we have some many resistant populations.
[00:17:12.880]But doing anything you have to do
[00:17:14.260]to manage those populations
[00:17:16.370]or those patches when they're small, I think,
[00:17:18.800]goes a long way to helping you manage those weed populations
[00:17:23.320]in your field in the long run.
[00:17:26.710]Again, this is just another way of showing
[00:17:28.320]that if you can manage populations early on
[00:17:30.990]before they explode, your chances go up quite a bit.
[00:17:34.480]This is showing the comparison of kochia density
[00:17:38.450]across two years.
[00:17:39.340]So across the x-axis, that's kochia density in corn
[00:17:44.938]in 2012 or just the first year of the study.
[00:17:48.670]And on the y-axis, that's showing what happens
[00:17:51.970]to that kochia population a year later.
[00:17:54.550]So this was done in sugar beet.
[00:17:57.380]If we just look at this,
[00:17:58.320]if you look at, for example,
[00:18:00.610]if you have a kochia population
[00:18:02.437]that's about five in year one
[00:18:06.410]and you don't do anything to that population,
[00:18:08.950]by the second year, you've jumped almost
[00:18:11.980]to a thousand kochia plants per hundred footer row.
[00:18:16.620]You've gone 10 times as high a population of kochia.
[00:18:20.970]The challenge in managing 10 times
[00:18:23.020]as many kochia plants go way, way up.
[00:18:24.490]Your costs go way, way up.
[00:18:25.897]The options you have to manage it go up
[00:18:28.540]by a significant amount.
[00:18:30.510]That's why it's really important
[00:18:31.530]if you can identify these problems early,
[00:18:34.480]if you can manage 'em early before they really explode
[00:18:38.350]or expand across your fields.
[00:18:40.630]It makes a big difference.
[00:18:44.560]In thinking about these herbicide tools,
[00:18:46.190]so we have these toolboxes of herbicide options available,
[00:18:50.070]and it's really important,
[00:18:51.310]especially as we move towards more resistant populations,
[00:18:54.480]that we use these tools as effectively as we possibly can.
[00:18:57.640]So one way to think about this is what's the difference
[00:19:00.700]between tank-mixing herbicides versus rotating?
[00:19:04.030]'Cause we know that it's important
[00:19:05.900]that we have multiple modes of action
[00:19:08.010]in our herbicides to manage our weeds,
[00:19:10.880]but is multiple modes of action, is it all the same?
[00:19:14.540]As long as we're using more than one mode of action,
[00:19:16.280]does it matter what that looks like
[00:19:18.410]in terms of weed control?
[00:19:19.550]There's a couple of studies that have been done.
[00:19:22.150]Here's one in particular where they compared mixtures
[00:19:26.010]of an herbicide versus rotation,
[00:19:27.900]which means they used different modes of action,
[00:19:29.890]but they used 'em over time.
[00:19:32.120]So they set this study up by seeding
[00:19:36.393]an ALS-resistant weed population to 5% within a field,
[00:19:40.300]and they used different herbicide combinations
[00:19:42.580]over a period of four years.
[00:19:44.970]What they found is if they used no ALS inhibitor at all,
[00:19:48.630]they used different modes of action
[00:19:49.870]other than the one that population was resistant to,
[00:19:54.410]the weed population in that field remained.
[00:19:57.270]It actually dropped just a little bit compared to
[00:19:59.750]as if they applied no herbicide at all
[00:20:01.220]in terms of the number
[00:20:02.200]of herbicide-resistant weeds in that field.
[00:20:07.610]We weren't selecting for ALS resistance,
[00:20:09.650]because we weren't using ALS herbicides in that case.
[00:20:12.850]Now, if we use one ALS herbicide once every four years,
[00:20:16.610]so we were rotating.
[00:20:17.443]We only used one in four years that we use ALS,
[00:20:20.080]but the other three we were using some other mode of action.
[00:20:24.300]You can see there's a huge jump
[00:20:26.080]in the number of resistant weeds
[00:20:27.780]that showed up in that field at the end of four years.
[00:20:31.240]Even though it was rotated,
[00:20:33.580]the fact that once every four years we were selecting
[00:20:36.210]for those ALS-resistant weeds made
[00:20:40.680]that population jump quite a bit.
[00:20:42.580]Whereas if you compare that
[00:20:43.700]to using more than one mode of action,
[00:20:46.190]so that's using an additional mode of action
[00:20:49.750]in addition to that ALS herbicide in the tank
[00:20:52.090]at the time you applied,
[00:20:53.880]you're able to maintain that weed population
[00:20:55.950]at the end of four years pretty similar to
[00:20:57.440]as if you applied no herbicide at all,
[00:20:59.400]so you weren't applying at any selection pressure.
[00:21:01.870]That population remained about the same.
[00:21:04.180]Really what they were able to show is that
[00:21:08.620]by mixing herbicides, it's certainly gonna be more effective
[00:21:11.760]than rotating over time.
[00:21:15.350]This other study in Illinois found that
[00:21:18.050]if you use at least 2 1/2 modes of actions,
[00:21:22.370]so two or more modes of action in mixture,
[00:21:25.950]you were 83 times less likely to develop resistant weeds.
[00:21:28.970]So just by having that additional mode
[00:21:31.180]of action in the tank,
[00:21:34.440]the chances that a weed in the field
[00:21:36.770]is gonna have resistance to both of those modes
[00:21:39.400]of action simultaneously is quite a bit higher
[00:21:41.410]than if you're once every so many years exposing that weed
[00:21:45.240]to the resistant mode of action.
[00:21:49.540]And finally, I'll just end on this,
[00:21:52.080]but this idea that we try something different.
[00:21:55.080]I think when it comes to managing resistant weeds,
[00:21:58.790]it can be frustrating, it can be challenging.
[00:22:01.180]I think sometimes you just gotta get
[00:22:02.310]outside the box a little bit and try something different.
[00:22:04.650]What else can I do other than keep spraying herbicides?
[00:22:08.947]Are there other things I can do
[00:22:09.880]to try to add to my system, add to my program
[00:22:14.390]to take a little bit of weight off of those herbicide tools?
[00:22:16.830]We ask those herbicides to carry quite a bit of weight
[00:22:19.020]in our weed management programs,
[00:22:21.130]and so I think trying something different
[00:22:22.740]can be important from time to time.
[00:22:25.650]Again, why is it important?
[00:22:28.090]Well, if we continue doing the same thing,
[00:22:30.570]if we continue putting a lot of weight
[00:22:32.000]on our herbicide programs,
[00:22:35.860]sometimes the results are less than ideal.
[00:22:39.480]So this was a situation where a grower had
[00:22:44.470]glyphosate-resistant waterhemp,
[00:22:46.960]but they didn't know that it was resistant
[00:22:48.740]at the time of application.
[00:22:50.060]So they had a number of glyphosate applications
[00:22:54.480]throughout that season that failed,
[00:22:57.400]and so then they came back at some later timings,
[00:23:00.500]trying to rescue this soybean field
[00:23:02.820]with some other modes of action,
[00:23:04.150]but the weeds had gotten too big by this time.
[00:23:06.980]You can see the number of applications
[00:23:08.720]that they applied trying to rescue this field.
[00:23:12.500]They even resulted to that inter-row cultivation,
[00:23:16.240]all to the tune of about $94 an acre,
[00:23:19.240]and yet they ended up with more waterhemp
[00:23:21.640]than they did soybeans.
[00:23:23.780]We gotta get outside the box.
[00:23:24.990]We gotta think creatively about managing these weeds
[00:23:28.070]so that we're not putting all that weight
[00:23:30.119]on our herbicide applications.
[00:23:33.537]So I'm just gonna highlight a study
[00:23:36.130]that we've done here at UNL,
[00:23:39.130]and this is looking at changing the maturity group
[00:23:42.070]of corn that we grow with the idea
[00:23:43.770]that we could establish a cover crop a little bit earlier
[00:23:47.080]in the fall and increasing the biomass of that cover crop
[00:23:50.730]with the hopes of that cover crop could provide a little bit
[00:23:54.160]of weed suppression.
[00:23:55.400]So it's not a silver bullet,
[00:23:56.490]it's not gonna replace our herbicides,
[00:23:58.080]but I think it can help carry that weight,
[00:24:00.640]reduce that weed pressure by a little bit
[00:24:03.110]and making our herbicides maybe a little bit
[00:24:05.040]more effective as a result.
[00:24:07.540]So this is showing six different
[00:24:11.890]relative maturity corn hybrids grown at Clay Center
[00:24:16.730]out there in south central Nebraska, as well as at Havelock.
[00:24:19.830]These range from an 80-day hybrid,
[00:24:21.890]all the way up to 115-day hybrids.
[00:24:23.900]We had a pretty large range of hybrids.
[00:24:25.950]We just know what impact does growing different
[00:24:28.400]relative maturity groups have on yield?
[00:24:31.290]We found that at those really low relative maturities,
[00:24:35.140]we certainly saw yield loss.
[00:24:36.320]Those 80-day, 86-day, we saw decreasing yield.
[00:24:39.360]But in our initial data we show that anything
[00:24:42.440]above that 95-day hybrid, if it was planted early,
[00:24:47.420]so kinda that early part of May,
[00:24:49.600]we didn't really see a decrease in our corn yield.
[00:24:52.980]This suggested that maybe there's an opportunity
[00:24:55.210]to scale back which corn hybrid we're using
[00:24:59.620]to try to open up a little bit of a window in the fall.
[00:25:02.920]If you compare this then to cover crops planted
[00:25:06.220]at different times in the fall
[00:25:08.020]following the harvest of these different maturity groups,
[00:25:11.450]you can see the amount of biomass difference that you see.
[00:25:15.770]Depending on the year,
[00:25:17.490]we either started planting early October,
[00:25:19.690]through the end of October, or the subsequent year.
[00:25:22.280]We actually, it would plant a little bit earlier,
[00:25:24.130]all the way as early as that last part of September.
[00:25:27.350]And you can see those earlier maturing corn hybrids
[00:25:31.260]allowed us an extra two or three weeks of growing season
[00:25:36.300]for those cover crops, and it made an enormous difference
[00:25:39.280]in the the amount of biomass that we were able to produce.
[00:25:42.110]So these really late planted,
[00:25:43.240]which would be kind of the typical planting date
[00:25:46.380]for a cover crop following a corn hybrid
[00:25:50.180]that's grown in Nebraska, so 111-day corn hybrid.
[00:25:53.630]We're somewhere in this 500 to a thousand pound
[00:25:57.600]per acre cover crop biomass,
[00:25:59.560]and we were able to almost double that
[00:26:01.750]by moving back even two weeks of growing season in the fall.
[00:26:07.940]That gives the opportunity
[00:26:09.030]to potentially suppress weeds by quite a bit.
[00:26:12.890]And here's this showing the difference
[00:26:15.630]of about two weeks in planting date
[00:26:17.360]of cereal rye planted in the fall.
[00:26:19.020]So on the left, that was planted the 21st of October,
[00:26:23.180]where the one on the right was planted
[00:26:25.040]about the first of October.
[00:26:27.100]That two extra weeks, you can even just visually see
[00:26:30.920]the amount of additional biomass that you accumulate.
[00:26:33.440]So using something like this in your system
[00:26:35.300]where maybe you tweak the system just slightly
[00:26:37.850]to give an advantage to your cash crop
[00:26:41.970]and try to put a little bit less weight
[00:26:43.700]on some of these herbicide management programs.
[00:26:45.480]I think it's important, and it should help out.
[00:26:49.698]As we collect more of this data,
[00:26:50.920]as we do more of this research, the hope is to be able
[00:26:54.160]to understand these systems a little bit better
[00:26:56.010]and how to optimize them and especially
[00:26:57.990]how to use these more effectively for weed management.
[00:27:02.040]So, again, I just highlight this idea
[00:27:04.140]that there's a number of things that you can do
[00:27:06.153]to manage weeds more effectively,
[00:27:08.890]but I think paying attention
[00:27:10.410]that you tackle the problems early,
[00:27:12.740]you target weeds when they're small,
[00:27:15.750]you're using your herbicide tools
[00:27:17.430]as effectively as possible, and then trying to think
[00:27:19.650]outside the box a little bit I think's important.
[00:27:21.950]So, again, thanks for your time.
[00:27:23.900]If you have questions for me,
[00:27:26.310]feel free to email me or call me, follow me on Twitter.
[00:27:30.240]I'm happy to have these discussions at more length.
[00:27:33.890]Thanks.
[00:27:34.922](bright music)
[00:27:43.280]In this PowerPoint, we really wanna cover
[00:27:46.900]how to have a successful weed control program,
[00:27:50.510]as well as some information on pesticide application
[00:27:54.630]to help you control your weeds.
[00:27:57.980]One of the things we see is
[00:27:59.770]how much can weeds affect yield loss?
[00:28:03.190]And you can see in this, it's basically about 50%
[00:28:06.790]for both corn and soybeans.
[00:28:09.270]Now, this is average losses.
[00:28:11.230]One thing, if you listen, though,
[00:28:12.360]to the plant pathologist and the entomologist,
[00:28:16.720]as well as weed scientist,
[00:28:18.370]you might come up with losses like 129%
[00:28:21.450]or something like that,
[00:28:22.730]so you wanna be just a little careful
[00:28:24.540]in adding those losses up.
[00:28:28.230]One of the thing you'll see here is you can have losses
[00:28:31.110]as much as a hundred percent here.
[00:28:34.620]This weed infestation in the untreated plot
[00:28:38.270]just knocked the yield to zero.
[00:28:41.060]Same in about this situation.
[00:28:43.990]The pesticide program or the herbicide program used here
[00:28:48.950]wasn't efficient controlling the weeds.
[00:28:52.380]They had a lot of resistant weeds in there.
[00:28:54.710]So the yield was another probably zero in this case.
[00:28:59.790]To really control weeds,
[00:29:00.730]you need an integrated weed management plan.
[00:29:05.570]And where can you get information on that?
[00:29:08.410]A real good source of information is the latest edition
[00:29:12.620]of our Guide to Weed, Disease,
[00:29:15.700]and Insect Management in Nebraska.
[00:29:18.940]You'll wanna get a new one of those each year,
[00:29:20.890]because there's a lot of updates in that.
[00:29:23.550]And a good source to get those Guides
[00:29:26.750]is the local Extension office.
[00:29:30.170]And of course to find information
[00:29:32.640]on integrated weed management,
[00:29:34.480]go to the Table of Contents in the Guide,
[00:29:37.210]and you can see it there.
[00:29:38.610]On this particular one, it's on page 11.
[00:29:41.660]Really details a lot of information
[00:29:43.950]on integrated weed management.
[00:29:46.320]Prevent weeds before they start.
[00:29:49.360]Help the crop to compete against weeds.
[00:29:52.690]Crop competition is a very effective weed control
[00:29:57.100]or management program.
[00:29:59.300]And of course one of our biggest problems now
[00:30:02.020]in Nebraska is our herbicide-resistant weeds.
[00:30:06.770]And this is going back a number of years.
[00:30:09.790]Gail Wicks and I got a call,
[00:30:11.460]this is in southwest Nebraska a good number of years ago,
[00:30:16.220]and this dealer said that he had kochia across this field.
[00:30:19.932]It didn't make any sense on how they sprayed the field.
[00:30:22.790]Gail and I thought we better get down there
[00:30:25.320]and see what the situation was.
[00:30:28.200]And I remember us looking at each other and saying,
[00:30:31.447]"Hey, we have triazene-resistant kochia
[00:30:35.157]"or atrazine-resistant kochia in that field."
[00:30:37.790]And I think that was probably the first case
[00:30:40.520]of triazene-resistant weeds in Nebraska at that time.
[00:30:47.760]For information on herbicide-resistant weeds,
[00:30:50.600]again, a good source of information is the Guide.
[00:30:55.840]And one of the real big keys that helps you
[00:30:59.530]in your weed management program is to look
[00:31:03.620]at the Efficacy Tables in the Guide.
[00:31:08.210]And as you go here,
[00:31:09.590]and we've got 'em for different treatment times.
[00:31:11.940]This happens to be for fall burndown herbicide treatments.
[00:31:16.870]And as you look in the first column here,
[00:31:19.025]you're gonna see the site of action or mode of action.
[00:31:22.660]This is how we wanna rotate herbicides
[00:31:25.090]to keep away from resistance.
[00:31:27.170]And then of course the various herbicides.
[00:31:29.590]And then you go to the right side there.
[00:31:32.070]We have the various weeds you'll be trying to control
[00:31:35.360]and the ratings.
[00:31:36.970]And usually you wanna have an eight, nine, or 10 rating
[00:31:40.450]on there if you have a problem with that particular weed.
[00:31:45.770]And of course you always wanna be aware
[00:31:48.070]of any replant options
[00:31:50.720]and rotation restrictions in the herbicides you select.
[00:31:55.210]We're doing a lot more on cover crops now,
[00:31:58.960]and a lot have those restrictions on that.
[00:32:02.640]And as you can see on this particular chart
[00:32:05.070]which is in the Guide here,
[00:32:06.820]and we have this about for all the herbicides,
[00:32:09.720]the herbicide listed, the common name,
[00:32:12.990]and then of course the rotation restrictions and so forth.
[00:32:18.070]The earlier ones just have days up there.
[00:32:20.710]Most of 'em are months.
[00:32:22.600]Some will say any time,
[00:32:24.650]and then some will even say the next cropping season
[00:32:27.587]and so forth.
[00:32:28.800]So you wanna check that out
[00:32:30.700]and make sure that it doesn't prohibit you
[00:32:33.390]from planting some of the cover crops
[00:32:34.810]that you would like to plant in your program.
[00:32:39.390]And of course you always wanna be aware
[00:32:41.880]of the potential human exposure
[00:32:45.330]and the environmental risk of using the various herbicides.
[00:32:50.590]And there's charts in the Guide again,
[00:32:53.530]list the product name, the active ingredient,
[00:32:57.810]and then the potential for human exposure,
[00:33:01.850]signal words, toxicity class,
[00:33:04.700]and of course the relative use rate,
[00:33:07.150]along with the relative leaching potential
[00:33:10.820]and the runoff potential.
[00:33:12.780]That runoff potential we have for both water and soil.
[00:33:18.720]And of course improve weed management, herbicides,
[00:33:22.860]be concerned about resistance.
[00:33:25.590]And there of course, as we mentioned earlier,
[00:33:28.870]select herbicides with different modes of action.
[00:33:34.320]And as you look here on the Acuron label,
[00:33:37.160]most of the new labels have this on now.
[00:33:40.220]What group on the site of action
[00:33:43.020]or mode of action it fits into.
[00:33:45.320]And this is really helpful
[00:33:47.730]in rotating your herbicide use
[00:33:51.120]to handle the resistance problems.
[00:33:55.305]And, again, charts in the Guide there
[00:33:58.210]and another one that's also usable.
[00:34:02.090]Putting together a weed management plan.
[00:34:06.400]One of the first things you wanna do
[00:34:08.160]is know the history of the field,
[00:34:10.530]current, past weed problems, any resistant issues,
[00:34:15.620]the herbicides used in the past,
[00:34:17.960]performance, problems, any carryover,
[00:34:21.240]and of course you always wanna know the soil type,
[00:34:23.890]organic matter, and pH.
[00:34:26.640]That really affects the use rate on a lot of the herbicides,
[00:34:30.910]and also the carryover potential.
[00:34:35.030]And of course you always wanna know
[00:34:37.170]if there's sensitive areas nearby.
[00:34:40.680]And some additional things here
[00:34:42.810]on putting together your weed management plan.
[00:34:46.300]Some weeds can travel a long distance like kochia.
[00:34:50.080]And if a weed population area is developing resistance,
[00:34:53.600]of course there's a good chance you're gonna have it.
[00:34:56.760]This is back to kochia again.
[00:34:59.010]This is what we saw
[00:35:00.080]in southwest Nebraska a good number of years ago.
[00:35:03.190]And it's easy to show here in our fallow
[00:35:05.270]where we're controlling weeds after wheat harvest.
[00:35:07.820]And you can see again where the kochia blew across the field
[00:35:11.900]that was resistant to the triazene herbicides.
[00:35:17.030]More information on that weed management program.
[00:35:20.420]How much does it take to activate the herbicides?
[00:35:23.430]In general, we usually say about 1/3 of an inch,
[00:35:26.760]but it does vary according to the texture of the soil.
[00:35:31.770]And if the soil is coarse-textured,
[00:35:33.860]of course we don't wanna use herbicides
[00:35:36.730]with a high leaching potential.
[00:35:40.090]And of course it's always important
[00:35:41.930]what crops to be grown now and of course in the future.
[00:35:46.210]And how can you manage those escapes?
[00:35:49.950]Look at the post-applications.
[00:35:51.740]If you have a major weed problem,
[00:35:53.760]you wanna go with those crops
[00:35:55.330]that have more post-application possibilities.
[00:35:58.630]Some cases, we might even have to resort to cultivation.
[00:36:02.930]In cases where we got a weed scattered across the field
[00:36:06.340]like we showed you with kochia,
[00:36:08.540]you might wanna even go in and mow down some of those areas.
[00:36:12.160]They probably won't be too big of areas,
[00:36:14.320]and you'll have a lot less of a problem
[00:36:16.330]if you destroy those and don't let 'em go to seed.
[00:36:20.780]The combine is really an excellent tool
[00:36:23.910]to spread weed seed,
[00:36:25.330]and that's why you wanna destroy those some way
[00:36:28.130]before you take your combine to the field
[00:36:30.510]and spread the weed seed.
[00:36:32.950]And of course we have a lot
[00:36:34.550]of different times we can put on herbicides.
[00:36:37.270]One thing we really have mentioned
[00:36:39.640]that these fall treatments have really been a real plus
[00:36:43.980]to our weed management program,
[00:36:46.040]especially for the winter annuals.
[00:36:48.290]What happens with the fall treatments
[00:36:50.480]is you weaken the plant,
[00:36:53.200]and of course then you've got the winter to finish it off,
[00:36:56.700]where applications applied in the spring,
[00:36:59.210]you've got excellent growing conditions for recovery.
[00:37:03.170]Here was a treatment in that same field we showed
[00:37:06.500]as the second slide with a good program put together,
[00:37:10.560]and it was really effective
[00:37:12.550]in controlling the weeds in that field.
[00:37:16.250]And as we look at all these treatment options and so forth,
[00:37:19.490]you'll see that to increase efficacy
[00:37:24.020]and manage spray drift
[00:37:26.850]when applying pesticides, you always wanna check the label
[00:37:31.550]and information in the Guide.
[00:37:33.860]One thing we gotta really stress, though, is treatments.
[00:37:37.570]They gotta be timely.
[00:37:41.190]Here you see on this slide, use full rates.
[00:37:45.910]Don't try to get by with 1/2 rates, 1/3 rates,
[00:37:49.020]2/3, or so forth.
[00:37:51.220]It's really important to get the full coverage
[00:37:54.773]that you need, the spray volume.
[00:37:58.324]Crop intersection can be a real problem.
[00:38:02.180]And dense weeds can greatly affect
[00:38:05.513]the weed control program.
[00:38:08.140]Weed size is really important.
[00:38:09.840]This just shows you here.
[00:38:11.650]The front row basically has the same treatments on,
[00:38:14.990]and kochia in three inches were pretty effective,
[00:38:17.740]those treatments applied.
[00:38:20.150]Whereas a four-inch, just a inch bigger,
[00:38:23.690]the treatments were not near as effective.
[00:38:27.580]Going back, this is a call I actually had from a farmer,
[00:38:31.120]and he had bought a new sprayer.
[00:38:34.570]The weather didn't cooperate with him,
[00:38:36.300]so he couldn't get everything applied timely,
[00:38:38.710]so he called an aerial applicator
[00:38:40.640]to help him catch back up in his weed control program.
[00:38:46.150]He related to me that he was surprised
[00:38:49.260]that the aerial applicator actually had better results
[00:38:53.630]in weed control than he did with his brand new sprayer,
[00:38:57.470]and he wanted me to figure out why.
[00:38:59.920]Well, as we got to looking at it,
[00:39:02.000]and the herbicide he was using
[00:39:04.530]really called for the Coarse droplet size
[00:39:08.590]for good coverage.
[00:39:11.000]On his sprayer,
[00:39:12.140]he had the biggest spray particle nozzles,
[00:39:16.680]which gave him an Ultra Coarse droplet size,
[00:39:20.070]and those are greater than 665 microns.
[00:39:23.630]Many of the herbicides do call
[00:39:25.330]for about a Coarse droplet size.
[00:39:27.630]But we are using that Ultra Coarse now
[00:39:30.340]where we're really concerned about spray particle drift.
[00:39:36.680]I'm sure the farm was concerned about drift,
[00:39:39.370]but he didn't have enough gallonage
[00:39:42.070]to give him good coverage
[00:39:44.080]with that larger spray particle size.
[00:39:47.880]As a result, his control was not as good
[00:39:52.110]as the aerial applicator.
[00:39:55.450]And what do we want?
[00:39:56.720]Of course we want a hundred percent weed control
[00:39:59.940]and 0% spray drift.
[00:40:02.800]In this particular slide,
[00:40:04.220]you can see that we basically really have
[00:40:06.930]that excellent weed control there on the fallow,
[00:40:10.260]and then of course no drift over on the wheat.
[00:40:16.240]For pesticide application information,
[00:40:19.620]again, go to the Guide.
[00:40:22.130]And we've got a section in there on equipment and practices
[00:40:26.700]that can really be helpful
[00:40:28.950]in your application procedures and equipment.
[00:40:32.760]One of the questions we get a lot of is
[00:40:34.930]what spray nozzle spacing
[00:40:38.400]should you have on your sprayer?
[00:40:41.640]And we really prefer 15-inch nozzle spacing.
[00:40:46.770]And the reason we're going to that 15-inch nozzle spacing is
[00:40:51.810]that when we're spraying low gallonage,
[00:40:54.520]we gotta shut off every other nozzle
[00:40:57.000]and then use that as a 30-inch nozzle spacing
[00:41:00.220]on our sprayer so we can get those lower application rates
[00:41:04.750]without going to such a fine spray particle size.
[00:41:10.250]When we get to the high gallonage rate,
[00:41:12.180]let's say 15, 20, 25 gallons and so forth,
[00:41:16.010]we'll use the 15-inch nozzle spacing.
[00:41:19.150]And, again, big advantage there
[00:41:21.620]is we can maybe even use the same nozzles
[00:41:24.240]that we used on 30-inch spacing,
[00:41:26.970]because we'll double on the gallonage.
[00:41:28.910]For a person going from like 10 gallons to 20 gallons,
[00:41:32.340]he could use the same nozzle spacing,
[00:41:35.990]or he could go from like eight to 16
[00:41:38.810]or like even eight to 18 or something like that
[00:41:42.070]would all be possibilities
[00:41:44.150]without changing spray nozzle size.
[00:41:48.540]How do we like to set up a sprayer?
[00:41:51.090]This is different than most books have
[00:41:54.370]on setting up a sprayer and the coverage you need
[00:42:00.200]from your sprayer.
[00:42:01.920]Most of 'em are saying 30 to 50% overlap.
[00:42:05.820]My experience shows I like to have a hundred percent overlap
[00:42:10.000]where the pattern from one nozzle ends up
[00:42:14.370]under the adjoining nozzle at target heighth.
[00:42:19.530]That gives you a hundred percent overlap.
[00:42:21.430]So if you have 30-inch nozzle spacing,
[00:42:23.237]you'll need 60-inch of pattern width.
[00:42:26.860]As we look at this with 110 degree nozzles,
[00:42:30.070]and most of the new nozzles now are just coming out
[00:42:33.060]on 110 degrees, we're gonna have to have at least 60 inches.
[00:42:37.600]Well, if you look at this chart
[00:42:39.120]under 24 inches of boom heighth,
[00:42:40.640]and that is a pretty standard heighth right now.
[00:42:44.690]With a 110 degree nozzle, 24 inches above the target,
[00:42:48.940]we're gonna have a 69-inch spread.
[00:42:51.280]We're gonna pull in just a little bit
[00:42:53.740]from that theoretical coverage.
[00:42:55.970]Now, one of the things we're also finding
[00:42:58.420]on some of the new nozzles,
[00:43:00.520]like the Turbo TeeJet Induction nozzle has
[00:43:05.620]about a 15 degree orientation to the back.
[00:43:10.140]And a 24-inch nozzle heighth,
[00:43:12.750]that adds an additional about 6.3 inches of coverage.
[00:43:16.980]So you can see again with that particular nozzle
[00:43:19.830]in 110 degrees,
[00:43:21.650]we'll probably have about 75 inches of coverage.
[00:43:24.770]Now, it's better to have a little bit extra
[00:43:27.360]than not enough coverage in that
[00:43:29.680]to get that hundred percent overlap.
[00:43:32.090]And this is one of the nozzles we just talking about.
[00:43:35.510]And if you look at the deflector shield
[00:43:37.700]and if you have these put in right,
[00:43:39.660]they spray towards the back, not forward and so forth.
[00:43:44.510]If you aim forward,
[00:43:46.210]you get a lot of fine particles breaking up
[00:43:49.540]as they're spraying forward,
[00:43:50.880]so you get better control if they spray back
[00:43:54.410]and get 'em into the airstream.
[00:43:57.680]Another thing here as we look at spray particle size,
[00:44:01.120]which is very, very important,
[00:44:03.610]and you can see as we run through that.
[00:44:05.670]And a couple of new categories was added
[00:44:10.310]by the ASABE Standard several years ago,
[00:44:15.330]from the Extremely Fine one
[00:44:17.830]and the Ultra Course that we did not have before.
[00:44:22.190]And you're gonna see this is some of the new nozzles
[00:44:25.890]that's recommended for we really are concerned
[00:44:29.110]with spray particle drift.
[00:44:32.800]Here are the Ultra Coarse
[00:44:34.530]out of the Turbo TeeJet Induction nozzle.
[00:44:37.480]You can see if you keep the nozzle pressure 60 and below
[00:44:41.800]on all but the smallest nozzle.
[00:44:45.190]And, again, on nozzle selection,
[00:44:47.930]I like to go with the smallest nozzle.
[00:44:50.570]I use the 25 or .25,
[00:44:54.590]the lavender one there and bigger on up.
[00:44:58.020]Those smaller ones are a lot easier to plug,
[00:45:00.870]and that's the reason I like
[00:45:02.500]to say go to the .25 or the 25
[00:45:06.377]as you look at the chart there and and bigger nozzles.
[00:45:10.790]Okay, as we look at the spray particle size
[00:45:13.390]and what kinda coverage we get.
[00:45:15.810]Now, the human hair is about a hundred microns,
[00:45:18.120]just to kinda give you an idea.
[00:45:21.070]Standard staple, about 420 microns.
[00:45:24.940]Paper clip, 850.
[00:45:27.510]And of course the old number two pencil leads,
[00:45:30.520]2,000 microns.
[00:45:33.040]As we look at a 500 micron
[00:45:36.310]diameter spray droplet,
[00:45:38.750]we get about 90 droplets per square inch.
[00:45:42.720]Pretty good coverage at that.
[00:45:44.820]But when we start getting in those bigger particle sizes
[00:45:47.890]like a thousand, we don't have near the coverage.
[00:45:51.960]And then it is important probably
[00:45:54.400]to go up our 10 gallons or maybe even 15.
[00:45:57.410]It's not gonna be enough with those larger spray droplets
[00:46:02.700]to give us the coverage.
[00:46:04.490]And in our case we recommend probably going
[00:46:07.320]to 20 gallons per acre
[00:46:09.270]when you get to those bigger spray particle sizes.
[00:46:14.010]This kinda summarizes it then as you look at it.
[00:46:17.190]The size of the droplets there was Extremely Fine and small.
[00:46:22.100]And you go across that.
[00:46:24.190]Retention on difficult to wet leaves.
[00:46:27.200]It's really excellent with those really small droplets.
[00:46:31.200]Drift potential, though, of course
[00:46:32.900]with those small droplets is gonna be high.
[00:46:36.470]You go all the way to the bottom of the chart,
[00:46:39.150]and where you have the Ultra Coarse,
[00:46:40.900]the largest particle size,
[00:46:42.900]of course the droplet is gonna be large.
[00:46:46.230]If you look at that, though,
[00:46:47.460]on retention on difficult to wet leaves,
[00:46:50.190]it's not gonna be very good,
[00:46:51.620]because they're gonna run right off.
[00:46:53.810]And of course when you look at drift potential, though,
[00:46:57.120]with a spray particle being that big, it's gonna be low.
[00:47:02.600]And one of the things that we have in the guide also,
[00:47:05.830]this is the last several years
[00:47:07.130]we've increased this information by a long ways.
[00:47:11.870]We got there the droplet size classifications
[00:47:15.190]recommended on the label
[00:47:17.830]and then the ground application rate.
[00:47:21.600]And as you look there for AAtrex 4L,
[00:47:26.520]they recommend the Coarse droplet size,
[00:47:29.560]minimum of 10 gallons per acre.
[00:47:32.500]And you're gonna see different ones recommended.
[00:47:35.030]We got several pages in there on herbicides,
[00:47:39.350]again, on the drop size classification recommended
[00:47:43.240]and then the ground application gallons per acre
[00:47:46.470]that they recommend for good coverage.
[00:47:49.090]We also have charts in there
[00:47:51.650]for insecticides and fungicides.
[00:47:57.410]And this is one of the charts we have in there.
[00:48:00.550]We have speeds from six to 14 mile an hour
[00:48:04.300]on 20-inch nozzle spacing, what nozzle you use
[00:48:07.660]and the pressure you use, and at 15-inch nozzle spacing.
[00:48:11.320]Now, this chart happens to be for Coarse spray quality.
[00:48:14.860]We have various ones
[00:48:16.190]from Medium up to Ultra Coarse on there
[00:48:20.030]and at 10, 15, and 20 gallons per acre,
[00:48:23.610]so it really helps you in selecting your right nozzle type
[00:48:27.740]and the pressure to give you that kinda coverage
[00:48:31.510]at the various travel speeds.
[00:48:34.140]And in general as we get over about 10 mile an hour,
[00:48:39.120]we feel it's important
[00:48:40.720]to go to the 15-inch nozzle spacing to really get coverage.
[00:48:46.640]That's another factor that enters in.
[00:48:49.750]You can use lower gallonage rate and coverages
[00:48:53.580]when you're in the eight mile an hour and slower speeds.
[00:48:58.760]One thing to a nozzle selection that can really help ya,
[00:49:02.240]a standard spray nozzle tip, the tip is just one part
[00:49:06.770]and then the nozzle cap is another part.
[00:49:10.840]I really prefer the XRC nozzles
[00:49:14.440]or the combination
[00:49:16.270]where the tip is built into the cap as one piece.
[00:49:20.100]It's not coming apart.
[00:49:21.760]They're not much more expensive.
[00:49:24.070]They're a lot easier to use.
[00:49:25.770]Of course they're color-coded and make it a lot easier
[00:49:28.920]so you can keep track of the various nozzles
[00:49:32.330]and know if you got the wrong nozzles in there
[00:49:34.990]just because it's bigger and easier to see
[00:49:37.730]and color-coded and doesn't come apart.
[00:49:43.390]Should you buy ceramic nozzles?
[00:49:45.850]And how do they compare the life of 'em
[00:49:48.580]with stainless steel?
[00:49:50.750]And they're at least five times longer life.
[00:49:54.130]Now, as we look at the chart on the right hand side there,
[00:49:57.690]life of ceramic nozzles
[00:49:59.730]is five to 16.7 times that of stainless steel.
[00:50:05.460]And as you look at our chart here
[00:50:07.100]on the bottom of that on the left, we have an AIC nozzle.
[00:50:12.030]That's an air induction combination nozzle,
[00:50:15.560]tip built right into the cap.
[00:50:17.870]And they're $16.30 for the stainless steel.
[00:50:22.580]This is the list price.
[00:50:24.290]The ceramics are even a little bit cheaper in this case.
[00:50:28.290]About $3 cheaper.
[00:50:30.760]And they can last at least five times as long
[00:50:34.050]and almost 17.
[00:50:36.060]So if you use that 10 in there or something like that,
[00:50:39.300]a nozzle that's cheaper that can last a lot longer
[00:50:43.430]is certainly a better investment.
[00:50:47.170]And avoiding spray drift at the application site
[00:50:51.080]is the responsibility of the applicator.
[00:50:53.670]We always wanna remember that.
[00:50:55.610]One thing that's really important, of course,
[00:50:57.557]the number one factor in a spray drift is wind speed.
[00:51:02.420]How do you measure it?
[00:51:04.720]Well, the WeatherFlow meters are really good.
[00:51:08.130]They work in conjunction with a smartphone.
[00:51:11.600]It can log the information right in your smartphone.
[00:51:14.460]Makes it a lot easier than having to make notes.
[00:51:17.240]And you really wanna consider this in your spraying.
[00:51:20.720]You wanna take these measurements at spray boom heighth,
[00:51:24.830]and it's very important.
[00:51:26.040]Some of the new labels on pesticides require you
[00:51:30.560]to take these measurements and record 'em.
[00:51:33.870]And, again, the easiest way to do this
[00:51:36.080]is getting something like a WeatherFlow meter here.
[00:51:38.810]The one we recommend,
[00:51:40.170]they call is the AG one at about $85.
[00:51:44.270]Really works nice with your smartphone
[00:51:48.100]in recording the information.
[00:51:50.980]There's a lot of factors that affect off-target movement.
[00:51:55.850]And the second biggest factor in spray drift
[00:51:58.770]of course is boom heighth.
[00:52:00.280]We was talking about that earlier.
[00:52:02.320]And you can see as the chart over here,
[00:52:04.930]as you go out to the higher boom heighths,
[00:52:07.170]get out to three feet out here,
[00:52:09.120]some of those lines are going up pretty good.
[00:52:12.130]For some of the new pesticides,
[00:52:13.840]they're recommending keeping the boom heighth
[00:52:16.030]not over two feet.
[00:52:18.100]And you can see that really reduces the spray particle
[00:52:21.860]distance that the particles can move
[00:52:24.940]by keeping the spray boom at lower heighth.
[00:52:28.320]Weather factors, really a big concern.
[00:52:31.860]The temperature, humidity,
[00:52:33.960]all affect spray drift,
[00:52:37.320]and they can also affect of course efficacy.
[00:52:41.600]Inversions, we gotta really watch those.
[00:52:44.879]There's a lot more inversions out there,
[00:52:46.780]and we really at the slow wind speeds
[00:52:51.560]can indicate a temperature inversion.
[00:52:54.860]And of course what's an inversion?
[00:52:56.590]That of course is when the temperature
[00:52:59.390]at ground level is cooler than the air above,
[00:53:03.370]and of course that's the opposite.
[00:53:04.710]You think about going up in the mountains,
[00:53:06.290]it's cooler up there.
[00:53:07.650]But in this case we got the coolest air at ground level.
[00:53:12.280]And these small suspended droplets
[00:53:16.560]form a concentrated cloud
[00:53:19.160]that can move in unpredictable directions and so forth.
[00:53:23.620]And here you see how that can happen in there,
[00:53:26.640]the smoke just hanging in there.
[00:53:30.410]How often can these occur?
[00:53:32.590]University of Missouri has conducted quite a lot
[00:53:35.030]of research in there,
[00:53:36.650]and they were kinda surprised to find
[00:53:39.150]that inversions can occur at least 1/2 the evenings
[00:53:43.630]in March to July.
[00:53:45.440]And they're occurring a little bit earlier
[00:53:47.970]in the March to May period.
[00:53:50.900]And one thing you always wanna do there
[00:53:53.410]of course is calibration.
[00:53:55.570]Very, very important.
[00:53:57.330]You wanna check the pressure, though,
[00:53:58.930]before you start calibration.
[00:54:01.047]And you really need a couple of pressure gauges to do this.
[00:54:04.270]You wanna actually put 'em on side-by-side
[00:54:07.090]and then rotate 'em and compare 'em to each other
[00:54:10.190]in how they read.
[00:54:11.490]And then usually you're gonna find one
[00:54:13.370]of the gauges reads a pound or two more or less
[00:54:16.010]than the other ones.
[00:54:17.240]You'll wanna mark that on the gauges,
[00:54:19.920]one of the gauges how it reads to the other one,
[00:54:22.820]and then leave one in place
[00:54:24.780]and go up and down the boom, check for even pressure.
[00:54:28.150]The other thing you wanna do is compare the boom pressure
[00:54:32.790]with the pressure in the cab.
[00:54:36.550]The boom pressure is the important one,
[00:54:38.700]and then right in the cab, how that one compares
[00:54:42.700]to the pressure out on the boom.
[00:54:46.540]And of course cleaning the sprayer, very, very critical.
[00:54:50.710]This is a place that actually sprayed three loads
[00:54:54.200]of Roundup on Roundup Ready soybeans,
[00:54:58.910]and then they were loading the fourth load.
[00:55:03.250]And they looked to the west and they'd say,
[00:55:04.757]"It's gonna rain here pretty soon.
[00:55:06.847]"We better not spray."
[00:55:07.787]And this was on a Friday afternoon.
[00:55:10.310]Well, it rained pretty good on that Friday afternoon.
[00:55:12.560]They couldn't get in and start spraying
[00:55:14.900]until Monday afternoon.
[00:55:17.350]And this is where they started spraying.
[00:55:19.320]You can see the injury they had.
[00:55:21.910]The worst injury they had was from the spray boom,
[00:55:25.560]the concentrate in the spray boom.
[00:55:27.060]So you really need to do a good job
[00:55:29.540]of cleaning the sprayer.
[00:55:31.360]We got a new NebGuide that's just available now
[00:55:34.180]that's gonna be quite helpful to ya
[00:55:37.060]in cleaning your sprayer.
[00:55:39.780]And, again, we've got more information on that in the Guide.
[00:55:44.360]And this is what can happen on some of these end caps.
[00:55:47.300]You wanna make sure you really, really clean the sprayer.
[00:55:51.580]And hoses,
[00:55:54.760]some of the older hoses really can become impregnated
[00:55:58.660]with a lot of chemical.
[00:56:00.910]Get some of the new quality hoses,
[00:56:03.100]and that will greatly reduce your injury
[00:56:06.610]from applying some of these herbicides
[00:56:10.450]that can build up in the hoses.
[00:56:12.020]But really do a good job on cleaning the sprayer.
[00:56:16.310]Really very important,
[00:56:17.910]because you can do a lotta crop damage
[00:56:20.440]if you don't have proper cleaning procedures.
[00:56:24.130]Thank you.
[00:56:25.211](bright music)
[00:56:32.990]Okay, hello, everyone.
[00:56:33.890]I'm Justin McMehan.
[00:56:34.877]I'm a Crop Protection and Cropping Systems Specialist,
[00:56:37.190]and today I'm gonna be talking to you
[00:56:38.230]about insect management.
[00:56:40.260]And we're gonna focus on the three different
[00:56:41.750]main cropping systems found in Nebraska here,
[00:56:43.830]so corn, soybeans, and wheat.
[00:56:45.770]And we'll cover various pests,
[00:56:47.450]looking at early, mid, and late season.
[00:56:51.270]Really what we wanna focus on today
[00:56:52.550]and we're gonna see throughout this presentation
[00:56:54.360]is the IPM Principles, which is pest identification,
[00:56:57.690]really important when making management decisions,
[00:57:00.560]monitoring and assessing numbers and damage
[00:57:03.560]of those insects, and then those guidelines
[00:57:06.410]for making a management action.
[00:57:09.190]We're really looking to prevent pest problems,
[00:57:11.210]so we're not focusing on always making a spray application
[00:57:13.610]or doing some remedial action,
[00:57:14.900]but actually doing things ahead of time,
[00:57:16.340]crop rotation and other things.
[00:57:17.480]So you'll see that in the pest examples we're gonna cover.
[00:57:20.300]And really our goal is to use a combination
[00:57:22.760]of management practices.
[00:57:23.810]So, yes, we may need to use pesticides on occasion,
[00:57:26.420]but we're looking once we find a pest,
[00:57:27.980]what else can we do for the following season?
[00:57:30.370]And then if we do take action,
[00:57:31.610]we wanna assess that effect of that practice to determine
[00:57:34.270]if it's something we wanna do again in the future.
[00:57:37.890]So, as I mentioned before,
[00:57:39.380]we're gonna cover some common insects
[00:57:40.700]or arthropods found in corn, soybeans, and wheat.
[00:57:43.970]We're gonna divide the growing season up,
[00:57:45.300]so we're gonna knock through each one of these crops,
[00:57:47.100]starting in the early part of the season
[00:57:48.840]with a lot of below ground pests
[00:57:50.150]and things that show up as the crops emerge,
[00:57:52.860]to middle of the season, then late season
[00:57:54.570]where we get a lot of the reproductive portion
[00:57:56.120]of the plants accessible to certain insects.
[00:57:59.370]We're gonna focus on that arthropod identification
[00:58:01.330]and what kinda damage they're causing,
[00:58:03.220]and then looking at the biology of that pest.
[00:58:04.777]And that informs us of the management practices
[00:58:07.250]that we're gonna need to use
[00:58:09.310]to most effectively cost-wise manage that insect.
[00:58:12.890]And then we're gonna look at different management practices
[00:58:14.950]that are available for some of these pests.
[00:58:16.980]So beginning with white grub,
[00:58:18.110]white grub spans wheat, corn, and soybeans, all three crops.
[00:58:21.870]It's a C-shaped grub or a larvae,
[00:58:24.000]as you can see in the photo here.
[00:58:25.180]And there are a number of different species
[00:58:26.730]based on the raster.
[00:58:27.580]So the raster, as you can see here at the far side.
[00:58:29.720]We have Japanese beetle and masked chafer.
[00:58:31.810]Those are annual grubs,
[00:58:33.290]so they typically don't cause a lot of damage
[00:58:35.700]in our agricultural crops,
[00:58:37.160]whereas the May/June beetle,
[00:58:38.700]which has a two to three-year life cycle,
[00:58:40.400]towards the end of its life cycle
[00:58:41.580]it can cause a lot of problems.
[00:58:42.760]So if you're out there and scouting fields,
[00:58:44.810]you wanna be sure that you're identifying
[00:58:46.100]the right kind of grub,
[00:58:47.460]and that will inform you of the potential risk
[00:58:49.120]in that coming season.
[00:58:53.290]So another one is wireworms.
[00:58:54.560]Both the sampling for white grub and wireworm are similar,
[00:58:58.120]with the exception of using these baits for wireworms.
[00:59:00.810]But essentially you're digging an area of soil
[00:59:03.010]and turning that over and determining the number of counts,
[00:59:05.360]and that will inform you by the crop
[00:59:06.770]what the threshold might be.
[00:59:09.060]In the case of wireworms, they live for three to six years,
[00:59:11.590]so they have a very long life cycle.
[00:59:13.250]So if you do have a problem one year,
[00:59:15.330]potentially you could have problems
[00:59:16.390]the following year as well.
[00:59:18.500]In the case of wireworms,
[00:59:19.730]you'll find a lot of different sizes then as well.
[00:59:22.540]But what they're doing is they're feeding
[00:59:23.590]on the seeds or seedlings,
[00:59:24.790]especially when the soil temperatures are cool.
[00:59:26.280]So right after planting when we get
[00:59:27.440]to 50 degrees Fahrenheit, they'll start feeding.
[00:59:30.720]But they do move with soil temperature,
[00:59:32.290]so as the soils begin to rise in the spring,
[00:59:34.070]they're gonna move down in the soil profile
[00:59:35.580]away from the root system is.
[00:59:37.300]So maybe you had a problem, say, this year
[00:59:38.790]'cause it was cold,
[00:59:39.740]but then next year it's warm and you don't see that problem.
[00:59:42.930]It's probably 'cause they're out of that area
[00:59:44.840]where they can cause damage.
[00:59:46.910]They're attracted to decomposing materials.
[00:59:49.300]Any time you have a lot of decomposing material present
[00:59:51.657]in the fall, the adults are attracted to that.
[00:59:53.730]They're these click beetles.
[00:59:55.160]They get their name because right in the space
[00:59:58.170]between their thorax and their abdomen,
[00:59:59.890]they can actually make a clicking noise
[01:00:01.100]when you grab ahold of 'em.
[01:00:01.933]So if you pick 'em up and hold 'em,
[01:00:03.210]they'll make that clicking noise.
[01:00:05.080]And the immature form is the wireworm.
[01:00:09.120]The last one I'll kinda hit
[01:00:10.040]for below ground insects is the seed corn maggot.
[01:00:12.550]This is only a problem in corn and soybean systems,
[01:00:15.010]and I have a setup here that follows corn,
[01:00:16.770]but you could reverse this
[01:00:17.720]and see this in soybeans as well.
[01:00:19.700]And they're really an increased risk around feedlots
[01:00:22.360]where you have a lot of manure or decaying vegetation.
[01:00:24.890]The example here is a cover crop
[01:00:26.320]that would be decaying in the spring.
[01:00:28.260]And it's not just spring.
[01:00:29.600]Usually it's some sort of tillage,
[01:00:30.900]something that incorporates that residue into the soil
[01:00:33.490]and gets decomposing.
[01:00:34.950]And the adults are actually attracted to this material.
[01:00:37.120]They lay eggs.
[01:00:38.470]They do this in a very predictable manner.
[01:00:40.470]Usually what we're looking for
[01:00:41.520]in the field is weakened plants
[01:00:42.393]that are behind in development
[01:00:44.520]within a given row or unemerged.
[01:00:46.660]Literally, they're missing plants within the row.
[01:00:48.400]So if you dig those up,
[01:00:49.280]you may find what you see in this photo here,
[01:00:51.320]which is a seed corn maggot.
[01:00:53.060]And they don't have a head capsule
[01:00:54.430]like you'd find on a lot of other beetles
[01:00:55.810]or things we were discussing earlier.
[01:00:57.820]They run on a degree day system.
[01:00:59.350]A lot of insects do this,
[01:01:00.530]and they're very easy then for us to predict
[01:01:02.950]when they might be a problem in the system.
[01:01:04.380]So for this particular insect,
[01:01:06.130]we have a max and min temperature.
[01:01:07.640]So if you take your daily temperatures
[01:01:09.130]and plug them into this equation starting at January 1,
[01:01:12.270]at 350 degree days, they'll actually show up in the system.
[01:01:14.690]So you know if you're planting during that period,
[01:01:17.070]you're at high risk
[01:01:17.960]if you meet all the criteria listed on the slide.
[01:01:21.040]If you use seed treatments or other things,
[01:01:22.730]you're usually safe from this type of insect,
[01:01:25.010]but it'll give you an idea
[01:01:25.960]if you're at higher risk and need to scout for it.
[01:01:29.930]Another early season pest is black cutworm.
[01:01:32.080]This insect is not overwinter in Nebraska.
[01:01:34.470]It attacks, again, corn and soybeans.
[01:01:36.870]It's primarily at the eastern end of the state.
[01:01:38.940]That's where we see it each year.
[01:01:41.070]And they're attracted to dense vegetation in the spring.
[01:01:43.330]So we're kinda setting up what's the worst case scenario?
[01:01:45.670]Again, if you were coming to this next year,
[01:01:47.050]you might wanna control that vegetation earlier
[01:01:49.600]and potentially avoid that type of issue.
[01:01:51.710]So the identification in adults is pretty easy.
[01:01:54.360]We monitor for them with a pheromone trapping system.
[01:01:58.440]But what you're likely to see
[01:01:59.720]in the field is the black cutworms themselves,
[01:02:02.470]which you can see they have these spots.
[01:02:04.290]And if the spots are uneven in size, that's black cutworm.
[01:02:07.080]If they're even in size, it's dingy cutworm,
[01:02:08.820]which is actually native to the state, overwinters
[01:02:11.780]and is not as much of a problem to agricultural crops.
[01:02:13.940]So, again, identification as listed in the IPM Practice
[01:02:17.310]is really important for determining the relative risk
[01:02:20.180]of different insects in the system.
[01:02:22.640]So here's an example
[01:02:23.570]of some of those average moth traps or counts per night.
[01:02:27.760]Really we have a biofix on here that you can see
[01:02:30.180]that starts the counts for significant moth capture,
[01:02:33.700]and that's defined as eight or more over two nights.
[01:02:36.330]If we capture eight or more of those,
[01:02:37.530]we usually put this out on CropWatch.
[01:02:39.150]And then this click you see here
[01:02:40.570]are all these degree days start counting.
[01:02:43.750]By the time you get to the first to third instars,
[01:02:45.730]they start feeding on the leaves.
[01:02:47.217]That's so you can start scouting your fields and determining
[01:02:48.850]do I need to make some additional management practice
[01:02:51.400]for that particular field?
[01:02:53.440]They do this little bit of leaf damage.
[01:02:54.940]You can see here we've got those little holes
[01:02:56.990]in the leaves next to the knife.
[01:02:58.880]And then in some cases
[01:02:59.713]they're actually cutting the plants off
[01:03:00.770]and almost pulling them below ground.
[01:03:02.430]If you're getting three to 5% cuts,
[01:03:03.810]you're getting to a point
[01:03:04.643]where you may need some additional control.
[01:03:07.880]We look for wilted plants.
[01:03:09.660]You can dig.
[01:03:10.493]You won't find the larvae.
[01:03:11.590]This is another tricky thing with a lot of insects.
[01:03:13.660]You may see the damage; you may not see the insect.
[01:03:15.290]And that's part of their biology.
[01:03:17.040]They tend to hide.
[01:03:19.280]You may have to dig around the soil a bit
[01:03:20.640]or turn over soil clods to find these hanging around.
[01:03:24.440]They do cut.
[01:03:26.950]The number of plants they cut varies
[01:03:28.310]depending on the temperature, and this is really important
[01:03:30.183]when we're trying to make a management decision.
[01:03:32.650]In some cases at 80 degrees Fahrenheit,
[01:03:35.310]they only cut 2.3 plants in their life cycle,
[01:03:38.270]and that's 'cause corn is growing fast.
[01:03:40.020]The larger the corn gets, the more they have to eat.
[01:03:42.710]If we look at lower temperatures like 60 degrees Fahrenheit,
[01:03:44.960]they can cut up to 12 plants.
[01:03:46.690]That's quite a concern,
[01:03:47.630]because they can cut significantly more.
[01:03:49.470]So if you're finding these in the field
[01:03:50.700]and you're looking at the temperatures for the next 10 days
[01:03:52.980]and they're cool, I would take that into consideration
[01:03:55.350]when you consider the amount of damage
[01:03:57.170]that might be out there.
[01:03:59.690]We'll move on to stink bugs.
[01:04:00.870]This is only a pest of corn.
[01:04:02.240]So as we talk about stink bugs and soybeans,
[01:04:04.500]it's typically a late season pest.
[01:04:06.540]They only classify to this crop.
[01:04:08.130]We're kinda narrowing in on insects
[01:04:09.800]that are kind of almost specific to one crop
[01:04:11.640]at that time of the season.
[01:04:13.410]Stink bugs like grassy areas, woodland areas, cover crops,
[01:04:17.490]places where they can overwinter.
[01:04:18.740]They overwinter as adult, unlike a lot of the other insects
[01:04:21.030]that we've been discussing.
[01:04:22.720]But they can actually kill small plants.
[01:04:24.730]They do that because if we seed in wet conditions,
[01:04:27.080]you'll leave an open furrow.
[01:04:28.490]And they can get down in that furrow
[01:04:29.740]and feed on the growing point.
[01:04:30.810]And they inject an enzyme to digest the tissue,
[01:04:33.940]and that can result in the plant actually dying outright.
[01:04:36.820]In other cases, they just cause significant tillering
[01:04:39.270]of the plant which, as we know, isn't that helpful.
[01:04:43.160]Tillering plants don't produce.
[01:04:45.220]Those tillers often don't produce,
[01:04:46.800]and so these plants can become weeds in the field.
[01:04:49.720]But often what you're looking for
[01:04:50.950]and what I often see in the field
[01:04:52.550]is this repeated hole pattern.
[01:04:53.950]So you come out and you find this repeated holes
[01:04:56.150]all the way through the leaves,
[01:04:56.983]and that's a good indication
[01:04:57.850]you likely have stink bugs in your field.
[01:05:00.540]There is thresholds
[01:05:01.480]that were just recently published for this.
[01:05:03.310]So 5% damage with brown stink bugs present in the field
[01:05:07.420]can trigger an application, or greater than 10% infested
[01:05:10.960]with corn less than two feet tall.
[01:05:12.270]So two different thresholds that can be used,
[01:05:15.040]depending on the situation.
[01:05:17.680]We'll move on to common stalk borer.
[01:05:19.780]This is a native insect to the area.
[01:05:21.870]It does overwinter in ditches usually as small larvae,
[01:05:25.050]and they begin to develop in the spring.
[01:05:27.184]They're pretty easy to ID once they get older.
[01:05:28.430]This have this big purple band on them
[01:05:30.190]and this brownish white stripe
[01:05:31.530]as you can see here towards the back.
[01:05:33.620]They're about an inch and 1/2 when they're fully grown.
[01:05:37.170]These, unlike a lot
[01:05:38.003]of the other insects we've been discussing,
[01:05:39.520]lay their eggs in the fall.
[01:05:40.820]They overwinter as eggs.
[01:05:41.900]They hatch in the spring.
[01:05:42.830]They begin their development in the spring.
[01:05:44.230]And they also have a degree day system associated with them.
[01:05:46.727]And if you're familiar with corn,
[01:05:48.030]the base temperature for corn is 50.
[01:05:49.860]So these can actually develop
[01:05:50.970]at a lower temperature than corn.
[01:05:52.920]But essentially what we're interested is
[01:05:54.320]when do we start scouting?
[01:05:55.690]We could do that at 13 to 1,400 degree days.
[01:05:58.330]We usually publish this every year in CropWatch
[01:06:01.250]as a map of the state
[01:06:02.650]and where they're reaching their thresholds.
[01:06:04.460]And then the thresholds can be established depending
[01:06:06.180]on the development stages you see here,
[01:06:09.320]and assuming that the price and production.
[01:06:12.080]So you'll see that a lot of equations for insects,
[01:06:14.730]because it's not just getting control.
[01:06:16.140]We wanna make sure it's an economical decision
[01:06:17.870]that we're making.
[01:06:19.040]You can see as you get to later stages,
[01:06:20.330]it takes a lot more infestation
[01:06:22.320]to warrant any sort of pesticide treatment.
[01:06:25.560]Also a number of Bts available for this particular insect.
[01:06:29.710]Often these are the primary means
[01:06:31.390]of controlling some of these,
[01:06:32.410]but they can move large enough
[01:06:33.670]that they can actually overcome some of these Bt traits.
[01:06:36.970]So we're gonna switch to an insect
[01:06:38.730]that's specific to soybeans that's an early season pest,
[01:06:41.640]which is bean leaf beetle.
[01:06:42.920]I've got a number of bean leaf beetles put up here.
[01:06:44.600]They all look different in terms of color
[01:06:46.790]or they have no spots or the spots are actually,
[01:06:48.840]in the case of the one that's far over there,
[01:06:51.200]the two spots are joined together.
[01:06:53.110]But the center photo, the drawing,
[01:06:54.860]is what you really wanna look for,
[01:06:56.130]which is this triangle shape right behind the head.
[01:06:58.580]That's often an indication that it's bean leaf beetle,
[01:07:01.220]and all of these images that you see have that.
[01:07:04.440]These overwinter as adults as well.
[01:07:06.620]They are in leaf litter or residue, kinda like stink bugs.
[01:07:10.110]And they don't like warm winter,
[01:07:11.480]so often you'd think like us, we like warm winters.
[01:07:13.770]These insects do not like warm winters.
[01:07:15.480]That's because it increases their metabolism,
[01:07:17.640]reduces the fat reserves that they have,
[01:07:19.530]and they can actually starve to death
[01:07:20.690]before any plants emerge in the spring.
[01:07:22.850]They usually begin feeding on alfalfa in early spring,
[01:07:25.230]April, May, and then begin transitioning
[01:07:27.300]to soybeans later after the first cutting.
[01:07:32.040]Move to early planted soybeans.
[01:07:33.200]They damage the cotyledons.
[01:07:34.630]You can see one damaging a cotyledon here.
[01:07:36.560]Takes quite a bit of damage
[01:07:37.550]to really cause any significant yield loss.
[01:07:40.120]The adults live for quite awhile.
[01:07:41.300]They lay a lot of eggs, and they lay these eggs in the soil.
[01:07:43.500]And we get a lot of questions about,
[01:07:44.610]well, what damage could the larvae do?
[01:07:46.510]And as far as we're aware,
[01:07:47.840]they don't cause any significant losses.
[01:07:49.870]One of the primary concerns in the photo
[01:07:51.270]that you can see here is bean pod mottle virus.
[01:07:54.890]If this transmitted early enough,
[01:07:56.800]it can cause significant losses.
[01:07:58.740]But it has to be prior to V3
[01:08:00.370]to really cause any significant yield losses.
[01:08:04.120]Here are some of the thresholds for this insect
[01:08:05.850]based on the value of the crop.
[01:08:08.020]You can see the stage of development also affects that.
[01:08:12.110]But as the crop price increases or crop value increases,
[01:08:16.770]the threshold drops.
[01:08:17.840]The management crops increase,
[01:08:18.960]then the thresholds increase as well.
[01:08:21.410]And once you get to that V2 stage,
[01:08:23.190]then it takes 50% defoliation.
[01:08:25.510]We can't even see significant yield losses.
[01:08:27.810]So really it's these very early stages
[01:08:29.940]just after this crop emerges
[01:08:31.550]that you'd be concerned about an insect like this.
[01:08:35.740]One of the recommendations for this is
[01:08:37.240]to wait till mid-May to plant.
[01:08:38.730]That makes a lot of growers angry,
[01:08:40.300]'cause they don't wanna wait.
[01:08:41.280]They wanna get these crops in early.
[01:08:42.500]We know that after the first of May,
[01:08:44.750]yields begin to decline subsequently each day
[01:08:47.650]depending on how good the season is.
[01:08:50.483]But being the first planted
[01:08:52.220]in the area puts you at the highest risk,
[01:08:53.530]so having somebody else plant first in the area,
[01:08:55.650]that's likely the draw for those bean leaf beetles.
[01:08:58.450]This could also link back to subsequent populations,
[01:09:00.560]as they'll emerge in those fields as well.
[01:09:02.750]And seed treatments with early planting
[01:09:04.590]is a pretty good way of controlling this.
[01:09:05.890]We kinda have area-wide suppression of this insect
[01:09:08.450]using neonicotinoid seed treatments.
[01:09:10.870]So finally we're gonna transition to wheat.
[01:09:12.210]This is a pest specific to wheat, the Hessian fly.
[01:09:16.390]The adults deposit eggs on seedling wheat.
[01:09:18.370]The larvae suck on the plant sap causing stunting.
[01:09:21.140]The adults are very short-lived,
[01:09:22.230]and that's part of the management
[01:09:23.063]of this particular insect is to delay planting
[01:09:25.630]or to follow these planting guidelines
[01:09:27.630]for the different counties within the state of Nebraska.
[01:09:30.390]There also are some resistant varieties,
[01:09:32.098]Brule, Millennium, and Vista, that can be used,
[01:09:34.927]and some moderately resistant ones as well.
[01:09:37.600]If you look in the Extension articles,
[01:09:38.880]they have more details on these.
[01:09:41.140]Planting date by far the most effective way
[01:09:43.230]to manage this type of insect.
[01:09:45.860]Last one we'll focus on
[01:09:46.780]for wheat is the wheat-mite-virus complex.
[01:09:49.233]It's a particularly tricky complex.
[01:09:51.670]It's a combination of a mite
[01:09:53.410]that you see here that's quite small.
[01:09:55.050]You can fit 'em on an eyelash.
[01:09:57.420]They transmit three viruses in wheat,
[01:09:59.530]and it's a significant cause of loss
[01:10:01.140]and was a significant cause of loss
[01:10:04.990]in western Nebraska in the last couple years.
[01:10:08.930]What it does is the mites rapidly build in population
[01:10:11.140]as wheat begins to mature in the spring
[01:10:14.020]coming up to harvest.
[01:10:15.910]There's this green bridge period,
[01:10:17.260]and this is where all the management really comes in
[01:10:18.950]for this particular insect or this particular mite.
[01:10:22.100]It's controlling plants through that green bridge.
[01:10:24.360]They have to make it to fall planting here
[01:10:26.550]when we'll plant, say,
[01:10:27.500]in an adjacent field somewhere the wheat.
[01:10:29.560]So typically what happens is we get hail in these systems.
[01:10:32.740]This is kind of a combination
[01:10:34.440]of the animation you see here and then this image.
[01:10:37.770]So the two correspond with one another.
[01:10:39.320]So this pre-harvest volunteer wheat was generated
[01:10:41.640]by a hailstorm.
[01:10:43.420]And what they do is the mites move
[01:10:45.610]and infest that volunteer wheat.
[01:10:47.400]Basically, they build in population all summer long.
[01:10:50.130]And then this new crop,
[01:10:51.100]which is an adjacent wheat field
[01:10:52.483]that might be adjacent to this field,
[01:10:54.550]the one you see up here receiving the virus impact,
[01:10:57.090]that's what the mites move onto in the fall.
[01:10:59.730]So breaking this green bridge is really
[01:11:01.100]the most effective way to manage this particular insect,
[01:11:05.360]and it begins with the germination or mite.
[01:11:07.770]It begins with the germination of this volunteer wheat.
[01:11:12.060]Like I said, breaking the green bridge
[01:11:13.230]is the most important way to manage this.
[01:11:14.550]Breaking that 10 to 14 days prior to planting new wheat.
[01:11:17.530]There is resistant varieties.
[01:11:18.970]Unfortunately, they break down under high temperature.
[01:11:21.470]But if a grower was met
[01:11:22.460]with populations in adjacent fields and were concerned,
[01:11:26.420]they could plant, Mace is a way of doing that,
[01:11:28.950]or planting an alternative crop.
[01:11:30.047]And this is an example of Mace relative to Tomahawk,
[01:11:33.580]which is a highly susceptible variety.
[01:11:36.160]And next to one other screen, we set this up
[01:11:38.690]to show the potential difference between these.
[01:11:41.420]So now we're gonna focus on mid-season pests of crops.
[01:11:44.310]We're gonna start with European corn borer.
[01:11:46.450]And for those who have been around for awhile,
[01:11:48.460]they'd wonder why we ever talk about European corn borer.
[01:11:51.180]It's been relatively silent since 1996
[01:11:53.253]when all these different Bts came out
[01:11:55.720]and effectively controlled this insect on a wide area.
[01:11:59.070]But we do have more non-Bt acres going in,
[01:12:01.180]a lot of white corn and popcorn,
[01:12:02.910]and so these fields are at risk.
[01:12:05.540]We monitor for this insect using black light traps
[01:12:07.620]every year across the state.
[01:12:10.010]And it's pretty easy to ID.
[01:12:11.260]It has this serrated pattern on the bottom of its wings.
[01:12:15.070]The eggs are laid on the underside of the leaf.
[01:12:16.390]They kinda look like a fish scale.
[01:12:17.520]So if you're out there looking, you'll see this fish scale.
[01:12:19.160]And they turn black.
[01:12:20.050]That's the head capsules just prior to hatching.
[01:12:23.000]Two egg masses per night.
[01:12:24.400]They usually hatch about three to seven days.
[01:12:26.590]And once they hatch, they begin feeding.
[01:12:28.100]And they have these little holes
[01:12:29.710]and it's kinda like stink bug,
[01:12:30.760]except it's irregular patterns.
[01:12:32.500]So it's not straight across on the leaf,
[01:12:33.870]but there are just little shot-holes in different places.
[01:12:36.530]So that's the first thing I look for
[01:12:38.070]when I'm scouting for an insect like this.
[01:12:40.610]The development or cycle of this insect is really important,
[01:12:43.450]because it dictates when it might move into the plant.
[01:12:45.640]Once it's in the plant,
[01:12:46.870]there are no effective management practices
[01:12:48.540]that can be done for this.
[01:12:49.870]So with first generation,
[01:12:51.060]which we're gonna talk about in a second on scouting,
[01:12:53.600]they move in at the third instar.
[01:12:55.190]And there are sizes for each one of these.
[01:12:56.680]The relative size is an inch on this screen.
[01:12:59.360]But once they get to that third instar,
[01:13:00.840]they're gonna move into that plant.
[01:13:01.900]So if you're seeing third instar out there
[01:13:04.010]and you're at threshold,
[01:13:05.070]you need to make that decision really quickly,
[01:13:06.990]whereas later in the season it takes another stage
[01:13:09.170]of development before they can move into the plant.
[01:13:11.820]They complete two generations per year.
[01:13:14.240]And the thresholds differ on how we scout for them
[01:13:16.880]depending on the generation.
[01:13:17.940]So early season live larvae or damage on the plants,
[01:13:21.870]and then egg masses towards the later part of the season.
[01:13:24.970]There are a number of worksheets
[01:13:25.900]that we have available for this.
[01:13:27.950]So scouting for the moth flight,
[01:13:30.110]basically we track moth flights,
[01:13:32.060]so we'll tell you when that's occurring.
[01:13:33.340]It's usually in late June or early July.
[01:13:35.910]You can check the whorls for damage,
[01:13:37.240]looking for those pinholes or shot-holes, as I mentioned.
[01:13:39.180]There's the same photo.
[01:13:40.390]And you're recording the percentage of damaged plants
[01:13:42.730]and then pulling up those whorls
[01:13:44.000]and confirming whether or not they are present
[01:13:46.290]and recording the number of live larvae.
[01:13:49.060]And, again, those treatments should be made by third instar.
[01:13:51.430]If you're making it after that,
[01:13:52.590]the insecticide application is ineffective
[01:13:55.380]for something like this.
[01:13:57.850]Inverse to what we'll see later in the season,
[01:14:00.470]female moths are attracted to tall plants.
[01:14:02.030]So corn that's planted early
[01:14:03.670]and is taller than other corn in the area,
[01:14:05.460]if you're scouting multiple fields
[01:14:06.750]or looking at multiple fields, go to those fields first.
[01:14:09.210]Especially if they're non-Bt,
[01:14:10.300]they're likely to be the ones they first show up in.
[01:14:13.500]Scouting mouths in the second flight.
[01:14:15.590]It's about mid-July, a minimum of 50 plants.
[01:14:17.800]You're looking in the upper part of canopy now,
[01:14:19.470]so this is the egg-laying region on the plant.
[01:14:21.570]Looking at the undersides of the leaves,
[01:14:22.960]those scaly masses of eggs.
[01:14:26.670]What we assume is that we get three borers per egg mass.
[01:14:30.430]And if we have irrigated fields, it can get up to four.
[01:14:33.250]And there's a worksheet that actually accounts for that
[01:14:34.950]so you can determine the likelihood of significant damage.
[01:14:37.560]But what you're doing is you're making this decision
[01:14:39.220]based on scouting for those egg masses.
[01:14:43.460]The damage can be pretty significant,
[01:14:44.950]as you see in the photos here.
[01:14:45.783]Lots of lodging, because they tunnel into the stalk
[01:14:48.490]and ear shanks and ear tips.
[01:14:50.870]Obviously we can have ear drop
[01:14:52.280]as an issue on something like this,
[01:14:54.110]reduced grain production, stalk breakage.
[01:14:56.530]In addition to that, we can have these grain molds
[01:14:58.690]which decrease the quality of this grain.
[01:15:00.650]So if you're planting susceptible corn,
[01:15:03.810]popcorn, white corn, or non-Bts,
[01:15:05.830]this is one to scout for during the season.
[01:15:10.610]For mid-season pests, we also have western bean cutworm.
[01:15:12.790]This has been growing in importance.
[01:15:14.920]It's been relatively confined
[01:15:16.610]and kinda goes on a cyclic cycle every couple years.
[01:15:19.267]The last couple years it's been quite high.
[01:15:21.760]This is kind of its origin of population.
[01:15:23.420]It's been spreading up into Canada as well.
[01:15:27.270]It lays a lotta eggs.
[01:15:28.280]You can see it relative to scouting for European corn bore.
[01:15:31.910]They look quite a bit different.
[01:15:33.100]They're kind of all, in the case of European corn bore,
[01:15:35.280]connected together,
[01:15:36.400]whereas you can see individual eggs in this case.
[01:15:39.140]Five to 200 in an egg mass, top third of the plant.
[01:15:42.230]They're white, and depending on when you find them
[01:15:44.580]in the system, they can be a problem or not.
[01:15:47.720]Late whorl, prior to tassels emerging,
[01:15:49.870]they have less chance of survival.
[01:15:51.520]But if you're at tasseling,
[01:15:53.410]then this can be one that could be a significant problem.
[01:15:57.510]We have Extension Circulars for scouting
[01:15:59.180]to speed this scouting process up,
[01:16:00.610]because it is fairly labor-intensive.
[01:16:03.200]Five to 8% with 95% tasseled is kind of the trigger
[01:16:07.370]for this particular insect.
[01:16:08.840]So pay attention to stage of development
[01:16:11.150]when you're accounting for that threshold.
[01:16:13.130]Here's the different developmental stages of this insect.
[01:16:16.720]And it's that pattern behind their head
[01:16:19.410]that's most apparent.
[01:16:20.243]So this going from black to white to black,
[01:16:22.870]that's what I look for in this insect.
[01:16:24.140]No other real markings on its entire body,
[01:16:26.110]as you can see here.
[01:16:27.740]It's just kinda drab in color.
[01:16:29.710]So that's what I would look for.
[01:16:30.680]The earlier stages, as you see further over here,
[01:16:32.810]don't have that as apparent,
[01:16:34.140]so it can be harder to identify them when they're smaller.
[01:16:38.800]For soybeans we really focus on a whole complex of insects
[01:16:41.920]during the middle part of the season,
[01:16:43.120]and this extends into the reproductive stages.
[01:16:45.990]But we're looking at specific insects like bean leaf beetle.
[01:16:48.820]It shows up again.
[01:16:49.653]It can feed on pods.
[01:16:50.486]That's why we look at it as an individual and do counts.
[01:16:53.110]But there are a barrage of other insects,
[01:16:54.700]like blister beetles.
[01:16:56.300]We have imported longhorn weevil, grasshoppers.
[01:16:59.650]This is the spotted cucumber beetle.
[01:17:02.490]We have loopers in the system, yellow-striped armyworm,
[01:17:05.900]fall armyworm, corn earworm, and Japanese beetle.
[01:17:09.340]That's just to list a few.
[01:17:10.210]There are a lot in the system.
[01:17:11.810]So we consider all those different insects
[01:17:13.380]that are in the system.
[01:17:14.960]We generalize the threshold for these,
[01:17:16.610]'cause it's usually not any one insect in the system
[01:17:18.930]that's causing problems,
[01:17:20.300]but a combination of them in the system.
[01:17:22.750]And the last thing I'll note on these
[01:17:23.960]is they feed in different parts of the canopy,
[01:17:25.970]so it's important to know what you're dealing with to say,
[01:17:27.590]well, where should I continue to find this?
[01:17:29.680]Is it in the upper or lower part of the canopy?
[01:17:32.740]So when estimating insect defoliation, often overestimated.
[01:17:36.781]This particular infographic helps you
[01:17:39.820]kinda walk through that.
[01:17:41.120]You wanna remove leaves from the top, middle,
[01:17:43.460]and bottom of the plant.
[01:17:45.140]And then on that individual leaflet,
[01:17:46.610]you actually wanna remove the highest defoliated portion
[01:17:48.910]of those leaflets and the lowest and keep the middle one.
[01:17:51.620]We're looking for an average amount of defoliation.
[01:17:54.570]And it looks quite bad,
[01:17:55.740]so if you reference the bottom part of this photo
[01:17:58.180]where we get up to 50% here,
[01:18:00.470]50%, to the untrained eye, looks like 80 or 90% defoliated,
[01:18:04.260]so you kinda have to train your eye on something like this.
[01:18:06.880]You wanna repeat this on several plants.
[01:18:09.390]But really you're looking at a threshold of 20 to 30%.
[01:18:11.770]So vegetative stage, 30%, reproductive stage, 20%.
[01:18:17.670]You can see that the defoliation is pretty considerable
[01:18:20.010]for something like that.
[01:18:22.150]It's hard.
[01:18:23.400]Do some practice runs
[01:18:24.870]to gain a handle on something like this.
[01:18:26.880]We look at wheat.
[01:18:27.713]We look at Russian wheat aphid.
[01:18:28.920]This is one where we have to kinda backtrack to the fall.
[01:18:31.130]Winter wheat is planted in the fall.
[01:18:33.970]During the fall development stages,
[01:18:35.320]it can be quite important,
[01:18:37.820]but most important during the tillering stages.
[01:18:40.610]Feeds on newly emerging leaves.
[01:18:41.930]So once you have the head out, they will infest the head,
[01:18:43.740]but that's the biggest problem for them.
[01:18:46.210]And then this really highlights the need
[01:18:47.960]to scout for insects.
[01:18:49.680]There are lots of other examples like this.
[01:18:51.240]But lady beetles and other biological agents
[01:18:53.620]keep these things in check.
[01:18:54.660]So if we're spraying early for something like this,
[01:18:56.750]we can eliminate the beneficials
[01:18:58.530]and then these can get out of hand.
[01:19:00.290]So as I mentioned, those fall thresholds.
[01:19:01.820]Actually, it's just a standard threshold.
[01:19:03.130]10 to 20% infested plants.
[01:19:05.840]As we move into the spring prior to heading,
[01:19:07.820]this is the symptoms we're gonna see on the plant,
[01:19:09.400]which is these white stripes going down the leaf.
[01:19:12.930]But if we're doing infested tillers, and it varies.
[01:19:16.150]This infested tiller percentage or number
[01:19:18.390]for threshold varies depending on the control costs.
[01:19:20.900]We have this constant factors of 200,
[01:19:23.060]a market value, and an expected yield.
[01:19:24.730]So these are the best thresholds,
[01:19:26.090]because it really tunes in to the operation
[01:19:28.610]for that particular year.
[01:19:31.300]We look at stink bugs later in the season for corn.
[01:19:33.470]They show up again.
[01:19:34.303]They're a problem for corn, as I mentioned earlier
[01:19:36.230]when we were talking about early season pests.
[01:19:37.540]They're a problem all year long.
[01:19:39.620]These highlight the two time points during the season
[01:19:41.187]why they can really cause significant economic losses.
[01:19:44.160]So here they are in the system again.
[01:19:46.020]They've laid eggs, they're developing as adults.
[01:19:49.200]At this point in the season,
[01:19:50.200]they're really causing aborted kernels or banana ears.
[01:19:52.440]So here's a banana ear,
[01:19:53.520]and here's some of these aborted kernels
[01:19:54.960]depending on the time of infestation.
[01:19:56.810]So there are two thresholds,
[01:19:58.090]and they vary depending on where we are in development.
[01:20:00.240]So when the ear is forming to pollen shed,
[01:20:02.690]the threshold is lower.
[01:20:03.610]One stink bug in every two plants.
[01:20:05.570]Or as we get past pollen shed and into blister,
[01:20:07.680]we're one stink bug for every four plants.
[01:20:09.990]So this is one to watch for.
[01:20:13.690]There are stink bugs and soybeans
[01:20:15.040]at this time of the year as well.
[01:20:16.870]The species do vary.
[01:20:17.760]I have green stink bug listed up here.
[01:20:19.360]There's redbanded.
[01:20:20.350]There's actually 21 species in the state that we can find.
[01:20:24.240]But they cause seed and pod damage, delayed maturity.
[01:20:27.370]And depending if it's an early pod development,
[01:20:29.640]they can cause this Stay-Green syndrome
[01:20:31.630]where the pods don't actually mature,
[01:20:33.247]and it can cause problems with harvest.
[01:20:35.870]Two different thresholds here,
[01:20:36.790]depending if you have a sweep net or not.
[01:20:37.923]5% of plants exhibiting symptoms.
[01:20:40.100]And then the last one here is the 10 stink bugs
[01:20:41.927]and 25 sweeps.
[01:20:43.770]So a sweep net, as you can see,
[01:20:45.040]is a really good resource to have in the field.
[01:20:47.530]I was talking about all those defoliators earlier.
[01:20:49.440]Having that sweep net out there can tell you
[01:20:52.100]all the different defoliators you might not pick up
[01:20:54.230]if you're just looking with your eye.
[01:20:57.070]I put this up because I tend to,
[01:20:58.860]after talking about stink bugs for awhile,
[01:21:00.200]everybody assumes that every stink bug's a problem.
[01:21:03.010]So this is simply to show you they're not.
[01:21:04.880]One of these is actually a beneficial stink bug.
[01:21:07.530]This is the spined soldier stink bug.
[01:21:09.890]It has this broad stylet relative to the brown stink bug
[01:21:12.610]which you can see here which has a fairly narrow stylet.
[01:21:15.336]The antennae are slightly different too.
[01:21:17.030]You kinda have this restricted pattern here
[01:21:19.330]for the brown stink bug.
[01:21:20.420]So pest, and beneficial insect on the far side.
[01:21:23.150]So not every stink bug's a pest.
[01:21:24.810]When you're out in the field looking for these,
[01:21:27.010]make sure you're actually looking at a pest.
[01:21:28.920]You often see these feeling on loopers
[01:21:31.010]and other insects in the field
[01:21:32.920]for the spined soldier stink bug.
[01:21:35.480]Soybean aphids can be a problem year to year.
[01:21:37.670]Typically show up later in the season.
[01:21:39.080]So these are the late season pest of soybeans.
[01:21:41.770]They originate up in Minnesota and then usually move down.
[01:21:44.513]They're looking, they have an overwintering host,
[01:21:46.840]which we don't have a lot of in Nebraska.
[01:21:48.990]But the yield losses can be really significant, 15 to 40%.
[01:21:52.240]And the great part for ID is they're the only colony
[01:21:54.300]forming aphid in Nebraska soybeans, so that helps us.
[01:21:58.160]We don't have to worry
[01:21:58.993]about anything else complicating the system.
[01:22:00.550]So you see large numbers of something
[01:22:02.037]and it looks even remotely similar to this,
[01:22:04.140]it's probably soybean aphids.
[01:22:06.570]So as I mentioned,
[01:22:07.403]they have limited overwintering sites in Nebraska.
[01:22:10.610]They typically start up in the northeastern part
[01:22:12.400]of the state and move down.
[01:22:14.320]And they have to start on buckthorn.
[01:22:15.610]That's their overwintering source.
[01:22:17.250]So you can see that, that's the Rhamnus,
[01:22:19.640]usually catharticas or other species
[01:22:21.900]that they overwinter on.
[01:22:23.810]And then they'll move onto soybeans,
[01:22:25.097]and they can rapidly reproduce on soybeans.
[01:22:27.400]15 generations, even arriving in mid to late August.
[01:22:31.220]But they have this lower optimum temperature,
[01:22:33.400]so when we have a cooler season,
[01:22:34.480]they do better under that cooler temperature.
[01:22:37.710]So this is one to watch for.
[01:22:39.410]This is an example from Tom Hunt
[01:22:42.360]on when the populations typically show up.
[01:22:44.740]They're showing up back here in late July, early August,
[01:22:48.530]and then they're building in population by August.
[01:22:50.330]So most of our treatments are occurring
[01:22:51.810]in mid to late August here
[01:22:53.650]when they get up into those peak numbers.
[01:22:55.730]We're talking numbers in the thousands here,
[01:22:57.940]so this is quite a bit of aphids per plant.
[01:23:01.710]I think this bothers a lot of people,
[01:23:03.040]because they assume at that high a number,
[01:23:04.620]they're getting significant losses.
[01:23:05.840]But the threshold for these for conventional scouting
[01:23:07.840]is actually 250 aphids per plant.
[01:23:10.780]And they're economically damaging,
[01:23:12.150]as I mentioned, in the northeast.
[01:23:13.600]But we really have to be careful in spraying this.
[01:23:15.890]We don't wanna be spraying below thresholds,
[01:23:18.020]because as these populations increase,
[01:23:19.640]there are a lot of beneficial insects in this system
[01:23:21.520]that can knock those populations down,
[01:23:23.590]preventing any economic losses.
[01:23:25.530]I think the 250 is hard for people to count,
[01:23:27.520]so we have a Speed Scouting binomial sampling plan,
[01:23:30.540]a yes/no based on a certain number,
[01:23:32.450]which I'll go through here now.
[01:23:34.540]So this Speed Scouting app,
[01:23:35.520]you can download it on your phone.
[01:23:37.730]Basically, it's infested or uninfested plants,
[01:23:39.730]rather than counting 250 aphids.
[01:23:42.310]It has you go through a sampling plan
[01:23:44.170]of 11 different samples in the field,
[01:23:46.820]and then it tells you based on
[01:23:48.650]how many of those are infested
[01:23:49.800]whether or not you need to sample more plants.
[01:23:51.890]And if by chance you do reach a threshold,
[01:23:53.540]it tells you to revisit that field,
[01:23:54.980]'cause if you just reach that threshold,
[01:23:56.410]there's possible there's beneficial insects out there.
[01:23:58.940]So you can treat and then confirm in three to four days
[01:24:03.100]to confirm that.
[01:24:04.530]There's a non-app version of this
[01:24:07.300]that's done on an Excel sheet, and you can download this
[01:24:09.540]from the EC that's listed on there.
[01:24:11.870]It provides you another way
[01:24:13.360]of scouting for this particular insect.
[01:24:16.620]We look back at wheat.
[01:24:17.870]Wheat, we have a wheat head armyworm.
[01:24:20.100]We find these every year, usually in our black light traps.
[01:24:23.580]They feed on developing kernels, as you can see here.
[01:24:26.080]They're really easy to catch with a sweep net sample
[01:24:28.660]or a sweep net.
[01:24:29.960]And the infestation are usually
[01:24:31.190]on the borders of the field,
[01:24:32.130]so as soon as you walk on the field,
[01:24:33.319]that's when you wanna start looking for this.
[01:24:34.947]And they're really difficult to control
[01:24:36.300]because we're so close to harvest.
[01:24:37.520]So with any insecticide that you're applying
[01:24:40.200]or any pesticide,
[01:24:41.033]you gotta watch those pre-harvest intervals
[01:24:42.920]and make sure you're not getting to a point
[01:24:44.870]where you might have problems
[01:24:46.450]with being able to harvest that crop.
[01:24:49.330]Wheat stem sawfly is another insect
[01:24:51.570]that can show up during this time,
[01:24:53.130]or at least the symptoms of it show up.
[01:24:55.200]It feeds within the stem as a larvae.
[01:24:58.220]It cuts the stem close to harvest,
[01:25:00.770]and so often we have a lot of standing wheat.
[01:25:02.490]And usually what I do is if I'm walking a wheat field,
[01:25:05.020]as I walk it and then I come out
[01:25:06.040]and I look down at my legs.
[01:25:07.020]And if I've got wheat wrapped around my legs,
[01:25:09.580]good chance there's gonna be
[01:25:11.860]some wheat stem sawfly out there.
[01:25:13.550]It's most abundant in no-till wheat.
[01:25:15.070]They do fairly well overwintering in that.
[01:25:17.867]And they usually are infesting adjacent fields
[01:25:20.550]with a wheat-fallow rotation.
[01:25:23.450]So one of the only good control options
[01:25:25.190]for this particular insect is resistant varieties.
[01:25:28.430]This is not one you wanna be spraying for.
[01:25:31.530]So to summarize, scouting is a fundamental component
[01:25:34.923]of an IPM program.
[01:25:36.820]As you can see here,
[01:25:37.653]without scouting for a lot of these insects,
[01:25:39.090]we would end up doing maybe calendar applications.
[01:25:41.410]Those are not beneficial,
[01:25:42.670]'cause we can have a lot of problems show up in the system.
[01:25:45.260]Applying an insecticide only when necessary,
[01:25:47.740]avoiding pest resurgence of the pest that was the target.
[01:25:50.740]But then also other pests.
[01:25:52.510]We have spider mites and other things
[01:25:53.750]that reproduce very quickly
[01:25:55.760]if their natural enemies are taken out.
[01:25:58.070]So we wanna make those decisions
[01:25:59.210]based on a lot of different considerations.
[01:26:01.860]When an action is taken, timing is a critical component.
[01:26:04.870]We talked a lot of different insects,
[01:26:06.290]western bean cutworm and others,
[01:26:08.040]where you've gotta get out there at the right time
[01:26:11.580]or essentially that practice doesn't have much value.
[01:26:15.770]Pest presence in the system doesn't mean yield loss.
[01:26:17.920]So we talked about a lot of insects
[01:26:19.130]can be very high numbers in these systems.
[01:26:21.170]It doesn't mean a significant yield loss will occur
[01:26:23.440]or the pesticide application will warrant any return.
[01:26:27.800]And then pest biology
[01:26:28.770]to estimate those future risks or losses.
[01:26:31.750]So we understand the pest biology,
[01:26:33.710]especially in the case of white grubs
[01:26:35.510]right at the start of this presentation.
[01:26:37.360]Whether it's an annual white grub,
[01:26:39.290]which is not really a problem, because it feeds in the fall,
[01:26:41.720]versus a three-year grub which feeds for multiple years.
[01:26:45.500]Those biologies are different.
[01:26:48.670]Ecologies in the system can really dictate the amount
[01:26:50.630]of risk or loss.
[01:26:52.460]Thank you for your time.
[01:26:53.505](bright music)
[01:27:01.970]Hi, my name is Tamra Jackson-Ziems,
[01:27:04.050]and I'm an Extension Plant Pathologist
[01:27:05.880]for Nebraska Extension.
[01:27:07.520]And today I wanna talk to you
[01:27:08.960]about Fungicides are for Fungi.
[01:27:11.550]And the presentation that I'm gonna share for you now
[01:27:14.920]was actually a collaborative effort
[01:27:16.520]with our Extension Plant Pathology team.
[01:27:18.490]That includes my coauthors that are on the screen here.
[01:27:23.260]Unfortunately, there are a lot of different diseases
[01:27:26.080]that can look a lot like diseases that are caused by fungi.
[01:27:30.630]It's important for us today when we talk about this
[01:27:33.260]for you to know and understand that it's important to know
[01:27:36.610]which diseases are caused by fungi
[01:27:38.840]or bacteria or other things
[01:27:40.550]and which of those fungal diseases
[01:27:42.600]can be controlled effectively by our fungicides.
[01:27:47.130]Some of the most important diseases that we deal with
[01:27:49.870]on crops here in Nebraska are caused by a bacteria.
[01:27:53.320]And unfortunately many of them have very similar symptoms
[01:27:56.410]that look identical to those caused by fungi.
[01:27:59.810]We're gonna talk today
[01:28:00.643]about how to accurately diagnose those diseases
[01:28:03.130]and tell them apart from the ones that look a lot like them,
[01:28:06.280]like the one on the screen right now.
[01:28:09.950]Moving forward, let's start with corn,
[01:28:12.160]because that's probably gonna be our most important crop
[01:28:14.470]in Nebraska and maybe the most common one
[01:28:16.630]that you're gonna work with too.
[01:28:18.300]And there's a number of diseases on corn,
[01:28:20.880]some of them that we do use foliar fungicides to control.
[01:28:24.570]But this one that I wanna share
[01:28:25.930]with you right now is bacterial leaf streak.
[01:28:28.150]And bacterial leaf streak is a newer disease to us.
[01:28:32.910]We only just confirmed this disease in 2016, actually.
[01:28:37.300]And that was the first time it'd been reported in Nebraska,
[01:28:39.930]so it's still relatively new to all of us.
[01:28:43.410]As I move forward, be sure and take a look
[01:28:45.310]at all the pictures that we've got on the screen
[01:28:47.800]and familiarize yourself with that disease
[01:28:50.640]and know that this disease is common
[01:28:54.230]in some parts of the state,
[01:28:55.890]but it also can look very much
[01:28:57.450]like another important disease that we have.
[01:29:00.340]We know that this disease is in South Africa,
[01:29:02.720]it's in Argentina,
[01:29:03.740]but it's also quite widespread here in Nebraska too.
[01:29:08.330]For instance, one of my students, Terra Hartman,
[01:29:11.130]is conducting her master's research project,
[01:29:13.650]and as part of that research she has learned
[01:29:16.730]and her survey funded by the Nebraska Corn Board,
[01:29:19.710]we know now that this disease is in
[01:29:22.270]at least 60 of the 93 Nebraska counties,
[01:29:26.700]and so it is quite widespread across the state.
[01:29:29.850]That doesn't mean every county is affected,
[01:29:32.380]and that doesn't mean that the ones
[01:29:33.870]that are not highlighted in red
[01:29:35.430]don't necessarily have disease either.
[01:29:38.040]You just need to be mindful
[01:29:39.460]that there are diseases out there
[01:29:41.470]and that we're still learning
[01:29:42.730]about their distribution in the state
[01:29:44.500]and where those might be and what effects they may have.
[01:29:52.200]When we look at the symptoms
[01:29:53.940]that a disease like bacterial leaf streak causes,
[01:29:57.140]the symptoms are long, narrow streaks
[01:29:59.370]that are between the veins of a corn plant.
[01:30:01.900]Well, those are the same characteristics
[01:30:03.530]of gray leaf spot too, the fungal disease that's
[01:30:06.100]in almost the entire state of Nebraska.
[01:30:08.940]And since these diseases can look very similar,
[01:30:11.870]it's critical that you're able to tell them apart
[01:30:14.790]or can at least get help diagnosing it if it's not,
[01:30:18.250]because a foliar fungicide application is not expected
[01:30:21.780]to control bacterial leaf streak.
[01:30:24.610]That's something that we don't wanna make
[01:30:26.150]a misidentification about.
[01:30:28.660]Look closely at some of these pictures again,
[01:30:30.740]like the one we have on the screen.
[01:30:32.420]That looks very similar to gray leaf spot,
[01:30:34.340]but in fact it is bacterial leaf streak.
[01:30:37.870]In the summary table that we have here,
[01:30:40.260]these are just some of the characteristics
[01:30:42.370]that you can look for and some of the weather conditions
[01:30:45.000]that you might expect to favor one or both diseases.
[01:30:49.720]In particular when you look at this,
[01:30:51.600]we talk about bacterial leaf streak in this column,
[01:30:55.060]gray leaf spot in the far right hand column,
[01:30:57.250]and then we're talking about
[01:30:58.960]on the left hand side the other characteristics.
[01:31:03.780]One of the things that's most important
[01:31:05.700]for identifying bacterial leaf streak
[01:31:07.860]and gray leaf spot and telling them apart is
[01:31:10.180]to keep in mind when these diseases normally develop.
[01:31:13.840]Well, we've seen bacterial leaf streak develop
[01:31:16.160]very early in the season,
[01:31:17.660]as early as June during the seedling stages.
[01:31:20.940]That is something that does not happen routinely
[01:31:23.410]for gray leaf spot,
[01:31:25.080]because the fungus that causes gray leaf spot
[01:31:27.400]in contrast needs warm conditions and very humid conditions.
[01:31:32.010]Those aren't conditions we usually have
[01:31:33.720]during the early part of the season,
[01:31:35.460]and that's why you should doubt that it's gray leaf spot
[01:31:38.360]if you see bacterial leaf streak type symptoms lower
[01:31:42.390]on the plant that may look like rectangles.
[01:31:46.619]You should question that
[01:31:47.452]and possibly submit a sample for identification.
[01:31:50.810]In addition, the types of weather that favor both diseases.
[01:31:54.830]Wet weather certainly does favor both,
[01:31:56.880]but we know now that has a big impact
[01:31:59.120]on when these diseases develop.
[01:32:01.750]There are some other characteristics, though,
[01:32:03.510]that I'm gonna ask you to look very closely
[01:32:05.530]at the lesions when you see them
[01:32:07.260]and look at some very subtle differences between them,
[01:32:09.950]much closer than we have in the past, in fact.
[01:32:13.130]In particular, I want you to look at the lesion margins,
[01:32:15.650]the edges of those lesions.
[01:32:17.900]And it's very common, for instance,
[01:32:20.030]for a gray leaf spot to have clear, rectangular margins,
[01:32:25.100]lesion shapes, and those edges are very smooth,
[01:32:28.090]linear, and very simple.
[01:32:29.710]Well, in contrast, the ones caused by bacterial leaf streak
[01:32:34.160]are often very irregular and the margins can be very wavy.
[01:32:39.100]That's common for bacterial lesions in general,
[01:32:41.620]but you're gonna have to look very closely
[01:32:43.240]to tell these apart for bacterial leaf streak.
[01:32:46.470]And finally, we often see bright yellow discoloration
[01:32:50.090]caused by a bacterial leaf streak too.
[01:32:53.060]That's something else that you can look for.
[01:32:55.080]But you can't necessarily rely on that characteristic,
[01:32:58.080]because some hybrids or even some seed corn inbreds
[01:33:02.090]may actually react a bit differently.
[01:33:04.160]And even lesions caused by gray leaf spot
[01:33:06.740]may have a yellow halo around them.
[01:33:09.790]Let's look at some pictures
[01:33:10.870]to try to differentiate some of these.
[01:33:13.590]We've got bacterial leaf streak on the left.
[01:33:16.210]We've got gray leaf spot here on the right.
[01:33:19.110]In particular, look at gray leaf spot
[01:33:20.890]and look at some of these pictures
[01:33:22.450]and the clear rectangular shape that some of these have.
[01:33:26.650]Well, this fungus can't cross the veins of a corn plant.
[01:33:30.350]And since these veins are gonna be parallel,
[01:33:32.920]these lesions take on that characteristic rectangular shape
[01:33:36.580]and often the ends of them look squared off
[01:33:39.040]or a little bit blocky,
[01:33:41.260]sometimes, like this one, with a little yellow around it.
[01:33:44.430]That rectangular shape is maybe even more clear
[01:33:46.860]on this other picture or the one at the bottom.
[01:33:49.590]Those are textbook classic gray leaf spot lesions,
[01:33:52.750]the fungal disease.
[01:33:54.290]Well, in contrast, bacterial leaf streak lesions,
[01:33:57.350]if you look very closely, do look different.
[01:33:59.970]And instead of being a perfect rectangle,
[01:34:02.350]many of these lesions actually have that wavy edge
[01:34:06.000]that I was talking about earlier.
[01:34:09.030]For you to see that
[01:34:10.360]and to be comfortable identifying that characteristic,
[01:34:13.160]you're probably gonna have to look
[01:34:14.580]at a lot of different lesions and leaves.
[01:34:17.040]The important thing here, though,
[01:34:18.350]is that if ever you have any difficulty
[01:34:20.600]telling these diseases apart
[01:34:22.090]or identifying any other diseases,
[01:34:23.780]you have a lot of resources and people
[01:34:25.680]out there available to help you,
[01:34:27.450]like the Plant and Pest Diagnostic Clinic
[01:34:29.440]where you can submit samples for identification.
[01:34:33.720]In addition, those two diseases are not the only ones
[01:34:36.730]in corn that are hard to tell apart.
[01:34:39.460]A couple of others, common diseases
[01:34:41.410]like Goss's bacterial wilt and blight
[01:34:44.450]and northern corn leaf blight.
[01:34:47.230]Well, northern corn leaf blight is caused by a fungus,
[01:34:50.190]and these diseases behave somewhat differently,
[01:34:53.040]but they also do look somewhat different too.
[01:34:55.670]I hope that you'll become comfortable with that as well.
[01:34:58.890]As far as distribution goes,
[01:35:00.710]Goss's bacterial wilt and blight is almost statewide
[01:35:03.760]here in Nebraska.
[01:35:05.240]Well, in contrast, northern corn leaf blight
[01:35:07.410]has only developed in about the eastern half of Nebraska,
[01:35:11.470]especially in the northern and northeastmost counties
[01:35:14.410]where it's been most severe in recent years.
[01:35:17.470]But one thing we need to keep in mind is
[01:35:19.680]that the weather conditions
[01:35:23.037]that do favor northern corn leaf blight are cool and wet,
[01:35:27.590]and so we often see this disease in a cool, wet spring.
[01:35:31.050]And you might even see it in seedling corn.
[01:35:34.070]Well, that's also the case for Goss's wilt,
[01:35:36.880]although it is favored more by warmer weather.
[01:35:40.180]The other important part about Goss's,
[01:35:42.210]what you should understand,
[01:35:43.220]is that that disease very commonly develops
[01:35:46.000]after a hail event or some other wounding event.
[01:35:50.393]You will often see damage to the leaves
[01:35:52.350]and lesions starting along there.
[01:35:55.530]Remember that that bacterium can take advantage
[01:35:57.670]of those wounds, but it doesn't necessarily require them.
[01:36:01.390]There are some subtle differences
[01:36:02.780]between those lesions as well.
[01:36:05.710]Maybe those are things that we'll save for the next slide
[01:36:08.610]where we've got more photos to share.
[01:36:11.440]Here we have northern corn leaf blight lesions.
[01:36:15.270]We refer to these as being more elliptical or cigar-shaped
[01:36:19.330]because they do have rounded ends on there.
[01:36:22.600]And they're pretty regularly shaped,
[01:36:24.590]often with that margin around the edges.
[01:36:27.440]Sometimes you'll have multiple lesions on there.
[01:36:30.530]Well, in some cases you may notice
[01:36:32.660]that the middle of those lesions
[01:36:34.600]look a little bit dirtier, darker, or dusty.
[01:36:37.470]And it may even rub off on your fingers.
[01:36:40.000]That's common for this fungal disease,
[01:36:41.840]and that's actually the spores of that fungus
[01:36:44.300]that help it reproduce.
[01:36:45.300]They splash and blow around
[01:36:47.040]and they cause infection on other leaves.
[01:36:49.470]Well, in contrast, if you look at those lesions caused
[01:36:52.480]by Goss's bacterial wilt and blight,
[01:36:55.500]they are also quite large sometimes,
[01:36:58.250]but they look a little bit messier,
[01:37:00.150]a little more irregular in shape, for example.
[01:37:03.690]They can be jagged and have wavy edges,
[01:37:06.880]and the color is much less uniform,
[01:37:09.300]because we often have a symptom we call freckling
[01:37:12.460]on the edges, and that's very common with that disease.
[01:37:16.290]Goss's wilt is the only disease, in fact,
[01:37:18.400]that we know of that causes those dark green
[01:37:20.420]to black freckles on the edges of lesions.
[01:37:23.690]If you find those freckles
[01:37:25.260]and in particular if you also find shiny bacterial exudate
[01:37:29.650]or ooze on the surface, the top or the bottom side,
[01:37:33.300]you can bet that that probably
[01:37:34.930]is Goss's bacterial wilt and blight instead,
[01:37:37.720]which cannot be controlled by a foliar fungicide
[01:37:41.140]like we might use instead on northern corn leaf blight.
[01:37:47.040]In corn, we also use fungicides quite routinely
[01:37:51.200]in some areas, and it's important for you to understand
[01:37:54.440]what some of the effects might be
[01:37:55.860]and what some of the risks might be as well.
[01:37:59.260]For example, in some of our research trials,
[01:38:01.390]we are trying to show efficacy
[01:38:03.530]and how well foliar fungicides control diseases in corn,
[01:38:07.000]in particular usually gray leaf spot.
[01:38:10.140]There are other characteristics you might be looking for,
[01:38:12.590]and you may have heard about things
[01:38:14.140]like the plant health effects
[01:38:16.030]that some fungicides may provide.
[01:38:19.130]I wanted to talk about that a little bit
[01:38:20.720]and the results from some of our research that we did.
[01:38:23.970]Most of these trials that I'm gonna share
[01:38:25.610]with you were conducted at the South Central Ag Lab
[01:38:27.970]near Clay Center, Nebraska.
[01:38:30.180]So we made these applications with a ground rig,
[01:38:33.370]a customized sprayer like you see here in the photo.
[01:38:37.650]But in the photo, or in the following graphs,
[01:38:41.490]you're also gonna notice some of the treatments
[01:38:43.660]and the treatment effects.
[01:38:45.237]But let me help you interpret what these are.
[01:38:48.310]In this particular graph, what we're showing are yield data
[01:38:52.270]and yield responses to some of these treatments.
[01:38:55.580]In particular on the far left hand side,
[01:38:58.040]these are the yield data on the left hand side.
[01:39:01.870]And in particular, the farthest left treatment
[01:39:04.790]is the non-treated control.
[01:39:07.380]You can compare that versus all of the other treatments
[01:39:10.410]that we've got on here.
[01:39:13.210]In 2009, years ago,
[01:39:15.200]you'll notice we had tremendous improvements
[01:39:17.900]in yield and impacts.
[01:39:19.690]That was because in 2009 we had a lot of disease.
[01:39:23.300]There was a lot of gray leaf spot in particular
[01:39:25.440]in those trials, so it's not surprising
[01:39:28.520]that we had a lot of good benefits
[01:39:31.990]from foliar fungicide use.
[01:39:34.290]All of these treatments in particular were applied at VT
[01:39:37.680]or tassel emergence,
[01:39:39.950]which is a common application timing during our season.
[01:39:45.810]Well, that's not a surprise
[01:39:47.890]to see benefits from a fungicide
[01:39:49.880]when we have a lot of fungal disease,
[01:39:51.810]and that makes it important to scout those crops
[01:39:54.570]and know which diseases are out there.
[01:39:57.230]The other things that we wanna talk about are some
[01:39:59.340]of the plant health effects.
[01:40:01.250]You might notice in 2010, the very next year
[01:40:04.340]when we look at the yield differences
[01:40:06.320]and the yield effects, we did not see yield benefits
[01:40:10.890]from the same treatments that we used the year before.
[01:40:15.330]What you're not seeing here,
[01:40:16.510]you're not seeing letters above these treatment bars
[01:40:20.290]indicating that they are statistically different.
[01:40:23.900]The differences that you see were inconsistent
[01:40:26.420]across the experiment.
[01:40:28.867]In 2010, we can explain that
[01:40:30.730]because we didn't have very much disease
[01:40:32.850]because weather conditions were not favorable that year.
[01:40:36.710]It's not surprising that we might not see that.
[01:40:39.770]Well, in other years, we had other effects too.
[01:40:43.410]And in fact, we measure a lot of different effects
[01:40:46.350]throughout that experiment, not just yield.
[01:40:49.150]We follow disease development.
[01:40:50.720]We also take measurements at the end of the season
[01:40:53.640]to estimate standability or stalk strength.
[01:40:57.450]And that's what this data set represents.
[01:41:00.380]On the far left hand side,
[01:41:02.040]you see what we're calling push lodging ratings.
[01:41:05.360]That means that's the percentage of plants
[01:41:07.500]that fell over with pressure
[01:41:09.300]as we walked through the field
[01:41:10.910]and we pushed on all of the plants
[01:41:12.700]and counted the ones the snapped back upright,
[01:41:15.600]versus the ones that lodged.
[01:41:17.860]So this represents what might happen
[01:41:20.300]in the fall right before harvest
[01:41:22.670]if we have a wind event.
[01:41:24.940]Well, it was exciting for us to see
[01:41:26.880]that in many of the trials that we've conducted
[01:41:29.520]that foliar fungicides actually did
[01:41:31.690]help improve standability.
[01:41:34.570]For instance, you'll see as many as 45%
[01:41:37.790]of those plants lodged
[01:41:39.310]that did not get treated with a fungicide.
[01:41:41.890]And we were able to improve standability.
[01:41:44.930]We cut lodging in half in many of these treatments.
[01:41:48.870]That was very exciting,
[01:41:49.930]and that probably does demonstrate some
[01:41:52.790]of the plant health benefits
[01:41:54.150]that people have been discussing.
[01:41:56.470]However, this effect does not occur every year,
[01:41:59.380]and it's important to understand not even
[01:42:01.210]in every hybrid or field.
[01:42:03.350]There are other effects that you should look for.
[01:42:05.600]Another example would be what we did in 2012.
[01:42:08.950]Now, you may remember in 2012, we had a tremendous drought.
[01:42:13.280]We had very hot weather.
[01:42:15.150]Conditions were not favorable at all
[01:42:17.270]for foliar diseases like gray leaf spot,
[01:42:19.800]and so we had almost no disease out there.
[01:42:23.110]It may not surprise you to see
[01:42:24.980]that we didn't see a lot of yield benefits
[01:42:27.300]or differences between the non-treated control
[01:42:31.080]or any of the other treatments.
[01:42:33.000]You don't see statistical letters
[01:42:34.800]up above there, for instance.
[01:42:37.020]But in spite of the fact
[01:42:38.270]that we didn't see yield differences in that year,
[01:42:40.880]we did see improvements in standability again.
[01:42:45.210]You'll notice that 23% of those plants lodged
[01:42:48.330]with some pressure.
[01:42:49.750]However, when you look at the other data,
[01:42:52.920]you'll notice we had tremendous improvements
[01:42:55.150]in standability, reductions in lodging.
[01:42:59.600]That was also exciting to see.
[01:43:02.910]Again, this effect has not occurred for us every year
[01:43:06.840]or even in every field or every hybrid.
[01:43:08.740]It depends a lot on disease severity and other factors
[01:43:12.640]that we don't fully understand yet.
[01:43:14.890]But when you take all of our experiments,
[01:43:17.200]our foliar fungicide trials
[01:43:18.770]from that location across the years,
[01:43:21.200]from 2009 all the way through 2016,
[01:43:25.630]and you start looking at how many
[01:43:27.610]of those trials experience differences
[01:43:29.550]in push lodging ratings or in yield,
[01:43:32.070]it starts to tell a story
[01:43:33.440]about how commonly you might expect to see this occur.
[01:43:37.986]In the second column, you'll see that's the total number
[01:43:40.700]of fungicide trials that we conducted
[01:43:43.500]during that particular year.
[01:43:45.660]And you'll see in the third column,
[01:43:48.980]the number of those trials that had significant differences
[01:43:52.470]in push lodging or what we would call standability,
[01:43:55.580]likewise in those same trials,
[01:43:58.300]the number of ones where we had differences in yield.
[01:44:01.530]For example, looking at 2009,
[01:44:05.610]only five out of 12 did we see
[01:44:08.440]the improvements in standability.
[01:44:10.940]Likewise, though, we had a few others
[01:44:13.460]that were pretty low too,
[01:44:14.530]but there were examples of ones
[01:44:16.040]that had much higher incidence, eight out of 13
[01:44:19.260]or even eight out of 14 down here on the bottom.
[01:44:22.900]It's not a benefit you can expect every year.
[01:44:25.180]It is a secondary benefit that we might be pleased about,
[01:44:29.360]but it's not something and a good reason
[01:44:31.990]to apply fungicides to every field
[01:44:33.990]and make blanket applications.
[01:44:36.580]What we have to do is we have to get out
[01:44:38.300]and scout those fields, see which diseases are out there,
[01:44:41.300]and making sure that we identify them correctly.
[01:44:44.827]That is a bit of advice
[01:44:46.290]for the corn fields based on our past data.
[01:44:49.950]Moving forward, there are other diseases and other crops
[01:44:53.520]that we must be very careful differentiating,
[01:44:55.850]and soybean is no different.
[01:44:58.280]There are a number of research trials
[01:45:00.050]that have been conducted in recent years
[01:45:01.890]with multi-state teams,
[01:45:03.310]like collaborators that you see listed
[01:45:05.180]on this research article.
[01:45:09.123]This experiment in particular was conducted
[01:45:11.140]in four different states between 2009 and 2014.
[01:45:16.797]In 2011 and '12, we had locations here in Nebraska
[01:45:20.230]that will represent more of what you're talking about
[01:45:22.660]and seeing in your own fields.
[01:45:25.160]What we looked at was multiple modes of action,
[01:45:27.520]and they looked at including insecticides
[01:45:30.070]with or without fungicides, sometimes both of course.
[01:45:34.380]And when you look at the overall economic analysis
[01:45:36.900]from this research article,
[01:45:38.990]you'll wanna look closely to see
[01:45:40.930]how it compares to the current conditions,
[01:45:43.420]because when these experiments were conducted,
[01:45:46.030]soybean prices were up to almost $11 1/2 per bushel.
[01:45:50.690]Now prices are significantly lower,
[01:45:53.300]and so you'll need to make adjustments in expectations.
[01:45:57.868]The results that were observed are listed on the bottom.
[01:46:00.650]Using a fungicide alone,
[01:46:02.150]the average across all of those experiments
[01:46:04.490]across four states was about a $36.50
[01:46:09.400]return on the investment per acre.
[01:46:12.010]When insecticides were used alone,
[01:46:13.920]it was a $55, almost $56.
[01:46:17.970]But when fungicides and insecticides were used alone,
[01:46:21.400]that was $79 per acre.
[01:46:23.870]It didn't happen on every field, though,
[01:46:26.250]and so beside that average you're gonna notice the range
[01:46:29.460]of reactions from, for example, for the fungicide alone,
[01:46:33.220]a loss of about $8 1/2 per acre to,
[01:46:38.460]excuse me, up to $125 gain
[01:46:42.860]in that particular field.
[01:46:45.110]There was a full range of reactions,
[01:46:47.060]and you need to know how common it was,
[01:46:49.030]because averages don't tell you anything
[01:46:51.610]about the extremes or the probabilities.
[01:46:57.000]When you look at some of these data graphed out,
[01:46:59.180]it might make more sense.
[01:47:00.380]On the left hand side on the y-axis,
[01:47:03.510]that is your change in revenue in dollars.
[01:47:07.970]When you look at this again,
[01:47:09.200]it's at $11.43 per bushel, the soybean price,
[01:47:13.100]which may or may not reflect what you're seeing.
[01:47:16.460]On the bottom of the graph,
[01:47:17.640]you're gonna notice we have fungicides down at the bottom,
[01:47:20.900]fungicides alone, insecticides alone,
[01:47:23.570]or fungicide plus insecticide treatments.
[01:47:26.710]And that's assuming a cost
[01:47:28.880]of about $25 to $26 per acre
[01:47:32.770]like you see where this line is stretched across here.
[01:47:36.770]When you look at those averages,
[01:47:38.380]you see just what we talked about.
[01:47:40.360]Fungicides did provide a return alone.
[01:47:43.160]Insecticides provided a larger return used alone.
[01:47:47.050]And when they were used together,
[01:47:48.420]you got the biggest return across all of those locations.
[01:47:53.430]But, again, that doesn't tell us
[01:47:54.960]about the probability of that happening on your own farm.
[01:47:59.010]This graph tells us more about how frequently that occurred.
[01:48:03.710]Looking on the left hand side here,
[01:48:05.510]this is the percentage of return when it exceeded the cost.
[01:48:12.440]Looking over here at fungicide use alone,
[01:48:15.230]that was less than 15% of the time.
[01:48:18.970]Likewise for insecticide use, that was less.
[01:48:22.920]You got a return on that investment less than 40%
[01:48:25.690]of the time across all those states.
[01:48:28.200]And, again, only 45% of the times did using
[01:48:32.440]both a fungicide and an insecticide provide a return
[01:48:35.250]on the investment.
[01:48:37.410]This makes it more difficult to make those decisions.
[01:48:43.440]When you want to consider that for your own location
[01:48:46.180]under our current prices and the cost of application,
[01:48:49.510]we have a new tool that's available to you now.
[01:48:53.230]On this slide, I encourage you
[01:48:54.960]while we're talking about this to make sure
[01:48:57.160]and capture this website address,
[01:48:59.480]because that's gonna be how you access this online tool
[01:49:03.020]that will help you predict
[01:49:04.560]whether those products are gonna provide that return.
[01:49:07.670]The way you work this is you put the current soybean price
[01:49:10.940]per bushel in the upper left hand box
[01:49:14.170]and you put the cost of that application
[01:49:16.020]in the upper right hand box.
[01:49:17.670]And then you get the probabilities
[01:49:19.330]of getting those returns listed in that text box below
[01:49:25.190]based on the type of fungicide that you're using,
[01:49:28.290]which mode of action, whether it's a QoI,
[01:49:30.640]which is a strobilurin fungicide here,
[01:49:33.180]or a DMI, which is a carboxamide fungicide.
[01:49:39.790]Likewise in wheat,
[01:49:41.140]we also have a number of different diseases
[01:49:43.450]that can be very difficult to differentiate.
[01:49:47.900]The best examples in wheat are bacterial streak
[01:49:51.670]and Septoria tritici blotch.
[01:49:53.870]Well, bacterial streak is obviously a bacterial disease,
[01:49:57.770]and it is quite common,
[01:49:59.520]and likewise, so is Septoria tritici blotch.
[01:50:02.840]Well, unfortunately, when you have a lot of damage caused
[01:50:05.500]by either one of them,
[01:50:06.860]those large, dead, or blighted areas
[01:50:08.800]of the leaves can be impossible to differentiate between.
[01:50:12.950]Take a look at the pictures
[01:50:14.220]of what bacterial streak looks like on wheat
[01:50:17.230]versus Septoria tritici blotch, the fungal disease.
[01:50:21.200]Now, that can be controlled by a fungicide,
[01:50:23.900]but you have to know which disease you're working with
[01:50:26.360]to know if the fungicide is going
[01:50:27.910]to effectively control that disease.
[01:50:30.970]A few extra tips in how to differentiate this.
[01:50:34.440]Septoria tritici blotch on the right,
[01:50:37.640]but bacterial streak looks a lot
[01:50:39.710]like the bacterial streak disease in corn.
[01:50:42.620]You notice those small streaks,
[01:50:44.460]but you also notice beads right here and right here.
[01:50:49.160]They may or may not be present.
[01:50:50.930]But if you find those, there's a good chance
[01:50:52.950]that that is bacterial exudate that is pushed out.
[01:50:56.970]That's not something you're gonna see
[01:50:58.910]on the Septoria tritici lesions.
[01:51:01.500]There's no bacteria there,
[01:51:02.660]so you're not gonna see the beads.
[01:51:05.330]That's one thing that you'll wanna watch for
[01:51:07.540]out in the field.
[01:51:09.000]Likewise, Septoria tritici blotch is a fungus.
[01:51:12.900]And this particular fungus reproduces with pycnidia.
[01:51:16.370]This is where the spores are produced.
[01:51:18.480]But it can make small black dots
[01:51:20.670]on the surface of the lesions.
[01:51:23.290]You wanna look for those, and you might even be able
[01:51:25.810]to feel them rough on the surface like sandpaper.
[01:51:29.100]Well, while you might see that for Septoria blotch,
[01:51:32.360]you're not gonna see that if it's bacterial streak.
[01:51:36.330]Hopefully that'll be helpful to you
[01:51:37.870]in looking for those two characteristics
[01:51:39.950]and telling those apart.
[01:51:42.250]Again, as a summary, look for bacterial ooze
[01:51:45.440]on the surfaces of all of those plants.
[01:51:47.460]Sometimes you might need to look at the underside
[01:51:49.740]in case rain or irrigation has washed them off.
[01:51:52.770]And sometimes Septoria tritici blotch
[01:51:55.280]is gonna have the presence of these black pycnidia.
[01:51:58.160]That's where the spores are produced.
[01:52:00.780]You also wanna keep track
[01:52:02.080]of which fields may have had a history of diseases,
[01:52:05.530]because that'll also help you predict
[01:52:07.020]which ones may develop the following years.
[01:52:11.750]Last but not least of course, we've got sugar beets.
[01:52:14.380]All the crops in Nebraska have examples of diseases
[01:52:17.870]that can be caused by fungi or bacteria
[01:52:20.810]and are of course hard to tell apart.
[01:52:23.390]And in sugar beet, Cercospora leaf spot,
[01:52:27.100]that's a fungal disease,
[01:52:28.160]a very common fungal disease that we have.
[01:52:30.990]It's in Nebraska.
[01:52:33.030]And these are the lesions that you're gonna look for,
[01:52:35.370]these small round to oval lesions
[01:52:38.340]that usually have a dark margin around them.
[01:52:41.700]They may vary somewhat of course from variety to variety.
[01:52:45.840]And this is a disease favored
[01:52:47.550]by moist, high humidity conditions,
[01:52:50.020]and so you may see it develop
[01:52:51.530]after you've had a period of wet weather
[01:52:54.020]or you have that canopy develop.
[01:52:56.510]Likewise, another fungal disease,
[01:52:58.440]that's Alternaria leaf spot.
[01:53:00.410]It's favored by similar conditions.
[01:53:02.370]Moist conditions in general favor fungal diseases,
[01:53:05.870]and in some cases bacterial diseases as well,
[01:53:08.840]also causing these conspicuous leaf spots on that leaf.
[01:53:14.670]Well, unfortunately, there's also a bacterial disease
[01:53:17.560]in sugar beet that looks very, very similar
[01:53:20.320]to those diseases, and that's called bacterial leaf spot.
[01:53:24.120]And those lesions are nearly identical
[01:53:26.820]and very, very difficult to tell apart.
[01:53:30.100]For you to tell it apart,
[01:53:31.450]perhaps you need to submit a sample
[01:53:33.000]to the Plant and Pest Diagnostic Clinic,
[01:53:34.790]either in Lincoln or in Scottsbluff
[01:53:36.610]to get help identifying these diseases,
[01:53:39.510]because a fungicide applied
[01:53:41.050]for bacterial leaf spot is not gonna control that disease.
[01:53:45.800]Likewise, when you see a lot of disease
[01:53:48.900]like bacterial leaf spot,
[01:53:50.580]you're gonna see parts of those leaves falling out.
[01:53:53.490]This is a pretty severe example.
[01:53:55.940]You have to be judicious when making fungicide applications,
[01:53:58.930]because they can be costly to our producers.
[01:54:02.850]Likewise, there are other diseases, like rust diseases.
[01:54:06.350]Rust diseases are caused by fungi,
[01:54:08.630]and they can be controlled with foliar fungicides.
[01:54:12.670]There's a few characteristic to look for for rust diseases
[01:54:15.750]that will help you identify that.
[01:54:18.540]Often, rust diseases are down in the canopy
[01:54:21.120]and difficult to find.
[01:54:22.580]Sometimes, though, they can be very severe
[01:54:24.720]and cause a big impact on plants
[01:54:26.410]that you can see often from the road.
[01:54:29.170]There are rust look-alike diseases too, though.
[01:54:32.900]Keep in mind, rust diseases produce spores
[01:54:35.080]on the surface of the leaves that you can rub off often
[01:54:38.060]with your fingers and see evidence of that.
[01:54:41.320]There's other problems that we see
[01:54:42.690]on dry bean and other crops
[01:54:44.830]that might be difficult to tell apart from that as well.
[01:54:49.470]Just always look for those spores that you can rub off,
[01:54:51.990]and see, you have evidence of that here.
[01:54:54.970]All of our crops have a rust disease that we'll see
[01:54:58.060]that may affect them and might be managed
[01:55:01.140]with a foliar fungicide use.
[01:55:03.060]If you want more information
[01:55:04.370]about any of these disease problems or you need help,
[01:55:08.500]please see some of the resources
[01:55:10.050]that we've got on the CropWatch website online.
[01:55:13.500]There are also some disease diagnostic videos
[01:55:15.960]that are very short to help you identify diseases
[01:55:19.230]on either the Market Journal website
[01:55:21.700]or on the CropWatch channel on YouTube.
[01:55:25.140]Likewise, there are other resources
[01:55:26.870]and publications at the Crop Protection Network.
[01:55:29.520]Or go to your county Extension office
[01:55:31.930]or contact your UNL Plant and Pest Diagnostic Clinic
[01:55:35.190]or follow some of our social media links
[01:55:37.400]for additional information
[01:55:38.560]on current disease problems in those crops.
[01:55:41.410]Thank you.
[01:55:42.414](bright music)
[01:55:49.960]This concludes the Recertification Training
[01:55:52.170]for Category 01, Agricultural Plant Pest Control.
[01:55:56.910]We hope this video has provided some new insights
[01:55:59.240]for your work, while also offering a review
[01:56:01.850]of important pest management principles.
[01:56:04.640]Visit us anytime at pested.unl.edu
[01:56:08.940]for more information on a variety
[01:56:10.860]of pesticide safety topics.
[01:56:13.140]Thank you for your time, and be safe out there.

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Agricultural Pest Control - Plant Recertification

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